WO2003056140A1 - Apparatus for power generation - Google Patents

Abstract

An apparatus for generating power in a circulating closed loop system comprising an evaporator in a first part of the closed loop to evaporate a working medium, a riser in a second part of the closed loop to raise the evaporated working medium to a pre-determined height, a condenser in a third part of the closed loop to condense the evaporated working medium and create a dynamic head, a collector which collects the condensed working medium, a down-comer in a forth part of the closed loop to deliver the collected working medium to the turbine a turbine and generator which are driven by the dynamic head in a fifth part of the closed loop, and a means for returning the working medium to the first part of the closed loop.

Description

Apparatus For Power Generation

SUMMARY

The present invention relates to an apparatus for power generation

The prime objective of this research work was to achieve and accomplish (bring about) the economic utilization of the widely available (unlimited) and accessible solar and other sources of renewable energy, directly or indirectly, to generate large quantities of electricity, or other forms of energy, in a safe and environmentally friendly manner, and with minimal or no emission of Carbon Dioxide (C0₂) or other pollutants to atmosphere.

The fundamental theoretical principles of this idea and relating invention, have emerged and evolved from the detailed study and thorough scrutiny of the stages of a naturally and continuously occurring phenomenon (process), which is: "Water cycle in nature" and consists of:

a- Water vaporization f om the oceans and seas by the effect of solar energy, b- Rising of vapors to high altitudes (colder atmosphere) through the layers of air and the gain of significant amount of potential energy, relative to the sea level, c- Condensation of vapors at higher altitudes to clouds and formation of rain/snow d- Falling back of rain/snow to oceans and earth (formation of rivers),

Potential energy gained by water vapors, is lost as heat when water (rain) droplets hit the earth or ocean surfaces.

Numerous rivers have been dammed worldwide, and hydroelectric power is being generated in significant quantities. (Utilization of a portion of the potential energy through the creation of water dynamic head behind the dams.)

Thermodynamic principles of this natural phenomenon (process) are based on the evaporation of water at ground and sea levels followed by condensation at higher geographic levels. This principle and the associated physical, mechanical, hydraulic, etc. processes had attracted the interest of several previous inventors who have tried to utilize it, and design a corresponding operation system for power generation. However, the various engineering schemes proposed for utilization of this principle, embodied many shortcomings and deficiencies, which were probably the reason for not been applied by the power industry, and will be explained in this report. As such, intensive efforts were dedicated to the crucial issue: How to invent and design a practical, reliable, stable, continuous, physically constructible and economically feasible operating system, which would closely emulate this natural phenomenon in a scientific manner, and realize the set objective. Hence, it was envisaged that the new system should assist to utilize such relatively low level energies, as the thermal energy stored in the vast Ocean waters with temperatures of less than 25.0 °C, or even less than 8.0 °C, to economically generate electricity. The system should also be flexible, complete and eliminate (as far as possible) shortcomings of the previous systems and designs.

An important characteristic (parameter) of the 'natural water cycle process', is the fact that atmospheric temperature decreases noticeably with increasing vertical height at the same point, at a rate of about 0.8 to 1.5 °C per 100 m height. The much lower temperature at higher atmospheric altitudes provides the necessary driving force for water vapors to condense back to liquid, at those high altitudes. However, the process of water vapors rising through the air layers and condensation (cloud formation) is also affected by many other factors, such as the relative humidity, dew point (temperature), air turbulence, etc. which are not the concern of this work.

A quantitative illustration of the temperature difference, for instance: if the mid day time atmospheric temperature at the sea level (on the north western costs of Europe - such as Ireland, United Kingdom, Norway, Germany, France, etc.) is -say 15.0 °C, then the same mid day time temperature at the vertical heights of 700 and 1500 m on the same point, will most probably be about 9.0 and 3.0 °C respectively (or even lower). Temperature difference (delta) for both points from the sea level will be about 6.0 and 12.0 °C, which are very significant in conditions of natural processes.

Temperature difference between sea level and higher altitudes, will be more significant (magnified), relative to a reliable source of energy with relatively stable and higher temperature, such as the Ocean water adjacent to the lower level, with temperature of -say 12.0 to 20.0 °C, particularly during night times. Temperatures of Ocean waters are usually stable and are not prone to sharp fluctuations of day and night air temperatures (on land temperature). In W. European countries the air temperature could fluctuate by more than 8.0 10.0 °C in 24 hours, while sea waters temperature would not change by more than 0.5 °C.

Despite these noticeable temperature differences, particularly during night times, the research work revealed that they are not sufficient alone, to design a practical and reliable operating system for power generation, as it will experience prolonged and repeated system stoppages during day times (with no power generation).

Prior systems proposed for utilization of the said principle of evaporation at ground level and condensation at higher geographic level were found to depend solely on the natural climatic conditions alone to operate those systems. Consequently, they either lacked theoretical support and clarity (weak, complicated and impractical) or lacked operation stability (totally dependent on the natural weather conditions, which fluctuate very sharply and will cause long periods of no power generation), or constructively cumbersome and prohibitively costly as compared with other technologies used for power generation due to numerous factors. These and other deficiencies were probably some of the reasons for not been taken up by industry.

The present invention, proposes practical measures to overcome many of those uncertainties and difficulties, through the incorporation of an auxiliary loop(s) in the process, to stabilize operation of the proposed system. The auxiliary loop will be used to extract thermal energy from 'sea water' by means of vaporizing a suitable auxiliary working medium. A compressor will then be used to compress those vapors to increase their temperature sufficiently and attain a higher energy level (expressed as higher saturation temperature) of the auxiliary medium. The auxiliary medium will then be used to vaporize a suitable working medium at much higher temperature than the 'sea water' temperature, which is a crucial factor (extra dimension) for the stable operation of the system, particularly during mid-day summer periods, as will be described in this report.

The compression temperature (output pressure) will be selected and controlled so that the auxiliary loop should provide the required stability, reliability and flexibility for operation of the proposed power system, in terms of:

a- Utilization of variety of sources of energy ,but primarily the Ocean waters unlimited energy (practically at any temperature), b- Site selection and geographic (topographic) variation, c- System characteristics variation:

- Size and design to suite the site conditions and land topography,

- Eliminate the necessity for the riser and down-comer to be Vertical, and they do not need even to be straight, but only upward or down ward along the site (land) topography, d- System operating conditions (could operate under any pressure or even vacuum) e- Operation stability through the provision of suitable temperature for the controlled vaporization of working medium at lower operation level and condensation at the upper level, f- Eliminate the un-controlled effect of weather fluctuation (particularly temperature fluctuations during 24h day and night) on system operation and stability, g- Independent operation of the power system from rain fall periods, and the system does not require rain water gathering facilities, although rainfall may increase it's efficiency, h- System engineering simplicity and economics, (more efficient, practical construction and does not require many sensing devices or complicated control system),

All these and other advantages of this invention over the previous systems, will become clear in the detailed theoretical, design, operation, etc. discussions which are presented in the next sections of this report.

This invention introduces a new and integrated technological system comprising a specific and elaborate arrangement of equipment, units, processes and suitable working mediums (fluids) in a closed and continuous operative path to form (create) a new power generating cycle. Each component/ unit of the system is carefully selected and designed to perform the assigned function(s) and allow the power cycle to complete and repeat the operation and generate electricity, in a manner, which is substantially different from the currently employed power cycles.

The idea defines a new approach and brings futuristic thinking to the issue of power generation and offers practical solutions to the immediate and long-term supplies of energy from the reliable and renewable (unlimited) solar related sources. It likewise represents an important technological advance (breakthrough) in positively addressing the current problems of global warming, as it should enable massive reductions in Carbon Dioxide (C0₂) emission to atmosphere from the power sector initially and other sectors subsequently.

SUMMARY OF THE INVENTION

The fundamental theoretical principles of this idea and relating invention, have emerged and evolved from the detailed study and thorough scrutiny of the stages of a naturally and continuously occurring phenomenon (process), which is: "Water cycle in nature". Scientific, hydrodynamic, and techno-mechanical principles (driving forces) of the said naturally occurring process are based on the fact that atmospheric temperature decreases noticeably with increasing vertical height over the same pointy at an average rate of about 0.8 to 1.5 °C per 100 m elevation. This temperature decrease represents the first motive (trigger) of the overall thoughts, to investigate the possibilities of exploiting the principles of this natural phenomenon.

The process starts from the vaporization of Ocean water by solar energy, then rising of vapors to high altitude, condensation by the effect of very cold high altitude atmosphere and cloud formation, falling back to earth as rain and snow. As such, this phenomenon is intimately based on the principle of evaporation at ground level and condensation at higher geographic level.

Rain fall on land forms streams, rivers, lakes, etc. and flow to seas and oceans. In some suitable locations many rivers have been dammed, resulting in the establishment of workable liquid dynamic head behind the dams and generation of huge quantities of hydroelectric energy.

The obvious question was:

"How to economically create a sizable, stable and workable dynamic head similar to that of the water behind the dams"?

To achieve the said task, this invention provides the necessary knowledge, know- how and technological means for the economic exploitation (utilization) of scientific principles of the said natural phenomenon of 'evaporation at ground level and condensation at higher geographic level'. In addition to the prevailing un-controlled natural climatic conditions, this invention incorporates an 'AUXILIARY LOOP(S)' in the operative scheme, as a means to properly control operation of the new system and minimize (probably eliminate) the effect of sharply fluctuating natural climatic conditions during 24h and winter/summer periods. Thus, combination of the thermodynamic inputs of the natural climatic conditions and those of the auxiliary loop provision would force the new process to progress and the power cycle to operate as follows: (figs. 6 and 7 , for reference)

a- Energy (heat) absorption from the ocean waters by means of conventional tube and shell heat exchangers to vaporize a suitable auxiliary medium, b- Increase temperature of the auxiliary medium by compression, to a level suitable for vaporization of a suitable working medium and provide the required conditions for condensation of the said medium, at the higher geographic level,

c- Controlled evaporation of the selected suitable working medium at a predetermined temperature by the effect of condensing auxiliary medium (release of latent heat). Evaporation temperature will be sufficiently high to provide the expected condensation temperature (conditions) of the working medium vapors at the top working level,

(Condensed auxiliary medium will be collected in a stabilizing tank and returned to the 'sea water' vaporizer and repeat the cycle)

d- Controlled raising (lifting) of working medium vapors through a riser pipe to a pre-determined height (to acquire potential energy), by means of the developed positive pressure of medium's vapors, e- Controlled Condensation of the working medium vapors (energy rejection) at the geographically elevated operation platform, (liquid medium will have the acquired potential energy), f- Collection of the condensed working medium in a tank (reservoir), for stable operation of the system, g- Controlled formation of an operative liquid dynamic head (working medium flow by gravity) in the down-comer pipe, h- Controlled feeding of the liquid working medium to a turbine system at the lower operation level (sea level) to convert the acquired potential energy to kinetic energy,

(Liquid pressure at the turbine entrance will be very high and proportional to the VERTICAL height of the riser)

— and hence, i- Generation of electrical power.

The auxiliary loop will be used to extract solar energy directly or as thermal energy stored in Ocean waters, by vaporizing a suitable auxiliary medium. The loop will then be operated on the 'heat pump principle' to economically elevate the energy level of the auxiliary medium and thus, introduce the required stability into the power system. As such, the auxiliary loop will incorporate a controlling tool in this invention, which should enable it to overcome most (or all) of the deficiencies experienced by the previous systems, suggested for the utilization of the said principle of evaporation at ground level and condensation at higher geographic level, as explained below:

When water vaporizes from oceans and seas or from rain water on the earth surface by the effect of direct and indirect solar energy, water vapors having much lower density than air, will readily rise through the air layers to higher altitudes of over 1500 to 5000 m. Atmospheric temperature at those altitudes is lower by at least 12 to 40 °C than the sea level temperature. Such low temperatures (condensation driving force), combined with sufficient vapor concentration in air, will result in increasing relative humidity and dew point (wet bulb temperature). The process will lead eventually to air over saturation with vapors, partial condensation of vapors to water droplets, cloud formation and then falling back of droplets to earth as rain or snow. (Fig. 1 , )

To successfully utilize and emulate principles of vaporization at ground and sea levels and condensation at a higher geographic location (utilization of energy sources with temperature of less than 8.0 °C), the present invention (system) relies for it's operation on the aggregated net effect of 3 (three) inputs, which are:

Input No 1 Atmospheric air thermal effect Input No 2 Sea water thermal effect Input No 3 Auxiliary loop operation thermodynamics effect

Effect of each of these inputs on the novel power system is in accordance with a well defined operative process with identifiable boundaries, and has specific but interdependent parameters (characteristics), as explained (stage wise) below:

Input Nol: Atmospheric Air Thermal Effect

This input is derived from the derived emulation thinking of this invention with water cycle natural phenomenon in some actual prevailing climatic conditions, which are experienced at various locations.

For instance, in Northern Europe (particularly the costal areas of U.K, Ireland, Norway etc.) the average summer and winter temperatures are about 15 °C and 4 °C respectively. Temperature difference (delta) from sea level and height of -say 700 m could be between 6.0 to 8.0 °C. Hence, if the air temperature at sea level is -say 18 °C (Summer day times), then temperature differences (day and night time profile) between the sea level and vertical height of 700 m, will (likely) be 7.0 °C and 6.0 °C respectively, (Only the effect of atmospheric air) as shown schematically on the following diagram, Fig. 2.

Temperature differences between sea level and the height of 700 m are: Day time 18.0 - 11.0 = 7.0 °C

Night time 11.0 - 5.0 = 6.0 °C

The above shown temperature differences are not wide enough to allow for an economic utilization of the said principle of evaporation at ground level and condensation at higher geographic level. They will not be suitable for a working medium (pure materials or mixtures) with:

Molecular weight of over 50

Boiling point between 0.0 °C to 10.0 °C

Latent heat of vaporization between 40 to 70 Kcal/Kg

These characteristics are very important factors for designing and providing stable operation of the intended power generating systems. A working medium such as a mixture of water and ammonia, which could provide suitable molecular weight (about 17.3) for the above low temperature differences, but in actual practice their thermodynamic characteristics will involve prohibitively high investment costs per MW power, due to the very high latent heat of vaporization of over 450 Kcal/ Kg (1900 Kj / Kg).

Input No 2: Sea Water thermal Effect:

In addition to the atmospheric air thermal (temperature) effect, if a source of reliable and stable thermal energy such as Ocean water, would exist at the lower level, then combination of higher and stable sea water temperature and lower atmospheric temperature at heights of over 700 m, could further improve the targeted temperature difference. Average temperature of Ocean waters is usually stable and is not prone to the sharp fluctuations of day and night air temperatures (on land temperature). In W. European countries, for instance, air temperature (near the shores) could fluctuate by more than 8.0 °C in 24 hours, while sea water temperature would not change by more than 0.5 °C. Hence, if the selected site is close to a coastal area, with 'sea water' temperature of also 18.0 °C (the warm Gulf Stream Effect), then the possible theoretical temperature difference between sea water temperature and air temperature at the height of 700 m will be significantly increased, particularly during night times.

The following schematic diagram (Fig. 3), shows the positive effect which 'sea water' with 18.0 °C could have on the 'Delta temperature' increases between the said two operation levels, as shown below:

Temperature differences between sea level and the height of 700 m are:

Day time 18.0 - 11.0 = 7.0 °C

Night time 18.0 - 5.0 = 13.0 °C

Figure 3, indicates that Ocean water could indeed have a positive effect and increase the possible theoretical condensation driving force, in terms of temperature difference between the condensation temperature of a working medium vapors and the outside atmospheric temperature at the height of 700 m. During night times the delta (difference) could be from 11.0 °C to about 13.0 °C, which is very high in terms of natural conditions. However, during mid day time (peak temperature), the temperature difference will still be relatively low at about 5.0 to 7.0 °C, which may not be sufficient for a reliable operation of power generating systems. It will probably force the system to stop operation and will not generate power, which may last repeatedly for several hours during long summer days.

Hence, these temperature variations (differences) may still not be adequate to provide the necessary conditions for stable, reliable and continuous operation of a power generation system, in terms of condensation driving force (temperature Delta between the working medium vapors at the top operation level and the outside air) during 24h day and night times. It is un-likely that such climatic conditions (alone), which reasonably reflect the prevailing conditions in most geographic locations, could support the 'economic' utilization of this phenomenon for power generation in many locations. Above crucial conclusion, was probably one of the major deficiencies (restricting factors) of the previous proposed designs (systems) to utilize this principle in actual practice, and therefore did not attract interests and were not taken up by industry.

The following stepwise temperature profile of inputs No 1 and 2, expresses the said deficiencies and conclusion:

STEPWIZE TEMPERATURE INCREASE (Summer Time as a Representative Case)

^ CASE No 1 ; Without Auxiliary Loop Temperature DELTA (Inputs No 1 and 2) Day Time Night Time

1- Sea water to Outside air Temperature (At sea level)

Day 18.0 °C ► 18.0 °C 0.0

Night 18.0 °C 11.0 °C 7.0

2- Sea water to air at a height of 700 m Temp.

Day 18.0 °C 11.0 ^υC 7.0 Night 18.0 °C 5.0 °C 13.0

3- Auxiliary loop

0.0 °C 0.0 ^ϋC 0.0 0.0

'NET' Maximum Temperature Variation Between 7.0 °C 13.0 °C Sea Level and 700 m Height 4- Envisaged temperature drop in the operation system: a- Through Working Medium vaporizer 2.5 °C 2.5 °C b- Through the RISER 5.0 °C 5.0 °C

'NET' Condensation 'Driving Force' None 5.5 °C at the top level °C Input No 3: Auxiliary loop Thermodynamics Effect

Further to the combined effect of the above natural inputs 1 and 2, the said temperature differences (delta) could be significantly and economically increased. This will be achieved by introducing an auxiliary loop into the system, which will operate on the 'Heat Pump principle', and is a unique characteristic for this invention. The said auxiliary loop represents input No 3 and will operate as follows: (Fig. 6),

A suitable 'Auxiliary Medium' will be vaporized in a vaporizer, where 'sea waters' will be used as the source of thermal energy. A compressor then will be used to re-compress those vapors and increase their saturation temperature by -say 10.0 to 12.0 °C (or even higher as appropriate), with acceptably low energy input. Hence, compressor's output temperature profile (auxiliary medium temperature) could be controlled by compressor's output pressure, as follows: (Explained in details^— in the next sections and example No 1)

Assuming:

• Ocean temperature

Summer times 18.0 ^ϋC Winter times 8.0 °C

• Vaporization temperature of the auxiliary medium in the sea water vaporizer 14.5 °C

> Compressor outlet temperature, will be:

Summer times, (18.0 - 2.5) + 10.0 = 25.5 °C Or (18.0 - 2.5) + 12.0 = 27.5 °C (Extreme cases)

Winter times, (8.0 - 2.5) + 10.0 = 15.5 °C

Or (8.0 - 2.5) + 12.0 = 17.5 °C (Extreme cases)

NOTE: Higher temperature output could also be contemplated, but will depend On the atmospheric conditions and economics. As such, combination of the higher Ocean water temperature, magnified with inclusion of a 'heat pump auxiliary loop' in the system, and the naturally occurring lower temperature at heights of over 700 m, will create a temperature difference between the lower and higher geographic locations, of about 14.5 to 16.5 °C during day time and 19.5 to 21.5 °C during night time. This temperature 'Delta' is indeed very significant in conditions of the natural world, and is comparable to the temperature differential between 'sea level' and a vertical height of over 3000 m. Such a wide 'Temperature Delta' will provide an excellent opportunity to exploit those conditions for the economic creation of an operative dynamic head of over 700 m, similar to the water dynamic head, created by dammed rives behind the dams.

Regarding the actual 'net' condensation driving force of the working medium vapors reaching the top level (height of 700 m), in terms of temperature difference between working medium vapors temperature and the outside air temperature, and assuming:

1- Temperature drop across the working medium vaporizer: 2.5 °C

2- Temperature drop across the riser: 5.0 °C (From the lower operation level to the top operation level)

The aggregated NET temperature of working medium vapors reaching the height of 700 m (which will be close to the condensation temperature) at different times, is expected to be:

Summer times, 25.5 - 2.5 - 5.0 = 18.0 °C

Or 27.5 - 2.5 - 5.0 = 20.0 °C (Extreme cases)

Winter times 15.5 - 2.5 - 5.0 = 8.0 °C

Or 17.5 - 2.5 - 5.0 = 10.0 °C (Extreme cases)

Net condensation driving force, expressed as the temperature difference between the working medium vapors temperature reaching the height of 700m and the outside air temperature, is expected to be:

Summer time:

Day times: 18.0 - 11.0 = 7.0 °C

Night times: 18.0 - 5.0 = 13.0 °C

Winter time:

Day times: 8.0 - 3.0 = 5.0 °C

Night times: 8.0 -(- 4,0) = 12.0 °C These temperature differences (condensation driving force) are noticeably large in terms of natural conditions, and will force the effective and efficient condensation of working medium at the geographical higher working level, at any time during day and more favorably during night times, in summer and winter times. This will provide indeed the aimed practical and reliable operating conditions for the proposed power system.

Based on these facts and analysis, the discovered idea and invented 'power cycle' (operative system), are intended exactly to realize the task of economic, reliable and practical utilization of principles of the illustrated natural phenomenon, in combination with the induced auxiliary loop (heat pump principle), for electrical power generation (or other powers), as shown schematically in Figs. 4 & 5.

If the system is applied in a W. European country then the expected operation of the system during summer and winter times will be per the figs. No 4, 5, 6 and 7, and as described below (for representative cases):

A- During Summer time:

The system will absorb thermal energy from 'sea waters' at about 15.5 °C, by means of vaporizing a suitable 'auxiliary medium' in the auxiliary medium vaporizer. These vapors will then be re-compressed in the compressor, to elevate their temperature to about 25.5 to 27.5 °C (stage 1 of fig 4). The re-compressed auxiliary medium's vapors, with elevated temperature, will be fed to the 'Working Medium Vaporizer' to vaporize a suitable working medium at a convenient temperature of about 23.0 to 25.0 °C (stage No 2 of fig. 4). The vaporized working medium will be pushed (by the created positive pressure) through a large diameter 'Riser pipe' to the top operation level of: 700 m (plus) (stage No 3 of fig. 4). Temperature drop along the riser should be made as low as possible, and ideally less than 5.0 °C, to provide better condensation temperatures at the top level of -say about 18.0 to 20.0 °C.

At the top operation level, working medium vapors will be fed to a condenser (stage No 4 of fig. 4), where they will be condensed by the effect of the lower outside air temperature of less than 1 .0 °C during day time and less than 5.0 °C during night time. The condensed working medium (liquid), with significant potential energy stored in, will be collected in a stabilizing tank, which is another feature of this invention. The stabilized liquid will be directed (under control) to flow downward by Gravity, through a down-comer (pipe) and establish a dynamic head, which will be equal to the vertical height of the riser (Stage No 5 of fig 4). The established dynamic head could then be used to operate a liquid turbine and generate sizable NET POWER (Stage No 6 of fig 4). Temperature variations of all the streams and major points are shown on the following diagram, figs. 6 and 7, (and above fig. 4). (Explained in details in the next sections).

B- During Winter Time

As regarding the 'Winter Times' operation of the system, all the above mentioned summer conditions (heading A), will be equally applicable, and even with much more favorable temperature differentials, as the average sea water temperature in North European countries, is about 4.0 to 5.0 °C, higher the average air temperature in W. European countries. Seasonal air temperatures drop much more rapidly and steeply than the 'sea water' temperature, particularly during the transitional period from summer to winter times and back.

Hence, the aggregated net effect of the three inputs is expected to readily provide the necessary thermodynamic conditions for the proposed system to operate in a controlled, continuous and reliable manner and generate electrical power.

As the climatic conditions (temperatures) are expected to vary and change continuously, seasonally and during 24h periods, any different set of the possible temperatures (reflecting the particular time conditions) could be presented as examples. However, the overall temperature variations and changes (net) upward or downwards will be block-wise and with minimal net impact on the operating conditions of the proposed power system.

The diagram shows that the system will be most practical with the use of the auxiliary loop (medium), which will provide favorable and stable operation conditions (condensation driving force) for power generation throughout the day and night times and during all seasons.

The following schematic presentation (diagram) also shows the expected temperatures of all streams and important points involved on both operation geographic levels per either of the two operation cases, (summer or winter as shown on the figs. 6 & 7 above). However, to widen examples and scope of applicability, operation conditions assumed below are for an intermediate period of the year, with 'sea waters' temperature at 12.5 °C. This is to show the applicability of this system to the year round climatic conditions and variety of locations.

The diagram shows the expected stepwise increases and variations of those temperatures with the anticipated temperature drop along the rise pipe, to best suit each case. (To be read with figs. 1 to 6)

STEPWIZE TEMPERATURE VARIATIOS

Assuming: a- Average temperature variation during day and night (24h) 7.0 °C b- Average temperature difference between sea level and the height of 700 m, Day time 7.0 °C Night time 6.0 °C

i> CASE No 1 ; Without Auxiliary Loop Temperature DELTA (For Inputs No 1 and 2) Day Time Night Time

2- Sea water to Outside air Temperatures (At sea level) Day 12.5 °C ► 12.5 °C 0.0

Night 12.5 ^υC 5.5 °C 7.0

3- Sea water to air at a height of 700 m Temp. (Assuming sea temperature also at 12.5 °C)

Day 12.5 °C ► 5.5.0 °C 7.0

Night 12.5 °C -0.5 °C 13.0

3- Auxiliary loop

0.0 °C 0.0 ^ϋC 0.0 0.0

'NET' Maximum Temperature Variation Between 7.0 °C 13.0 °C Sea Level and 700 m Height 4- Temperature drop: a- Through Working Medium vaporizer 2.5 °C 2.5 °C b- Through the Riser 5.0 °C 5.0 °C

'NET' Condensation Driving Force at the top level 0/ C None 5.5 ^ϋC

= CASE No 2 ; With Auxiliary Loop Day Time Night Time (For Inputs 1, 2 and 3)

1- Sea water to Outside air Temperature at the Same level Day 12.5 °C ► 12.5 °C 0.0

Night 12.5 ^υC 5.5 °C 7.0

2- Air (sea level) to Height of over 700 m Temp, (assuming sea temperature also at 12.5 °C)

Day 12.5 ^υC 5.5 °C 7.0 Night 12.5 °C -0.5 °C 13.0

3- Auxiliary loop Working medium vapors temperature at sea level and air temperature at height of over 700 m : Assuming sea temperature also at 12.5 °C and boosted with Auxiliary loop by 10.0 °C: (12.5 -2.5) = 10.0 °C ► 20.0 °C

20.0 - 5.5 = 14.5

20.0 -(-0.5) = 20.5

'NET' Maximum Temperature Variation Between 14.5 °C 20.5 °C

Sea Level and 700 m Height 4- Temperature drop: a- Through working medium vaporizer 2.5 2.5 b- Through the RISER 5.0 5.0

'NET' Condensation Driving Force at the top level 7.0 °C 13.0 °C (Difference between the temperature of working medium vapors reaching the top geographic operation level and outside air temperature at that level)

The above schematic presentation of temperatures profiles, clearly confirms that the condensation driving force conditions, in terms of temperature difference between the condensation temperature of the working medium and the outside atmospheric temperature, are most favorable with the use of auxiliary loop throughout the day and night times. The auxiliary loop will ensure the stable and reliable operation of the power system.

As such, the new invention would facilitate (allow) the effective use of vast amounts of stored thermal energy of Oceans (unlimited), with temperatures of less than 20.0 °C (even less than 8.0 °C , to generate large quantities of electrical power. The novel technology conforms to an integrated and closed type operative 'power cycle', which would force the intended process to progress in a continuous mode along a predetermined path, as follows: (Fig. 7)

a- Thermal Energy absorption from the 'Ocean waters' by means of vaporizing a suitable auxiliary medium in a conventional tube and shell type heat exchangers, where ocean waters will be used as the source of thermal energy. Temperature of the auxiliary medium (vapors) will be increased by re- compression and then be used to vaporize a suitable working medium in another tube and shell type vaporizer. b- Controlled raising (lifting) of the working medium's vapors through a riser pipe to a pre-determined height to acquire potential energy, by means of the developed positive pressure of working medium's vapors,

c- Condensation of the working medium vapors (energy rejection) at the elevated operation platform by means of either: a. A condenser comprising of pipe banks, with pipes exposed to the effect of the natural air flow, b. A conventional cooling tower condenser, with natural air flow, c. A conventional cooling tower condenser, with water sprayers, etc, Condensed liquid medium will have the acquired potential energy,

d- Controlled formation of an operative liquid dynamic head, with gravitational flow of the liquid working medium through the down-comer pipe, e- Feeding the liquid working medium to a turbine/generator system at the lower operation level (sea level) to convert the acquired potential energy to kinetic energy, f- Generation of electrical power in the turbine system.

g- Feeding back the liquid working medium to the vaporizer where the auxiliary medium with elevated temperature will be the source of energy, and repeat the cycle.

Dynamic head is therefore, the crucial factor and necessary (must) component of this operative power cycle and is the actual hydro-mechanical (physical) driving force that operates the turbine.

To establish the required dynamic head, a liquid medium will need to be lifted to a pre-determined height. For this purpose a suitable auxiliary medium (fluid) with the appropriate thermodynamic, chemical and physical properties will be selected (also environmentally friendly as far as possible), which could be vaporized by the effect of a relatively low ocean water temperature (7.0 to 26.0 °C, where applicable).

An essential component for the successful implementation of the new idea is also, to select a site with the adequate topography, features and energy source, which should provide the required operative conditions to smoothly operate the new power cycle (system), namely:

+ Sea water (energy source), large river, large lake, etc, with sufficiently high temperature, + A near by mountain with suitable height/cliff, preferably more than 650 m, vertical height, and sufficient top area to construct the condensation equipment and facilities,

+ A reasonable access to the top working level, which will not require excessive capital costs to build a suitable access road,

+ Exposed mountain top to the wind flow direction,

+ A good source of fresh water near by, (which may be required in some cases),

+ A workable temperature difference (drop), from the sea level (bottom) to the mountain top level, Etc,

There are many suitable mountain cliffs and slopes near the Ocean and sea shores in many regions and countries, which would provide the required operational vertical height with sufficient working tops, desirably over 650 ni high. Such a height will reach a level where the ambient temperature is noticeably lower than the sea level air temperature. In some cases the site may be actually fully or partially constructed (built), if economics would be favorable.

Furthermore, the use of the 'auxiliary mediums and loops' will introduce an important controlling means to provide the necessary pressure and temperature conditions for a continuous and un-interrupted condensation process of the working medium to proceed at the top operation level during day and night times and at extreme temperatures of summer and winter times.

Working medium will be selected with the suitable properties such as:

a- Boiling point sufficiently low ideally in the range 0.0 to 15.0 °C to be able to vaporize it with the auxiliary medium, and develop the required pressure to lift the vapors to a pre-selected height, b- Molecular weight suitable (as low as possible and ideally less than 60) to ensure minimum temperature drop across the riser, between the lower and top working geographic levels, at controlled operating conditions, c- Stable and with very good environmental properties, etc.

This invention aims at generating power not from the pressurized vapor phase of the working medium (as is the case with Rankine and all the other power cycles which depend on fossil fuels), but from the liquid phase, through the creation (formation) of a suitable and workable dynamic head.

Rising medium's vapors will undergo along the riser the adiabatic expansion and gradually cool down. At the top end of the riser pipe, the reached vapor will have also gained an appreciable amount of potential energy, which is the fundamental characteristic (feature) and operating principle of this cycle. Thermodynamic conditions of those vapors reaching the top working level (platform) are therefore, crucial and should be such to allow the sustained condensation of vapors to liquid at the expected operative conditions. Vapor temperature at the top level will need to be at least 3.0 to 5.0 °C, higher than the ambient temperature, if the natural draft air cooled condensation is contemplated. Inclusion of the auxiliary loop in the system will ensure a higher temperature and hence, efficient condensation of the working medium.

Potential energy (E_p) acquired (stored) by the condensed working medium (liquid) at the top geographic level, will be proportional to the vertical height of the mountain/cliff (potential dynamic head), as follows:

E_p = H x Q

Where;

E_p ; Is the potential energy Kg. M.

H ; Vertical head m

Q ; Liquid weight Kg

Condensed medium (liquid) will be collected in a holding tank for stabilization, and then directed by the gravitational force to the bottom level through the down- comer pipe, where it will be fed to a liquid turbine. Pressure at the feed point to turbine will be very high as compared with the much lower vaporization pressure (will be described in the next sections). Turbine will convert the potential energy of the liquid to kinetic energy, turn the generator and generate electrical power. Dynamic head formed in the down-comer will be equal to the vertical height between the top and bottom levels of the system, and sufficient to operate the turbine. Liquid leaving the turbine will be fed by gravity, back to the working medium vaporizer and repeat the cycle.

As noticed, the system does not rely for it's operation, on the fossil fuels combustion as the source of energy and will, therefore, not produce carbon dioxide (C0₂). This system could prove indeed to be a very clean and environmentally friendly power cycle, and open new frontiers and prospects for the power industry (sector).

The idea utilizes various known lows of physics, mechanics, thermodynamics, hydraulics, etc., which enable this power cycle to manipulate the absorbed thermal energy and use it to increase: a- Internal energy of the working medium b- Volume during vaporization and the subsequent adiabatic expansion of the vaporized working medium,

The new operation arrangement/path will enable the power cycle to convert a portion of the absorbed thermal energy to the useful and exploitable potential energy, through the significant increase of the medium's (vapor) volume during vaporization process and the subsequent adiabatic expansion.

Within those lows and operating principles, this idea (invention) identifies, formulates, describes and represents a new and specific power cycle or cell, where the working medium (fluid) undergoes a series of pr-determined processes, phase changes and finally returns to the initial state (starting point conditions). Each component (element or unit) of the power cycle will harmoniously operate, interact and perform the assigned functions and collectively effect a workable change in entropy of the working medium, which will provide an ideal opportunity to extract net beneficial work.

It is appropriate that this new power cycle to be named " Atalla Energy Cycle" and will be referred to as " AEC", (will be described in details in the coming sections). It is a closed type energy cycle, with the working medium(s) continuously circulating through the system without direct communication with outside atmosphere.

AEC utilizes many of the existing operations and processes (thermodynamic, physical, thermal, mechanical, hydrodynamic, etc.) which are also being used extensively by several of the well known power generating cycles, such as the famous "Vapor Power Rankine Cycle". The processes include:

a- Energy absorption ( vaporization in boilers, vaporizers) b- Energy elevation (pressurization, dynamic head creation) c- Energy release (expansion in turbine, or trans-conversion) d- Energy rejection (condensation in condensers ) e- Energy induction ( pumping, compression, gravity pressure, etc) f- Medium preparation, transportation, storage, g-Energy source preparation, transportation, storage,

The present invention is defined in it's various aspects in the appended claims, to which reference should now be made.

A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which:

Figure 1 shows the "water cycle in nature'

Figure 2 shows the temperature differences (day and night time profile) between sea level and height of 700m, Figure 3 shows the temperature difference with effect of Sea water temperature Figure 4 shows the temperature increase of the working medium vaporization with inclusion of the 'Auxiliary Loop' Figure 5 shows the typical Flow Diagram of AEC Power Cycle, With Auxiliary medium recompression, (summer time- extreme cases)

Figure 5a shows the typical flow diagram of AEC power cycle (without auxiliary mediums loop)

Figure 6 shows the typical Flow Diagram of AEC Power Cycle, With Auxiliary

Medium Recompression. (Summer Time - Extreme cases)

Figure 6a shows the typical flow diagram of AEC power cycle with auxiliary medium recompression (summer time - exceptional cases)

Figure 7 shows the typical Flow Diagram of AEC Power Cycle, With Auxiliary

Medium recompression. (winter Time - Extreme cases)

Figure 8 shows a temperature-entropy showing the narrow range of AEC operation.

Figure 9 shows a pressure-volume diagram showing the operation steps of AEC. Figure 10 shows the Atalla Energy Cycle (AEC) power cycle which operates on dynamic head, Figure 11 shows a simple power plant which operates on the Rankine cycle, Figure 12, 12a and 12b is diagrams representing examples 3, Figure 13 shows condensation with the help of an auxiliary medium. DESCRIPTION OF THE SYSTEM

The proposed new idea and invention provide knowledge, know how and means (operative system), to tap into the stored energy (unlimited) in the vast volumes of the Ocean waters or (to lesser extend) directly from the sun, and exploit significant quantities of those low level energies to generate electrical power, in a much more environmentally friendly manner.

The newly invented process (power cycle) resembles (simulates) exactly the very important and continuously occurring natural phenomenon, namely:

"Water vaporization by solar energy, rising of vapor to higher altitude (through air movement- carrier), condensation of water vapor by the cool atmosphere at those heights and then falling back to the earth's surface in the form of rain and snow. In some suitable locations, water flow is harnessed to produce power as Hydropower, by damming the rivers." ( Figure 1 for reference of the water cycle in nature).

The huge scale and astronomical magnitude of this natural process could be reflected from the fact that the amount (rate) of water vaporized by solar energy from Oceans in this manner, is over 12,000,000 m³ per second, which rises to over 2500 m height, condenses (cloud formation) and then falls back to the earth surface as rain and snow. If it was possible to utilize (harness) only 500,000 m³ per second, from the height of 500 m, it will generate power equal to the entire world demand of about 2,300,000 MW, as of today (end of year 2000). This amount of energy is less than 1.0 % of the potential energy of the vaporized/condensed water by sun, and less than 0.17 % of energy of vaporization (latent heat of vaporization) of water. It is a known fact that thermal energy received from sun in only about 30 minutes is sufficient to supply the total world's electricity in one year.

It is of course not practical to expect that a major portion of this energy could ever be utilized, as most of rain and snow, fall over the Oceans, seas and frozen earth poles Oceans. Only insignificant portion is currently being exploited as hydropower, some times with compromising important environmental issues.

The suggested operative system comprises the following main steps (stages). Fig. 7 below (and also fig. 6), Shows an example of the many possible schemes of this power cycle. They are:

1- Evaporation / energy absorption in vaporizers, (two stage vaporization involving auxiliary medium vaporization and working medium vaporization) 2- Elevation / energy trans- activation transformation, in the riser

3- Condensation (energy rejection) and stabilization by means of hold tanks,

4- Accumulation and creation of dynamic head, in the down-comer

5- Energy release in turbine, net power generation,

Repeat the cycle — ►

Fig. 7, shows also the differences between AEC and the Rankine power cycle shown on fig. 10, in terms of modifications, re-arrangements, steps sequence of processes, etc, which enable the economical exploitation of the much lower levels of the renewable energy with temperatures much lower than 8.0 °C, by AEC.

DESCRIPTION OF THE PROCESS STEPS:

1- Evaporation / Energy Absorption, Fig. 7, for reference, This is a two stage process comprising the following:

a- Auxiliary loop System

The selected auxiliary medium in the auxiliary medium holder tank (4) will be fed by gravity to a vaporizer (1), where the Ocean water (sea water) is used as the source of energy. Hence, the boiling point of the auxiliary medium will be selected sufficiently lower than the 'sea water' temperature, to initiate the vaporization of the medium and develop a pressure high enough to push the vapors through the working medium vaporizer tube section. However, the practice may suggest that the boiling point should be selected sufficiently higher than the sea water temperature and vaporize the auxiliary medium under vacuum, and then re-compress the vapors to increase their temperature just over the boiling temperature or any other suitable temperature, (vacuum vaporization may prove to more economical).

The vaporizer will be submerged in the 'sea water', to avoid (minimize) the need for pumping and un-necessary power input.

The vaporized auxiliary medium will be fed to a compressor (2) where they will be compressed to increase their temperature (energy level). Compression temperature of the auxiliary medium vapors will be selected to suit the working medium vaporization:

- At elevated temperature, which could be noticeably higher than the sea water temperature

- At the prevailing climatic conditions at the selected site,

- And any time during day or night periods,

There are many liquids organic and inorganic as pure components, mixtures, solutions, azeorropes, etc. which could serve as auxiliary mediums. The actual selection of a suitable medium (in practice) will depend on many factors and will require it to have the appropriate physical, chemical, thermodynamic, etc. properties, such as:

a- Suitable boiling temperature, b- Higher latent heat of vaporization, c- Lowest possible ratio of specific heats, (k) = Cp / C_v (as close as possible to unity) d- Preferably higher molecular weight, e- Lower density, f- Non corrosive, g- Non toxic, - Environmentally friendly as far as possible, etc.

Compressed auxiliary medium will be fed to the working medium vaporizer (3), at the elevated temperature. The auxiliary medium will condense in the working medium vaporizer and the released latent heat of condensation will be absorbed by the working medium and vaporize it at a pre-determined temperature. The condensed auxiliary medium will be collected in the auxiliary medium hold tank (4), from where it will be fed back by gravity to the auxiliary medium vaporizer and repeat the cycle.

b- Working Medium system

The selected working medium will be fed (by gravity) to the working medium vaporizer (boiler) (3), where the auxiliary medium vapors will condense and release their latent heat of vaporization as the source of thermal energy. Boiling point of the working medium will be selected sufficiently lower than the condensation temperature of the auxiliary medium, to initiate the vaporization of the working medium and develop a pressure high enough to push their vapors upward though the riser (5), to the top level (operating platform) of the selected site. However, boiling point of the working medium could also be selected close to condensation temperature of the auxiliary medium and create suction effect (vacuum) at the top level by colder air temperature, to pull the vapors upward. Decision to select any method will depend on the prevailing conditions and economic considerations. Temperature difference (delta) across the working medium vaporizer will depend on many factors and realistically could be 2.5 to 4.0 °C.

There are many liquids organic and inorganic as pure components, mixtures, solutions, azeotropes, etc. which could serve as working mediums. The actual selection of a suitable medium (in practice) will depend on many factors and will require it to have the appropriate physical, chemical, thermodynamic, etc. properties, such as: a- Suitable boiling temperature, b- Lower latent heat of vaporization, c- Preferably lower molecular weight, d- Lower density of liquid phase, e- Non corrosive, f- Non toxic, g- Environmentally friendly as far as possible, etc.

One of the most crucial factors in the selection of the medium is that, it should cause minimum possible temperature drop (delta) between the vaporization level (sea level) and condensation at the top geographic working level. Vapor temperature at the top level should be sufficiently high, as compared with the ambient temperature, to provide suitable and stable conditions for the effective condensation of working medium vapors to take place. (Figs. 4 and 6. Explained in details also in example No 1 for reference).

Such favorable conditions could be achieved with the use of lower molecular weight medium of - say 50 to 70, and boiling point (temperature) at atmospheric pressure of 8.0 to 20.0 °C. For example a medium with;

Boiling point at 1.0 Bar abs. 14. 5 °C

Molecular weight 55

'Delta' temperature across the riser, between vaporization temperature and the condensation temperature at the top level of -say 750 m, vertical height, could be as low as only 4.0 to 5.0 °C, as follows:

Sea water temperature 18.0 °C

Auxiliary medium vaporization 15.5 °c

Compression temperature 25.5 °c

Boiling temperature of working medium 23.0 °c

Temperature drop across the riser 5.0 °c

Corresponding condensation temperature at the top level 18.0 °c

In physical terms, this implies higher specific volume of the vapors: m^J 3 / Kg. A provision of vapor temperature of 18.0 °C, at the top operation level will provide an excellent driving force to readily condense those vapors, as the average annual ambient temperature at heights of 750 m, in northern countries of the globe, is expected to be significantly lower, for over 85 % of the annual time. During winter time, it could be lower than - 15 °C.

This step of the new power cycle simulates in nature, Ocean water vaporization by the effect of direct or indirect solar energy (heat) received by radiation. However, water vaporization is also affected by the air conditions, which are out of the scope of this work. 2- Elevation of the Vapors:

Despite the fact that this step consists of a very simple pipeline (or a tunnel)- riser (5), it is an essential part of the system's operation, responsible to direct and transport the formed vapors upward to the top of the working level (platform). Riser's large volume provides the necessary operative conditions to convert a portion of the absorbed thermal energy to the useful potential energy. This is achieved by receiving vapors from the working medium vaporizers (3) (acting as a part of the vaporizer), and then allowing for the subsequent adiabatic expansion of vapors, as they are forced to move progressively upward through the riser pipe to the top geographic working level. Both pressure and temperature of the vapors decrease along the riser as a result of the adiabatic expansion (controlled).

There will also be a very slight change (positive or negative) in the entropy of rising vapors, as the temperature decreases. However, the change is sufficient to allow the accumulation of noticeable potential energy in the condensed vapors. The amount of potential energy (E_p) acquired by rising vapors at the top level of -say: 750 m vertical height will be:

E_p = H x Q

Where;

H ; Is vertical height m

Q ; Vapor weight reaching the top level Kg

For example, potential energy gained by 1.0 Kg of working medium vapors at the top operative level, will be:

E_p = 750 x 1.0 = 750 Kg. M.

Riser shape, diameter, physical length, etc. could be of any geometry and size and will depend on the expected vapor flow rate, designer's preference and topography of the selected site. The main aim will be to minimize physical length (to minimize investment costs) and the energy loss of the moving vapors due to mechanical friction.

This step of the new cycle simulates in nature, the un-controlled rising of water vapors from the Ocean surface, and transport by air to the higher altitudes.

3- Condensation and stabilization, Condensation step is a very important stage of operation of this power cycle, where the phase change takes place, and the elevated vapors are condensed back to liquid, with significant amount of potential energy stored in. Temperature difference between the working medium vapors temperature reaching the top level and ambient air temperatures is crucial to initiate and sustain the condensation process. Hence, selection of the proper working medium, suitable site, equipment design, etc, should be well controlled, to ensure the prompt condensation at the top operation end and smooth operation of the power cycle.

Working medium vapors reaching the top level will be fed to the working medium condenser (6). Condensation will take place in the condenser, which could be of many types and designs, such as:

a- Air cooled heat exchanger pipes organized in bank (s), and exposed directly to the effect of cold outside winds, at the selected vertical high of over 700 m. Such schemes may require proportionally larger surface area of the heat exchangers, if the delta temperature is not controlled at more than 5.0 °C. Incorporation of the auxiliary medium is expected to provide exactly the desired delta temperature of more than 5.0 °C, probably over 7.0 °C, (explained in details in example No 1).

Condensation could be improved by using a water sprinkler (fresh or sea water), to spray water directly on the pipes, as the prevailing wet bulb temperature will most likely be significantly lower at those high levels, than condensation temperature.

This option may prove to be most economic, in the actual practice.

b- Cooling towers (water evaporative systems), with natural draft (convection) air flow (forced draft may prove un-economical). Such towers will need to be properly designed and constructed, to provide an economic and efficient condensation of the medium.

However, this method will require significant amount of energy input to lift water to the top level, circulate around the tower and operation of the fan. A major improvement could be introduced if the source of the fresh water is itself high (say over 500 m), and does not require much power for lifting water.

c- Condensation by the use of a heat carrier medium(s) with ordinary heat exchanger types of tube and shell, (fig. 12 example 3) This scheme may prove to be of significant importance, as it could eliminate the reliance on ambient conditions for it's operation.

The heat carrier medium will act as a heat carrier from the top level to the bottom level. This medium will require a different set of properties, from those of the working medium. It will also be selected to provide the most economic operating conditions, with ideal environmental considerations.

The heat carrier medium will be pumped to the top level of the process and used to condense the working medium, which means that, this medium will have (or vaporized at) a lower boiling point than the condensation point of the working medium at the top level conditions. This medium will also have a much higher latent heat of vaporization than the latent heat of condensation of the working medium, preferably more than the ratio of 10 / 1. Thermal energy carried down by the heat carrier will then be either elevated to a level, where it will be re-used to vaporize the working medium, or condensed by the deeper colder sea water, which will require to be brought up from depths of over 800m, or another source of cold water such as rivers or lakes, with temperatures of 2.0 to 4.0 °C.

Elevation of the energy level to be re-used for vaporization of the working medium, will be performed by a third medium, as the auxiliary medium, which will have properties different from both other mediums. This implies raising the temperature of the auxiliary medium to the same temperature as that used to vaporize the working medium. The increase will be achieved by employing a compressor to compress vapors of the auxiliary medium to a pressure, where the outlet temperature will be sufficiently high so as to allow the heated auxiliary medium to be re-used for vaporization of the working medium.

However, economics of such an option will be determined based on the choice of the proper materials and operating conditions. This option will require significant power input, which could be as high as 25 to 35 %, of the total energy output of the system. Nonetheless, the other attractive advantages of this option may still justify it's choice, as compared with the other schemes, despite the fact that there are three operation loops and more materials and investments involved.

As for the step, it simulates in the natural world, the condensation of water vapors at the higher altitudes under the effect of very cold ambient temperature, cloud formation (water droplets) and rain (snow) fall.

4- Accumulation / Creation of Dynamic Head The condensed liquid will be collected in a stabilizing holder tank (7), to establish a steady but controlled flow, and will be then directed to flow downward by gravity through the down-comer pipe (8), which will have approximately the same vertical height as the riser pipe (tunnel). If the riser has a height of 750 m, then the down- comer will have a vertical height, very close to 750 m. This height will act as the active dynamic head for the process (cycle), and is much higher than the water head created by any of the world dams.

Dynamic pressure (Pd_y) developed at the bottom end of the down- comer (at the entrance to turbine) will be proportional also to the liquid density.

P _dy = H x d / 10

Where,

P_dy ; Dynamic pressure at the bottom of the down-Comer, Bar

H ; Vertical height of the liquid column, m d ; Liquid density g / Cm³ or ton / m³

If liquid density is - say 1.4 g / Cm³, (1.4 ton / m³), then the expected pressure at the bottom end of the down-comer will be;

P _dy = 750 x 1.4 / 10 = 105 Bar

This pressure is indeed very high as compared with the very low pressure of vaporization of only 0.35 to 3.5 Bar gauge. Hence, only a modest liquid flow rate could generate significant quantities of electricity. For instance, from a flow rate of- say only 2.0 ton / s, theoretical amount of power (electricity) KW generated will be:

K W = 750 x 2000 / 100 = 15000

Or 15.0 MW

Pressure ratio (P_pr) between the vaporization and power generation points (bottom level) will also be very high, and for this example will be:

105

R_pr = = 35

If the vertical height was higher, with the dynamic head of over 1000 m, and liquid medium's density of- say 1.6 g / Cm³, then the height could be divided into two or more stages for power generation, for the operation convenience or if the material's properties would not allow for one stage.

This stage of the new cycle simulates in the natural world, creation of a working dynamic head of water, with the construction of dams on rivers to elevate the water level and store sufficient quantities behind the dam.

There are only a number of large dams worldwide, which generate more than 1000 MW power, such as the Tarbela dam on Indus river in Pakistan, (generates more than 4000 MW), Hoover Dam in USA, several large dams in Russia, the High dam in Egypt, etc. however, the dynamic head is mostly less than 200 m, but with very large water flow rate and in some cases, in excess of 5,000 m³ /second.

Theoretical water flow rate required to generate 2,300,000 MW, from a height of 750 m, to satisfy the entire world demand for electricity, will be:

2,300,000 x 100

Water flow rate = = 307 000 m³ / s

750

If a working medium is used with the latent heat of vaporization of -say 50 Kcal / Kg, then the equivalent amount of water vaporization by sun will be:

307 x 50

Equiv. Vapor, water = = 24,760 m /s

620

This quantity (flow rate) is less than 0.2 % of the amount (flow rate) of water vaporized by the effect of sun's energy.

As for the step, it simulates in the natural world, damming of rivers and formation of lakes behind those dams. The active height of the dam will be the dynamic head and could be used to generate electrical power.

5- Energy Generation/ Release

The accumulated liquid (working medium), at the bottom end of the down- comer, will be fed to a suitable liquid turbine (9), which will be connected to an electrical power generator. Turbine will convert the potential energy of the working medium to kinetic energy ( E_k), which will be used to operate the turbine and, hence release a 'NET ENERGY' ( E_n ), in the same manner as that of the hydropower generation from the dams. The amount of power developed (KW), will be proportional to: a- Dynamic head b- Liquid flow rate

KW = H x Q / ( 3.6 x lO⁵ )

Where:

H ; Dynamic head m.

Q ; Liquid flow rate Kg / h

If H = 750 m. and Q = 10 000 ton / h

Then:

750 x 10⁶

KW = = 20,833 KW

3.6 x lO⁵

The discharged liquid from turbine will be collected in the working medium hold tank (10), and then returned back by gravity (with sufficient pressure -head) to the working medium vaporizer and repeat the process cycle again and again.

In the actual practice there will be some losses in all steps, in the form of friction, heat losses, mechanical losses, etc. and will be considered for design purposes of the operating plants.

As for the step, it simulates in the natural world, this step represents electrical power generation by utilizing the dynamic formed head behind dams built for this purpose.

Figure 13, shows how an auxiliary medium is used to condense the working medium. The working medium is in a vaporized state, passes up the riser pipe into the working medium condenser 20. The working medium condenser is cooled by the auxiliary medium which is in a liquid state and has a lower boiling point than the working medium. The working medium is cooled within the condenser 20 and condenses back to liquid state. The condensed working medium then enter the stabilization tank 30 and is passed down the down-comer 40 to drive the turbine.

When the working medium is condensed in the condenser 20 the energy released during condensation is absorbed by the auxiliary medium. This energy is used to vaporize the auxiliary medium. The vaporized auxiliary medium is compressed at 50 and then condensed at the auxiliary medium condenser 60. The condensed auxiliary medium is then passed back into the working medium condenser 20 to cool the working medium condenser 20.

MACHENERY AND EQUIPMENT

Machinery, equipment, materials for civil works, etc., required for engineering, construction and erection of a power generating complexes, based on this invention, are generally similar to those currently used in the contemporary power projects. They are also widely used in a large number of other industrial and construction sectors. They are:

a- Boilers, evaporators, condensers, heat exchangers, b- Compressors, fans, blowers, c- Pumps of different types and sizes d- Turbines, e- Piping for liquids, gases, vapors f- Generators, transformers, cables and other electrical materials g- Control equipment h- Storage tanks

Equipment involved is not complicated or difficult to manufacture in the engineering shops. Some sections could be of larger size but are not expected to pose difficulties for their production or to be excessively costly as compared with similar capacity power plants operating on other technologies, on the contrary:

+ There are no exotic, unusual or untested materials involved,

(Some corrosive chemicals may be required ) + Equipment could be small or large, within the usual limitations applicable to the other industries and power plants, + Capacity of a single train could be very large (over 200 MW) and hence, the equipment scale is expected to be proportionally large, + Equipment could be obtained from most industrialized countries,

Figs. 6 and 7, Show the flow diagram of the process and the major units (sections).

THEORETICAL BACKGROUND OF THIS IDEA

As the auxiliary medium is used only to elevate the energy level, it will not contribute much to the general thermodynamic status of the power system and will be neglected.

Energy input (E_in) into the system is in the form of thermal energy, which is introduced through the working medium vaporizer heat exchanger fig. 6, (3), and is used to heat (E_h) and vaporize ( E^) the working medium at a specified temperature and pressure.

L i_n — Ji yp ^~r ϋ

When the vaporized working medium rises through riser's pipe, it undergoes adiabatic expansion and cools down. Expansion of medium's vapors continues until it reaches the top level and starts to condense. At the top end of the process, the medium would have acquired significant amount of potential energy (E_pot), which is directly proportional to the vertical height of the riser. E _pot ⁼ H (vertical height) x Q (flow rate or weight)

This potential energy is thermo- acquired and could be designated as "Thermo- Acquired Potential Energy - TAPEN". It is the beneficial portion of the absorbed energy, and as such, could be used to describe the system's performance.

NOTE: In the natural world, some birds use this phenomenon to gain height

(potential energy) by expanding their wings and circling in the rising

Isotherms (expanding warmer air, which is usually heated by the solar energy), in some favorable locations of the world.

Hence, a measure of the system's performance could be introduced in the form of the Ratio ( R ) of the useful energy TAPEN, to the amount of the absorbed energy E_in, as follows:

E _pot (TAPEN)

However, the input energy is actually equal to the potential energy plus the latent heat of condensation (h_c) of the medium, at the top level conditions, namely: n ^xlc ' ^x-¹ pot

Hence,

It would be more appropriate to express the system's performance as the ratio of the two components of the absorbed energy (heat) at the top working level, namely: thermo-acquired potential energy (TAPEN), which is the useful energy, to the latent heat of condensation (or vaporization) of the working medium at the same temperature, which is the rejected energy, as follows:

E _Pot ( TAPEN)

R =

This is the theoretical beneficial portion of the induced energy (E_in), which will be exploited to extract net gain in the turbine section from each unit of weight passed though the turbine. It is a dimensionless unit (number), and will always be less than unity in the prevailing conditions on earth. In actual practice, it will be much less than "One". For instance, if some water vapor rises to a height of -say 20,000 m, then the potential energy it will acquire per Kg, will be:

E_pot = 20,000 x 1 / 438 = 25. 66 Kg. m.

While the latent heat of vaporization (condensation) of water at - 70 °C, is 670 Kcal/ Kg, then the Ratio will be:

25.66 R = = 0.0383

670

As such, this number will actually specify, characterize and determine some important parameters and operating geometry (dynamic head) of the relevant systems. It will also reflect some thermodynamic properties of the medium(s) used in the process, etc. It would be appropriate to name this Ratio as " Atalla Number - AN", and hence:

AN = 25.66 / 670 = 0.0383

It is clear that only a small portion of the absorbed energy is actually converted to the useful output energy, during one full cycle of the working medium around the system, particularly for those materials with very high latent heat of vaporization, such as water. The main part of that energy will be lost either to the cooling air or other means of cooling.

To increase the Ratio -AN, (the beneficial portion of the absorbed energy) the medium should be selected to have lower latent heat of vaporization (L.H.O.V.). For example, if the L.H.O.V. of the medium in the example above was -say 60.0 Kcal / Kg, with other parameters stay the same, then AN will be:

25.6

AN = = 0.427

60

This is a relatively high value and will not be possible to achieve in practice. A mixture of ethane and hydrazine may produce a reasonable AN value of -say 0.050.

" If the sea level is taken as the reference plane (datum) for the physical calculation of the value of AN, (has been used for the calculations in the above examples), then it could be postulated as follows: " As every material in the earth composition can be vaporized by the effect of high temperature (heat energy) and then condensed by allowing it a free rising through the atmosphere (away from earth center), then every material on earth can have (thermo acquired potential energy - TAPEN), and the said constant number 'AN' (in a relative expression), in any point above the sea level " ".

The absorbed energy could also be used to the complete exhaustion, by means of using auxiliary mediums, (as will be explained in example No 3). The condensation heat is recycled (put) back into the system by means of the auxiliary medium, and then elevating it's level to the vaporization temperature of the working medium, by the use of a re-compression turbine (compressor).

These calculations express the very near real situation, but are also approximate, as there could be other component(s), particularly if the expanding medium in the riser, would undergo some superheating or partial condensation (due to the thermodynamic properties of the medium). In the case of superheating, temperature of the rising vapors at the top level, could be several degrees higher than the condensation temperature. However, the amount of internal energy of the vapors, used to superheat them is relatively small, as compared with the latent heat of condensation and will have only a negligible effect on the value of AN. For the exact and precise calculations, these effects may also be taken to consideration, though insignificant.

The change in vapor's entropy (S_f) of the working medium, between the lower and top working levels will indeed be very slight. For instance, for the refrigerant R- 124 (appendix 1), the change in vapors entropy, between saturation temperatures of 30.0 °C to 10.0 °C, will be:

Delta s_f = 0.3771 - 0.3765 = 0.0006 Kcal

However, the saturation pressures at those temperatures will allow the system (power cycle) to push the vapors to a height of over 950 m. The change in entropies of the vapor S_f and liquid phases s_g at the assumed condensation temperature of 10.0 °C, will be: s_g- s_f = 0.3765 - 0.2479 = 0.1286 Kcal

This change is more significant and will provide the opportunity to store and then extract appreciable amounts of potential energy from the condensed medium. Figs. 8, shows the operation of AEC, on temperature - entropy diagram (T-s), and shows the very narrow range of entropy change during the steady operation of this cycle, which takes place as follows: Point 1 Start of the cycle. - Path l to 2 heating of the liquid medium from the inlet temperature to vaporization temperature ,

- Path 2 to 3 vaporization process of the medium, (increasing volume at constant pressure and temperature),

- Path 3 to 4 adiabatic expansion of rising vapors through the riser.

** During these two processes (between points 2, 3 and 4), a portion of internal (thermal) energy of the medium, is converted to the exploitable potential energy (useful energy).

- Path 4 & 1 (5) condensation of medium at the top level, physical status of medium changes to liquid. However, the liquid medium will perform the process of accumulation in the down-comer and then energy release in the turbine section, before returning to the vaporizer.

Medium status does not change between the top level, feeding to turbine and feeding back to vaporizer (stays as liquid). Medium's entropy does not change either with the change of potential energy between the top level and lower level of the process. It stays at the same value as that of the medium at the feeding point to vaporizer, point No 1.

Fig. 9, shows the same steps of the AEC cycle on the Pressure - Volume (P-V) diagram, with the following operation paths (corresponding to steps of fig, 8), which clearly shows the operating steps of the liquid phase of the cycle, as follows:

- Point 1 Start of the cycle,

- Path 1 to 2 Vaporization of the medium and rising of vapors to the top level, through the riser, where adiabatic expansion takes place, (conversion of thermal energy to potential energy),

- Path 2 to 3 Condensation of medium at the top level, with potential energy stored in,

It shows the very low vapor pressure between the vaporization and condensation at the top level and the very high liquid pressure at the entrance to the turbine (point No 3¹), which is an important feature of this new power cycle.

- Path 3 to 3¹ Pressure rise (accumulation of medium) in the down-comer,

- Path 3¹ to 4 Liquid medium feeding to turbine and energy release

- Point 5 represents turbine outlet point, where liquid's pressure could be controlled to the same as that required by vaporizer. However, it will be better controlled by the effect of the liquid column from an intermediary tank between the turbine and vaporizer.

Hence, point 5 will represent the turbine outlet, where pressure will be atmospheric, and different from point No 1, which represent the start of the cycle, with some positive pressure.

Future research and development will probably concentrate on those aspects and significantly improve the overall performance of the system, and make it totally environmentally friendly.

AEC OPERATIVE CHARTERISTICS / SIMILARITY WITH OTHER POWER CYCLES

A careful analysis of AEC 's theory, principles and the operative system, will reveal that many of the individual units and operations employed by this power cycle, are well known and are also being widely applied in the contemporary industrial, petrochemical, oil & gas, refining, power, etc. sectors. They are very familiar to the relevant experts, engineers, designers and operators in those fields. There are no chemical reactions (processes) in the operation of AEC. The involved operations, which are also used in all those economical sectors, are confined to: a- Heat (energy) transfer/ transport

- Vaporization, condensation, heating, etc. b- Mass transfer/ transport

- Liquid or vapor transport between units, within the cycle, c- Momentum transfer

- Power transfer from the medium (liquid) to the turbine, vapor expansion, Power generation, Etc.

These are indeed simple processes and are widely used by all industries. If a number of those familiar processes are combined in an operation complex or power cycle to perform a specified and defined integrated function (process), then it should be possible to conduct an appropriate techno-economic accounts, estimates and calculations.

Figs. 10 and 11, show the operating steps of the new AEC and Rankine power cycles, which are fundamentally different. AEC involves some major modifications and re- arrangements of those processes, with changing roles, emphasis and aims to create this new power cycle, and are shown in the following comparison.

Comparison of Rankine power cycle with AEC.

As could be noticed, the main emphasis of AEC, is the creation of favorable conditions for the progressive trans-conversion of thermal energy of the vaporizing, rising and expanding medium vapors, to the useful potential energy, which will be stored in the condensed liquid at the selected high altitude (platform). The process steps are organized and arranged therefore, in a manner to achieve such a task.

While the main aim of Rankine cycle is to provide the ideal thermodynamic conditions for the exploitation of the developed very high steam pressure.

Despite the huge size and wide spread of the power sector to all corners of the globe, the generating technologies share the few power cycles and principles in offer, which are based mainly on the following processes:

+ Thermal processes Rankine Cycle

(Coal fired, heavy fuel fired, etc.) + Gas based processes Open Jet Cycle or Combined Cycle

+ Internal combustion processes Otto, Diesel, Cycles or Two Stroke Cycle + Nuclear power, (Steam plants) Rankine Cycle

+ Hydropower + Wind Power

The most widespread of these cycles in the power generation sector, is the Rankine cycle, which accounts for over 50 % of the installed power capacity worldwide. It is being used predominantly in the 'coal fired' power plants and all the other plants which use pressurized steam such as the nuclear power.

As shown earlier, AEC uses three of the processes, which are also used by Rankine cycle but in different order, magnitude and for different purpose. They are:

1- Energy absorption,

2- Condensation (energy rejection)

3- Energy conversion (vapor pressure to mechanical work)

In addition to these Rankine 's steps, AEC includes the important element of the hydropower system (is not a power cycle) in the form of dynamic head with liquid turbine, and follows the path:

(step 1) ( step 2) (step 3) _► Riser (adiabatic

Liquid turbine

(energy release) (accumulation)

(step 5) (step 4)

Since long times (more than 60 years), no new power cycles have been introduced into the industry. The research and development efforts have been concentrated on the improvement of the operating efficiencies and utilization of the renewable sources of energy, with the application adaptation of those individual cycles, or combination(s). Significant achievements have been made and very high efficiency equipment and machinery have been developed and introduced. Nonetheless, a new system's entry into the power generating sector, may prove to be a welcome news. The operative size of the single production unit (model) could be small or large depending on the need. However, it will also depend on:

+ Specific conditions of selected site and energy source in the vicinity, + Availability of supporting infrastructure and services, + Engineering and mechanical limitations of materials

Capacity of a single unit could be as high as 250 MW or even higher (actual experience could determine the highest sizes and limitations). For larger capacities, several units will be employed. The economic size of the unit is expected to be higher than 1.0 to 2.0 MW, to justify the required investments. Smaller units could be economical if very good conditions are available in the selected site, with suitable energy supply sources.

ENVIRONMENTAL IMPACTS/ ASPECTS OF AEC

The newly invented power (energy) cycle (AEC) relies for it's operation mainly on the direct or indirect solar related renewable energy and could be operated without much requirement for the combustion of fossil fuel. It is no exaggeration to state that, this energy cycle could be operated efficiently and safely with 0.0 kg / hr of coal per MW power, (no emission of Carbon Dioxide C0₂ to atmosphere), while Rankine cycle will require over 350 kg/ hr of coal per MW, at 33 % cycle's efficiency.

This clearly indicates the possibility of huge reduction of Carbon Dioxide and other pollutants emissions to atmosphere, which could be achieved by utilizing this power cycle (AEC technology) to generate electricity. For instance, for a power plant of only 600 MW, AEC could reduce emission of those polluting gases from over 5 Mil tons per year for Rankine cycle to 0.0 tons per year.

There will be no other gases or fumes emission to atmosphere as a result of the operating this cycle (only very minor quantities of the working medium(s) during maintenance period). Working medium itself will be selected based on the environmental properties, with minimal (preferably no) impact at all on the environment. There are numerous such chemicals and their mixtures, which could provide the required environmental properties.

The pure mediums or mixtures will circulate within the system without any direct communications with outside environment (atmosphere). Hence, NO deliberate discharges to atmosphere will ever be contemplated and will be avoided by all means as it will be considered as a violation of the environmental role and regulations. The medium will be kept in the tightly arranged system with all the necessary safety and emergency means and measures, to ensure that NO discharge to atmosphere will ever occur. During periods of required maintenance, all precautions and measures will also be taken to ensure that NO material will be discharged from the system, without full safety and protection steps properly in place.

Planed or necessary disposal of any material will be conducted according the role and regulations of the environmental authorities, and the large plants will be provided with on-site safe disposal facilities.

One of the most important characteristic strengths of this new operative power cycle, could prove to be the conversion of the entire absorbed energy from the Oceans to electricity, to the total destruction (extinction). Such a possibility will open huge potentials for applications of this technology worldwide, for a cleaner environment and unlimited source of energy.

DIRECT ABSORPTION OF SOLAR ENERGY

Direct absorption of solar energy by an auxiliary medium in an exposed and purposely designed pipe coil to the sun radiation could be considered, particularly in some desert locations, where favorable conditions may exist. All theoretical and operation principles which, have been mentioned in this report for the sea water heat exchanger case, will also be applicable to the direct absorption of energy. However, as the solar energy is available only during day times, it could cause some problems with control and stability of the system in such conditions.

Combination of both systems could also be applied, if economics of such schemes should support it. Sea water canal(s) may be constructed to take water through the very hot tropical and desert areas exposed to sun and store energy to be used by the submerge heat exchangers system.

In all cases, site selection and conditions it can provide will be of utmost importance for the proper operation of the system.

CONCLUSIONS

The new Invention provides the required knowledge and know-how to formulate, design and construct the novel operative system, which depends for it's operation on the renewable energy in the form of solar energy.

Energy absorption (introduction into the system) will be either directly, through the ordinary heating coil (pipes) exposed to sun, or indirectly as the heat energy stored in the vast ocean waters (or other waters), through the use of the conventional tube and shell heat exchangers

The new system does not rely for it's operation, on the combustion of significant amounts (probably none) of fossil fuels as a source of energy, and will therefore, not generate much (or any amounts of) carbon dioxide (C0₂). As such, this system could prove to be indeed, a very clean and environmentally friendly process (energy cycle).

The new idea outlines, introduces and suggests a new approach and futuristic thinking to the issue of power generation and offers practical solutions to the immediate and long term supplies of energy from the solar related sources. It also presents an important technological advance and breakthrough in positively addressing the current problems of global warming as it should enable massive reductions in Carbon Dioxide (C0₂) emissions to atmosphere.

The idea utilizes well-known lows of physics, mechanics, thermodynamics, hydraulics, etc., which will enable the new system to convert the significant volume increases of vaporization and subsequent adiabatic expansion of the vaporized medium to the useful and exploitable potential energy, through the establishment (creation) of a workable dynamic head (liquid), and electrical power generation in the turbine system. Within those lows and principles, this idea formulates and represents a new and identifiable energy (power) cycle or cell, which enables to perform the required (assigned) functions and generate power. It is appropriate the new Cycle be called " Atalla Energy Cycle" and referred to as " AEC". It is a closed type energy cycle, with the working medium(s) continuously circulating through the system without direct communication with the outside atmosphere.

AEC utilizes many of the existing processes thermodynamic, physical, thermal, mechanical, hydrodynamic, etc, to perform the required functions.

AEC involves major modifications and re-arrangements of those processes, with changing roles, emphasis and aims as compared with those of Rankine cycle.

EXAMPLE 1

It is required to generate 20 MW power 'Net' in a location, which is close to the Sea Shore with the following specific data: i- Sea waters:

a- Depth, Suitable with good tidal water exchange b- Maximum water temperature, which lasts 19.4 °C for about 3 months, c- Minimum water temperature, which lasts 7.3 °c for about 3.8 months, d- Average annual temperature . 12.6 °c ii- A mountain cliff is available nearby with:

a- Maximum vertical height (peak) from sea level 879 m b- Suitable (exploitable) height 765 m c- Maximum air temperature at sea level 24.8 °C d- Maximum temperature (air) at that level, 16.5 °C which lasts only for short periods,

- with Wet Bulb temperature of : 12.6 °c e- Minimum air temperature at sea level -7.0 °c f- Minimum winter temperature -15.8 °c at the top working level, e- Average winter temperature at the top level 2.5 °c f- Average annual temperature at the top level + 6.8 °C

Solution : It is intended that the system will be relying totally on the ambient conditions for it's operation,

> An auxiliary loop will be used to elevate the energy level of the sea water temperature to suit the operation conditions, Power input to the system will be kept to minimum or avoided as far as possible,

> Assume the working conditions of the proposed power system per the following fig. 6a. (fig. 6 as another reference),

Steps: - Required liquid flow rate to Turbine to generate 20.0 MW power:

-1 Assume the Turbine/ Generator's efficiency (μ) at 88.5 % , which is achievable in the existing liquid turbines, offered by several manufactures,

-2 Working medium (Liquid) flow rate (G_wm) will be found as follows, from the equation:

XI X (Jwm

KW = x μ ( efficiency)

3.6 x lO⁵ Where:

H- Is the vertical height m, G_wm- Is the flow rate Kg / h

KW x 3.6 x 10⁵ 20 000 x 360 000

H x μ 750 x 0.885

G_wm = 10 850 t / h Or 3.01 t / s

This flow rate will become the basis for all the subsequent 'Design and engineering estimates' and hence, the cost implication of each element or component involved. 2- Selection of the Mediums

a- Auxiliary medium

There are many pure materials, mixtures, solutions, azeotropes, etc, which could be used as suitable auxiliary mediums. For this particular case, the material selected as the auxiliary medium and it's properties are as follows:

Material ; A mixture of n-Pentane and Neo-Pentane n-Pentane CH3-CH2-CH2-Ch2-CH3 n-Butane CH3-CH2-CH2-CH3

Properties:

- Boiling point ( B.P.) at 1.0 Bar Pressure 24.5 °C

- Molecular Weight 66

- Latent heat of vaporization at B.P. 86 K cal / Kg

- Specific heat 0.538 Kcal / Kg. °C

- Ratio of specific heats C_p / C_v at 24 °C 1.08

This is a very important property for the auxiliary medium to ensure minimum power consumption for re-compression. The ratio will have a lower value at operating temperature range of 8.0 to 20.0 °C (close to 1.05), which means (approximately):

Pi x Vi = P₂x V₂ = Const

And: = = Const

P₂ x V₂ T₂

- Submerged auxiliary medium vaporizers in the 'sea water' will be used, to minimize power input into the system.

b- Working medium

The re are many pure materials, mixtures, solutions, azeotropes, etc, which could be used as suitable mediums. For this particular case, the material selected as working Medium and it's properties are as follows: Material : A mixture of ethane and ethylbenzene

Ethane CH3-CH3 28 to 32 % Wt.

Ethylbenzene CH3-CH2-(C6H5) 68 to 72 % Wt.

Properties:

- Boiling point ( B.P.) at 1.0 Bar Pressure 6.5 to 8.5 °C

- Molecular Weight (approx.) 58 to 62

- Latent heat of vaporization at B.P. (about) 55 to 57 K cal / Kg

- Specific heat (about) 0.525 Kcal / Kg. °C

Other suitable mixtures of pure materials for working medium, could be:

- Carbon Dioxide and Acetic Acid,

- Ethane and Hydrazene,

- Ethane, Octanes and Hydrazene,

- Etc.

3- Vaporization Process

A- Auxiliary loop Vaporization Operation

Assume the process to proceed as per the diagram in fig. 6a.

Auxiliary loop will be used to extract thermal energy from 'sea waters' in the auxiliary medium vaporizer (1) and then elevate the energy level by compressing the auxiliary medium's vapors in a low pressure compressor (2) to increase their temperature. Compressor's output temperature (pressure) will be selected to ensure the efficient condensation of the working medium at the top operation level at any time during day or night times.

However, the temperature increase will be adjusted also to obtain the best economic operation of the power system in terms of compressor's power input and system's overall power output. Hence, it is expected that power input to be highest during summer mid day times and least (or non) during night times, particularly during winter nights.

A- 1 Auxiliary Medium Circulation Rate (G_aux) Amount of auxiliary medium (G_aux) with latent heat of vaporization (L_aux) of 86 Kcal/ Kg, required to vaporize 3.01 T/s of working medium with latent heat of vaporization (L_wm) of 56 Kcal/Kg, and assuming the overall efficiency of the system (μ) including thermal energy required to heat the working medium to boiling point temperature, at 88 %, will be:

G_m„ = x 3.01 x 100/ 85 = 2.3 T / s

A-2 Auxiliary Medium Vaporization

Liquid auxiliary medium from the holding tank (4), will be fed by gravity to the auxiliary medium vaporizer (1), where sea water will be used as the source of energy. Vaporization will be accomplished under vacuum, which will be created by the compressor's suction, to improve system's performance.

Vaporization temperature of the auxiliary medium (driving force) will be 2.5 to 3.5 °C lower than the 'sea water' temperature. However, re-compression of the auxiliary medium by compressor (2), will allow to raise the temperature (energy level) of auxiliary medium, sufficiently to be used for vaporization of the working medium in the working medium vaporizer (3). More details of the temperature profile of the power system operation are presented in Heading 5 (Condensation) below.

A-3 Auxiliary Medium Vaporizer Heat Load (Q_aux)

Heat load of the auxiliary medium vaporizer (1), where sea water will be used as the energy source, assuming the heat transfer efficiency (η) at 92 %, should be such to ensure the efficient vaporization of the working medium, and will be as follows:

Q_aux = 2,300 x 86 x 100/92 = 225,000 Kcal/ s

Or 810 Mil Kcal/ h

A-4 Compressor Power Input ( MW) Assume that the maximum compression delta temperature increase to be 12.0 °C, as is the case with this proposed mid summer day time temperature of 24.5 °C, fig. 6a, However, the average annual temperature increase by compressor throughout the year, day and night times, is expected to be about 4.0 to 6.0 °C (or probably less).

Power required (E_aux) to compress 2.3 T/s of the selected auxiliary medium vapors at saturation conditions and increase it's temperature by 7.0 °C, at compressor's (2) efficiency of 90 %, is expected to be per the equation: (Chemical Engineering Handbook, 7^th edition)

Power (KW) = 9.81 x 10⁴ x PAX

Where:

PI Is the inlet pressure (absolute), K Pascal (KPa), Gl Is the volumetric flow rate (gas) m3/ h,

X Is a factor, which expresses the effect of the specific heat ratio C_p/ C_v, (k) of the material (gas) on the compression power. Values of X are tabulated and presented in "Chemical Engineering Handbook", for a wide range of operation conditions and any vapors or gases, and in calculations they are used as 'X factor'.

Theoretical power (compressor capacity) required to compress 2.3 x 3600 = 8,280 Ton per hour, at compressor's efficiency of 90 %:

Power (KW) = 9.81 x 10⁴ x Volume (8280/ 2.43 x 10³) x Pressure (80.0 KPa) x x ( X factor) (0.200 x 0.065)/ 0.9

Power (KW) = 3,865 KW

Ratio (R ) of the output power (P_out) to the input power (P_in) will be:

R = = = 5.17

R_in 3,865

This is a relatively high ratio of the average power output, particularly for an assumed continuous power input to the system. The ratio is expected to be even higher in the actual practice, with selection of suitable materials, sites and operation optimization. Auxiliary medium with elevated temperature will be fed to the working medium vaporizer (3), where it will condense and will transfer it's thermal energy (latent heat of vaporization) to the working medium and vaporize it. Temperature drop across the working medium vaporizer will be optimized to ensure efficient vaporization of the working medium and process economics, but 2.5 °C could be reasonable.

The condensed auxiliary medium will be collected in a hold tank (4) and fed back by gravity to the auxiliary medium vaporizer (1) and repeat the cycle.

B- Working Medium Loop Operation

Auxiliary medium with elevated temperature (when required) from sea water temperature, will be fed to the working medium vaporizer (3). Auxiliary medium vapor temperature at the outlet of re-compression compressor will be regulated and controlled to suit the prevailing atmospheric conditions and ensure system operation most efficiently and economically. Auxiliary medium temperature will allow:

- Vaporization of the working medium

- Development of sufficient vapor pressure to push the working medium through the riser, to upper geographic operation level at acceptable linear speed, but also with minimum pressure drop across the riser pipe,

In the exceptional operation case presented in fig. 6a, auxiliary medium temperature will be increased through compression to 27.5 °C, which is sufficient to vaporize the working medium at 25.0 °C (Boiling point 8.0 °C, at atmospheric pressure) and develop a pressure of over 0.75 Bar gauge. This pressure is high enough to counter the weight of the working medium vapor column of 750 m height and deliver vapors to the top level at over 100 m/s, in a riser pipe with about 4 to 5 m diameter.

Vapor column weight pressure: about 0.300 to 0.350 Kg/ cm²

B-l Working Medium Vaporizer Heat Load Required heat load of the vaporizer to vaporize 10 850 1 / h of the selected medium at 25.0 °C will consist of: a- Heating the medium from inlet temperature T_in, to the Vaporization temperature T_vap. b- Latent heat of vaporization of the medium h_v Hence:

Where:

Q _a - Total heat absorbed by the medium,

Q _n - Heat required to raise temperature of the medium from condensation

(T_con) to vaporization temperature (T_vap). h _v - Latent heat of vaporization,

Assuming vaporizer's efficiency (η ) at 92 %,

Q_ab = { 0.525 ( 25.0 - 20.0) + 56 }x 10,850,000 / 0.92 Q_ab = 690,000,000 Kcal / h

This heat load is significantly lower than the heat load of the auxiliary medium vaporizer, which was 810,000,000 Kcal/ h. This will allow for further efficiency and improved system operation.

4- Elevation / Condensation

The vaporized medium in the working medium vaporizer, will rise through the riser pipe (5) to the top geographic level (end), and vaporization pressure is sufficient to force vapors to reach the top level. To ensure the minimum pressure loss (drop) through the riser, the total length of the riser should be kept to minimum also. The practical linear length for a vertical height of 750 m, could be up to - Say 3000 to 4500 m. However, further lengths could be contemplated, depending on the overall assessment of the site conditions. Pressure, difference between the top and bottom levels will depend on many factors such as;

+ Linear velocity of the working medium vapors through the riser,

+ Molecular weight of working medium,

+ Physical length of the riser and surface roughness (conditions), + Condensation of working medium in the riser pipe, + etc.

In this case (example) the pressure drop (ΔP) will be the difference between the vaporization pressure (P_v), and condensation pressure (P_c),

Δ P = P_v - P_c

ΔP = 1.75 - 1.050 = 0.700 Bar.

However, a significant portion of the pressure drop is actually due to the effect of weight of the vapor column of 750 m, which in this case amounts to about 0.300 to 0.350 Bar. The actual pressure drop is about 0.400 Bar (400 m Bar), and is sufficient to overcome the losses in the riser and deliver vapors at the top level at linear speed of over 120 m / sec, as the riser's large diameter will cause much less pressure drop.

At the top level, the delivered vapors will be fed to an 'air cooled' condenser (6) or cooling tower. Condensation temperature (t_c), will always be lower than the vaporization temperature (t_v), if the working medium vapors are not recompressed. The acquired Potential energy by the rising vapors (per unit weight, Kg), will be:

E _p = H x Kg

E _p = 750 x 1.0 (Kg) = 750 Kg. M.

In terms of energy, expressed as heat:

E _p = 750 x υ Kcal

Where : υ , Is the conversion factor : Kcal = 438 Kg .m.

1

E_p = 750 x = 1. 712 Kcal /Kg

438

It is clear that only small fraction of the absorbed energy, will be utilized as the Potential Energy, and released in the Turbine System. However, as the cost of energy is insignificant for this process, then the issue of efficiency of heat utilization, becomes less important, and will only be taken into consideration in terms of effect on the associated total capital costs. 5- Condensation :

Thermodynamic conditions of the working medium vapors reaching the top operation level in terms of temperature and pressure are crucial for the stable and reliable system operation. These conditions depend intimately on working medium vaporization conditions, which are controlled by the auxiliary loop. They will be tuned to ensure a condensation driving force for working medium vapors, expressed as temperature delta with outside air temperature at that height, of at least 2.5 to 3.5 °C, during most extreme summer mid day time high temperature, and over 8.0 °C in the other times, to achieve and improve system's economics.

Auxiliary loop will be operated to give the compressor output temperature as follows:

T -¹ com = T -¹ ai .r + ' τ πser + ' T vap + ' Y

Where:

T_com Compressor outlet temperature °C

T_air Outside air temperature at the top operation level °C

T_ris_er Temperature drop across the riser °C

T_vap Temperature drop across the working medium vaporizer °C

Y Condensation driving force °C,

Hence, regardless of the sea water temperature (energy source), the required compressor outlet temperature (T_COm) will be achieved, by sensing the air temperature at the top operation level and feeding that temperature to the compressor controller, which will process the data along-with other inputs and adjust operation accordingly.

Compressor's outlet temperature (T_com ), as compared with the sea water temperature (T_sw) (energy source), determines the power requirement for compressor operation and will be selected to ensure:

a- Reliable and stable operation of the power system, b- Best economics of the system operation,

The annual cycle of the system operation will encounter two scenarios of working medium condensation at the top operation level, they are 5-1 Condensation during periods of ' Maximum Sea Water Temperature', as per the fig 6a,

5-2 Condensation process during periods of minimum sea water temperature, as per the fig. 6a,

However, despite the much lower 'sea water' temperature during winter time in W. European countries, this power system is expected to operate better during winter time, because the average air temperature is much lower during the same times, and particularly at higher geographic levels.

The presence of the auxiliary loop will assist the system to minimize (and eliminate) the effect of un-expected freak high temperatures, which may be experienced during some times and moment.

-3 Working Medium Condenser Heat Load

Condenser's (6) heat load will be similar to the heat load of the working medium vaporizer as the amount of heat (energy), required to be rejected is very close to that absorbed by vaporizer ( heat load will actually be slightly lower for condenser). Hence, the heat load of the condenser will be assumed also at:

Q_c = 690,000,000 Kcal / h

This will also give a safety margin for better operation of the system. The difference between the heat loads of the two processes, will be approximately equal to the potential energy gained by the working medium at the top geographic level (platform). As defined earlier the potential energy gain of the unit weight at the vertical height of 750 m, is 1.712 Kcal / Kg, then the heat load difference will be:

tab Q_c = 1.712 x 10 850 000 = 18 575 200 Kcal / h

This is only 2.3 % of the total condenser's load and is indeed very minor amount (within the margin of error) and could be neglected for this particular case. However, it could also be significant, if the latent heat of vaporization of the medium is much lower -say less than 25 to 30 Kcal / Kg. In such cases it may be important that this heat to be considered, to avoid over sizing the condenser. Some condensation will also take place in the riser's pipe, particularly the upper parts, which will further improve condenser's operation, (will act actually as partial condenser).

6- Accumulation / Energy Generation

The condensed working medium liquid will be collected in a stabilizing tank (7) of appropriate size. The liquid is then allowed to flow by gravity to the down-comer (8), which will also have the vertical height of 750 m. The down-comer will be filled with liquid, to establish the required dynamic head, before it is allowed to enter into the liquid Turbine (9). Pressure at the bottom end of the down-comer (prior to entering the turbine), will then be proportional to the liquid density.

P _liq = ( H x d)/ 10 Bar.

Where:

Pii_q : Is pressure at the entrance to the turbine Bar.

H : Is vertical height of the liquid's column m d : Is liquid density g / Cm³

Density of working medium mixture is expected to be 0.550 g/Cm³ , or 0.500 ton /m³. Hence, pressure at the entrance to turbine system will be:

P_liq = 750 x 0.550 /10 = 41.25 Bar.

This pressure is very high as compared with the vaporization pressure of only 0.750 Bar gauge, which means pressure magnification (P_mag) (ratio) of:

41.25

P J- m maags = = 23.6 1.750

The accumulated liquid will be fed to the liquid turbine, which will convert (with efficiency at 88.5 %) most of the potential energy to electricity in the connected generator. Turbine load will be (estimated earlier):

H x Q

KW =

3.6 x lO⁵ 3.6 xlO⁵

Q = x 20xl0⁵= 9600 ton/h

750

or 2.667 ton / s (second)

If turbine and generator's efficiency (combined) is assumed at 88.5 %, then the actual flow rate will be:

Q = 9600/0.885 = 10850 ton/h or 3.010 ton/s

As indicated earlier, this is the main datum for the design and construction purposes of the unit.

Liquid working medium from the turbine will be collected in a hold tank (10) and then fed back to the working medium vaporizer (3) and repeat the cycle.

EXAMPLE No 2:

-Assume all the site and operation conditions, materials properties, etc. of example No 1 to be the same for this example, but:

a- Latent heat of vaporization of the medium is 36.0 Kcal/Kg, b- Density of the medium is: 1.35 g/Cm 3 c- Specific heat of liquid medium is: 0.323 Kcal / Kg . °C.

— ► Solution :

1- Heat load of the vaporizer will be :

Q_ab = { 36.0 + 0.32 (25.0- 20.0 )}x 3010

= {36.0 + 1.6 }x 3010

= 113,176 Kcal/s

= 407,434,000 Kcal/h This shows significant reduction in the heat load of the vaporizer and condenser, which means a proportional reduction in the required heat exchanger's areas, and subsequent reduction in the investment cost of the project.

However, this is only an example and mediums with such favorable properties may be difficult to find in actual practice, particularly those mediums with lower latent heat of vaporization, but yet also with such lower molecular weight. Such condition will indeed be very favorable to significantly improve the AEC performance and efficiency. Nonetheless they could be formulated from mixtures of suitable pure materials, such as those proposed in example No 3 -A, and others.

EXAMPLE No 3

Example with heat carrier medium, and an auxiliary medium:

a- Assume all the site conditions the same as those of example No 1,

However, the cliff height is 1100m, and the exploitable height is 1200 m. Working level will be at 1000 m height.

b- Selection of the Mediums b-1 Working Medium

There are many pure materials, mixtures, solutions, azeotropes, etc, which could be used as suitable mediums. For this particular case, the material selected as working Medium and it's properties are as follows:

Material : A mixture of:

Flouromethane CH3-F 5 to 8 %

Diflouromethane CH2-F2 12 to 15 %

Dibromodiflouroethane Br2C2H2-F2 80 %

Properties (expected)

- Molecular weight 110

- Density (liquid) 1.7 g/cm³ Boiling point (at 1.0 Bar pressure) 4.0 to 6.0 °C

Latent heat of vaporization 35 Kcal/ Kg

Specific heat 0.195 Kcal/ Kg

Refrigerant R-318 (Octafluorocyclobutane) thermodynamic properties shown in appendix 1,

- Molecular weight 200

- Density (liquid) 1.612 g / cm³

- Density (liquid) 1.0 g / cm³

b-2 Heat Carrier Medium

Assume a medium to be used as the 'Heat Carrier', which is a mixture of ammonia and water with:

- Boiling point of - 4.0 to - 3.0 °C

- Molecular weight of such mixture is about 17.2

- Latent heat of vaporization 450 Kcal/ Kg

b-3 Auxiliary medium

Assume a third medium (auxiliary) to be used for the heat recovery and transfer between the heat carrier and the working medium, Fig. 6, at the bottom (lower) level.

This will be accomplished through the vaporization (preferably under vacuum), and compression of the auxiliary medium, which will allow to raise the temperature (energy level) of auxiliary medium, sufficiently to be reused for the vaporization of the working medium.

There are many pure materials mixtures, solutions, azeotropes, etc, which could be used as suitable auxiliary mediums, such as: h- Pentane , Diethyl ether, Methyl ethyl ether, Methyl ethyl amine, Iso- ' Hexane, etc. Their mixtures could also be used to obtain the suitable boiling conditions. For this particular case, the material selected as the auxiliary medium and it's properties are as follows:

Material ; A mixture of n-Pentane and n-Butane n-Pentane CH3-CH2-CH2-Ch2-CH3 n-Butane CH3-CH2-CH2-CH3

Properties:

- Boiling point ( B.P.) at 1.0 Bar Pressure 24.5 °C

- Molecular Weight 66

- Latent heat of vaporization at B.P. 88 K cal / Kg

- Specific heat 0.538 Kcal / Kg. °C

- Ratio of specific heats C_p / C_v at 24 °C 1.08

This is a very important property for the auxiliary medium to ensure mimmum power consumption for re-compression. The ratio will have a lower value at operating temperature range of 8.0 to 20.0 °C (close to 1.05), which means (approximately):

Pj x Vi = P₂x V₂ = Const

And: = = Const

P₂ x V₂ T₂

Submerged auxiliary medium vaporizers in the 'sea water' will be used, to minimize power input into the system.

c- The same circulation rate of the medium 10 850 t / h, ( 3.010' t / s), will generate higher power, as follows:

Power = (3103 x 1000) / 100 x μ (0.90 efficiency) = 27.00 MW

SOLUTION:

Vaporization of working medium: vaporization will be effected at: 22.00 °C ,

- Corresponding vaporization Pressure 1.850 Bar. abs, - Corresponding condensation pressure at the top level (height of 1000 m) 1 1..005500 BBaarr.. aabb:s.

- Corresponding condensation temperature 7.0 °C

-Vaporizer's heat load to vaporize 10 850 t/h of working medium, will be:

Q_v = Latent heat of vaporization hv + Heating of working medium

Q_v = j 35 + (0.195 x 151 x 10850 x 1000

= 411,486,000 Kcal / h

The rest of the process of power generation estimates will be similar to that conducted for example No 1.

The role and effect of the heat carrier and auxiliary mediums are described as follows:

3-2 Heat carrier

The heat carrier's role is to carry the heat of condensation from the top level, down to the vaporization level. This will be achieved by pumping the heat carrier ( water ammonia mixture), with boiling point at - 4.0 to - 3.0 °C, to the top level. The mixture will have the latent heat of vaporization of about 455 Kcal / Kg. It will be fed to the condenser at +4.0 to +4.25 °C, which will have the vapor pressure of about 1.35 Bar. abs. (or 0.35 Bar g). The circulation rate of the heat carrier ( G_w ), required to remove the heat of condensation of the working medium will be estimated from the heat of condensation of 35 Kcal/ Kg:

G_w = 35 x 10 850 000 / 455 = 835,000 Kg / h

This is a relatively small amount as compared with 10 850 000 Kg /h, of the working medium due to the much higher latent heat of vaporization of the heat carrier. Every one Kg, of the heat carrier will remove the heat of about 13.0 Kg, of the working medium. Hence, energy required to lift the heat carrier medium ( E _car ) to the top level will be: 835,000 x 1000

E car = = 2,730 KW

360 000 x 0.85

Or 2 .730 MW

Where, 0.85 is the pumping efficiency

The heat carrier will be fed to the working medium condenser at the top level and allowed to vaporize, to remove the heat of condensation of the working medium, and then will be allowed to flow down to the bottom level in a vaporized phase, and will be fed in turn to the auxiliary heat exchanger. The vertical column of the heat carrier vapor of (1000 m), will help to raise the pressure at the bottom level by about 0.110 Bar. and hence, the temperature by about 1.8 to 2.0 °C. Temperature of carrier medium vapors at the inlet to the auxiliary heat exchanger, is expected to be about 6.35 to 6.5 °C.

It is required to raise this temperature to above 22.0 °C, to be suitable for use again in the vaporizer. To achieve this aim, the above selected auxiliary medium will be used, comprising a mixture of n-Pentane and n-Butane and with the boiling point of about 21.0 °C. To condense the heat carrier at 6.5 °C, the auxiliary medium will need to be boiled at 3.75 to 4.0 °C, which means, boiling under vacuum of 0.55 to 0.565 Bar absolute pressure.

3-3 Auxiliary medium

a- Circulation rate of the auxiliary medium ( G ^ will be:

Latent heat of vaporization of the selected auxiliary medium at 4.5 0C is estimated at about 90 kcal/ Kg.

G_ax = Working medium weight (per hour) x Latent heat of vaporization (35 Kcal/ Kg) + heat to increase temperature (3 Kcal/ Kg - / Latent heat of vaporization of auxiliary medium (90 Kcal/ Kg)

G ^ = 10 850 000 x 38 / 90 = 4,582,000 Kg /h

b- The auxiliary medium will be fed to the heat carrier's condenser to condense it at 6.5 °C, ( at the same vertical level as the working medium vaporizer - just above the sea level ), which means creating a vacuum of about 0.55 Bar abs, to vaporize the auxiliary medium (to boil) at 4.0 °C, and condense the heat carrier.

c- To create the vacuum required for vaporization of the auxiliary medium, a vacuum compressor will be used to effect the vaporization process, and compress the vaporized auxiliary medium at the compressor's outlet, to a pressure just over One Bar abs, at 22.0 °C, so that it could be re-used to vaporize the working medium. The heat carrier will be condensed in this auxiliary condenser, and then pumped back to the top level to be used again.

Power (Eg_x) required to operate the compressor at an efficiency of 90 %, which is possible with the modern and large units, will be:

Power (KW) = 9.81 x 10⁴ x P X Where:

Vι Is the inlet pressure (absolute), K Pascal (KPa), Gi Is the volumetric flow rate (gas) m³/ h,

X Is a factor, which expresses the effect of the specific heat ratio C_p/ C_v, (k) of the material (gas) on the compression power. Values of X are tabulated and presented in "Chemical Engineering Handbook", for a wide range of operation conditions and any vapors or gases, and in calculations they are used as 'X factor'.

Theoretical power (compressor capacity) required to compress 4,582 Ton per hour, at compressor's efficiency of 90 %:

Power (KW) = 9.81 x 10⁴ x Volume (4,582/ 1.67 x 10³) x Pressure (55.0 KPa) x x ( X factor) (0.175 x 0.175)/ 0.9

E^ = 5.05 to 5.15 MW

-4 A similar loop will also be included to use the same principle of the Auxiliary system's scheme of vaporizer/condenser to extract heat from the seawater at -say 12.0 °C, and increase it to 22.0 °C, as the make up heat to maintain the heat balance of the system, fig. 12 ,

-5 It would be advantageous to use the same auxiliary liquid (mixture of n- Pentane and n-Butane), as it will suit also this application also. The amount of make up heat, (E_mu) to be supplied to the working medium, will be approximately equal to that produced by the turbine (as output), namely:

E_mu = 27.00 x 820 x 1000 / 0.90 = 24,600,000 Kcal /h

As such, another vacuum compressor will be used to raise the temperature of the auxiliary medium from 19.25 °C to 34.5 °C. The amount of this portion of the medium (G_mu),required will be:

G_mu = 24,600,000 / 90 = 280 000 Kg /h

Power (E_mu), required to operate the compressor will be about :

E_mu = 0.150 to 0.200 MW 3-6 Total input power ( E_iπ), required to operate all the internal systems will be: ϋin ^— ^car ' -E'a ' -t u

E_k = 2.730 + 5.150 + 0.200 = 8.080 MW

3-7 Ratio (R), of the output power (E_out) to the input power (Ei_n), then will be:

E_iπ 27,00 R = = = 3.34

E_out 8.080

This is a reasonably good ratio (per the current engineering practices) for those systems, which operate on the renewable sources of energy. It could be significantly improved with the use of higher vertical heights, as the required rise of the vaporization temperature of the working medium, does, not require any further increase of the temperature difference (delta), needed to effect the process of vaporization or condensation of the working medium or the heat carrier. For a height of -say 1500 m, the ratio ( R ) could probably be increased to about: 3.5 to 3.65 or even higher.

The ratio could be increased also by means of using more suitable materials in the generation cycle of AEC in terms of:

+ lower molecular weight, but also lower latent heat of vaporization + Use of auxiliary mediums which could recycle higher quantities of heat with less power, A significant improvement to the operation of the cycle in this example could be achieved (made), if instead of the auxiliary medium a source of cold water is available at or near, the sea level, such as a river with water temperature of -say 4.0 to 6.0 °C, which will also require some changes in the system operation.

The available information indicates that systems, which can achieve such a ratio (more than 3.0) in the actual practice, will have very good prospects of the successful commercialization.

It will be clear to those skilled in the art that many variations to the embodiments described are possible without departing from the invention, which is limited solely by the claims attached.

Appendix 1

Thermodynamic properties of Refrigerant R 124

Reference: Perry's Chemical Engineer's Handbook Seventh Edition

Appendix 2

Thermodynamic properties of Refrigerant C 318 (Octaflourocyclobutane C₄F8)

Reference: Perry's Chemical Engineer's Handbook Seventh Edition

Appendix 3

Thermodynamic properties of Refrigerant R 23 (Triflouromethane C H F₃)

Reference: Perry's Chemical Engineer's Handbook Seventh Edition

Claims

- A method for generating power efficiently and reliably in a circulating closed loop system, by utilizing the principle of vaporizing a working medium in the ground and sea levels and condensation of the same medium in a higher geographic level and comprising the steps of:

1-1 Auxiliary Medium Loop

Evaporating an auxiliary medium in the first part of the closed auxiliary loop,

Compressing the auxiliary medium vapors in a second part of the auxiliary loop, to increase their temperature and create controlled condition of the power system,

Feeding the higher temperature auxiliary vapors to the first part of the working medium loop,

Collecting the condensed auxiliary medium from the first part of the working medium, in a third part of the auxiliary loop,

Returning back the condensed auxiliary medium back to the first part of the auxiliary loop,

1 -2 Working Medium Loop

Evaporating a working medium in a first part of the closed working medium loop under controlled conditions,

Passing the evaporated working medium through a riser which represents a second part of the closed working medium loop,

Condensing the working medium in a third part of the closed working medium loop,

Collecting the condensed working medium and creating a stable dynamic head in a forth part of the closed working medium loop, Releasing the collected working medium,

Driving a turbine and generator with the condensed working medium in a fifth part of the working medium loop, and

Subsequently directing the condensed working medium back to the first part of the closed working medium loop.

- A method according to claim 1 wherein the energy used to evaporate the auxiliary medium is supplied by sea water or other waters. - A method according to claim 1 wherein the energy used to evaporate the auxiliary medium is direct or indirect solar energy.

- A method according to claim 1 wherein the energy used to evaporate the working medium is supplied by an auxiliary medium.

- A method according to claim 1, 2, 3 or 4 wherein there is a temperature difference between the evaporator and the condenser.

- A method according to claim 1, 2, 3, 4 or 5 wherein the working medium boils at a temperature, rises through a riser to a pre-determined height and gains potential energy.

- A method according to claim 1, 2, 3, 4, 5 or 6 wherein the working medium condenses at a temperature below the boiling temperature of the working medium, at the top end of the riser.

- A method according to claim 1, 2, 3, 4, 5, 6 or 7 wherein the gained potential energy of the condensed working medium is used to create and establish a dynamic head.

9- A method according to claim 1, 2, 3, 4, 5, 6, 7 or 8 wherein the working medium condenser is a bank of air cooled exchange pipes.

0- A method according to any of the preceding claims wherein the condenser is cooling tower.

11- A method according to claim 10 wherein the cooling tower is cooled by water.

2- A method according to any preceding claim wherein the working medium condenser includes an auxiliary medium and a closed loop.

3- A method as claimed in claim 1 substantially as herein described, with reference to the drawings.

- An apparatus for generating power in a circulating closed loop system comprising:

14-1 Auxiliary Medium Loop Apparatus An evaporator in a first part of the closed auxiliary loop to evaporate an auxiliary medium,

A compressor in a second part the closed auxiliary loop medium, to compress and increase temperature of the auxiliary medium vapors and control operation of the power system,

A condenser of auxiliary medium (evaporator of the working medium) in a first part of the working medium closed loop, to evaporate the working medium, A collector tank in a third part of the auxiliary loop, to hold the condensed auxiliary medium from the first part of the working medium, A means to returning the condensed auxiliary medium from holding tank back to the first part of the auxiliary loop,

14-2 Working Medium Loop Apparatus

An evaporator in a first part of the closed loop to evaporate a working medium under controlled conditions, A riser in a second part of the closed loop to raise the evaporated working medium to a pre-determined height, A condenser in a third part of the closed loop to condense the evaporated working medium and create a stable dynamic head, A collector which collects the condensed working medium, A down-comer in a forth part of the closed loop to deliver the condensed working medium to the turbine under controlled conditions,

A turbine and generator in the fifth part of the closed loop which are driven by the dynamic head of the collected working medium, and A means for returning the working medium to the first part of the closed loop.

- An apparatus according to claim 14 wherein the energy used to evaporate the auxiliary medium is supplied by water. - An apparatus according to claim 14 wherein the energy used to evaporate the auxiliary medium is direct or indirect solar energy. - An apparatus according to claim 14 wherein the energy used to evaporate the working medium is supplied by an auxiliary medium. - An apparatus according to claim 14, 15, 16 or 17 wherein there is a temperature difference between the evaporator and the condenser of the working medium. - An apparatus according to claim 14, 15, 16, 17 or 18 wherein the working medium boils at a temperature and rises through a riser. - An apparatus according to claim 14, 15, 16, 17, 18 or 19 wherein the working medium condenses at a temperature below the boiling temperature of the working medium, at the top end of the riser. - An apparatus according to claim 14, 15, 16, 17, 18, 19 or 20 wherein the condensed working medium is used to create and establish a dynamic head. - An apparatus according to claim 14, 15, 16, 17, 18, 19, 20 or 21 wherein the condenser is a bank of 'air cooled' heat exchange pipes.

- an apparatus according to claim 14, 15, 16, 17, 18, 19, 20, 21, or 22 wherein the the condenser is a cooling tower.

- An apparatus according to claim 23 wherein the cooling tower is cooled by water.

An apparatus according to claim 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 wherein the condenser includes an auxiliary medium and loop.

- An apparatus according to claim 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 or 25 wherein the evaporator includes an auxiliary medium and a loop.

- An apparatus as claimed in claim 14 substantially as herein described, with reference to all the drawings.