Absorption heat pump for extreme operating conditions

Abstract

An absorption heat pump with a system for improving its efficiency under extreme conditions by bleeding off refrigerant downstream of the condenser and mixing it with the rich solution after this latter has been at least partially heated by the absorber and before it is fed into the desorber.

1 . An absorption heat pump comprising:
 a generator or desorber for generating , from a first fluid, vapor fed via a first line to a first condenser in heat exchange contact with a transmission fluid,   downstream of the condenser there being provided a second line entering an evaporator,   the second line comprising at least a first lamination valve,   an evaporator outlet being connected by a third line to an inlet for vapor from said first fluid into an absorber, comprising an absorber outlet for an enriched solution of said first fluid absorbed in a second fluid,   the absorber outlet being connected to a heat exchanger in heat transmission contact with the transmission fluid,   a heat exchanger outlet of the heat exchanger being connected to a suction side of a pump, a delivery side of the pump is connected by a fourth line to an inlet of a circuit in heat transmission contact with the absorber,   a fifth line connecting said circuit to a rich solution inlet of the generator,   the generator having a poor solution outlet connected by a sixth line provided with a second lamination valve to a poor solution inlet provided in the absorber,   wherein an introduction point of condensed vapor from said first fluid circulating through the circuit is provided between the inlet of the circuit and the rich solution inlet of the generator.   
     
     
         2 . A heat pump as claimed in  claim 1 , wherein the condensed vapor is withdrawn at a withdrawal point positioned directly downstream of the condenser by a withdrawal line. 
     
     
         3 . A heat pump as claimed in  claim 1 , wherein a non-return valve is provided in the withdrawal line, between the withdrawal point and the introduction point. 
     
     
         4 . A heat pump as claimed in  claim 1 , wherein the introduction point is in the form of a venturi. 
     
     
         5 . A heat pump as claimed in  claim 1 , wherein said introduction point is provided between a first and a second portion of said circuit. 
     
     
         6 . A heat pump as claimed in  claim 1 , wherein said withdrawal line comprises a valve arranged to exclude the withdrawal line when necessary. 
     
     
         7 . A heat pump as claimed in  claim 1 , wherein a rectifier in heat exchange contact with the fluid leaving the pump is provided between the generator and condenser. 
     
     
         8 . A heat pump as claimed in  claim 1 , wherein the sixth line is in heat exchange contact with a central portion of the generator. 
     
     
         9 . A heat pump as claimed in  claim 1 , wherein the fluids present in the second and third line are brought into heat transmission contact by means of a heat exchanger. 
     
     
         10 . A pump as claimed in  claim 9 , wherein a further lamination valve is provided at the inlet of the heat exchanger. 
     
     
         11 . A method for improving the efficiency of an absorption heat pump according to  claim 1 , when under desorber power modulation conditions, comprising the step of:
 bleeding off liquid refrigerant downstream of the condenser, and   mixing the liquid refrigerant with the rich solution after this rich solution has been at least partially heated by the absorber and before the rich solution undergoes further heat exchange with the absorber and is fed into the desorber.   
     
     
         12 . A method as claimed in  claim 11 , wherein the refrigerant is bled off between the condenser and the evaporator. 
     
     
         13 . A method as claimed in  claim 11 , wherein the refrigerant is mixed with the rich solution at a point in which the difference between the temperature of the solution before its mixing and the temperature resulting from mixing the solution with the refrigerant is between −5° C. and 5° C. 
     
     
         14 . A method as claimed in  claim 11 , wherein the introduction point is in a region in which the solution temperature is between 60° C. and 90° C. for the heat pump in which the refrigerant is ammonia and the liquid in which the ammonia is absorbed is water. 
     
     
         15 . A method as claimed in  claim 11 , wherein said mixing is achieved by a venturi. 
     
     
         16 . A method for improving the efficiency of absorption heat pumps according to  claim 1 , when under desorber power modulation conditions, comprising the step of:
 bleeding off liquid refrigerant downstream of the condenser and   mixing the liquid refrigerant with the rich solution after this rich solution has been at least partially heated by the absorber and before the rich solution undergoes further heat exchange with the absorber and is fed into the desorber, wherein said bleeding can be excluded, depending on the pump working conditions.   
     
     
         17 . A method as claimed in  claim 11 , wherein the introduction point is in a region in which the solution temperature is between 70° C. and 80° C., for the heat pump in which the refrigerant is ammonia and the liquid in which the ammonia is absorbed is water.