Heat Engine System

Abstract

A heat engine system for producing work by expanding a working fluid comprising first and second components, the system comprising, an apparatus for combining the second component of the working fluid as a liquid with the first component, the first component being a gas throughout the system, a compressor for compressing the first component, a pump for compressing at least most of the second component, a heater for heating the first and second components, an expander for expanding the first and second components to produce the work, and a recuperator for transferring at least some of the energy of the working fluid from the outlet of the expander, to the working fluid from the outlet of the apparatus, wherein a substantial portion of the energy transferred in the recuperator is at least a portion of the latent heat of the second component from the outlet of the expander.

1 . A heat engine system for producing work by expanding a working fluid comprising first and second components, the system comprising, an apparatus for combining the second component of the working fluid as a liquid with the first component, the first component being a gas throughout the system, a compressor for compressing the first component, a pump for compressing at least most of the second component, a heater for heating the first and second components, an expander for expanding the first and second components to produce the work, and a recuperator for transferring at least some of the energy of the working fluid from the outlet of the expander, to the working fluid from the outlet of the apparatus, wherein a substantial portion of the energy transferred in the recuperator is at least a portion of the latent heat of the second component from the outlet of the expander. 
     
     
         2 . A heat engine system as claimed in  claim 1 , wherein the apparatus is arranged to spray the liquid second component into a space having the first component therein. 
     
     
         3 . A heat engine system as claimed in  claim 1 , wherein the apparatus is arranged to diffuse the first component into the liquid second component. 
     
     
         4 . A heat engine system as claimed in any one of the preceding claims, wherein the recuperator is in the form of a shell and tube heat exchanger. 
     
     
         5 . A heat engine system as claimed in any one of the preceding claims, wherein the recuperator is in the form of a falling film condenser. 
     
     
         6 . A heat engine system as claimed in any one of the preceding claims, wherein the recuperator is arranged to provide separation of a liquid fraction of the working fluid from a gaseous fraction upon cooling of the working fluid from the outlet of the expander. 
     
     
         7 . A heat engine system as claimed in any one of the preceding claims, wherein the system also comprises at least one cooler for cooling the first and/or second components prior to combining them in the apparatus. 
     
     
         8 . A heat engine system as claimed in  claim 7 , wherein at least one of the cooler comprises an intercooler in the compressor to provide interstage cooling of the first component. 
     
     
         9 . A heat engine system as claimed in either one of  claim 7  or  claim 8 , wherein the or at least one of at least one cooler comprises a post compressor cooler for cooling the first component after it has been compressed. 
     
     
         10 . A heat engine system as claimed in any one of  claims 7  to  9 , wherein the or at least one of at least one cooler comprises a pre-compressor cooler for cooling the first component prior to being compressed in the compressor. 
     
     
         11 . A heat engine system as claimed in any one of  claims 7  to  10 , wherein the or at least one of at least one cooler comprises a liquid cooler for cooling the liquid second component. 
     
     
         12 . A heat engine system as claimed in any one of the preceding claims, wherein the pump compresses at least most of the liquid second component to a pressure above the ambient pressure. 
     
     
         13 . A heat engine system as claimed in any one of the preceding claims, wherein the pump compresses the liquid second component to at or about the pressure to which the compressor compresses the first component. 
     
     
         14 . A heat engine system as claimed in any one of the preceding claims, wherein the system also comprises a condenser for cooling the working fluid from the expander after it exits the recuperator. 
     
     
         15 . A heat engine system as claimed in  claim 14 , wherein the condenser is arranged to substantially condense the second component of the working fluid from the expander to a liquid. 
     
     
         16 . A heat engine system as claimed in either one of  claim 14  or  claim 15 , wherein the condenser is a separator for separating the second component as it condenses from the first component. 
     
     
         17 . A heat engine system as claimed in any one of the preceding claims, wherein the system is a closed system having substantially no mass inputs or outputs during operation of the system, other than replacement of incidental losses. 
     
     
         18 . A heat engine system as claimed in any one of the preceding claims, the system also comprising an energy transfer controller for controlling the energy transfer in the recuperator during operation of the system. 
     
     
         19 . A heat engine system as claimed in any one of the preceding claims, wherein the system also comprises a mass flow controller for controlling the mass flow rate of the second component relative to the mass flow rate of the first component. 
     
     
         20 . A heat engine system as claimed in any one of the preceding claims, wherein the first and second components of the working fluid are substances which are substantially inert with respect to each other. 
     
     
         21 . A heat engine system as claimed in any one of the preceding claims, wherein the second component is a substance which has a high volumetric expansion ratio from liquid to gas. 
     
     
         22 . A heat engine system as claimed in any one of the preceding claims, wherein the first component is a substance which is highly compressible as a gas. 
     
     
         23 . A heat engine system as claimed in any one of the preceding claims, wherein the first component is nitrogen and the second component is water. 
     
     
         24 . A heat engine system as claimed in any one of the preceding claims, wherein the heater comprises at least one volume of material arranged to be heated to at or above the melting temperature of the material, the heater also comprising passages through the at least one volume of material for the flow therethrough of the working fluid. 
     
     
         25 . A heat engine system as claimed in  claim 24 , wherein the at least one volume of material is heated using a heating fluid flowing through space through the at least one volume of material. 
     
     
         26 . A heat engine system as claimed in either one of  claim 24  or  25 , wherein the heater comprises at least two volumes of material, the materials in the volumes being different and having different melting temperatures. 
     
     
         27 . A heat engine system as claimed in claim  26 , wherein the materials are of progressively decreasing melting temperatures from the first volume to the last volume, the passages being arranged for the flow of the working fluid through the last volume first and the first volume last. 
     
     
         28 . A heat engine system as claimed in  claim 25 , wherein the working fluid is arranged to flow through the at least one volume of material countercurrently to the flow of the heating fluid. 
     
     
         29 . A heat engine system as claimed in any one of  claims 24  to  28 , wherein at least one of the volumes of material contains a mixture of two or more different materials. 
     
     
         30 . A heat engine system as claimed in  claim 29 , wherein one of the materials in the mixture of materials of the or each volume is for improving the heat transfer of the or each volume of material. 
     
     
         31 . A heat engine system as claimed in either one of  claim 29  or  30 , wherein one of the materials in the mixture of materials of the or each volume is for effecting the melting temperature of the or each volume of material. 
     
     
         32 . A method for producing work, the method comprising the steps of:
 compressing a first component of a working fluid in a compressor, the first component being a gas at all times during the method;   at least most of compressing a second component of the working fluid as a liquid in a pump;   combining the second component as a liquid with the first component in an apparatus;   heating the combined first and second components in a heater;   expanding the heated first and second components to produce the work in an expander; and   transferring in a recuperator at least some of the energy of the working fluid after it has been expanded to the working fluid prior to it being heated in the heater, wherein a substantial portion of the energy transferred is at least a portion of the latent heat of the second component after the working fluid has been expanded in the expander.   
     
     
         33 . A method as claimed in  claim 32 , wherein the step of transferring at least some of the energy in the recuperator converts at least some of the second component from liquid to gas prior to it being heated in the heater. 
     
     
         34 . A method as claimed in either one of  claim 32  or  33 , wherein the step of transferring at least some of the energy in the recuperator converts at least some of the second component from gas to liquid after it has been expanded in the expander. 
     
     
         35 . A method as claimed in any one of  claims 32  to  34 , wherein the method is a closed cycle method also comprising the step of repeating the steps of the method performed on the working fluid after at least some of its energy has been transferred in the recuperator to the working fluid which is yet to be heated in the heater. 
     
     
         36 . A method as claimed in any one of  claims 32  to  35 , the method also comprising the step of returning the first component to the compressor. 
     
     
         37 . A method as claimed in any one of  claims 32  to  36  the method also comprising the step of returning at least most of the second component to the pump. 
     
     
         38 . A method as claimed in any one of  claims 32  to  37 , the method also comprising the step of cooling the first and/or second components prior to the step of combining them. 
     
     
         39 . A method as claimed in  claim 38 , wherein the cooling step comprises cooling the first component between at least two stages of the compressor using an intercooler. 
     
     
         40 . A method as claimed in either one of  claim 38  or  39 , wherein the cooling step comprises cooling the first component after the step of compressing the first component. 
     
     
         41 . A method as claimed in any one of  claims 38  to  40 , wherein the cooling step comprises cooling the first component prior to the step of compressing the first component. 
     
     
         42 . A method as claimed in any one of  claims 38  to  41 , wherein the cooling step comprises cooling the second component prior to combining the second component with the first component. 
     
     
         43 . A method as claimed in any one of  claims 32  to  42 , wherein the method comprises the step of maintaining the temperature of the first component, prior to the step of combining it with the second component, to a temperature which is less than one which would cause vaporisation of the second component during the combining step. 
     
     
         44 . A method as claimed in any one of  claims 32  to  43 , wherein the method also comprises a step of separating a liquid fraction of the working fluid from a gaseous fraction after the working fluid has been expanded. 
     
     
         45 . A method as claimed in  claim 44 , wherein the step of separating occurs at least partially in the recuperator. 
     
     
         46 . A method as claimed in either one of  claim 44  or  45 , wherein the step of separating comprises separating at least most of the second component as a liquid from the first component as a gas. 
     
     
         47 . A method as claimed in  claim 46 , wherein the step of separating the first component from the second component comprises cooling the working fluid to condense most of the second component. 
     
     
         48 . A method as claimed in any one of  claims 32  to  47 , wherein the method also comprises the step of controlling the energy transferred in the recuperator. 
     
     
         49 . A method as claimed in  claim 48 , wherein the step of controlling the energy transferred in the recuperator comprises changing the conditions of the working fluid prior to expanding it in the expander. 
     
     
         50 . A method as claimed in either one of  claim 48  or  49 , wherein the step of controlling the energy transferred in the recuperator comprises changing the amount of the second component which is combined with the first component in the apparatus. 
     
     
         51 . A method as claimed in any one of  claims 32  to  50 , wherein the method also comprises the step of controlling the mass flow rate of the second component relative to the mass flow rate of the first component. 
     
     
         52 . A method as claimed in any one of  claims 32  to  51 , wherein the step of heating comprises flowing the combined first and second components through at least one volume of material which is heated to at or above the melting temperature of the material. 
     
     
         53 . A method as claimed in  claim 52 , wherein the step of heating also comprises heating the at least one volume of material using a heating fluid. 
     
     
         54 . A method as claimed in  claim 53 , wherein the step of heating comprises flowing the heating fluid through the at least one volume material in a counter current direction to the flow of the combined first and second components. 
     
     
         55 . A method as claimed in any one of  claims 32  to  54 , wherein the step of heating comprises heating the working fluid to a super-critical gas.