GB2597236A - A solar assisted microturbine utilizing a photothermal mechanism for reducing clean energy generation costs and impacting climate change - Google Patents

Abstract

A solar energy concentrator uses microwaves to heat concentric cones of air within the atmosphere. The cones are directed to the sun and internally receive the incoming solar radiation 21. This causes the incoming solar rays 21 to undergo total internal reflection within the cones which act as waveguides, and focus the radiation at receiver 1 which is located at the apex of the cones. The conical shape is achieved by directing a microwave beam through an axicon 17, to produce a non- diffracting Bessel beam to heat up the air layers in the atmosphere to generate a temperature and hence a refractive index gradient therein. The energy from the receiver is utilized to heat air in a microturbine 3, 5. As the concentric cones are nonsolid, equipment costs and total generation costs are reduced. The system may also be used to capture infrared radiation from the earth surface at night.

Description

3 A SOLAR ASSISTED MICROTURBINE UTILIZING A 4 PHOTOTHERMAL MECHANISM FOR REDUCING CLEAN ENERGY GENERATION COSTS AND IMPACTING CLIMATE.

6 CHANGE.

7 This invention relates to a solar assisted microturbine utilizing a 8 photothermal mechanism for clean energy cost reduction and 9 impacting climate change...

io BACKGROUND OF THE INVENTION

ii Major international efforts are currently underway to reduce carbon 12 emissions. Developing countries are facing major energy access 13 problems. They must also base their sustainable development 14 using more clean energy resources to keep emissions within safe is levels. The sun is our major clean energy source and delivers 16 2000 Watts/ sq. m to earth and has the potential to meet these 17 clean energy generation targets. Diesel power generators offer a 18 method of energy generation but they burn fossil fuels which 19 increases carbon emissions. Existing parabolic mirrors, solar cells and wind turbines are useful for clean energy generation but have 21 a low efficiency of around 10 -20%. Solar energy therefore 22 contributes only around 0.2 % of the global energy mix. It is 23 hence important to design an alternative method of increase solar 24 radiation conversions to lower clean energy costs and impact climate change.

3 Microturbines are useful means cleaner power generation and 4 offer number advantages over diesel power generators. They essentially consist of receiver, air tanks, compressor, combustor, 6 recuperator, turbine and a generator.

7 Their main advantage is on-site power generation which saves in 8 power losses resulting from long distance power transmission 9 loses from solar farms and wind energy installations. They burn natural gas and have lower emission than diesel generators. They 11 also have a higher efficiency and lower electric generation costs.

12 They are compact in size, have lower manufacturing cost, higher 13 efficiencies, fewer components, and quieter operation than diesel 14 generators. They can also be installed inside building which is a major advantage over wind turbines and solar cells for potentially 16 impacting climate change.

17 Another major advantage of microturbine is that they generate AC 18 power and do not require any invertor like solar panels which 19 generate DC power.

Solar hybrid microturbines utilize a concentrated solar power 21 using parabolic mirrors together with and natural gas and reduce 22 carbon emissions to a certain degree.

2 However, existing solar hybrid microturbines have a number of 3 disadvantages preventing their wide-spread use. They are not 4 compatible with the existing parabolic mirrors because of size difference. Urban areas are responsible for 40 % of the global 6 carbon emissions. Existing solar thermal equipment consist of 7 reflectors, lenses and mirrors which are too large to be installed 8 near homes and super markets because of confined spaces in 9 urban areas. An average parabolic mirror has ten times the size of to the common satellite dish and therefore they cannot be used for 11 individual homes in urban areas where energy is required most.

12 It is also difficult to get planning permission for installations of solar 13 thermal in urban areas.

14 The other problem is that e existing parabolic mirrors have a low is efficiency of 16 %. Solar thermal is already operating in many 16 countries and costs $0.12-.20/kWh which is competitive with fossil 17 fuels. Also they consist of large mirrors and solar towers which are is too large to fit on microturbines. Moreover they the equipment 19 designs rely on increasing the size of the mirrors for more output which hampers advanced product development.

21 Parabolic mirrors are utilized for converting microturbines to solar 22 hybrid microturbines so that the microturbine can operate from 23 solar energy instead of natural gas thus help reduce emissions.

24 Parabolic mirrors basically consist of mirrors, solar tacking mechanism, receiver, working fluid, and boiler. Power is generated 26 directly through Brayton engine.

2 The parabolic mirrors are mounted onto solar tracking steel 3 frames for the purpose of receiving solar radiation for clean energy 4 generation as follows. The tracking mechanism has a slow motorized motion and point 6 Towards the sun and follow it during day to collect the maximum 7 amount of solar radiation.

8 The working fluid is contained inside the receiver and located at 9 the focal point of the parabolic troughs. These are reflected the io parabolic mirrors receive the on-coming solar radiation to focus ii them on the receiver and working fluid. The heat is then 12 transferred to the water inside the boiler for steam and power 13 generation. The air is utilized for energy storage during the night 14 when solar radiation is not available. However, parabolic mirrors also have a number of problems affecting their wide spread use, 16 First, they are mainly manufactured of solid glass which is both an 17 energy and material intensive process. They also rely on reflection is for focusing solar radiation in which the reflecting surface absorbs 19 some of the energy causing energy losses.

They must also be installed in remote desert locations with 21 suitable solar intensities and require large areas of land.

22 Another major problem facing solar energy is reliability of clean 23 energy generation. This is because the sun is only available during 24 the day and batteries are needed to store energy to insure reliability which increases costs further. Another problem is that 26 solar farms are located in remote areas.

2 The number of megacities is increasing around the world 3 particularly in developing countries. It is therefore important to 4 reduce their carbon emissions even further. The other problem is that require high upfront costs from both domestic installation and 6 solar farms. This is because clean energy is high risk area for most 7 investors.

8 The smart grid requires external energy sources which can be 9 switched on and off for grid integration. This is not possible with io existing solar equipment 11 Yet another problem is that existing solar equipment are not 12 designed to harvest infrared. Silicon is a major component of solar 13 cells and the capacity for clean energy conversion is fixed by the 14 chemical properties which cannot be changed. The design of wind turbines has not changed for decades and is still based on that of 16 ancient wind mills. These constraints limit the clean energy 17 generation capacity. Wind turbines rely on increasing the size of 18 the blades for more energy generation due to this old design. This 19 contributes to high component costs.

Existing solar thermal equipment therefore fall short of meeting 21 the increasing demand for clean energy particularly in developing 22 countries with limited income.

23 OBJECT OF THE INVENTION 24 The object of the invention is to provide an optical and hence non- solid method of concentrating solar radiation which is more scale- 26 able, reliable and affordable than existing equipment to increase 1 global clean energy access and help reduce carbon emissions 2 causing global warming. Lasers and optics have played a major 3 role in product development in transportation, telecommunication, 4 medicine, information technology etc. These are economically vital fields and lasers have been a major enabling factor for 6 advanced product development. Clean energy generation must 7 therefore follow steps of these industries. The major object of the 8 invention is to utilize laser or optics for advanced product 9 development in solar energy to reduce equipment costs for more affordable clean energy.

11 Another object of the invention is to provide an airborne 12 photothernnal non-solid and scale-able reflecting surface to replace 13 parabolic mirrors in concentrate solar power ( CSP) generation 14 methods to reduce equipment size to provide low profile solar IS equipment for installation n urban and confines areas. Another 16 objective of the invention is to provide a mechanism which 17 increases the operational energy density inside the solar-hybrid 18 microturbine to accelerate incoming air velocity thus enhancing 19 solar radiation conversion efficiency for more advanced product development.

21 Another objective is to provide for temperate regions with low solar 22 radiation intensities in industrialized countries a photothernnal 23 method for concentrating solar radiation which is optical and hence 24 more easily scale-able than existing solids-based parabolic mirrors to increase the use of solar energy utilization and reduce their 26 emissions.

1 Another object of the invention is to provide an optical method of 2 clean energy generation which utilizes the safe and 3 environmentally friendly atmospheric components and its optical 4 properties for advanced product development without introducing optical component which are harmful to humans, animals and 6 birds. This will result into new products which can be safely 7 installed near homes and offices.

8 Gaussian beams tend to lose intensity during their propagation in 9 the atmosphere. Another object of the invention is to provide photothernnal beams which do not attenuate during their 11 propagation in the atmosphere to insure performance and utility of 12 the invention.

13 Another object of the invention is provide a new product with a 14 lower profile than the large parabolic mirrors which can then be installed in urban areas near offices and homes for a more wide 16 spread use.

17 Water shortages are affecting many regions around the world. An is object of the invention is to provide a method of reducing the cost 19 of desalination by lowering the cost of solar energy generation as outlined above.

21 Another object of the invention is to provide an external clean 22 source which can be controlled and switched on and off at a 23 moment's notice to facilitate smart grid integration

1 SUMMARY OF THE INVENTION

2 In this invention there is provided a solar assisted microturbine 3 utilizing a photothermal mechanism for clean energy cost reduction 4 and impacting climate change comprising receiver, air tank, compressor, recuperator, turbine, generator, solar panels, 6 battery microwave transformer, magnetron, prism, an axicon 7 and solar tracking mechanism in which the battery is connected 8 to the solar panel generates a small voltage which the microwave 9 transformer changes into a high voltage to generate microwave radiation from the magnetron which then impinges on the axicon 11 to convert the microwave beam into a microwave Bessel beam to 12 further generate a number concentric microwave Besse! beam 13 cones and in which further the tracking mechanism directs the 14 concentric microwave Bessel beam cones towards the incoming is solar radiation and in which further microwave Besse! beam 16 have a suitable wavelength for atmospheric water molecule 17 absorption, vibration and heat generation herein 18 so that the air layer in the atmosphere around the beams 19 making up the hollow cone walls are heated to a higher temperature than the surrounding air thus changing the refractive 21 index of the air and in which further the incoming solar radiation 22 impinges on the photothermal interface separating the 23 microwave Bessel beam cones at a suitable angle of incidence for 24 total internal reflection so that this interface acts as a waveguide 1 for the incoming solar radiation to direct the solar rays towards 2 the narrow apex of the concentric hollow cone to focus the 3 incoming solar radiation onto the receiver to heat the salt in the 4 salt tanks and in which further prevailing air is taken into the microturbine via the air inlet to accelerate it to a high velocity to 6 operate the microturbine for more reliable power generation.

9 Parabolic mirrors are a major capital cost in concentrated solar power generation. The major advantage of the present invention 11 is that the photothermal effect in this invention can be used to 12 replace existing parabolic mirrors for cost saving for clean energy 13 generation and impacting climat change. The photothermal 14 mechanism can also be scale up more easily than existing solar equipment at very little extra cost increase output and meets the 16 increasing customer needs for clean energy.

17 The present invention relies on total internal reflection of solar 18 radiation which has 100% efficiency rather than normal reflection 19 in solid mirrors which has a lower efficiency thus increasing the utility of the invention.

21 Existing solar thermal farms occupy much land surface due to their 22 horizontal orientation. In our proposal the rotating beams can 23 cover large areas in the atmosphere to reduce land use for 24 increasing output and are hence more suitable for meeting the increasing for clean energy than existing solutions. I0

1 The axicon converts the normal beam into a cone shaped 2 microwave Bessel beam. The beams overlap after the leaving the 3 axicon lens which results into constructive interference of the in the 4 overlap area.

Normal laser beams are prone to atmospheric attenuation but the 6 microwave Bessel beams can cover larger distances with intensity 7 loss thus increasing the efficiency of heated air layer and hence 8 the photothermal mechanism formation thus enhances the utility of 9 the invention further.

to The invention consists of few components and hence has the 11 capacity to be integrated in existing power plants to enhance the 12 reduction of carbon emissions.

13 Furthermore, power plants generate water vapor and steam into 14 the atmosphere and these can be used for microwave absorption is and the photothermal mechanism generation due to their high 16 concentration around cooling towers thus extending the utility of 17 the invention further.

is The invention is used for concentrating incoming solar rays during 19 the day. During the night when the sun is not shining the invention can be used for concentration infrared energy which the earth 21 emits into the atmosphere thus insuring continuous and reliable 22 energy generation.

23 The photothermal mechanism is optical and hence non-solid 24 increases the surface area of parabolic to reduce the amount of equipment and land use and hence has the capacity to reduce 26 energy generation costs for the customer for more affordable 27 energy access especially in developing countries. Ii

2 Moreover, existing solar equipment are not scale-able enough to 3 deal with the solar radiation management, artificial rain making and 4 harvesting the large amounts of infrared radiation which the earth emits back into the atmosphere.

6 An alternative method which operates with large systems is 7 required to deal with these large scale problems currently facing 8 us. The invention has a flexible design and the capacity for more 9 advanced product development.

The photothermal design in this invention on heated air layers 11 which do not require factory manufacturing. They are also non 12 solid. They require less equipment and low energy input for and 13 directional control. They can also cover large areas in the 14 atmosphere and reduce the amount of land area required.

The heated air layers are non-solid and require no factory 16 manufacturing, transportation, installation and maintenance.

17 The solar rays are reflected from the heated air layer because their 18 refractive index is lower than that of the surrounding air. Therefore 19 they act like mirrors and reflect the solar rays.

The solar rays are then focused on the solar panels located at the 21 focal point of the heated air layers. The atmosphere contains both 22 CO2 and water vapor which absorb microwave radiation for 23 heating the air layer.

2 Existing solar thermal farms occupy much land surface due to their 3 horizontal orientation. Thus a large number of parabolic mirrors are 4 required to provide enough energy to utilize air system for operating day and night for reliable clean energy generation, the 6 problem is that such a large number of parabolic mirrors cannot 7 be installed in urban areas. This affecting the product development 8 of microturbines.

9 The heated air layers can cover large areas of 1 km diameter io without the the microwave beams losing intensity. Parabolic 11 mirrors of this size are difficult to manufacture and the invention 12 therefore extends solar energy generation capacity with simplified 13 solar equipment. Pulse beam s beams consist of energy packets 14 with higher intensity and hence can cover larger distances with is losing their coherence and atmospheric heating capacity.

16 This invention utilizes pulsed for longer distances and hence 17 increase the utility for photothermal mechanism and solar energy is generation further for more advanced product development.

19 Furthermore, the invention offers large scale clean energy solutions for developing and industrialized regions. It is estimated 21 that a round 60 % of the solar radiation reaching the earth consist 22 of infrared radiation energy. The earth therefore re-emits 100 23 million gigawatts as infrared radiation back into the atmosphere.

24 Most of this radiation is in developing countries facing energy access problems particularly at night.

2 Nano antennas are currently under development they are not 3 suitable for harvesting microwave energy due to their limited 4 surface areas. The photothermal mechanism in this invention offers a scale-able large surface area for focusing the low energy 6 density infrared radiation and therefore has the potential to 7 improve the energy shortages facing these and other regions.

8 Many regions.

9 The present invention utilizes heating prevailing air by concentrating incoming solar radiation using the photothermal 11 mechanism which accelerates the air to impinge on the turbine.

12 Prevailing air can be accelerated day and night for more reliable 13 energy generation thus increasing the reliability of the clean 14 energy generation.

Moreover, the present invention has an optical and easily scale- 16 able surface area to harvest and focus the low energy density 17 infrared to help overcome this problem.

18 Moreover, the countries in the northern hemisphere are 19 responsible for most of the carbon emissions. But the sun is rarely overhead in these regions. This limits the amount of clean energy 21 they can generate from this abundant energy source. The sun is 22 in the southern sky for most of the year. Microwave radiation is 23 used for remote sensing, infrared sounding, atmospheric profiling, 24 and astronomy.

2 The microwave beam can travel long distance of thousands of KM.

3 The photothermal mechanism in this invention can then be 4 pointed southwards to collect more solar radiation for countries in Europe, N. America, China and Japan to increase clean 6 Energy generation and impact climate change further.

9 The present invention therefore provides the following inventive io steps.

11 a) An inventive method of solar energy generation in which is 12 optical and hence non-solid photothermal interface reflects, 13 refracts and focuses solar radiation for clean energy generation to 14 replace existing solids-based parabolic mirrors to reduce is equipment costs.

16 b) An inventive method of solar energy generation in which the 17 interface results from heating air layers in the atmosphere.

is c) An inventive method of solar energy generation in which the 19 generate beams of suitable wavelength for absorption by atmospheric water vapor for heating the air layers to different 21 temperatures resulting into temperature gradients herein.

22 d) An inventive method of solar energy generation in which the 23 temperature gradient results into refractive index gradient for total 24 internal reflection.

e) An inventive method of solar energy generation in which the 26 Axicon can be machined to accommodate the amplitude of 27 microwave beams.

2 f) An inventive method of solar energy generation in which the 3 Axicon generates concentric rings which enlarge during their 4 propagation through the atmosphere and hence result into hollow and concentric cones.

6 g) An inventive method of solar energy generation in which the 7 refractive index gradient operates in the space separating the 8 conical walls can be adjusted to suit the amplitude of the solar 9 radiation to receive the incoming solar radiation thus acting as 10..waveguides of the solar radiation.

11 h) An inventive method of solar energy generation in which the 12 environmentally friendly H20 molecules in the atmosphere absorb 13 the microwave to result in a molecular vibration which is then 14 transferred to the ambient air to heat the air layers to result into is an optical and hence non-solid waveguide herein.

16 I) An inventive method of solar energy generation in which the 17 cones can be scaled up to harvest the infrared radiation which the is earth emits at night to reduce the need for battery energy storage 19 and insure 24/7 clean energy access.

j) An inventive method of solar energy generation in which the total 21 internal reflection operates at 100% reflectivity to increase solar 22 energy conversion efficiency.

23 k) An inventive method of solar energy generation which is 24 mounted onto solar tracking mechanism so that the non-solid microwave cones to reduce the total weight of existing parabolic 26 mirrors to enable the manufacture of low profile solar equipment 27 suitable for high-rise, offices, factories and domestic buildings in 28 Urban areas.

2 An inventive method of solar energy generation with the 3 potential to reduce the cost of solar thermal below that of 4 photovoltaics to provide a more scale -able method of reduce carbon emissions.

6 m) An inventive method of solar energy generation in which the 7 low voltage from battery is converted to high voltage via the 8 transformer to generate a microwave beam to improve the energy 9 density operating within the solar -hybrid microturbine for more io advanced product development for impacting climate change as 11 explained further below.

13 n) An inventive method of controlling the temperature of the intake 14 air and outlet air temperatures to the pressure ratio of the intake is and outlet pressures have equal values to increase the efficiency 16 of the microturbine.

17 p) The sun is never over-head in the countries in the northern is hemisphere. This is affecting their clean energy access from the 19 sun and efforts to reduce carbon emissions. But microwaves can travel thousands of kilometers in space. The photothermal method 21 in these inventions can be launched over a long distance, 22 Therefore it offers an inventive way to help overcome this problem.

The invention therefore can help solve the problems hampering 26 the more wide-spread use of microturbhines.

2 BRIEF DESCRIPTION OF THE DRAWINGS.

3 An embodiment of the solar operated microturbine utilizing a 4 photothermal mechanism for clean energy cost reduction and impacting climate change will now be described with the help of 6 the following drawings in which: 7 Fig. 1 shows the locations of the solar panel, battery and the 8 magnetron and the fiber optic cable connection to the axicon as 9 well as the arrangement of the turbine, compressor, recuperator io and the receiver inside the microturbine and the launching of the 11 photothermal mechanism in the open atmosphere.

12 Fig. 2 shows a detail of the hollow cones constituting the 13 photothermal mechanism receiving the in-coming solar radiation 14 and the total internal reflection between the hollow cons which act is as waveguides as well as focusing of the solar radiation on the 16 receiver.

17 Fig. 3 shows an illustration of total internal reflection is Fig. 4 shows the infrared radiation absorption of the photothermal 19 mechanism.

2 DETAILED DESCRIPTION OF THE INVENTION

3 According to the attached drawings the solar operated 4 microturbine utilizing a photothermal mechanism for clean energy cost reduction and impacting climate change comprises a receiver 6 1, compressor 3, recuperator 4, turbine 5, generator 6, solar 7 panels 12, battery13, microwave transformer 14, magnetron 15, 8 prism 16, an axicon 17, fiber optic cable 18, solar tracking 9 mechanism 19 and an external casing 20.

11 The solar panel 12 is connected to the batter 13, transformer 14 12 and further to the magnetron 15 as shown in Fig. 1.. The fiber optic 13 18 connects the magnetron 15 to the axicon 17 as shown in Fig. 14 2. These components are then connected to the micoturbine as is shown in Fig. 1. Prevailing air is taken into the compressor via the 16 air inlet as shown in Fig. 1. The compressor 3 is connected to the 17 cooler side of the recuperator 4 and further to the receiver 1 as 18 shown in Fig. 1. The receiver 1 is connected to the turbine 5 19 generator as shown in Fig, 1.

2 Microturbines are classified by their power output. Large 3 microturbines which generate 25 to 80 kW or small or micro units 4 with less than 25 kW output. The large type is used in oil refineries, chemical plant and paper factories.

6 Small or micro units are used in hospitals, homes, offices, 7 shopping centers and small industrial facilities. Smaller 8 microturbines are needed for more affordable energy access as 9 well as impacting climate change. However, existing microturbines are not designed to generate power output of 10 kW or less. This 11 is affecting the wide-spread use of microturbhines and hampering 12 product development.

13 Microturbines have a higher capital costs than diesel generators.

14 The addition of parabolic mirror increases capital costs further thus affecting the efforts to reduce clean energy costs. The current 16 cost for small domestic installations is $3700 per kW and $2000 17 per kW for large scale solar farms.

18 This is mainly because they are made of mirrors which consist of 19 solid glass, as well as steel, aluminum components. The Parabolic mirrors are the major component of solar thermal installation. They 21 are made of mirrors which consist of solid glass which requires 22 manufacturing, transportation, installation and maintenance. The 23 main coast of parabolic mirrors is their material and manufacturing 24 process. The major problem is finding a suitable method for connecting microturbines to incoming solar radiation. Parabolic 26 mirror are the conventional method for concentrating solar 27 radiation to operate microturbines for clean energy generation.

2 However, parabolic mirrors have a number of problems affecting 3 their wide spread use. The major problems are manufacturing, 4 transportation, installation and maintenance cost.

They are mainly manufactured of solid glass which is both an 6 energy and material intensive process. Sand or fine silica is the 7 major raw material for glass making. The other constituents are 8 limestone and soda ash as well as other chemicals. These are 9 mixed together in controlled proportions and heated in a furnace io which cause the mixture to melt at around 1500 Deg. C. The glass 11 is then formed into 4 mm thick panels. The next step is to form the 12 panels into parabolic reflective shapes. This process basically 13 consists of two major steps of bending and mirroring. In the 14 bending process the glass is heated to 7000 Deg. C to from a thick is viscous material which is then shaped into the required parabolic 16 shape. The internal surface is then coated with silver nitrate and 17 reducing agent.

is The reflectivity must approach 99 °A) by using laser beams from 19 different orientations for high quality control. The heavy manufacturing process therefore contributes to the high cost of 21 parabolic mirrors.

22 The other costs are transportation, installations and maintenance 23 which prevent their wide spread use.

24 Another problem is the solids-based material of parabolic mirror which cannot be scaled up easily to meet increasing customer 26 clean energy requirements and advanced product development.

27 Of manufacturing.

2 Moreover, they are centralized and cannot be used in smaller units 3 for individual homes and buildings or small villages for rural 4 electrification where energy is required more directly.

They also require large areas of land and must be must be 6 installed in remote desert locations.

7 Also they cannot be installed in urban areas where energy is 8 needed most. They are too large to fit on top of buildings because 9 of the enormous size of the parabolic mirrors.

to Also, more parabolic troughs are required for increasing output.

11 Solar thermal farms therefore require more investment to meet the 12 demand for more clean energy. An optical approach offers 13 solutions for cost reduction to impact climate change.

14 Furthermore, the electric grid does not reach remote locations in is many developing countries.

16 The problem is that existing energy generation equipment such as 17 parabolic mirrors, solar panels and wind turbines were designed is decades ago when energy supply was plenty and pollution levels 19 were low or unknown. Machine efficiency, materials and environmental protection were therefore hardly a part of the 21 equation at design stage. These technologies are based on 22 designs which rely on increasing equipment size for more output 23 Developing countries are facing energy and water shortages even 24 though they receive large amounts of solar radiation throughout the year. Suitable solar-thermal powered generation can help 26 solve this problem and save costs in grid installations in these 27 regions. Solar thermal is a clean and more abundant energy 28 source than natural gas and other fossil fuels.

2 The price of clean energy generation has been falling in the past 3 thirty years to make it more and more affordable and compete with 4 the price of oil. Solar panel provides a good example. The price of clean energy generation from electric generator was $77 per Watt 6 in the 1970's.

7 The levelized cost of electricity (LCOE) is the general term used 8 for estimating the cost of electricity as shown in equations (i) , (ii) 9 and (iii). It represents the price at which electricity must be sold to cover all the fixed and variables investments in the power 11 generation equipment.

13 LCOE = TLC/ TLO 14 TLC = E Invt+0 Mt+ Ft)/ (1 +R)A t (ii) ILO = E Eti (1-FR)At (iii) 17 Where 18 TLC= the total lifetime cost.

19 ILO =Total lift time energy output.

Invt = Overall investment.

21 °Mt = Operation and maintenance costs.

22 Ft = Fuel expenditure.

23 R = Discount rate.

24 Et = Electrical output.

t = Duration of power generation.

2 The current price is $ 1 per Watt. The price for residential 3 electricity price range from 1 cent to 2 cent per Watt. Clean energy 4 is therefore still too expensive to compete with fossil fuels which have a much higher energy density.

7 It is important to reduce the above cost factors and the invention 8 achieves this as outlined below.

9 Equipment life span or duration of power generation (t) is an io important item which requires improvement in existing systems.

11 The parabolic mirrors are made of glass and other solid materials 12 which deteriorate over the years due to exposure to wear and tear 13 from harsh surroundings. However, the present invention consists 14 of heated air layers which do not rust and almost ageless and thus is extends the life span of this major component to reduce clean 16 energy generation costs.

17 The present invention replaces parabolic mirrors with a is photothermal reflecting surface which optical and hence nonsolid 19 and does not require the heavy manufacturing outlined above thus saving in capital costs (Invt) in Equation (ii).

21 Fuel expenditure (Ft) is another major item in the Total lifetime 22 costs in Equation (ii). The present invention utilizes solar energy 23 and high pressure air and this reduces the fuel costs to help 24 reduce clean energy generation costs further.

Operation and maintenance (0Mt) is another contributor to capital 26 costs as shown in Equation (ii). Existing parabolic mirrors and 27 solar panels collect dust and require constant cleaning. The 28 heated air layers do not collect dust thus reducing the O&M costs 29 for reducing capital costs in Equation (ii) further.

2 A typical solar hybrid microturbine with an electrical output of 30 3 kw and operating at turbine intake temperature TIT of 850 Deg C 4 has the following operating parameters.

Mirror Area = 176.7 square meters 6 Turbine Inlet Temperature= 850 Deg. C. 7 Compression ratio = 3.6 8 Optical efficiency = 0.883 9 Isentropic efficiency = 0.79/0.86 Mechanical/Electrical efficiency = 0.98/0.9 11 Receiver thermal efficiency = 0.8 12 Solar-to-electric efficiency = 19.8 c/o 13 Net Power = 30 kw It is also important to improve on these operating parameters to 16 reduce clean energy generation costs further as follows: 18 Fig. 1 shows the solar panels 12 are connected to the battery 13, 19 transformer 14 and further to the magnetron 15 to generate a microwave beam. Microwaves are electromagnetic waves with 21 frequencies in the range from 300 MHz up to 300 GHz.

22 This microwave beam is then delivered to the prism 16 via the fiber 23 optic cable 18 which changes the direction of the beam by 90 24 degrees to impinge on the axicon 17 as shown in Fig.1.

2 An axicon is an optical component consisting of flat and convex 3 portions. The convex potion focuses the incoming microwave 4 towards its focal point as shown in Fig. 2. The axicon therefore emits microwave beams 6a and 6b which intersect at area 30. This 6 intersection of beams result into constructive interference of the 7 microwave thus the axicon converts the normal Gaussian 8 microwave beam into a microwave Bessel beam which is non 9 diffracting has low atmospheric attenuation thus improving the heat transfer to the air layers around the microwave beams.

12 The atmosphere contains aerosols which are very fine particles 13 which scatter and absorb laser beams causing intensity loss or 14 attenuation.

16 The microwave Bessel beam has a special property of reforming 17 after this obstruction and hence maintain its intensity thus 18 improving the efficiency of the resent invention.

19 The microwave Bessel beam then expands further as it travels through the atmosphere to result into a heated air layer for the 21 photothermal mechanism generation. The microwave Besse! 22 beam 6f formed by the axicon is more coherent than that of the 23 microwave beam and can travel more distance without losing 24 much of its power thus enhancing the photothermal mechanism generation efficiency and hence the performance of the present 26 invention.

2 Furthermore, the Bessel beam consists of concentric cones of 3 microwave beams as shown in Fig. 2. The incoming solar radiation 4 passes between the concentric microwave Bessel beam and undergo total internal reflection and hence the concentric beams 6 act like wave guides for the incoming solar radiation much like fiber 7 optic cables.

8 The incoming solar radiation 21 is incident on the heated air layer 9 at an incident angle (a) as shown in FIG. 2. If the value of this to angle is large enough then total internal reflection takes place. In 11 this case all the energy in the solar rays is reflected to focus on the 12 receiver 4 13 Then on further increase of the angle of incidence an incoming 14 light is reflected back into the space separating the concentric is cone along BF causing total internal reflection at 100 % efficiency.

16 This because the interface between the two air layers act as a 17 waveguides.

is Water molecules in the atmosphere have a polar or triangular 19 structure which absorbs microwave radiation at a suitable wavelength. The molecules act like masses connected by a spring 21 mechanism and hence vibrate and reemit the microwave energy of 22 a suitable frequency. Water molecules change from steam to 23 liquid on cooling and hence do not cause global warming. This 24 results into a temperature and hence a refractive index gradient in the open atmosphere for generating the photothermal effect thus 26 providing an optical and hence nonsolid method for reflecting and 27 focusing incoming solar radiation thus increasing the utility of the 28 present invention.

2 Fig. 3 illustrate the concept of light refraction, total internal 3 reflection used for the photothermal mechanism in this invention.

4 The microwave beam heats up the air layer L1 to a temperature Ti while the air layer L2 above it remains at normal temperature T2 6 as shown in Fig 3. This results into two air layers at different 7 temperatures and hence different refractive indexes n1 and n2.

8 The two air layers are separated by an interface X1-X2.

9 The light AB passing from the cooler air layer L2 to hotter air layer io L1 is first refracted from its original path BC to BD.

12 Fig. 4 shows the energy input requirement for the photothermal 13 mechanism for the generating the microwave Besse! beam. For 14 microwave ovens the most suitable frequency for heating food is items is about 2.45 GHz.

16 It is possible to utilize low, medium or high power diode lasers for 17 generating the micro beams 6a and 6b to generate the is temperature or refractive index. The temperature difference of the 19 heated air layers is only 2 or 3 Deg. C. and from Fig. 4 we can see that a low power diode laser will be suitable for this purpose which 21 lower the energy consumptions and hence increases the utility of 22 the invention? 23 This facilitates the focusing of the solar radiation from large areas 24 in the open atmosphere thus enhancing the utility of the invention further.

2 The incoming solar radiation is focused on the receiver. The 3 receiver has an intake for prevailing air. The heat in the receiver 4 heats the incoming air to a high temperature reaching 1000 Deg C due to the high solar intensity. The high velocity air is then used for 6 operating the turbine for power generation via the generator.

7 absorbs the energy in the solar rays converting it to heat prevailing 8 air. The turbine typically rotates at 75,000 to 100,000 RPM which 9 generates high frequency output.

io The recuperator is provided for recovering the heat power 11 conditioner is provided to convert the power to 50-60 Hz which can 12 then be used for operating machinery for industrial purposes 13 Thus the present invention has a number of advantages over 14 existing equipment in a number of ways to improve on operating is parameter.

16 Existing solar thermal farms occupy much land area due to their 17 terrestrial based horizontal orientation.

is In the present invention the laser hollow cone are launched in the 19 open atmosphere can cover large areas in the atmosphere for increasing output and are hence more suitable for meeting the 21 increasing for clean energy than existing solutions.

22 The other advantage of the photothermal mechanism is that it 23 does not require high temperature for its operation.

24 This minimizes the energy input into the process of focusing solar rays compared to existing solar thermal farms thus increasing the 26 utility of the present invention.

2 We believe this also a practical way for achieving carbon 3 emissions, meet climate change mandates sustainable 4 development for rural communities.

The electric power generated must be first taken to the nearest 6 power plant via high voltage transmission lines to reduce the 7 voltage and then retransmitted to rural areas. This has two major 8 disadvantages. The long distance power transmission requires the 9 installation of large infra structures which increasers costs.

io Furthermore, the atmosphere contains water vapor which absorbs 11 the energy in the microwave Bessel beam radiation for heating the 12 air layers.

13 The surrounding air layers remain at a cooler temperature which 14 results into a temperature and hence a refractive index gradient. is The solar rays are reflected from the interface between the heated 16 air layer and cooler surround air layers due to the refractive index 17 gradient. Therefore the interface act like mirror and reflect the is solar rays. This provides an optical and hence non-solid method 19 of reflecting, refracting solar radiation with a number of advantages over existing equipment.

21 The axicon changes the Microwave beam into a microwave Bessel 22 beam which has lower attenuation than conventional beam and 23 thus improving heat transfer to the air layer and increase the 24.reflectivity and efficiency of the invention The heated air layer can then be generated in the open 26 atmosphere in urban and rural areas more conveniently than 27 existing equipment.

2 Green technology is also closely linked to natural systems and 3 this design approach can be useful for future product development.

4 Solar thermal equipment consists of large mechanical and optical equipment such as parabolic mirrors, absorber water, and solar 6 tracking equipment.

8 It is estimated that 60 % of the solar energy reaching the earth 9 consists of infrared radiation. Large Kilometer size reflecting surfaces are required for reflecting, refracting and focusing 11 infrared radiation for energy generation. However existing clean 12 energy generation equipment is not designed to make use of this 13 major energy source. energy conversion.

14 In this invention the photothermal method is optical and hence scale-able reflecting medium utilizes microwave beam for solar 16 focusing and has the capacity to harvest more infrared radiation 17 than existing solutions to provide cheaper and more efficient clean 18 energy conversion method.

2 The total clean energy reduction methods outlined above therefore 3 have the potential to enhance the wide-spread use of microturbine, 4 for more affordable clean energy access as well as impact climate change.

6 Power is generated via the microturbine components in the normal 7 way as shown in Fig. 1.

8 The invention therefore has the capacity to overcome the problems 9 mentioned above facing solar energy equipment.

Claims (3)

1. CLAIMS1. A solar assisted microturbine utilizing a photothermal mechanism for clean energy cost reduction and impacting climate change consisting of a method of converting low voltage battery power to a very high voltage, a method using the high voltage for microwave energy generation, a method of converting Gaussian microwave beams into special beams with low atmospheric attenuation, a method of hollow microwave conical beam ( HMCB) shaping, a method of absorbing, vibrating the water vapor molecules in the atmospheric for heat generation, a method of generating a temperature and hence a refractive index in the open atmosphere, a means for the HMCB to track and receive the incoming solar radiation during the day, a means for reflecting, refracting and focusing the solar radiation, a means for absorbing the solar radiation, a means for transferring the absorbed solar radiation to heat prevailing air to high temperatures and high velocities for power generation during the daytime as well as nigh time hours for moreCDC\I reliable solar energy and power generation.
2. CO 2. A solar assisted microturbine utilizing a photothermal mechanism for clean energy cost reduction and impacting climate change for clean energy cost reduction and impacting climate change in Claim1 in which a magnetron generate a microwave beam CD suitable for atmospheric water vapor absorption for heating thin air layers herein.
3. 3. A solar assisted microturbine utilizing a photothermal mechanism for clean energy cost reduction and impacting climate change in Claim1 in which an axicon converts the Gaussian microwave beams into Bessel beams which are non-diffracting to reduce atmospheric attenuation so that hollow microwave beam can cover larger distances in the atmosphere at a higher intensity for a more consistent refractive index gradients in the atmosphere 4. A solar assisted microturbine utilizing a photothermal mechanism for clean energy 25 cost reduction and impacting climate change in Claim1 and Claim 3 in which the means for HMCB shaping converts the microwave beam into Bessel beams with concentric and coaxial cones with different microwave beam intensities.5. A solar assisted microturbine utilizing a photothermal mechanism for clean energy cost reduction and impacting climate change in Claiml in which the microwave beam s have a suitable wavelength for atmospheric water vapor absorption to heat the air to result into a temperature and hence a refractive index gradients in the open atmospheric air.6. A solar assisted microturbine utilizing a photothermal mechanism for clean energy cost reduction and impacting climate change in Claiml in which the transformer converts the low DC voltage from the battery into a very high voltage to operate the magnetron to generate microwave radiation thus increasing the energy density herein thus lowering the number of solar panels in the system for more advanced product development for high-rise buildings with limited roof areas..7. A solar assisted microturbine utilizing a photothermal mechanism for clean energy cost reduction and impacting climate change in Claiml and Claim 3 in which the HMCB C\I internally receive the incoming solar radiation at a suitable angle of incidence for their C0/5 total internal reflection to simulate a photothermal mechanism effect thus directing theCDsolar radiation towards the apex of the concentric cones to provide a non-solid method cr) for focus the solar radiationCD8. A solar assisted microturbine utilizing a photothermal mechanism for clean energy cost reduction and impacting climate change in Claiml in which an axicon converts the Gaussian microwave beams into Bessel beams which are non-diffracting to reduce atmospheric attenuation so that hollow microwave beam can cover larger distances in the atmosphere at a higher intensity for a more consistent refractive index gradients in the atmosphere.9. A solar assisted microturbine utilizing a photothermal mechanism for clean energy 25 cost reduction and impacting climate change in Claiml and Claim 4 in which the means of solar tracking insures that the HMCB are always directed towards the incoming solar rays at a small angle of incidence for total internal reflection.10. A photothermal mechanism for solar energy generation in Claim 1 which provides a large scale reflecting, refracting and focusing of the infrared energy which the earth emits for more continuous and more reliable solar energy generation during the night when solar radiation is not available.11. A solar assisted microturbine utilizing a photothermal mechanism for clean energy cost reduction and impacting climate change in Claim 1 which converts the uncontrollable the photothermal mechanism in nature to result into a controllable the photothermal mechanism concept which can then be used for a reliable, scale-able, optical and hence non-solid method for focusing solar radiation and solar energy generation.10. A solar assisted microturbine utilizing a photothermal mechanism for clean energy cost reduction and impacting climate change in Claim 1 and Claim 2 in which the HMCB have different energy densities to result into different temperature gradients and hence C\I refractive indices so that the incoming solar radiation or infrared radiations undergo a C0/5 total internal reflection and the concentric cones act as wave guides along the length ofCDthe HMCB for their eventual focusing onto the receiver.12. A solar assisted microturbine utilizing a photothermal mechanism for clean energy cost reduction and impacting climate change according to any of the proceeding claims in which the heated air layer reflect refract solar rays thus providing an optical and non-solid method for focusing solar rays for solar energy generation.13. A solar assisted microturbine utilizing a photothermal mechanism for clean energy cost reduction and impacting climate change in Claim 1 which the prevailing air coming into the receiver is heated to high temperature and hence high velocities which is then delivered to the microturbine for power generation during the day and night time for more reliable clean energy generation round the clock.