Absorption heat pump with burner power modulation

Abstract

An absorption heat pump in which to improve heat efficiency when under desorber power modulation conditions, heat is exchanged between the rich solution, before it enters the desorber, and the poor solution withdrawn from the desorber, before this poor solution is fed into the desorber.

1 . An absorption heat pump comprising;
 a generator or desorber associated with a device for modulating its power, the 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  6  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, heat exchanger outlet of the heat exchanger being connected to a suction side of a pump, the 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 lamination valve to a poor solution inlet provided in the absorber,   the pump further comprising an intermediate heat exchanger arranged to bring the fluids present in the sixth line and in the fifth line into heat exchange contact,   wherein a lamination valve is provided in the sixth line prior to the inlet to the intermediate heat exchanger to lower the poor solution pressure in the intermediate heat exchanger.   
     
     
         2 . A pump as claimed in  claim 1 , wherein the heat exchanger is of concentric tube type defining an annular passage for flowing the poor solution through the annular passage, the annular passage cross-section sized to provide only a slight pressure drop at the heat exchanger outlet when this annular passage cross-section is traversed exclusively by liquid at the maximum throughput allowed by the heat pump. 
     
     
         3 . A pump as claimed in  claim 1 , wherein the slight pressure drop is between 0.05 and 0.5 bar. 
     
     
         4 . A heat pump as claimed in  claim 1 , wherein an introduction point for 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 intermediate heat exchanger. 
     
     
         5 . A heat pump as claimed in  claim 4 , wherein the condensed vapor is withdrawn at a withdrawal point positioned directly downstream of the condenser by a withdrawal line. 
     
     
         6 . A heat pump as claimed in  claim 6 , wherein a non-return valve is provided in the withdrawal line, between the withdrawal point and the introduction point. 
     
     
         7 . A heat pump as claimed in  claim 1 , wherein said introduction point is provided between a first portion and a second portion of said circuit. 
     
     
         8 . A heat pump as claimed in  claim 7 , wherein said introduction point is provided downstream of the second circuit portion outside the absorber. 
     
     
         9 . A heat pump as claimed in  claim 5 , wherein said withdrawal line comprises a valve arranged to close the withdrawal line. 
     
     
         10 . A heat pump as claimed in  claim 1 , wherein a rectifier in heat exchange contact with the fluid leaving the pump is between the generator and condenser. 
     
     
         11 . A heat pump as claimed in  claim 1 , wherein the sixth line is in heat exchange contact with a central portion of the generator. 
     
     
         12 . 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:
 exchanging heat between the rich solution, before the rich solution enters the desorber, and the poor solution withdrawn from the desorber, before this poor solution is fed into the desorber,   before undergoing the heat exchanging, the poor solution pressure is lowered to an intermediate value between the desorber pressure and the absorber pressure.   
     
     
         13 . A method as claimed in  claim 12 , wherein refrigerant is bled off downstream of the condenser and mixed with the rich solution after this rich solution has been at least partially heated by the absorber and before the rich solution undergoes heat exchange with the poor solution. 
     
     
         14 . A method as claimed in  claim 12 , wherein the refrigerant is bled off between the condenser and the evaporator. 
     
     
         15 . A method as claimed in  claim 12 , wherein the refrigerant is mixed with the rich solution at a point in which the difference between the temperature of the rich solution before the mixing and the temperature resulting from the mixing of the rich solution with the refrigerant is between −5° C. and 5° C. 
     
     
         16 . A method as claimed in  claim 12 , wherein refrigerant is optionally bled off, wherein said bleeding can be excluded, depending on the pump working conditions.