Heat-pump system with combined vapor expansion-compression stages and single-effect vapor absorption unit

A heat pump system, comprising:

• a boiler, the boiler operating at a boiler pressure, the boiler producing a vaporized working fluid;
• an expander fluidly coupled to the boiler, the expander having one or more vapor expander stages to produce mechanical power from the vaporized working fluid generated by the boiler;
• a high pressure condenser fluidly coupled to the expander, the vaporized working fluid condensing in the high pressure condenser to condensate and outputting heat;
• an absorber, the absorber operating at an absorber pressure, the absorber generating a solution that is highly concentrated in refrigerant;
• a generator fluidly coupled to the absorber, the generator thermally coupled to the high pressure condenser, the generator operating at a generator pressure, the generator receiving the heat outputted by the high pressure condenser, and thereby heating the solution that is highly concentrated in refrigerant so as to produce refrigerant vapor;
• a plurality of fluid feedlines fluidly coupling the absorber to the generator, a first one of the plurality of fluid feedlines comprising a generator solution feedline through which the solution that is highly concentrated in refrigerant flows from the absorber to the generator, a second one of the plurality of fluid feedlines comprising an absorber solution feedline through which solution that is low in refrigerant concentration flows from the generator to the absorber;
• a solution circulation pump fluidly coupled to the absorber and the generator in the generator solution feedline, the solution circulation pump raising the pressure of the solution highly concentrated in refrigerant that is discharged from the absorber;
• a solution heat exchanger comprising a thermally coupled cold side and a hot side, the solution heat exchanger being disposed on the generator solution feedline between the generator and the circulation pump and on the absorber solution feedline, the solution with the high concentration of refrigerant that is discharged by the solution circulation pump passing through the cold side to the generator feedline, the solution with the low concentration of refrigerant that is discharged by the generator passing through the hot side to the absorber solution feedline, and thereby the solution with high concentration of refrigerant passing through the generator feedline is being heated by the solution with the low concentration of refrigerant passing through the absorber solution feedline;
• a low pressure condenser fluidly coupled to the generator, wherein the refrigerant vapor produced in the generator is fed to the low pressure condenser, thereby producing condensate;
• a working fluid circulation pump fluidly coupled to the boiler, the working fluid circulation pump delivering the condensate from the high pressure or low pressure condenser to the boiler;
• an evaporator fluidly coupled to the low pressure condenser, the evaporator operating at an evaporator pressure, wherein condensate discharged from the low pressure condenser is fed into the evaporator;
• at least one compressor operatively coupled to the expander, the at least one compressor having one or more vapor compressor stages driven by the mechanical power generated by the one or more vapor expander stages of the expander, the at least one compressor including a first low pressure compressor having one or more low pressure compressor stages, and wherein refrigerant vapor produced in the evaporator is compressed by the one or more low pressure compressor stages of the first low pressure compressor to the absorber pressure, and flows into the absorber through an absorber vapor feedline;
• and
• a plurality of throttle valves, a first one of the plurality of throttle valves being disposed in the absorber solution feedline, and a second one of the plurality of throttle valves being disposed between the low pressure condenser and the evaporator;
• wherein the boiler operates at a pressure higher than the high pressure condenser, the high pressure condenser operates at a higher temperature than the generator temperature, the low pressure condenser operates at a pressure that is proximate to the generator pressure, the absorber pressure is intermediate to the pressure of the low pressure condenser and the evaporator pressure, and the mechanical power consumption of all of the one or more vapor compressor stages of the compressor and all shaft losses are supplied by the mechanical power produced by all of the one or more vapor expander stages of the expander.