GB2427249A

GB2427249A - Combined generator and water distillation plant

Info

Publication number: GB2427249A
Application number: GB0511946A
Authority: GB
Inventors: William Alexander Courtney
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-06-13
Filing date: 2005-06-13
Publication date: 2006-12-20
Anticipated expiration: 2025-06-13
Also published as: GB0511946D0; GB2427249B

Abstract

An extensive trough 3 containing water is heated by solar energy 1 or waste heat from an industrial process / power genereation, and the vapour produced is used to drive a multi stage turbine (figure 4). The stators 5, 6, 7 of the turbine are cooled by separate water streams 8, 9, 10, to at least partially condense the vapour passing through the turbine. The cooling water 14, 15, 16 is passed to a chamber 4 (figure 5) underneath the trough, to return some of the heat to the water being heated. A temperature gradient exists in the trough, from a cold to a hot end, so cooling water at different temperatures can be used to heat the water at different stages in the trough. A compressor 17 arranged downstream of the turbine compresses the exhaust back to atmospheric pressure. The condensed vapour may be used as a source of purified water.

Description

Combined Power Generator and Water Distillation Plant

Technical Field

This invention relates to improvements in devices used to convert lowgrade thermal energy into electricity When the device is rw using sea or brackish water as a thermal energy storing and transfer medium, potable water is produced as a by-product.

According to the present invention, there is provided, a device for converting energy stored in warm water vapour into electricity, with the device including a turbo-generator, a first supply of warm vapour, originating from the evaporation of water held in an extensive trough, inside a first chamber, with the first vapour being fed into the turbogenerator and a second supply of liquid vapour, originating from the evaporation of a cooling liquid inside the turbo-generator, with the second vapour condensing inside a second chamber, placed underneath and in thermal contact with the first chamber, characterised by a temperature gradient existing inside the first chamber, with water and overlying vapour towards the generator mouth end of the trough being at a higher temperature than at the far end of the trough, with a similar temperature gradient existing in the underlying second chamber, allowing thermal energy liberated by the condensation of the second vapour to be transferred to the first vapour, via the water in the trough, over a range of temperatures, lower than the temperature at which the first vapour enters the turbo-generator.

Brief description of the drawings

Figure 1 is a schematic diagram, which will be used to explain the principles of operation of a Manzanares type power station.

Figures 2a and 2b will be used to explain how a Newcomen engine first does work on the atmosphere, then extracts energy from the atmosphere to do useful work.

Figure 3 depicts a hypothetical "atmospheric" solar powered turbogenerator that at best, would have an operating efficiency equivalent to a Newcomen engine.

Figure 4 depicts a cross section through a turbo-generator according to the invention.

Figure 5 depicts how the turbo-generator is connected to stacked evaporation and a condensation chambers of a solar powered version of the invention.

Figure 6 depicts a condensing chamber that supplies heat to the evaporation chamber according to the invention.

Figure 7 depicts an illustrative example of a method for locally heating the brine inside the trough to a high temperature, in excess of 1000 C. Figure 8 depicts a part of the invention that extracts low grade heat resulting from the cooling and compression of hot, carbon dioxide rich flue gases.

Figure 9 depicts a compact form of evaporation building, used in versions of the invention that do not require solar heating. 2/

Figures IOn -lOc icpic1 an illustrative cxample of hcaLslo ng..sysiciulor smoothing c!cc+rici4y output from the invention,

The prior art

In 192. the pi'ototpc Ibi' a new design 0! solai' power station was constructed at Manzanarcs in Spain. An atLracii ieaiui'e uI tins t pe of sulai puwcr station is that it can function produciive!' when powered by low-grade solar heat, with inaximuni temperatures within the system, typically being below IOO Celsius. However, this has to be olLset against the disadvantage that because of its chimney height, quantity of building materials and land required, the design is expensive to build, compared with equivalent output, fossil fuel powered electricity generaluig stations. Figure 1 is a selienialic diagram. which will be used to cxplain the principles of opcraiion of a Manzanares type solar power station. In Figure 1. item 1 is a transparent glass/plastic roofed building, which is used to warm a large body of enclosed air, when sunlight 2, hills upon it. Item 3 is a tall chimney, 192 metres tall, for the Maiizanares power station. Warm air rises up the chuiuiiey and is replaced by air at ambient temperature, winch is drawii into the building, at points such as 4 and 5, at the extremities of the building, away from the chimney. As the warm air is pushed up the chimney, by the external air pressure difference, between the lop and base ol the chimney, the work done by the atmosphere drives a turbine, 6, coupled to an electricity generator. II caii be sceii from this brie!' explanation. that Man,.aiiares type solar power stations are inherently inefficient, because uiOst 01 th nci'gy is lost iiufll the top 01 the chimney. Ihe 0111) way of increasing their elliciency is to miicrease t1m height of tIme cluiuiiey, to increase the atmospheric pressure difference, winch drives the warni air through time turbo-generator. A general problem with existing power stations that produce electricity by extracting either low grade thermal or kimietic energy frouim air or other lluids. is that in order to extract the energy on a commeieiall useful scale, the size ol' the plant, and hence its capital costs, must be very large.

Disclosure of the invention

The lnveimu\e step revealed iii tins patetit application is an improved method and associated devices for converting low-grade thermal energy. in the form of heat, into electrical energy. Potable water is optionally produced as a by- product. Lxaiiiples of suitable low-grade themijial energy supplies include solar energy, geothermal energy, waste- heat homn industrial plants. 10551! Ibel and nuclear power stations. The specific!ealures of the device employed to imiiplenicimt the ineUmod will vary, depending on the source of the low-grade heat to be exploited.

Time iniproveiliclits offered by the iiiventioii are based on the following physical concepts: I. Phasc changes between the liquid and \apour states proide a very eompaet method for absorbing large quaiitities of thernial energy, compared with using thermal energy to change the temperature of a IUUSS Of liquid or gas. For example. converting one kilogram of water to steam at a boiling point of 1OOC requires 5.4 times the quantity of energy required to raise one kilogram of water froinOC to lOOC.

2. Phase changes between the \apour and liquid states result in large changes in olumes. This means, for example. that a gas expanding into time void created when one kilogram of vapour collapses into a liquid is able to do far more mechanical work, compared with a gas expanding into the void created when one kilogram of gas contracts in olumc. on cooling from lOOC to 0 C.

3. Water has a high specific heat and latent heat of vaporisation. compared with many other volatile liquids.

B) using atei and other olatilc liquids in ciiI1irent positive thermal kcdback loops, the scope of [lie invention can be extended, to optimise either electricity or desalinated water production, depending on consumcr requirements.

4. On a volwiie-lur-vohume basis, the ihenual ener&v storing capacity of water is at least two orders of magnitude higher than dry air lieii equal volumes of ihcsc materials arc raised through the same temperature range.

iinpruveniciits on [lie Mau.aiiares t pe solar power station offered b) the present invention include I. An alternative method for creating an air pressure difference to drive the turbo-generator. The new niethod dispenses with the requirement for a very tall chimney.

2. A method lOr recovering a large fraction of the thermal encrgy from the warm air or vapour and rec cling it, to increase [lie thermal effmcleiic\ of the power station.

3. For the solar energy version of thc present invcntion, the improved thermal efficiency reduces the required solar energy collecting surftice area, compared with the Mauzanares design. This reduces the plant construction costs.

4. L)ouble-glai.iiig of the solar ciicrgy collection building viIl be a more commercially viable option, compared mtli the ManLanales design, because of the comparatively small surface area involvcd.

5. The solar eliergy collection building may alternatively be constructed substantially front corrosion resistant metal sheeting, e.g. galvanised iron.

The lust type of steam engine that became a practical proposition is recorded as Thomas Neweomen's atmospheric engine of 1712. A shared characteristic of the present invention and Newcomens engine is that they operate at a iuaximiiuimi pressure comparable with the prevailing atmospheric pressure. Figures 2mm and 2b will be used to explain ho the Neeomen engine lmrst does work on the atmosphere, then extracts energy from the atmosphere to do useful urk.. In 1'iguie 2a. item 1 is a.atcr boiler heated by a source of heat 2. This is used to raise a head of steam that drives a piston 3 inside a cylinder 4 against the force of the prevailing atmospheric pressure. When the piston has 1ra ersed the length of the c linder. the source of steam is Cut oil by closing a tap, 5. Figure 2b depicts the power stroke of the piston, In Figure 2b, a ei of cold water 6 is introduced into the cylinder to cool the steam.

l'he steam condenses, creating a partial vacuum, which causes the atmospheric pressure to exert a resultant force on the piston. driving it back along the length of the bore and allowing it to do work.

F'iui'e 3 Uepe1s a li'poLlietical atimiuspherie' solar po'aered turbogenerator that at best, would have an operating ellicicnc cquialent to a Ncwcomen engine. It does however, introduce some key concepts, relating to the present inention. The turbine unit is powered b) a mixture of hot water apour and air. It comprises a rotor 1 placed between two stators 2 and 3. The inset to the diagram exposes in further detail a cross section through part of the turbine. losc to its periinctci.. lIme lust siator Consists of a series at' flared Laval noLLles of \hich item 4 is an example. The second stator 5 acts as a hcat sink, absorbing thermal cncrg from the sapour plus air mixture, with the mixture experiencing a drop in pressure as it moves through the tunnels in the stator.

lhc pressure drop dia s Lh illixiure through the first stator and rotor. ith the tunnels through thc rotor e.g. item 6 being shaped in a manncr known to thcrmodynaniics engineers, which allows the moving mass of the mixture to impart rotational kinetic energy to the rotor.

The source of the hot air plus vapour mixture is a large glass roofed chamber 7 fitted with a shallow trough filled with fresh water or brine. 8. The Llialuber and its contents are heated by solar radiation 9. At the cold end of the trough. away Irom the turbo-generator. the water temperature and vapour pressure arc low, so top-up air needs to be introduced via an inlet 10, to allow operation at atmospheric pressure. (For clarity in showing the detail, the turbo-generator has been drawn on a larger scale than the evaporation chaniber.) The turbine is coupled to an air coiripressor 11 and au electricity generator 12 via a shaft 13. The vapour that condenses out on passing through the second stator can be run-off through a tap 14, leaving residual air at low pressure. Iluis air is compressed back to atmospheric pressure by the compressor ii and is pumped out, into the atmosphere or returned to the inlet 10.

Ilue h)pollielteal Lurbo-geuieiator system described with reference to Figure 3 is not a practical proposition because most of the heat originating 1ioni the solar energy is dumped back into the atmosphere from the second rotor, via notional cooling fins 15.

In order to convert thus concept unto a commercially viable invention, the thermal eneri extracted by the second sLatOi neLds Lu be captured and ic-c) cled to assist in heating the water in the trough. Heat cannot pass [mm a cool body to a warmer body, so it is not possible to use the recycled heat to assist in heating the hottest water in the trough. However, because the fraction of water vapour in the vapour plus air mix increases, as the mix migrates towards the turbo-generator, the efficiency of the invention can still be improved, by contributing replacement thermal cnerg. to make up br heat losses, as ater apour is added to the mix at intermediate temperatures.

A modification to the turbine design that allows the heat absorbed by the stator(s) to be re-cycled at the highest possible feedback teuuupematures allowed by ilue laws of thermodynamics, will now be revealed.

Figure 4 depicts a cross section through a turbo-generator according to the invention. The turbine comprises a plurality of rotors 1, 2 and 3 set between stators 4, 5, 6 and 7. All the stators, from the second upwards arc hollow chambers. with the vapour flow channels being tunnels through them. The vapour flowing through the tunnels is cooled mndiretly by ater sprayed u\er thienu front Jets, 9 and 10. The chambers are closed units purged of air, allowing the cooling water to boil off the tunnel walls at reduced vapour pressure. The resultant saturated vapour is drawn oil lór re-e)eling ia ports 11. 12 and 13.

The invention, as revealed so far. requires two sources of water, both of which evaporate, to generate water vapour.

In order to aoid comifusmon, water vapour oruginatimig iii tile evaporation chamber will be referred to as primary vapuur. than originating ironi the indirect cooling of the primary vapour, as it passes through the stator tunnels ill be re1rred Lu as.,ceundary i'upuur.

The mass rate of flow of the primary vapour plus air mixiure through the first rotor depends on the rate at winch it is drawn thi'ough the succeeding parts 0 the turbine. Likewise, the mass rate of flow through the second rotor only depends wi the rate it is drawii through subsequent stages. This is an important differentiation between existing steam powered turbines and turbines according to the invention. For thc invention. ihc condensation of primary water vapour, as it passes throLigh the second and subsequent stators reinvigorates the iluxture, providing it with i'cplaeenent kinetic cnerg. to partiali make up for that lost as it passed tiu'ough the prcccding rotor. The replaceniem can only be partial, because the mass rate of flow' of the mixture is reduced as the prunary Water vapour condenses Out. This feature of the invention, that ii can reinvigorate vapour flowing through a turbine is not limited to low pressure systeimis, that operate at and below atniosplieric pressure. i'he scope of tile invention is extended to include high pi'cssum'c vapour drivcii turbines, as used in conventional power stations.

As the primary vapour passing through the turbine channels cools, it condenses out and is drawn off via drainage ports 14. 15 aiid 16. As explained above, with reference to Figure 3, tile SCOUS material flowing through the turbines is a mixture ol' water vapour and air. Ideally, the gaseous mixture emerging from the last stator comprises low pressure dry air and water vapour at its ambient temperature dew point. This iiuxlure passes through a compressor 17. eiiiergiimg as warmii gas at atmospheric pressure. This gs is preferably re-cycled through the system. by injecting it back into the cold cud of' the evaporation chamber. A generator 18, iiuouiited On the same axle as the turbine rotoi's, generates e!ecti'ucut' Figure illustrates how the turbo-generator is connected to stacked evaporation and coudensatioui chambers for the solar powered version oF the ins entuon. File diagram is not intended to represent tile relative sizes of the components. winch caui be calculated by engineers with a knowledge of thermodynamics. The version illustrated can opemule ii1ii fresh natei' in time trough or be used br distilling sea or brackish water to potable water.

In tile solar version of the invention the evaporation chamber receives heat from two sources: Solar energy and re- cycled heat l'romn the turbo-generator.

I "uliir eiiei',v Incident solai' radiation I ssarms a large trough ol'sah[ water 2 inside a closed, glass roofed building 3. The warm water end ot tIme trough. aljaceut to the turbo-generator may also receive additional solar radiation, reflected off large inuiriscU muiri ors. that track the apparent path ci' the sun in the sk throughout the dii) it-L vt/ed 1ietii Ji'ui/d the t'i,'u-eIie/'l1UI' A condensation chamber 4 having a similar surface area to tue base of the trough is built underneath and is in good thermal contact with the trough. Warm water vapour produced by the cooling System of the turbo-generator enters Lime condensauon chamber at its warni end.

Figure 6 depicts a condensing chamber 1 that supplies heat to the evaporation chamber from below. In order to allow a single condensing chamber to accept several inputs of water vapour at different temperatures and vapour pressures. a plurahiw of inlet pipes. in this example 2, 3 and 4 extend different distances into the chamber, such that the apour pressure ci each emerging jet 01 sapour is oni) slight!) higher than tile local sapour pressure inside tIme condensing chamber.

The following information is provided to assist competent engineers construct the invention.

I. For versioiis of the inveiltioti designed to produce potable water fresh brine (i.e brine that has not been eoneeiiirated b evaporation) is constantly added to the warm end of the evaporation trough. after passing through a heat excltaiiger, to warm it up.

2. Concentrated brine is removed at the cold end of the trough.

3. The interior bottom(s) of the evaporation trough(s) ma be painted inau black, to aid absorption of thcrmal radiation.

4. the lower interior surface of the evaporation clianiber and the upper interior surface of the condensation chamber may include angular protrusions, that act as nucleation centres, that aid boiling and eoiideiisauoti respeetivel.

5. 1 he bonoin(s) ol the underlying evaporation chamber(s) may be thermally insulated using expanded polymeric foaiii or other thernially insulating material.

(i. the troughs may be deep enough to store warm water overnight, to enable the device to generate eleetikity after sunset, using thermal eiiergy accumulated during the day.

7. Just suliiiem air is dravn into the evaporation chamber, to ensure that the combined pressure of the water vapour plus air mixture, at the cold end, is equal to the ambient air pressure.

8. l'he clearance between the roof of the evaporation chamber and the surface of the water in the trough iiiay be kept to a iniumniulti, towards (lie cold end ot' the trough.

9. For the solar encrg poveied version oi the invention, the glass or transparent plastic roof may optionally be replaced by a ga!vaiiised iron or other thermally conducting, corrosion resistant metal sheeting, painted maLt-black. Thermally conducting links between the inner surface of the roof and the water irough are also preferably added. to suppleiiieiit the radiant heat transfer. The conducting links, which nia be tlieinial siphons. are optionally disconnected at night, to help conserve thermal energy stored in the e\aporatioli chiaiiiber.

10. In the löhlowing circumstances. it is preferable to feed all of the thermal energy back into the evaporation building: (i) when the svstelim is waruwig up, (ii) operating at relatively low temperatures, or (iii) the ratio of potable vatcr to electricity output needs to be increased, in ally of these circumstances, the turbo- geiierator may operate on open circuit.

11. If the dominant function of the invention is to generate electricity, the drop in vapour pressure and the reduction in vapour volume resulting from (lie condensation process of the secondary vapour inside the condensation chamber iiia be used to generate additional electricity by introducing a secondary turbo- generator into the 1ed pipe(s) line(s) from the turbo-generator to the evaporation chamber. In this version uI the invention, a lov boiling point organic liquid such as pcntane or hexane may be used as the secondary vapour fluid. iii order to increase the vapour pressure available to drive the working vapour through the secondary turbo- generator.

12. If the dominant function of the invention is to generate potable water, brine iiiay be used as the liquid source ol the secondary apour, with ihc condensation water being drawn off as potable water. In this version, the brine is only allowed to partially evaporate, with warm concentrated brute beiiug drawn off and disposed oiL aller passing through a heal exchanger.

The inenUon is a means of converting low-grade thermal cncrgy into clcctrical encrgy. Low-grade heat being delned fur the present inveiluoii as. heat at temperatures too low, to cuiiuuercially run a turbo-generator, in a eonemioiiiI OCi station. An practical source of low-grade heat may be employed. Fossil fuel and nuclcar power sianulls produce waste eochiig heat. whieli still retaiiis sufficient thermal energy to drive the present iiwcntion. l he inenuon is extended in scope to utilise this waste heat as its requisite heat supply, instead of solar eiierg.

Nuclear energy may be used directly to generate the low-grade heat required for the invention to operate.

Compared with existing nuclear power station designs, a nuclear powered version of the present invention offers many advantages, including the fOllowing: I. Ilie iuivCiUluul is inure eliiciuit than a eouveiitional nuclear power station, because it does not reject low- giadc heat. This cuts down on the nuclear fuel costs for the power station and reduces the mass and oIuiiie of nuclear waste produced, per unit of electricity generated.

2. ih iiucleai power plant primary iherimial circuit, coupled to the reactor core will only be required to deii Cr heat a!dw degrees above ilie normal boiling puiiit of waler, because the secondary thermal circuit, used in the present incntion, for generating the warm, moist air, is in balance with the atmosphere. This restricts time nuclear power plant secondary circuit operating temperature to approximately lOOC. This greatly simplilics the nuclear reactor design requirements and reduces the manufacturing costs of the pressure vessel.

3. Low-giac nuclear lOel. which is only emitting thermal energy a few degrees above ambient temperature, can pla) a useful i-ole iii the invention. lhis extends the working life of the fuel rods and reduces the nuclear waste storage costs.

4. [lie relati'el siuiall size. low operating pressures and teuimperatures of the nuclear euiergy plant required or the present invention. reduce the costs and publicly perceived problems associated with designing a nuclear power plant, which is secure against earthquakes, terrorist and other forms of hostile attack.

5. It may be possible to postpone the decommissioning date for existing nuclear power stations, by changing 1hcr role iruui1 providiuig high temperature, high grade heat, to providing low grade heat for the present mnvcnuon.

in omder to comi cii power plants according to the in enlion into rapid response, demand led electricity generators; the invention uuuay be run continuously at niaxuunum output, with the excess electricity during offpeak periods being used to break down water into oxygen and hydrogen, by electrolysis. The stored gases could be compressed and stored locally, for use as combustion materials, for driving additional turbo-generators, during peak periods. 8.

Fhe low-grade heat generated b compressing the gases in preparation for storage could be transferred to the water in the troughs, in the c aporation building.

ii elec1iicit produced b the inenuion is used for clectrosis. to generate hydrogen lör use as a transport fuel,, a surplus oh UXVgOi u ill also be iiber:iied as a b -product. Ilus iiiay be used to burn carbon fuels, including waste materials. eliicicnti, at high temperatures.

Assuming iliat the in ention is coupled to the local atmosphere, ihcn thc maximum saturated aier vapour pressure is hunted to the atiiiosplicric pressure. I ins iiiiiits the iiiaximuni water vapour temperature to the boiling point of aid at the ple' alert atmospheric pressure. The interior of the body of the brine inside the trough however, can be transiently lifted to a higher temperature. Figure 7 depicts an illustrative example of a method for doing this. In Figure 7. a sealed heal exchange unit, constructed for example from gals anised iron sheeting, painted man-black has to chambers. 1 and 2. The chambers and connecting pipes are robust enough to operate at vapour pressures significantly in excess ol atmospheric pressure and temperatures in excess of IOO"C. Chamber 1 absorbs eoiieeutrated solar energy and is external to the principal evaporation chamber. Either super-heated water or an urgaiti. licalexeliazige fluid ovaporales. vith tiLe vapour t1o tug. via pipe 3, to the lugh-lemperature heat dissipation chamber 2. inside time principal evaporation chamber. 1 lie vapour condenses and returns to chamber 1 via pipe 4. Because the system is sealed, it can deliver saturated vapour to chamber 2 at temperatures that are only limited by the lift in temperature caused by the input of concentrated solar enery. Item 5 is a sun-tracking iiio'able concave solar reflector, used to deliver concentrated solar energy to the upper surface of chamber 1.

The low grade heat resulting from the cooling and compression of t'lue gases, froni fossil fuel power stations, prior to their sequestration. may also be used to power the invention. Figure 8 depicts a method for doing this. In Figure 8, hot flue gases 1 pass through a plurality of cooling cliaiiibers 2, 3, 4 and 5, similar to the evaporating ater cooled slators described. i1h relerence to Figure 4 aboc. l'hc hue gases arc compressed in stages by rotar) blade compressors (. 7 and 8, posered by a shah linked motor 9. Warm vapour produced by evaporation of the cooling u ater is led into the condensation chamber. as Ibr other versions of the invention, ia outlet pipes 10, 11, 12 and 13. Flue gases such as sulphur dioxide that have a high critical temperature can condense out as the flue gases a c eoinprcsscd aud cooled. lIcin 14 t a!epreseniati c outlet pipe. for dran ing off condensed hue gases. The gas mixture emerging from the port 15 consists mainly of a highly prcssuriscd mixture of oxygen-depleted air and carbon dioxide at about ambient temperature. By cooling the mixture below the critical temperature of carbon dioxidc. 31. I C. the carbon dioxidc can be separated out and drained off as a liquid. To ensure that the mixture is cooled eh! be1o 31. 1 C. the mixture is pumped into a chamber immersed in a aLer cooled bath 16. Oxygen- depicted air exits tile chamber via a pressure reduction noLLle 17 fitted with a spring loaded valve, that only releases gas if tile gas pressure exceeds the critical pressure of carbon dioxide. The oxygen-depleted air is vented off, into the auiiosphiere. after passing through a long water cooling tube IS. 9d

Flie data presented below indicates that the invention, operating down to low ambient temperatures can be used to captuic sulpiiui dioxide, iulrogcn dioxide and carbon dioxide but not nitrogcn monoxide or carbon monoxidc.

-- CLical temperature ( C) J Critical pressure (Atmospheres) Sulphur dioxide 158 77.8 Nitrogen dioxide l5$ tOo Carbon dioxide 31.1 72.9 Nitrogen monoxide -93 65.0 Carbon monoNide -ItO 34.5 Figure 9 depicts a compact foriii of evaporation building, used in versions of the invention that do not require solar lIcatilig. iii Figure 9. ilelli 1 is the evaporation building shell and iteni 2 is a broad, gently inclitung trough, which allows the warmed brine to flow slowly downiull, until concentrated briiie exits at 3. Re-cycled air from the turbo-geiieratoi enters the building through an iiilet port at 3. Item 4 is a section of the secondary vapour condensation chamber, which in this example. takes the form of a long, snaking pipe. The compact design of the evaporation chiaitiber. inch iii hiis case, is itiore appropriately described as an evaporation building, is thermally eliicicnt because the ratio ol evaporation building external surface area to total area of lroughs is low. minimising heat losses through the building walls.

In mdci tu cxteiiU Ie teiigthi ol the productive wrkiiig day for SOlUf powered versions of the invention and to help stabilise 1hi output Uuiing icmpral' periods al cloud eo er. phase change maicrials may be used tostore heat in parts 01 the e'aporation chamber. Figures ba -lOc depict an illustrative example of a phase change heal storing system. Figure IOn depicts a crtical cross section exposing an evaporation chamber 1, filled to a partial depth by a layer of brine 2. overlying a condensation chamber 3. but separated by an intervening sealed copper or aluminium container 4. hUed with a phase change material, that changes phase a few degrees below l00' C. A suitable material would be iiaphthalene, which has a inciting point of 80.2 C and a boiling point of 218 C. The length of the chaitibers is along a North-South axis. Figure iOa depicts the unit a few hours before noon. A miiovable concave mirror 5. backed by lagging 6 concentrates solar enerj onto the container of phase change iiiateriai. Figure 11th depicts the unit a hew hours alter iiooii, with the niirror having rotated. to track the apparent path ol time sun through the sky. Figure hOc depicts time unit at night, when the lagged mirror forms au insulating eu er o er the chambers. to minimise radiant heat losses to the cn ironmcnt.

Claims

Combined Power Generator and Water Distillation Plant Claims A d ice for

convertiiig eiiergy stored in warm water vapour into electricity, with the device including a turbo- genciator. a lust suppl ol arni vapour. originating from the caporation of watcr held in an exLcnsie trough, inside a first cliaiuubr, with the first vapour being fed into the turbo-generator and a second supply of liquid vapour, originating from the evaporation of a cooling liquid inside the turbo-gcncrator. with the second vapour cotideiisiiig iiisidc a secoiid chamber, placed uiideriieath and iii thermal contact with the first chamber, charaeterised b a temperature gradient existing inside the first chamber, with water and overlying vapour tO\\ urds the generator nioutli end of the trough being at a higher temperature thati at the far end of the trough, w ithi a similar temperature gradient existing in the underlying second chamber, allowing thermal energy libcratcL! b\ tL eoitdeiisatioii of the scuud \apour to be trauustrred to the first vapour, via the water in the trough. or a range 01 temperatures. lower than the temperature at which the first apour enters the turbo- generator.
2. A device, according to claim I. with additional theriiial energy bciiig supplied to the water in the first chamber, to:tssist in the e:iporaLion of the fliSj vapoui.

3. A dc ice. according to claim 2. with the additional thermal energy originating from a combustion or radioactive decay process or the absorption of solar radiation.

4. A device, according to claim 1. with the turbine including a plurality of stators that take the form of hollow cliambers. ith the oai'm iirst apour passing through a plurality of tunnels through each slator chamber, wunu time surhices of the tunnel walls that are on the inside of the chamber being doused with a liquid, that eapoma1cs. to lorni the second \apoui.

5. A dc ice, according to claim I. with the first chamber including a plurality of air inlet ports, at the cool end of thi chiatitber. to alloo nr tu be draw ii it. to supplenient the water vapour, to enable the vapour plus air pressure in the chamber to harnionise with the local environmental air pressure.

ô. A Uemcc, according to clami 5. with the air and an residual vapour that emerges from the turbine being compressed to at least the air pressure in the local environment, to enable the air plus residual vapour to be pumiiped back nLo the lust chamber. ia the inlet port.

7. A Je ice. according to claim I. uth the second apour being injected into the second chamber through a phirahit' of pipes. achi exteiidimmg a duti'eremit distaiice into the interior ol' the secoiid chamber.

8. A device. according to ehuiiii 1. with the water in the trough, in the first chamber, being saline or other polluted watet, that is distilled to Imesh watem, as it condenses inside the turbine, with the water in the trough being regularly replaced or supplemented, to regulate the degree of concentration of the pollutant chemicals in tIle tiuugh aict. 11 -

9. A dc icc, according to claim 4. ith the dousing liquid being saline or other pollutcd water, that is distilled to fresh water, as the second vapour condenses inside the second chanther, with oniy a fraction of the dousing liquid c apolalilig, n ith the icsidual eoncenualcd polluted atcr being drained off from the interior of the hollow stator chambers.

10. A device, according to claun 4. with the drop in vapour pressure caused by the condeiisatioii of the second vapour being used to dia the second vapour through a second turbo-generator, to generate additional elect ricitv.

ii. A device, according to claim 10. with the dousing liquid being a low boiling point organic liquid, for examples. pcntanc or lieaiie.

12. A device, according to claim 1, ith heat extracted horn the cooling and/or compression of flue or other poilu1nit gases being used to led tlieriiia! elierg into the water, in the first chamber.

Amendments to the claims have been filed as follows Claims 2. A device for converting energy stored in warm liquid vapour into electricity, mechanical or any other form of energy, with the device including a turbine, a first supply of warm vapour, originating from the evaporation of volatile liquid held iii an extensive trough, inside a first chamber, with the first vapour being fed into the turbine and a second supply of liquid vapour, originating from the evaporation ofa cooling liquid inside the body of the turbine unit, with the second vapour condensing inside a second chamber, placed underneath and in thermal contact with tilL' first clianiber, characterised by a tcmpei- ature gradient existing inside the first chamber, with liquid and overlying vapour towards the turbine iriouth end of the trough being at a higher temperature than at the far end of the trough, with a similar temperature gradient existing in the underlying second chamber, allowing thermal energy liberated by the condensation of the second vapour to be transferred to the first vapour, via the liquid it ihe trouh, over a range of temperatures, lower than the temperature at which the first vapour enters the turbine unit.
3. A device, according to claim I, with additional thermal energy being supplied to the liquid iii the first chamber, to assist in the evaporation of the first vapour.
4. A device, according to claim 2, with the additional thermal energy originating from a combustion or radioactive decay process or We absorption of' solar radiation.
5. A device, according to claim I, with the turbine including a plurality of stators that take the form of hollow chambers, with the wariri first vapour passing through a plurality of tunnels through each stator chamber, with the surfaces of the tunnel walls that are on the inside of the chamber being doused with a liquid, that evaporates, to form the second vapour.
6. A device, according to claim I, with the first chamber including a plurality of air inlet ports, at the cool end of the chamber, to allow air to be drawn in, to supplement the liquid vapour, to enable the vapour plus air pressure in the chamber to harniouise with the local environmental air pressure.
7. A device, according to claim 5, with the air and any residual vapour that emerges from the turbine being compressed to at least tile air pressure in tile local environment, to enable the air plus residual vapour to be pumped back into the first chamber, via the inlet port.
8. A device, according to claim I, with the second vapour being injected into the second chamber through a plurality of' pipes, each exteiidine, a di f'ireiit distaiice into die interior of the second chaniher.
9. A device, according to claim I, \vilh the liquid in the trough, in the first chamber, being saline or other polluted water, that is distilled to fresh waler, as it coiidenses inside the turbine unit, with the water in the trough being regularly replaced or slIppieIueiitL'Li, to regulate the degree of' Concentration of' the pollutant chemicals in the I rough water.
10. A device, according to claim 4, with the dousing liquid being saline or other polluted water, that is distilled to fresh water, as the second vapour condenses inside the second chamber, with only a fraction of the dousing liquid evaporating, with the residual concentrated polluted water being drained off from the interior of the hollow stator chambers.
11. A device, according to claim 4, with the drop in vapour pressure caused by the condensation of the secotd vapour being used to draw the second vapour through a second turbo-generator, to generate additional electricity.
12. A device, according to claim 10, with the (lousing liquid being a low boiling point organic liquid, for examples, ethanol, pentane or hexane.
13. A device, according to claim I, with heat extracted from the cooling andlor compression of fiqe or pollutant gases being used to feed thermal energy into the water, in the first chamber.
14. A device, according to claim I, with the turbine being coupled to an electricity generator.
15. A device, according to clanii 1, with any of the liquids being a mixture of two or more liquids, having djffrep boiling pints at normal atmospheric pressure, with the liquids partially separating out at different temperatures.
16. A device, according to claim 1, with the source of energy used to produce the warm liquid, that powers the invention being waste heat produced by exotliennal reactions in the manufacturing of cement.