Heat pump steam generator

Abstract

The disclosure provides a heat pump cycle that allows for an improved matching of the T(Q) slopes of the heat pump cycle. More particularly, in the heat pump cycle, the high temperature heat exchange is separated into two stages. Furthermore, a portion of the working fluid that was cooled in the first stage, is further cooled by expansion before being mixed with a heated working fluid for input to the recuperating heat exchanger.

What is claimed: 
     
         1 . A closed-loop, transcritical, recuperated heat pump cycle, comprising:
 a heat transfer source;   a heat transfer target;   a working fluid; and   a working fluid circuit transferring heat from the heat transfer source to the heat transfer target via the working fluid, the working fluid circuit including:
 a recuperator; and 
 a fluid expansion process that bypasses a portion of the working fluid around the recuperator to optimize the exergetic efficiency of the recuperator, thereby improving the coefficient of performance of the heat pump for certain types of applications in which heat is transferred from the heat transfer source to the heat transfer target over a limited temperature range. 
   
     
     
         2 . The closed-loop, transcritical, recuperated heat pump cycle of  claim 1 , wherein the fluid expansion process includes a first expansion device and a second expansion device. 
     
     
         3 . The closed-loop, transcritical, recuperated heat pump cycle of  claim 2 , wherein the fluid expansion process further includes a respective flow control valve for each of the first expansion device and the second expansion device. 
     
     
         4 . The closed-loop, transcritical, recuperated heat pump cycle of  claim 1 , further comprising a working fluid that, when the heat pump cycle is operating, circulates through the working fluid circuit. 
     
     
         5 . The closed-loop, transcritical, recuperated heat pump cycle of  claim 4 , wherein the working fluid is Carbon dioxide (CO 2 ). 
     
     
         6 . The closed-loop, transcritical, recuperated heat pump cycle of  claim 1 , wherein the heat pump cycle is a steam generating system and the heat transfer target is water. 
     
     
         7 . The closed-loop, transcritical, recuperated heat pump cycle of  claim 1 , further comprising a programmed control system. 
     
     
         8 . The closed-loop, transcritical recuperated heat pump cycle of  claim 1 , further comprising a compression process, the compression process including a plurality of compression stages with steam generation after each stage. 
     
     
         9 . A method for generating steam, comprising:
 circulating a working fluid through a working fluid circuit of a closed-loop, transcritical, recuperated heat pump cycle, the heat pump cycle including a fluid expansion process and a recuperator; and   bypassing a portion of the working fluid during the fluid expansion process around the recuperator to optimize the exergetic efficiency of the recuperator and improving the coefficient of performance of the heat pump for certain types of applications in which heat is transferred from the heat transfer source to the heat transfer target over a limited temperature range.   
     
     
         10 . The method of  claim 9  wherein circulating the working fluid through the working fluid circuit includes circulating Carbon dioxide (CO 2 ) through the working fluid circuit. 
     
     
         11 . The method of  claim 9 , further comprising generating steam from a heat transfer target during the steam generating process. 
     
     
         12 . The method of  claim 9 , further comprising controlling the method through a programmed control system. 
     
     
         13 . A heat pump system, comprising:
 a heat transfer source;   a heat transfer target;   a working fluid; and   a working fluid circuit through which, when the heat pump system is operating, the working fluid circulates, the working fluid circuit including:
 a recuperator disposed on:
 a first flow path between a heat transfer source and a steam generation process; and 
 a second flow path between the steam generation process and the heat transfer source, the second flow path including a fluid expansion process that bypasses a portion of the working fluid around the recuperator to optimize the exergetic efficiency of the recuperator, thereby improving the coefficient of performance of the heat pump for certain types of applications in which heat is transferred from the heat transfer source to the heat transfer target over a limited temperature range. 
 
   
     
     
         14 . The heat pump system of  claim 13 , wherein the heat transfer source includes waste heat, heat from an ambient atmosphere, or water. 
     
     
         15 . The heat pump system of  claim 13 , wherein the heat pump system is a steam generating system and the heat transfer target is water. 
     
     
         16 . The closed-loop, transcritical recuperated heat pump cycle of  claim 13 , further comprising a compression process, the compression process including a plurality of compression stages with steam generation after each stage. 
     
     
         17 . A closed-loop, transcritical, recuperated heat pump cycle that includes a fluid expansion process that bypasses a portion of a working fluid around a recuperator to optimize the exergetic efficiency of the recuperator, thereby improving the coefficient of performance of the heat pump for certain types of applications in which heat is transferred to the target over a limited temperature range. 
     
     
         18 . The closed-loop, transcritical, recuperated heat pump cycle of  claim 17 , wherein the closed-loop, transcritical, recuperated heat pump cycle comprises:
 a heat transfer source;   a heat transfer target;   a working fluid; and   a working fluid circuit transferring heat from the heat transfer source to the heat transfer target via the working fluid, the working fluid circuit including:   the recuperator; and   the fluid expansion process.   
     
     
         19 . The closed-loop, transcritical, recuperated heat pump cycle of  claim 18 , wherein the fluid expansion process includes a first expansion device and a second expansion device. 
     
     
         20 . The closed-loop, transcritical, recuperated heat pump cycle of  claim 18 , further comprising a working fluid that, when the heat pump cycle is operating, circulates through the working fluid circuit. 
     
     
         21 . The closed-loop, transcritical, recuperated heat pump cycle of  claim 18 , wherein the heat pump cycle is a steam generating system and the heat transfer target is water. 
     
     
         22 . The closed-loop, transcritical, recuperated heat pump cycle of  claim 18 , further comprising a programmed control system. 
     
     
         23 . The closed-loop, transcritical recuperated heat pump cycle of  claim 18 , further comprising a compression process, the compression process including a plurality of compression stages with steam generation after each stage.