GB2383613A

GB2383613A - Closed cycle power generation

Info

Publication number: GB2383613A
Application number: GB0131101A
Authority: GB
Inventors: Naji Amin Atalla
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-12-31
Filing date: 2001-12-31
Publication date: 2003-07-02
Also published as: WO2003056140A1; GB2400142B; GB0131101D0; GB2400142A; AU2002356342A1; GB0416966D0

Abstract

A working medium is evaporated in vaporiser 1, using a heat source such as sea water or solar energy, and passed via a riser to a condenser 2, where the vapour is condensed and collected to create a head. The condensed vapour is then allowed to pass down a down-comer to drive a turbine 4, which in turn drives a generator, after which the working medium is returned to the vaporiser. Heat may be transferred between a heat exchanger and the vaporizer and between the condenser and a heat exchanger by means of auxiliary heat carrier mediums (figures 6, 7 and 8).

Description

APPARATUS FOR POWER GENERATION

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 rn mal or no emission of Carbon Dioxide (COz) or other pollutants to atmosphere.

As a result of the intensive investigation and research work for a period exceeding 25 years, a novel idea has been discovered, which describes theoretical principles of, and proposes practical schemes (means) for the successful implementation and operation of this new idea and invention in a variety of configurations (operation modes) and numerous geographic locations. The invention also 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 arid repeat the operation and generate electricity, in a manner, which is substantially different Dom the currently employed power cycles.

The fundamental theoretical principles of this idea and 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 (consists of): a- Water vaporization from 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 rair:/snow d- Falling back of rain/sr ow 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. However, numerous rivers have also 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 darns.)

Su ult neously, intensive e lo[ts revere r.her dedicated to [lie c uc,:, , : Hole- to invent and d Sian practical operating svs e[rl7 which would embalm - tin, nodal phenomenon in a scientific replanner, and assist (a!lo,-i) to utili7e such low legal energies. the th2 21 en2rGv stored in the vast Occurs, i h;empera!, es O less than 0.0 C to Generate 212ricirv and realize the Said objec.i ie.

An important ch=act fistic (p =r neter) of the said n.nur21 process (and also the new Invention), is the fact that Ionospheric temperature decreases no ic- b!s;- -i- h increasing vertical height at the same pout, which provides The arriving force for water vapors to condense back to liquid, at the hider a osphenc aI, nudes.

However, water vapors rising and condensation (cloud formation) is also Elected by may other factors, such as the relative h mdi, dew pount (temperate), etc. which are not the conc=m of this work.

For instance, if the atmospheric temperature at the sea level (on the westem costs of Europe - suck as Ireland, Urnted Kingdom Norway, Germany, France, etc.) is -say 15.0 C, then the temperature at the vertical l eio ts of fOO and MOO m on the same point, will most probably be about: 10.0 C and 5.0 OC respectively (or even lower). Temperature difference for both points from the sea level will be about 5.0 and 10.0 C. Such temperature differences could be significantly increased (modified), if a reliable source of energy with relatively stable and higher temperature, such as the Ocean water, would exists near the lower level, with temperature of-say 22.0 to 25.0 C, which is the actual case in those comities.

Sumn ary of the Invention Combination of the higher sea water temperature and lower atmospheric temperature at heights of over 700 m, will provide a temperature difference of about 13.0 to 25.0 C, and hence, a reasonable oppor ty to exploit this phenorrrenon for the economic creation of a feasible operative dynamic head (similar to the hydropower stations)' which could then operate a liquid turbine and generate swable net power. This natural fact played a key role formulating We concept and developmc the operative system for the new idea and the discovered power cycle.

This Invention provides the necessary knowledge, know-how and technological means -for the economic exploitation (utilization) of scientific prunciples O,r the said a;ural phenorr.enon, whic'n would force the never process to prowess ncl t'-e power cycle to operate as follows: a- Ener v (heat) 'osorction from the ocean- x-.-rs bar r leans of cot,-rtio, l tube and shell he-;, e.xch Pricers to vapor,:ze suir 3le nor' mec t -

b- Controlled raising (lifting) of those vapors through a riser pipe to a pre-

deterrnined height by means of the developed positive pressure of medium's vapors (to acquire potential energy), c- (condensation of medium vapors (energy rejection) at the elevated operation platform (will have the acquired potential energy), d- Controlled formation of an operative liquid dynamic head (medium's gravitational flow) in the down-comer pipe.

e- feeding the liquid medium to a turbine system at the lower operation level (sea level) to convert the acquired potential energy to kinetic energy, ---and hence, f- Generation of electrical power.

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 (CO2) emission to atmosphere from the power sector initially and other sectors subsequently.

As mentioned above, the main thrust of the Research Work, was to try to emulate and exhibit some naturally occumog phenomena, which could provide a reasonable opportunity to extract net power output. If such a systems could be identified, then it will be much easier to grasp, comprehend and explain. Emulation of the water power (energy) exploitation as hydropower, was the prune target process for this investigation.

The process starts from the Ocean water vaporization by solar energy, rising of vapors to high altitude, condensation by the effect of very cold atmosphere and cloud formation, falling back to earth as rain and snow and then the creation of the workable liquid dynamic head through damming of rivers. The obvious question was: How to economically create a sizable and workable dynamic head similar to that of the water behind the darns? An important and essential component of this process (as mentioned earlier) is the fact that atmospheric temperature decreases progressively and noticeably, with increasing vertical height at the same point, which provides the natural driving force for vapor condensation to progress.

After extensive research work and efforts, a practical idea was developed and is being proposed, which reasonably reflects and exactly emulates this natural phenomenon and combines all it's stages. This idea involves the creation of a workable and econorruc liquid dynamic head, which could be utilized in the turbine section, to produce Net energy. Then an operative system for the successful implementation of this discovered idea was developed, formulated and described. It comprises several operation steps and a number of processes and units, simulations, specific materials (mediums), etc. which are arranged in a new operative path to form a new power cycle.

To establish the required dynamic heads, a liquid medium will need to be economically lifted to a pre-determined height, which could be achieved by vaporizing the medi am and pushing it upward by the effect of positive pressure.

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. To establish the required dynamic head, a liquid medium will need to be economically lifted to a pre-

determined height, which could be achieved by vaporizing the medium and pushing the vapors upward by the effect of a relatively low positive pressure.

For this purpose, a suitable medium (fluid) with the appropriate thermodynamic, chemical and physical properties will be selected, which could be vaporized by the effect of relatively low Ocean water temperature (18.0 to 25.5 C).

Medinm vapors will then be forced by means of the formed positive pressure, to rise through a large diameter pipe to the desired height (mountain or cliff top), where it will be condensed.

Hence, an essential component for the successful implementation of the new idea is therefore, to select a suitable site with proper topography, features and energy source, which should also provide the required conditions to smoothly operate the 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 650m, vertical height), and sufficient top area to construct the condensation equipment and facilities, + A reasonable access to the top, which will not require excessive capital costs to

build a suitable access road, + Exposed mountain top to the wind flow direction, + Preferably a good source of fresh water near by, (which may be required in some cases), + workable temperature difference (drop), from the sea level to the mountain top level.

+ Etc., There are many suitable mountains, cliffs and slopes near the sea shores in many regions and countries, which would provide the working vertical height, desirably (but not necessarily) over 650 m, to reach a level where the ambient temperature is noticeably lower than temperature at the sea levels. In some cases the site may actually be constructed (built), if economics would be favorable.

. Energy stored in the vast Ocean Waters, is the prime target source for the operation of this cycle. For instance, sea water temperature around the shores of most north European countries, Japan, N. America, etc. is usury more than 21.0 C, (annual average is about 23.0 C), while the temperature at heights of over 650 to 750 m, is mosHy below 15.0 C. It is for more than 70% of the annual time, actually lower than 7.0 C, with very strong and cold winds. In U.K., Ireland, Norway, north Pacific coast of USA and Canada, north of Japan, etc. the temperature at heights of over 750 m, is hardly ever more than 15.0 C, and the average annual temperature could be below 5.0 C. Such prevailing favorable climatic conditions, should provide an excellent opportunity to design the appropriate system for exploitation (utilization) of this vast storage of energy, as is explained in this report.

Working medium will be selected with the boiling point sufficiently lower than the prevalent ocean water temperature, to be able to vaporize it and develop the required pressure to lift the vapors to a pre-selected height. Rising mediums 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. Thennodynamic 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 drab air cooled condensation i contemplated.

Potential energy (Ep) acquired (stored) by liquid at the top platform, will be proportional to the vertical height of the mountain/cliff (potential dynamic head), as follows: Ep= HxQ Where; Ep As 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 downcomer 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 vapor er and repeat the cycle.

Power generated in MW, in the turbine section will be proportional to Me liquid flow rate and dynamic head (vertical height of the mountain), 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 (CO2). 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 medium b- Volume during vaporization and the subsequent adiabatic expansion of the vaporized 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 He 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 predetermined 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 slight change in the system's entropy, 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 medimn(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 Be famous "Vapor Power Rar kine Cycle". The processes include: a- Energy absorption ( vaporization in boilers, vaporizers) b- Energy elevation (pressunzation, dynamic head creation) c- Energy release (expansion in turbine, or trans-conversion) dEnergy rejection (condensation condensers) e- Energy induction ( pumping, compression, gravity pressure, etc) f- Medium preparation, transportations storage, g- Energy source preparation, transportation, storage,

The present invention is defined in its various aspects in the appended claims, to which reference should now be made. A preferred embodiment of the present invention will now 5 be described with reference to the accompanying drawings in which; Figure 1 shows a simple power plant which operates on the Rankine cycle.

Figure 2 shows the Atalla Energy Cycle (AEC) power cycle lo which operates on the dynamic head.

Figure 3 shows a typical flow diagram of the AEC power cycle. Figure 4 shows a temperature-entropy diagram showing the narrow of AEC operation.

15 Figure 5 shows a pressure-volume diagram showing the operation steps of the AEC.

Figure 6 is a diagram representing examples 3 and 3A.

Figure 7 shows condensation with the help of an auxiliary medium. 20 Figure 8 shows the improved vaporization conditions with the use of an auxiliary medium.

Figure 9 shows the water cycle in nature.

Description of the System

Figs. 1 & 2 show the operating steps of Rankine and Me new AEC power cycles, which are Find mentally 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.

q

Comparison of Rankine power cycle with AEC.

I Ranlcine Cycle AEC Step Vaporization, --Energy absorption Vaporization, --Energy absorption 1 --High pressure, --Low pressure, --High temperature, --Low temperature, Step Energy release + Elevation 2 -- Steam turbine -Conversion of thermal energy to potential energy Step + Energy rejection + Energy rejection 3 -- Condensation -Condensation/ stabilization Step + Medium pumping, + Accumulation 4 -High pressure & feeding to boiler Creation of dynamic head in the " Repeat the Cycle" down-comer Step + Energy release 5 -- Liquid turbine Step +Medium feeding by gravity 6 (pressurization), back to vaporizer " Repeat the Cycle" cad 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.

As could be noticed from the earlier descriptions and explanations, 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 9 '-or 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 l.O % 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.

Prospects envisaged for the future implementation (application) of power plants utilizing the new power cycle's principles to generate electricity worldwide, could indeed be very promising (rapid) and the aggregated installed capacity may overtake (exceed) the hydropower's total installed capacity within a short span of time.

The invented novel process includes all the steps of the mentioned natural phenomenon. Resemblance of the individual operative steps of the new system, with the corresponding phases (steps) of this natural phenomenon, are identified and cross referred in the description of each operative step of the new power cycle,

The proposed new idea and invention provide knowledge, know how and means (operative system), to tap into the stored energy (unlisted) 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, conformity and compliance.

The suggested operative system comprises the following main steps (stages) .

Fig. 3, Shows an example of the many possible schemes of AEC. They are: 1 Evaporation / energy absorption in vaporizers 2 Elevation / energy trapsactivation/ 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 Me cycle Fig. 3, shows also the differences between AEC and the Rankine power cycle shown on fig. 1, in terms of modifications, re-arrar gements, steps sequence of processes, etc. which enable the economical exploitation of We much lower levels of the renewable energy with temperatures much lower than 25.0 C, by AEC. These differences are shown below: ( Also figs. 1 and 2 for reference) It

DESCRIPTION OF THE PROCESS STEPS:

Evaporation / Energy Absorption, The selected working medium will be fed (by gravity) to a vapor er (boiler), where the Ocean water (sea water) is used as the source of energy. Hence, the boiling point of the 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 upward though the riser, to the top level (operating platform) of the selected site, but with rn mum temperature drop. However, the boiling point could also be selected close to the sea water temperature and create suction effect (vacuum) at the top level by colder temperature, to pull the vapors upward. Decision to select any method will depend on the prevailing conditions and economic considerations.

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, e- Non corrosive, f- Non toxic, gEnvironmentally friendly as far as possible, etc. One of the most crucial factors the selection of the medium is that, it should cause rr possible temperature drop between the vaporization level and condensation at the top working level. Vapor temperature at the top level should be sufficiently high, as compared with the ambient temperature, to provide suitable conditions for the effective condensation of vapors to take place. (Explained in details in example No 1).

-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 14.0 C. For example a medium with;

Boiling point at 1.0 Bar abs. 14. 5 C Molecular weight 55 Delta' temperature between vaporization temperature at the vaporwer's level (sea level) and the condensation at the top level of 750 m, vertical height, could be as low as only 4.0 to 5.0 C, as follows: Sea water temperature 23.5 to 24.5 C Boiling temperature 21.0 C Corresponding condensation temperature at the top level 16.5 C Then: Delta temp. - 2 1.0 -1 6.5 - 4. 5 C In physical terms, this implies higher specific volume of the vapors: m3 / Kg.

A provision of vapor temperature of 16.5 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.

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

This step of the new power cycle simulates in nature, Ocean water vaporization by the effect of solar energy (heat) received by radiation. However, water vaporization is also affected by the air conditions, which are out of We scope of this work. Elevation of the Vapors: Despite the fact that this step consists of a very simple pipeline (or a tunnel)-

riser, 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). It'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 vaporizers (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 working level. Both pressure and temperature of the vapors decrease along the riser as a result of Me adiabatic expansion (controlled).

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There will also be a Rely 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 (Ep) acquired by rising vapors at the top level of-say: 750 m vertical height will be: Ep= HxQ Where; H; Is verticalheight m Q; Vapor weight reaching the top level Kg For example, potential energy gained by l.O Kg of vapors at the top operative level, will be: Ep = 750 x 1.0 - 750 Kg. M. Riser's 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 m nize 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 hither altitudes.

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

There are many ways and means to provide the required temperature delta, particularly in north western Europe, north western coast of North America, Japan, New Zealand, etc. where the climatic conditions are more favorable. Condensation will take place in the condenser, which could be of many

types and designs, such as: a- Air cooled 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 1;

schemes will require larger cooling surface area of the heat exchan ers.-

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.

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 liking water.

c- Condensation by the use of amiliary medium(s) with ordinary heat exchanger types oftube and shell, fig. 6 (example 3).

This scheme may prove to be of significant importance, as it could eliminate the reliance on ambient conditions for it's operation, (explained in example No 3).

The 2nd medi am will act as a heat carrier from the top level to the bottom level.

This rnedi will require a different set of properties, from those of the working medium It will also be selected to pronde the most economic operating conditions, with ideal environmental considerations.

The 2n medium will be p Limped to the top level of the process and used to condense the working medium which means that this medi em will have (or vaporized at) a lower boiling point than the condensation point of the working medi.m at the top level conditions. This medi.m will also have a much higher latent heat of vaporization than the latent heat of condensation of Me working medium, preferably more than We ratio of 15/ 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 be re-used for vaporization of the working medium, will be performed by a - 3r liquid, as the auxiliary medium, which will

have properties different from both other mediums, (explained in example 3).

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 re-compress vapors of the auxiliary to a pressure, where the outlet temperature will be sufficiently high so as to allow to be re-used for vaporization of the primary 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 30 %, 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 hither altitudes under the effect of very cold ambient temperature, cloud formation (water droplets) and rain (snow) fall.

4 Acc nulation / Creation of Dynamic Head The condensed liquid will be collected in a stabilizing holder tank, to establish a steady but controlled flow, and will be then directed to flow downward by gravity through the down-comer pipe, 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 hither Man the water head created by any of the world dams.

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

Pay = Hxd/10 Where, Pay; Dynamic pressure at the bottom ofthe 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 ofthe down-comer will be; P by = 750 x 1.4/ 10 = 105 Bar.

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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 (Ppr) between the vaporization and power generation points (bottom level) will also be very high, and for this example will be: Rpr = ------= 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 MOO), 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 REV, hom 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 If a working medium is used with the latent heat of vaporization of-say 40 Kcal / Kg, then the equivalent amount of water vaporization by sun will be: 307 x 40 Equiv. Vapor. water = ------- - -------- = 19 000 m3 /s

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

5 À Energy Generation/ Release The accumulated liquid (working medium), at the bottom end of the down-

comer, will be fed to a suitable liquid turbine, which will be connected to an electrical power generator. Turbine will convert the potential energy of the working medium to kinetic energy ( Ek), which will be used to operate the turbine and, hence release a 'NET ENERGY' ( En), 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 bLiquid Dow rate KW = H x Q / ( 3.6 x 105) Where: H; Dynamic head m.

Q; Liquid flow rate Kg / h If H = 750 m. and Q = 10000 torah Then: 750 x 106 KW= - = 20,833 KW

3.6 x 105 The discharged liquid from turbine will be returned back by gravity (with sufficient pressure) to vapor er (sea water operated) 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.

Is

Figure 7 shows how an auxiliary medium is used to condense the working medium. The working medium, in a vaporized state, passes up the riser pipe 10 into the working medium condenser 20. The working medium condenser is cooled by 5 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 into liquid state. The condensed working medium then enters the stabilization tank 30 and is passed down the lo downcomer 40 to drive a 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 vaporise the auxiliary medium. The vaporized auxiliary medium is 15 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.

Figure 8 shows the improved vaporization conditions with zo the use of an auxiliary medium. The auxiliary medium, in a liquid state, is passed into an auxiliary vaporizer 110 at 100. Sea water is passed through the auxiliary vaporizer at 120 to warm the auxiliary vaporizer. The boiling point of the auxiliary is below the temperature of 25 the sea water and therefore the auxiliary medium is vaporized within the auxiliary vaporiser 110. The vaporised auxiliary medium is then compressed at 130 and used to warm the working medium vaporizer 140. The energy from the auxiliary medium is absorbed by the working so medium at 140 and the working medium is vaporized and passed up the riser 150. Since the energy from the auxiliary medium is absorbed by the working medium, the auxiliary medium is cooled and condenses. The condensed auxiliary medium is passed into and collected by the tank

160. The auxiliary medium is then fed back to the auxiliary vaporiser 100.

THEORITICAL BACKGRO D OF THIS IDEA

Energy input (Ein) to the system is in the form of thermal energy, which is introduced mainly through the heat exchanger, and is used to heat (Eh) and vaporize ( Evp) the working medium at a specified temperature and pressure.

E In = E vp + Eh When the vaporized 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 (Egos), which is directly proportional to the vertical height of the riser.

E pot = H (vertical height) 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 Ein, as follows: E pot (TAPEN) R= -- Ein However, the input energy is actually equal to the potential energy plus the latent heat of condensation (he) of the medium, at the top level conditions, namely: Fin = hC + E pot Hence, Evp + Eh = he+ E pot

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 ( T A P E N) R = --

hC This is the theoretical beneficial portion of the induced energy (En), 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 In, then the potential energy it will acquire per Kg, will be: Epot = 20,000 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 = ---a-- = 0.0383 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 11 cycle of the working medium around the system. The main part of that energy will be lost either to the cooling air or other means of cooling. To increase the Ratio -AN, ( e beneficial portion of the absorbed energy) the medium should be selected to have lower latent heat of vaporization (L.H.O.V.). If the L.H.O.V. of the medium in the example above was -

say 80.0 Kcal / Kg, with other parameters stay the same, then AN will be: 25.6

AN = -- = 0.321

" 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 TAPED), 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 approx nate, 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) Fig 4. In the case of superheating, which is more relevant in this analysis, 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 Me 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 (Sf) of the working medium, between the lower and top working levels will indeed be very slight. For instance, for the refrigerant R-

124 (appendix 3), the change ire vapors entropy, between saturation temperatures of 30.0 C to 10.0 C, will be: Delta Sf- 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 Sf and liquid phases sg at the assumed condensation temperature of 10.0 C, will be: Sg-Sf= 0.3765-0.2479= 0. 1286Kcal 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. 4, shows the operation of AEC, on temperature - entropy diagram (Ts), and shows the very narrow range of entropy change during the steady operation of this cycle, which takes place as follows: Point 1 Start ofthe cycle.

- Path 1 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.

** D=ng 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 medimn at the top level. physical status of media changes to liquid. However, the liquid medium will perforce the process of accumulation in the down- comer and then energy release in Me 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 pout to vaponzer, point No 1.

Fig. 5, shows the same steps of the AEC cycle on the Pressure - Volume (PV) diagram, with the following operation paws (corresponding to steps of fig, 4), 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 3'), which is an important feature of this new power cycle.

- Path 3 to 3 ' Pressure rise (accumulation of medium) in the down-comer, - Path 3' 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 He overall performance of the system, and make it totally environmentally friendly.

i AEC OPERATIC 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 Dom the medium (liquid) to the turbine, vapor expansion, Power generation, d- 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 perfonn a specified and defined integrated function (process), then it should be possible to conduct an appropriate techno-economic accounts estimates and calculations. 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 He following processes: + Thermal processes Rankine Cycle (Coal fired, heavy Mel 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 generating 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.

As shown earlier. AEC uses three of the operations which are used by Rankine cycle but in different order, magnitude and for different purpose. They are: 1- Energy absorption, 2- Condensation(energyrejection) 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) Vaporization Riser Condensation energy absorption) (adiabatic expansion) (energy rejection) i Liquid turbine Down-comer < ' r (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 10 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.

MACHENERY AND EQUIPMENT

Machinery, equipment, materials for civil works, etc., required for engineering, construction and erection of AEC complexes, are generally similar to Nose 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, 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 NIW) and hence, the equipment scale is expected to be proportionally large, + Equipment could be obtained from most industrialized counties, Fig. 3, Shows the flow diagram of Me process and the major units.

ENVIRONMENTAL IMPACTS/ ASPECTS OF AEC

As mentioned earlier, AEC relies for it's operation mainly on the solar related renewable energy and could be operated without much requirement for the combustion of fossil Mel. It is no exaggeration to state that, this energy cycle could be operated efficiently and safely with 0.0 kg / hr (non), of coal per NIW power, 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 emissions which could be achieved. For instance, for a power plant of only 600 MW, AEC could reduce emission from over 5 Mil tons per year for Rankine cycle to 0.0 tons per year. There will be no other gases or fames emission to atmosphere as a result of the operating this cycle (only very minor quantities of the working medium(s) during maintenance D1PECT ABSORPTION OF SOLAR ENERGY

Direct absorption of solar energy by an exposed and purposely designed pipe coil to the sun radiation could be considered, particularly 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 Me solar energy is available only dunug day time, 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 Me very hot areas exposed to sun and store energy to be used by the submerge heat exchangers system.

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

CONCLUSIONS

The new proposal 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 (CO2).

As such, this system could prove to be indeed, a very clean and envirorunentally friendly process (energy cycle).

The dea 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 tenn supplies of energy Mom 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 (CO2) 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 energr, 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 Cycled 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 Rankle 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- Seawaters: a- Depth, Suitable with good tidal water exchange b- Maxanum water temperature, which lasts25.0 C for about 3 months, c- Minimum water temperature, which lasts19.3 C for about 3.8 months, d- Average annual temperature22.6 C ii- A mountain cliff is available nearby with: a- Maximum vertical height (peak) from sea level879 m b- Suitable (exploitable) height765 m cMaximumtemperature(air)at atleVeL17.5 C which lasts only for short periods, - with Wet Bulb temperature of:12.6 C d-Mirurn 'mwintertemperature-15.8 C at the top working level, e- Average winter temperature at the top level2.5 C f- Average annual temperature at the top level 6.8 C Solution: It is intended that the system will be relying totally on 1 he ambient conditions for it's operation, e Power input to the system will be avoided as far as possible, Steps: 1- Required liquid flow rate to Turbine to generate 20.0 SAW power: 1-1 Assume the Turbine/ Generator's efficiency at 88.5 %, which is achievable in the existing liquid turbines, offered by several manufactures,

1-2 Liquid flow rate will be found as follows, hom the equation: H x Q KW = --------------- x r ( efficiency) 3.6 x 105 Where: H- Is the vertical height m, Q- Is the flow rate Kg / h KW x 3.6 x 10520 000 x 360 000 Q H x 750 x 0.885 Q = 10850 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 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 the working Medimn and it's properties are as follows: Material; A mixture of n-Pentane end NeoPentane n-Pentatle CH3-CH2-CW-Ch2-CH3 Neo-Pentane CH3-C- (CH3)3 *Boiling point ( B.P.) at 1.013ar Pressure 14.5 C ÀMolecular Weight 72 ÀLatent treat of vaporization atB.P. 76 Kcal/Kg Specific heat 0.538 Kcal / Kg. C 3- Vaponzation Process - Submerged Sea water vaporizers will be used Vaporization Pressure at the magnum and minis temperature:

vaporization temperature, assuming the Delta between the Sea water and vaporization temperatures at 2.5 C: Max. Vapor. Temp. 22. S C Min. Vapor. Temp. 17. 8 C For the selected medium the vaporization pressure will be: Vaporization Pressure at 22.5 C 1.395 Bar.

Vaporization Pressure at 17.8 C 1.185 Bar.

The developed pressure at max temperature, (Summer Time) is sufficient to push the vapors to the vertical height of 750 m, and provide a condensation temperature above the B.P. - at about 14.0 to 15.0 C.

The developed pressure at madmen vaporization temperature, (bottom Level) will not be sufficient to push the vapors and maintain the pressure at the top level above the atmospheric. It will actually be slightly less than atmospheric, at about 0.850 Bar. (slight vacuum), which will be created by the much lower outside temperature. Corresponding condensation temperature (at the top level), will be about 9.5 C.

3-1 Vaporizer Heat Load Required heat load of the vaporizer to vaporize 10 850 t / h of the selected medium at 22.5 C will consist of; a- Heating the medium from inlet temperature To, to the Vapor ationtemperatUre Top bLatent heat of vaporization of the medium hV Qab = Qh hv Where: Q ab Total heat absorbed by the medium, Q h Heat required to raise temperature of the medium Dom condensation (T. on) to vaporization temperature (Tvap).

h v - Latent heat of vaporization, Qab = { 0.538 ( 22.5 - 14.5) 76}x 1O, 850,000 Qab = 871,298,000 Kcal / h IS

Elevation / Conder sation The vapor ed medium will rise through the riser pipe to the top level (end), and vaporization pressure is sufficient to force vapors to reach the top level. To ensure the mint pressure loss (drop) through the riser, the total length of the riser should be kept to mining also. The practical length for a vertical height of 750 in, 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 medium through the riser, + Molecular weight of the medium, + Physical length of the riser and surface roughness, + Condensation of the medium in the riser, etc. In this case (example) the pressure drop (AP) will be the difference between the vaporization pressure (Pv), and condensation pressure (Pc), AP = Pv - Pc AP = 1.395 - 1.055 = 0.340 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 0.270 Bar. The actual pressure drop is about 0.070 Bar (70 m Bar), and is sufficient to overcome the losses in the riser and deliver vapors at the top level at linear speed of 20 to 35 m / see, 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 or cooling tower. Condensation temperature (to), will always be lower than the vaporization temperature (tv), if the vapors are not recompressed. The acquired Potential energy by the rising vapors (per unit weight, Kg), will be: Ep = H x Q E p = 750 x 1.0 (Kg) = 750 Kg. M. In terms of energy, expressed as heat: Ep - 750x u Kcal Where: 3G

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

Ep = 750 x --------- = 1. 712 Kcal /Kg 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: There are two scenarios of condensation, they are: aCondensation during periods of ' Maximum Sea Water Temperature', with temperature difference between the sea water and vaporization temperatures at 2.5 to 3.0 C, the temperature and pressure of the rising vapor, at the top end (level),are expected to be: Pressure 1.035 to 1.080 Bar.

Temperature 14.0 to 15.0 C In actual practice, these parameters will also depend on the physical length of the riser, which should be made as short as practically possible.

Expected temperature of the medium vapor at these conditions, would be about: 14.5 C.

Hence, the actual ambient temperature, during some short periods of time, will (could) be higher than the temperature of those vapors at the top end (level), particularly hotter mid-day summer periods, which are not expected to occur either frequently or to last for longer durations.

To Braze the effect of such cases, the site selection is very crucial. The situation could also be remedied (helped) win the addition of water sprinklers to the site, as the wet bulb temperature during such wormer periods, will most probably be sufficiently lower than the ambient temperature. By spraying some water directly on condensers, the condensation temperature will sufficiently drop to effect the required condensation of vapors to proceed.

3?

b- Condensation process during periods of minimum sea water temperature at 19.3 C, Condensation pressure and temperature at the top level will be: Pressure 0.900 Barabs.

Temperature 9.5 C During the winter months of the northern hemisphere, the ambient temperature at the condenser's level of 750 m height, is expected to average about 2.5 C, which could last also for periods of up to 7 months. This is a much lower than the condensation temperature, and shows that despite the lower sea water temperature, the energy cycle (AEC) will operate under more favorable operative conditions, with the actual temperature difference of more than 7.0 C, and could be as wide as 20 C. As such it will allow the system to generate power at All capacity, or even exceed, when it is needed most, during the colder spells.

Condenser's heat load will be similar to the heat load of 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: Qc = 871,298,000 Kcal / h This will also give a safety margin for better operation of the system. The difference between the heat load of the two processes, will be approximately equal to the potential energy gained by the media at the top level (platform). As defined earlier the potential energy gain of the mat weight at the vertical height of 750 m, is 1.712 Kcal / Kg, then the heat load difference will be: Qab - Qc = 1. 712 x 10 850 000 - 18 575 200 Kcal / h This is only 2.13 % of the total condenser's load and is indeed very minor amount (within the margin of error) arid 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 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).

Accumulation/Energy Generation The condensed liquid will be collected in a stabilizing tank of appropriate size.

The liquid is then allowed to flow by gravity to the down-comer, 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. Pressure at the bottom end of the down-comer (prior to entering the turbine), will then be proportional to the liquid density.

P ail = (Hx d)/ 10 Bar.

Where: PA 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 liquid Pentane is 0.626 g/Cm3, or 0.626 ton /m3.

Hence, pressure at the entrance to turbine system will be: PA = 750 x 0. 626/10 = 47 Bar.

Ibis pressure is very high as compared win the vaporization pressure of only 0.

395 Bar gauge, which means pressure magnification (ratio) of: PA _ = 34

1.395 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 105 3.6 x 105 -Q = ----x 20 10S= 9600 ton/in 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 - 9 600 / 0.885 = 10 850 ton / h or 3.010 ton / s As indicated earlier, this is the main dawn for the design and construction purposes of the unit.

EXAMPLE No 2:

- -Assume all the conditions ofthe example No 1, but: a- Latent heat of vaporization of the medium is 36.0 Kcal / Kg, b- Density of the medium is: 1.35 g /Cm3 c- Specific heat of liquid medium is: 0.323 Kcal / Kg. C.

Solution: 1- Heat load of the vaporizer will be: Qab = { 36 0 + 0.32 ( 22. 5 - 14.5)} x3010 = { 36.0 2.56} x3010 = 116065.6 Kcal/s = 417,836, 000 Kcal/h This shows significant reduction in the heat load of the vapor er 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 Dom 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- Working medium is the Refrigerant R-3 18 (Octafluorocyclobutane) with thermodynamic properties shownin appendix 1, - Molecular weight 200 Density (liquid) - 1.612 g / cm3 c-Assume a medium No 2, is used as the heat carrier, which is a mixture of ammonia and water with the boiling point of - 4.0 to - 3.0 C - Molecular weight of such mixable is about 17. 2 - Density (liquid) 1.0 g / cm3 d-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.

Ibis will be accomplished through the vaporization (preferably under vacuum), and re-compression of the auxiliary medium No 3, which will allow to raise the temperature (energy level) of medium No 3, sufficiently to be reused for the vaporization of the working medium No 1. There are many materials which could be used for this purpose such as: n- Pentane, Diethyl ether, Methyl ethyl ether, Methyl ethyl amine, Iso- Hexane, etc. Their mixtures could also be used to obtain Me suitable boiling conditions.

e- 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 (0. 885 efficiency) = 26.64 MW

Solution: From appendix 1, 3-1 vaporization willbe effected et: 31. 85 C(305 K), - Corresponding vaporization Pressure will be 3.900 Bar. abs.

- Corresponding condensation pressure at the top level (height of 1000 m) 1.672 Bar. abs.

- Corresponding condensation temperature 6.85 C (280 K) -Vaporizer's heat load to vaporize 10 850 t/h of R- 318, at 31.85 C (305 K),will be: Qv = Enthalpy of the vapor at 305K - Enthalpy of the liquid at 280 K Qv = (132.26 -101.74) x 10850 x 1000 = 331 142 000 Kcal / h The rest ofthe process of power generation estimates will be similar to Mat conducted for example No 1.

The role and effect of the heat carrier and auxiliary mediums are described as follows: 3-2 The heat carrier's role is to carry the heat of condensation from the top level, down to the vaporization level. Ibis will be achieved by pumping the heat carrier ( water arntr onia 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 ( Gw), required to remove the heat of condensation of the working medium will be estimated from the heat of condensation, which is lower (in this case) than the heat of vaporization as follows: (hv - he) x 1 Kg = 128.36 - 101.72 = 26.64 Kcal / Kg where, hi, hq, are the enthalpies of the vapor and the liquid of the it2-

working medium at 280 K (6.85 C) Gw 26.64 x 10 850 000 /455 - 635 260 Kg / h This is a relatively small amount as compared with l 0 850 000 Kg Ih, 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 17.08 Kg, of the working medium Hence, energy required to liD the heat carrier ( car) to the top level will be: 635 260 x l 000 E Or = -- = 2 075 KW 360 000 x 0.85 Or 2.075 IvI Where, 0.85 is the pumping efficiency The heat carrier will be fed to the working, medians condenser at the top level and allowed to vaporize, to remove the heat of cor densation of tl e working medium, and then will be allowed to flow down to the bottom level in 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 0.1 10 Bar. and hence, the temperature by about 1.8 to 2.0 C. Temperature of canter medium vapors at the inlet to the auxiliary heat exchang,cr, is expected to be about 6.2 to 6.4 C. It is required to raise this temperature to above 31.85 C, to be suitable for use again in the vaporizer. 'loo achieve this aim, an auxiliary medium will be used, comprising a mixture of e-Butane and lso-butanc with the boiling point of about 34.5 C. To condense the heat cakier at 6.3 C, the auxiliary medium will need to be boiled at 3.75 C, which means, boiling wider vaccine of 0325 to 0.345 Bar absolute pressure.

3 3 Auxiliary Medium - Material n- Pentane & Iso-Pentane(mixture], Boiling point 34.5 (: - Patent heat of vaporization at the B.P. 86 Kcal / Kg, At; 3.85 C: 92 Kcal / Kg,

- Molecular weight 72 - Cp / Cv (k) Ratio of specific heats at 86 C 1. 086 This is a very unportant property for the auxiliary medium to erasure my power consumption for re-compression. The ratio will have a much lower value at operating temperature range of 5.5 to 30.0 C (close to 1.0), which means: PI x Vat - P2 x V2 = Const PI x Vat To And: -----a ---= ------- = Const P2 x V2 T2 - Assume over physical and thermodynamic properties to be similar to those of the n-Pentane, a- Circulation rate of the auxiliary medimn ( G a,) will be: G a' = 289 044 000 / 92 = 3 141 780 Kg /h b- The auxiliary medium will be fed to the heat carrier's condenser to condense it at 6.4 C, ( at the same vertical level as the working medium vaporizer - just above the sea level), which means creating a vacuum of about 0.320 Bar abs, to vaporize Me auxiliary medium (to boil) at 3.85 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 34.5 C, so Mat it could be re-used to vaporize the worldling medium. The heat carrier will be condensed in this auxiliary condenser, and Men pumped back to the top level to be used again.

Power (EaX) required to operate the compressor at an efficiency of 90 %, which is possible with the modern and large units, will be: Ear= 5.8 to 6. 2 MW 3 A similar loop will also be included to use the same principle of the Auxiliary system' s scheme of vaporizer/condenser to extract heat Tom the sea water at -say 22 C, and increase it to 34.5 C, as the make up heat to maintain

the heat balance of the system, fig. 6, It would be advantageous to use the same auxiliary liquid (rnixb e of Pentanes), as it will suit also this application also. The amount of make up heat' (Emu) to be supplied to the working medium, will be equal to that produced by the turbine (as output), namely: EmU = 26.64 x 820x 1000/0.885 = 24 683 400 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 ofthis portion of the medium (Gmu),required will be: GmU = 24 683 400 /88 = 280 500 Kg/h Power (Emu)' required to operate the compressor will be about: EmU = 0. 350 to 0.400 MW 3-5 Total input power ( Ein), required to operate all the internal systems will be: Ein = E = + Eax + EmU Ein = 2.075 + 6.350 + 0. 375 = 8.800 MW 3-6 Ratio ( R), of the output power (Eout) to the input power (Bin), then will be: Fin 26.64 R= ------- - - --------- = 3.03

Eout 8.800 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 Me use of higher vertical heights, as Me 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: 3.25 to 3.45 or even hither.

4(

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, + Operation of working medium at critical pressure and temperature of some materials which could provide suitable conditions, 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.

Example 3- A

If a different medium with more suitable properties was used as the working medium instead of R- 318, such as a pre-determ ned mixbure of aDibromodiflouromethane, C Br2 F2 + Boiling point at atmospheric pressure 24.0 C Latent heat of vaporization at 7.0 C 27.8 Kcal /Kg Or DibromotetraDouroeth.ane C2 Br2 F4 + Boiling point at atmospheric pressure 47.3 C Latent heat of vaporization at 7.0 C 28.5 Kcal /Kg And: bTrifluoromethane ( R- 23), C H F3 + Boiling point at atmospheric pressure - 82.0 C Latent heat of vaporization at 7.0 C 23.0 Kcal /Kg Mixture' s composition will be formulated and made to give the following 4;

(approx nate) properties: A- 1 Boiling point-25.0 to -20.0 C A-2 Densityabout2.0 g/cm3 A-3 Latent heat of vaporization at saturation26 to 28 Kcal /Kg Pressure and temperature of 7.0 C A-4 Vapor volume at conditions of A-30.070 to 0.085 m3/ Kg It is expected that such a medium when boiled at 27.0 C, will reach the height of over 1200 m, with a saturation temperature (condensation) of about 7.0 to 10.0 C, at that height.

* If all other operating conditions are assumed as those of Example No 3, then the power requirement for re-compression of the auxiliary medium (En, ,,) will be about 4.8 to 5.30 KWh, instead of 6.350 KWh, and the recompression power required for the loop to bring energy into the system (increase the temperature from 22.0 C to 30.0 C), will be about 0.225 KWh, instead of 0.375 KWh. As such, the ratio of the E Offs to E in will then be: 26.64 26.64

A=-------- a----------- = ---- ------ = 3.50 2.075+ 5.30+ 0.325 7.60

This clearly shows that the Ratio could further be improved arid increased in practice, if better and more suitable materials are found.

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

Appendix 1 Therrnodynam c properties of Refrigerant C 318 (Octaflourocyclobutane C4F8) T. K | P. teal I Vf Vg | hf hv sg Cal m3 <g m3dKh KJ KJ {(g K] / Kg,K KJ / Kg,K K]/ Kg, K I/Kg 200 0.0216 5.507.4 3. 810 353.5 498.0 3.909 4.560

210 0.0449 5.593.-4 1.931 361.0 500.1 3.947 4.564

220 0.0875 5.683.-4 1.038 369.2 502.2 3.984 4.569

230 0.1608 5.778.-4 0.588 377.6 504.4 4.022 4.574 0.98

240 0.2810 5.879.-4 0.349 386.4 510.9 4.060 4.578 1.00

250 0.466 5.988.-4 0.2166 395.6 517.4 4.097 4.583 1.02

260 0.741 6.103.-4 0.1401 405.6 524.0 4.133 4.592 1.03

270 1.133 6.234.-4 0.0938 415.1 530.7 4.172 4.599 1.05

280 1.672 6.375.-4 0.0647 425.8 537.7 4.210 4.609 1.07

290 2.392 6.529.-4 0.0458 436.2 543.9 4.247 4.618 1.09

300 3.325 6.694.-4 0.0332 447.3 550.4 4.284 4.626 1.12

310 4.522 6.893.-4 0.0245 458.7 556.9 4.322 4.636 1.15

320 6.007 7.115.-4 0.0184 470.5 563.3 4.359 4.648 1.18

330 7.826 7.365.-4 0.0139 482.7 569.4 4.369 4.59 1.23

340 10.018 7.666.-4 0.0106 495.2 575.4 4.433 4.669 1.27

350 12.632 8.034.-4 0.0082 508.1 581.0 4.469 4.678 1.32

360 15.71 8.508.-4 0.0062 521.5 585.8 4.507 4.658 1.39

370 19.33 9.172.-4 0.0047 535.6 589.9 4.544 4.691

380 23.59 1.031.-3 0.0033 551.4 591.5 4.585 4.691

388.5C 27.83 1.613.-3 0.0016 577.2 577.2 4.651 4.651

1 i. Reference: Perry's Chemical Engineer's Handbook Seventh Edition

Appendix 2 TherrnodynaIruc properties of ReEigerant R 23 (Triflouromethar e C H Fib) T. K I P. Bar Vf Vg he hi Sf sg Cvf m3/Kg m3/ Kg KT/Kg KJ/Kg KJ/Kg.K KJ/Kg.K KJ/Kg.K 180 0.510 6.78.-4 0.4088 -66.0 181.1 -0.3179 1. 0549

190 0.950 6.93.-4 0.2279 -54.4 185.3 -0.2554 1.0062

191. lb 1.013 6.95.-4 0.2139 -53.1 185.7 -0.2485 1.0011 200 1.652 7.10.-4 0.1353 -42.6 189.1 -0.1948 0.9635

210 2.709 7.29.-4 0.0845 -30.3 192.4 -0.1353 0.9254

220 4.298 7.51.-4 0.0551 -17.5 195.4 -0.0764 0.8913

230 6.312 7.77.-4 0.0372 -4.3 197.8 -0.0182 0.8602 0.710

230 9,091 8.o7.-4 0.0259 9.4 199.6 0.0392 0.8314 1.043 250 12.69 8.44.-4 0.0183 23.6 200.7 0.0957 0.8042 1.289

260 17.25 8.89.-4 0.0132 38.1 200.9 0.1512 0.7773 1.497

270 22.94 9.49.-4 0.0095 53.5 199.8 0.2071 0.7493

280 29.98 1.031.-3 0.0068 70.5 196.4 0.2665 0.7162

290 38.68 1.169.-3 0.0048 92.0 188.1 0.3387 0.6605

299.1c 48.36 1.gO5.-3 0.0019 143.0 143.0 0.5062 0.5062 Reference: Perry' s Chemical Engineer's Handbook Seventh Edition

Appendix 3 Thermodynamic properties of ReEigerant R 124 T. K P. bar Vf Vg _ M3/ Kit M3/ Kg -40 0.2680 6.44.-4- - 0.5173

-30 0.4499 6.55.4 0.3185

-20,, 0.7197 6.68.-4 0.2049

-10 1.1044 6.81.-4 0.1369

0 1.6348 6.96.-4 0.0945 l 10 2.3447 7.11.-4 0.06703

20 3.2710 7.28.-2 0.04867

30 4.4529 7,47.-4 0.03604

40 5.9320 7.68.-4 0.02713

50 7.7521 7.91.-4 0.02069

60 9.9599 8.18.-4 0.01594

70 12.605 8.49.-4 0.01236

80 15.742 8.87.-4 0.00961

90 19.432 9.35.-4 0.00744

100 23.749 9.99.-4 0.00569

110 28.787 1.098.-3 0.00420

120 34.702 1.338.-3 0.00269

122.5 36.340 1.810.-3 0.00181

1 1 1 Reference: Persons Chemical Engineer's Handbook Seventh Edition

Claims

Claims

1. A method for generating power in a circulating closed loop system comprising the steps of: evaporating a working medium in a first part of the closed 5 loop, passing the evaporated working medium through a riser which represents a second part of the closed loop, condensing the working medium in a third part of the closed loop, lo collecting the condensed working medium and creating a dynamic head in a forth part of the closed loop, releasing the collected working medium, driving a turbine and generator with the released working medium using the dynamic head of the condensed medium in a Is fifth part of the closed loop, and subsequently directing the condensed working medium back to the first part of the closed loop.

2. A method according to claim 1 wherein the energy used to evaporate the working medium is supplied by water.

20 3. A method according to claim 1 wherein the energy used to evaporate the working medium is direct or indirect solar energy.

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

5. A method according to claim 1, 2, 3 or 4 wherein there is a temperature difference between the evaporator and the condenser. 6. A method according to claim 1, 2, 3, 4 or 5 wherein So the working medium boils at a temperature, rises through a SO

riser to a pre-determined height and gains potential energy. 7. A method according to claim 1, 2, 3, 4, 5, 6 or 7 wherein the working medium condenses at a temperature 5 below the boiling temperature of the working medium, at the top end of the riser.

8. 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 lo head.

9. A method according to claim 1, 2, 3, 4, 5, 6, 7 or 8 wherein the condenser is a bank of air cooled exchange pipes. 15 10. A method according to any of the preceding claims wherein the condenser is a cooling tower.

11. A method according to claim 8 wherein the cooling tower is cooled by water.

12. A method according to any preceding claim wherein the so condenser includes an auxiliary medium.

13. A method according to any preceding claim wherein the evaporator includes an auxiliary medium.

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

25 15. 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 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, 5 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, a turbine and generator which are driven by the dynamic head of the collected working medium in a fifth part of lo the closed loop, and a means for returning the working medium to the first part of the closed loop.

16. An apparatus according to claim 15 wherein the energy used to evaporate the working medium is supplied by water.

IS 17. An apparatus according to claim 15 wherein the energy used to evaporate the working medium is direct or indirect solar energy.

18. An apparatus according to claim 15 wherein the energy used to evaporate the working medium is supplied by an 20 auxiliary medium.

19. An apparatus according to claim 15, 16, 17 and 18 wherein there is a temperature difference between the evaporator and the condenser.

20. An apparatus according to claim 15, 16, 17, 18 or 18 25 wherein the working medium boils at a temperature and rises through a riser.

21. An apparatus according to claims 15, 16, 17, 18, 19 or 20 wherein the working medium condenses at a temperature below the boiling temperature of the working 30 medium at the top end of the riser.

22. An apparatus according to claim 15, 16, 17, 18, 19, 20 or 21 wherein the condensed working medium is used to create and establish a dynamic head.

23. An apparatus according to claim 15, 16, 17, 18, 19, 5 20, 21 or 22 wherein the condenser is a bank of air cooled exchange pipes.

24. An apparatus according to claim 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 wherein the condenser is a cooling tower. o 25. An apparatus according to claim 24 wherein the cooling tower is cooled by water.

26. An apparatus according to claim 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 or 25 wherein the condenser includes an auxiliary medium.

15 27. An apparatus according to claim 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 or 26 wherein the evaporator includes an auxiliary medium.

28. An apparatus as claimed in claim 15 substantially as herein described, with reference to the drawings.

S: