Heat transfer engine

Abstract

The invention provides a method for a thermally activated closed loop heat transfer system, and requires no other external power source other than the heat which it is transferring. The system is based on a two-phase (liquid/vapor) working fluid, with heat input through an evaporator and heat rejected through a condenser. All of the mechanical power produced by an engine, driven by the high vapor quality fluid leaving the evaporator, is consumed by the pump. The pump drives the low vapor quality fluid leaving the condenser back to the evaporator. Nearly isothermal heat transport can be achieved when using a pure or azeotropic working fluid, since the operation only requires the evaporator pressure to be marginally higher than the condensers pressure.

1 . A closed loop heat transfer system comprising:
 an evaporator, a condenser, an engine and a pump all fluidly connected to one another, wherein the engine comprises two or more counter-rotating lobes and the pump comprises two or more counter-rotating gears in communication with the two or more counter-rotating lobes, and wherein the two or more counter-rotating gears provide a timing mechanism for the two or more counter-rotating lobes, and wherein heat converted to work in the engine generates power to drive the pump which provides pressure gain necessary to overcome the hydrodynamic losses associated with fluid flow through the evaporator, condenser, engine and pump, and the couplings therebetween, as well as for the engine to operate.   
     
     
         2 . The closed loop heat transfer system of  claim 1 , wherein the engine is a positive displacement engine and the pump is a positive displacement pump, and the displacement ratio of the engine to the pump is greater than one and less than the density ratio of liquid to vapor of the working fluid. 
     
     
         3 . (canceled) 
     
     
         4 . The closed loop heat transfer system of  claim 1 , wherein the engine is a piston engine and the pump is a piston pump, and wherein the work generated in the engine is transferred to the pump through a shaft interconnecting the engine and the pump. 
     
     
         5 . The closed loop heat transfer system of  claim 1 , wherein the working fluid is an azeotropic working fluid. 
     
     
         6 . The closed loop heat transfer system of  claim 1 , wherein the working fluid is selected from the group consisting of a hydrofluorocarbon, a hydrofluoroolefin, a hydrofluoroether, a hydrocarbon, ammonia and water. 
     
     
         7 . The closed loop heat transfer system of  claim 1 , wherein the working fluid is a zeotropic or non-azeotropic working fluid. 
     
     
         8 . The closed loop heat transfer system of  claim 1 , wherein the working fluid is a mixture of two or more of a hydrofluorocarbons, a hydrofluoroolefins, a hydrofluoroethers, a hydrocarbons, ammonia and water. 
     
     
         9 . A closed loop heat transfer method comprising:
 circulating a working fluid through an evaporator, a condenser, an engine and a pump, wherein the engine comprises two or more counter-rotating lobes and the pump comprises two or more counter-rotating gears in communication with the two or more counter-rotating lobes, and wherein the two or more counter-rotating gears provide a timing mechanism for the two or more counter-rotating lobes, and wherein heat converted to work in the engine generates power to drive the pump which provides pressure gain necessary to overcome the hydrodynamic losses associated with fluid flow through the evaporator, condenser, engine and pump, and the couplings therebetween, as well as for the engine to operate.   
     
     
         10 . The closed loop heat transfer method of  claim 9 , wherein the engine is a positive displacement engine and the pump is a positive displacement pump, and the displacement ratio of the engine to the pump is greater than one and less than the density ratio of liquid to vapor of the working fluid. 
     
     
         11 . (canceled) 
     
     
         12 . The closed loop heat transfer method of  claim 9 , wherein the engine is a piston engine and the pump is a piston pump, and wherein the work generated in the engine is transferred to the pump through a shaft interconnecting the engine and the pump. 
     
     
         13 . The closed loop heat transfer method of  claim 9 , wherein the working fluid is an azeotropic working fluid. 
     
     
         14 . The closed loop heat transfer method of  claim 9 , wherein the working fluid is selected from the group consisting of a hydrofluorocarbon, a hydrofluoroolefin, a hydrofluoroether, a hydrocarbon, ammonia and water. 
     
     
         15 . The closed loop heat transfer method of  claim 9 , wherein the working fluid is a zeotropic or non-azeotropic working fluid. 
     
     
         16 . The closed loop heat transfer method of  claim 9 , wherein the working fluid is a mixture of two or more of a hydrofluorocarbon, a hydrofluoroolefin, a hydrofluoroether, a hydrocarbon, ammonia and water. 
     
     
         17 . A closed loop heat transfer system comprising:
 a non-azeotropic working fluid flowing through an evaporator, a condenser, an engine and a pump, wherein the lowest evaporator temperature is less than the highest condenser temperature, and wherein heat converted to work in the engine generates power to drive the pump which provides pressure gain necessary to overcome the hydrodynamic losses associated with fluid flow through the evaporator, condenser, engine and pump, and the couplings therebetween, as well as for the engine to operate.   
     
     
         18 . The closed loop heat transfer system of  claim 17 , wherein the engine is a positive displacement engine and the pump is a positive displacement pump, and the displacement ratio of the engine to the pump is greater than one and less than the density ratio of liquid to vapor of the working fluid. 
     
     
         19 . The closed loop heat transfer system of  claim 17 , wherein the working fluid is a mixture of two or more of a hydrofluorocarbon, a hydrofluoroolefin, a hydrofluoroether, a hydrocarbon, ammonia and water.