Low-pressure high-efficiency aqua ammonia absorption heat pump system for BCHP residential use

Abstract

A system of a low-pressure ammonia-water absorption chiller/heat pump combined with a thermal mass as a source of liquid coolant. The low-pressure ammonia-water absorption chiller/heat pump has a ratio of generator pressure to absorber pressure which is preferably not more than 2:1, and may include a condensate sub-cooler heat exchanger with a separate coolant supply. The thermal mass may be a swimming pool, a geothermal system, or a cooling tower, for example. Combined with an electrical power production device such as photovoltaic solar collector panels, or a fuel cell; the combined system produces residential electrical power generation along with residential space heating and cooling, thereby providing a residential BCHP (Building cooling, heating, and power) system having a very low carbon footprint and a high operating efficiency, such as measured by heat pump COP (Coefficient of Performance).

1 . A low pressure ammonia-water absorption chiller/heat pump system for residential BCHP (building cooling, heating, and power) use with a thermal mass, comprising:
 a low pressure ammonia-water absorption chiller/heat pump having
 an absorber cooled by a first thermo-fluid liquid liquid and having a preselected, or pre-determined, absorber internal pressure consistent with said first thermo-fluid liquid temperature, 
 a low pressure generator with a preselected, or pre-determined, generator internal pressure and having a generator external heat source, 
 a generator-absorber heat exchanger (GAX) system, 
 an ambient air heat exchanger which is a refrigerant-to-air heat exchanger having fluid communication with an ammonia refrigerant and being in thermal communication with a flow of ambient air, 
 an thermal mass heat exchanger which is a refrigerant-to-liquid heat exchanger having fluid communication with said ammonia refrigerant and being in thermal communication with said first thermo-fluid liquid having said first thermo-fluid liquid temperature, and 
 a thermal mass for storage and/or dissipation of thermal energy, said thermal mass being in thermal communication with said first thermo-fluid liquid; 
 wherein said thermal mass heat exchanger serves as a condenser when operating in a cooling mode (i.e. transferring heat from said ambient air to said first thermo-fluid liquid), and serves as an evaporator when operating in a heating mode (i.e. transferring heat to said ambient air from said first thermo-fluid liquid); and 
 wherein said ambient air heat exchanger serves as an evaporator when operating in said cooling mode, and serves as an condenser when operating in said heating mode; and further 
   wherein said low pressure ammonia-water absorption chiller/heat pump has a ratio of an internal absolute pressure within said low pressure generator to an internal absolute pressure within said absorber equal to or less than 2.8:1.   
     
     
         2 . The low pressure ammonia-water absorption chiller/heat pump system for residential BCHP (building cooling, heating, and power) use with a thermal mass as in  claim 1 , further comprising
 a primary power source in thermal communication with said ammonia-water absorption chiller/heat pump and with said thermal mass;   a pump & valve system in fluid communication with said absorption heat pump, with said thermal mass, and with said primary power source; and   a coolant reversing valve which provides a heat dissipation configuration of said pump & valve system, said primary power source, and said thermal mass whereby excess thermal energy may be dissipated to an external environment during a non-power producing time period.   
     
     
         3 . The ammonia-water absorption system for BCHP residential use with a thermal mass of  claim 2 ,
 wherein said ambient air heat exchanger is a plenum-mounted indoor heat exchanger in thermal communication with an ammonia refrigerant and in thermal communication with an air flow from a residential living space, said air flow having a living space temperature, and   
       said thermal mass heat exchanger is an outdoor heat exchanger in fluid communication with said ammonia refrigerant and in thermal communication with said first thermo-fluid liquid having said first thermo-fluid liquid temperature,
 wherein said thermal mass is selected from a group consisting of a reservoir of water such as a swimming pool, a geothermal system, and a cooling tower; and 
 wherein said primary power source is selected from a group consisting of at least one passive solar panel, at least one photovoltaic solar panel, at least one fuel cell, and a combination of at least one passive solar panel with at least one fuel cell. 
 
     
     
         4 . The low pressure ammonia-water absorption chiller/heat pump system for residential BCHP (building cooling, heating, and power) use with a thermal mass as in  claim 3 , further comprising:
 a refrigerant reversing valve allowing heat pump operation; and   a diurnal and seasonal thermal load balancing system having a control module by which said low pressure absorption chiller/heat pump and said pump & valve system are automatically reconfigured for daytime and nighttime, allowing a change between a heating mode and a cooling mode depending on a user input and seasonal ambient conditions;   wherein said ambient air heat exchanger is a plenum-mounted indoor heat exchanger in thermal communication with air from a residential living space, said thermal mass heat exchanger is an outdoor heat exchanger, and said control module includes a thermal mass cooling system, in thermal communication with said thermal mass, by which a flow of said first thermo-fluid liquid is cooled thereby serving to maintain stable conditions in said thermal mass through dissipation of excess thermal energy; and   wherein said control module provides
 a cooling configuration in which a flow of first thermo-fluid liquid to the thermal mass heat exchanger is in parallel to a flow of first thermo-fluid liquid to the absorber, and a heating configuration in which the flow of first thermo-fluid liquid to the thermal mass heat exchanger is in series with the absorber whereby the thermal mass heat exchanger receives the flow of first thermo-fluid liquid preheated by the absorber; 
 a daytime heating configuration in which the first thermo-fluid liquid is provided directly from said primary power source and provides direct heating to said plenum-mounted indoor heat exchanger; and 
 a nighttime heating configuration in which the plenum-mounted indoor heat exchanger is heated by a heat pump configuration in which the thermal mass heat exchanger is connected in series with the absorber by a flow of first thermo-fluid liquid from the thermal mass by which the absorber preheats said flow of first thermo-fluid liquid to the thermal mass heat exchanger operating as an evaporator. 
   
     
     
         5 . The low pressure ammonia-water absorption chiller/heat pump system for residential BCHP use with a thermal mass as in  claim 4 , further comprising a Domestic Hot Water (DHW) pre-heat exchanger which provides pre-heated water from a mains water supply. 
     
     
         6 . The low pressure ammonia-water absorption chiller/heat pump system for residential BCHP use with a thermal mass as in  claim 1 , further comprising a two-step condenser system having:
 a primary condenser which receives a flow of refrigerant vapor from said generator, and is in thermal communication with a flow of said first thermo-fluid liquid, which in a cooling mode is in parallel to a flow of said first thermo-fluid liquid that cools said absorber;   a condensate sub-cooler in thermal communication with a sub-cooler coolant, and receiving refrigerant condensate produced in said a primary condenser; and   a condensate sub-cooler coolant source of said sub-cooler coolant at a sub-cooler coolant temperature, said sub-cooler coolant source being in fluid communication with said condensate sub-cooler;   wherein said sub-cooler coolant temperature is lower than said first thermo-fluid liquid temperature; and   wherein said low pressure ammonia-water absorption chiller/heat pump has a ratio of an internal absolute pressure within said generator to an internal absolute pressure within said absorber equal to or less than 2:1.   
     
     
         7 . The low pressure ammonia-water absorption chiller/heat pump system for residential BCHP use with a thermal mass as in  claim 6 , further comprising
 a primary power source in thermal communication with said ammonia-water absorption chiller/heat pump and with said thermal mass.   
     
     
         8 . The ammonia-water absorption system for BCHP residential use with a thermal mass of  claim 7 , further comprising
 a pump & valve system in fluid communication with said absorption heat pump, with said thermal mass, with said primary power source, and with said condensate sub-cooler coolant source;   wherein said thermal mass is selected from a group consisting of a reservoir of water such as a swimming pool, a geothermal system, and a cooling tower; and   wherein said primary power source is selected from a group consisting of at least one passive solar panel, at least one photovoltaic solar panel, at least one fuel cell, and a combination of at least one passive solar panel with at least one fuel cell.   
     
     
         9 . The low pressure ammonia-water absorption chiller/heat pump system for residential BCHP use with a thermal mass as in  claim 8 , further comprising a diurnal and seasonal thermal load balancing system having a control module by which said low pressure absorption chiller/heat pump and said pump & valve system are automatically reconfigured for daytime and nighttime, selecting between a heating mode and a cooling mode depending on a user input and seasonal ambient conditions;
 wherein said control module includes a thermal mass cooling system, in thermal communication with said thermal mass, by which a flow of said first thermo-fluid liquid is cooled thereby serving to maintain stable conditions in said thermal mass through dissipation of excess thermal energy. 
 
     
     
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         21 . A hybrid double-effect sorption chiller/heat pump system; comprising
 at least one single effect absorption chiller stage based on a first refrigerant, and having a generator with an external heat source, an absorber, a first evaporator, a liquid-cooled primary condenser, a GAX (Generater-Absorber eXchanger), a heat recovery recuperator recovering heat from a flow of first refrigerant to the condenser and from a first solution flow out of the absorber;   at least one solid adsorption chiller stage based on a second refrigerant, further comprising a housing with at least one pair of adsorber/desorber sections, each of said sections having at least one adsorber/desorber heat exchanger in thermal contact with a quantity of adsorbent material, and in second refrigerant vapor communication with at least one adsorption-stage evaporator/condenser section by way of a thermal insulation layer permeable to vapor of said second refrigerant, said adsorption-stage evaporator/condenser section having at least one evaporator/condenser heat exchanger;   at least one hot thermo-fluid secondary loop having a pump and in thermal communication with said heat recovery recuperator, with said primary condenser, with said at least one adsorber/desorber heat exchanger and with said at least one evaporator/condenser heat exchanger;   at least one thermal mass in thermal communication with said at least one hot thermo-fluid secondary loop;   at least one chilled thermo-fluid secondary loop in thermal communication with said first evaporator and with said at least one adsorption-stage evaporator, and operating simultaneously with said at least one hot thermo-fluid secondary loop;   and a DHW (domestic hot water) heat exchanger in thermal communication with said at least one hot thermo-fluid secondary loop;   wherein each of said pair of adsorber/desorber sections cycles alternately between an adsorption phase and a desorption phase with one section of said pair being in an adsorption phase while the other section is in a desorption phase, and the evaporator/condenser section operates as an evaporator when it is in vapor communication with an adsorber/desorber section in an adsorption phase, but operates as a condenser when it is in vapor communication with an adsorber/desorber section in an desorption phase;   and wherein said adsorber/desorber section when in an desorption phase is driven, at least in part, by heat of condensation recovered from said at least one single effect absorption chiller stage, thereby acting as a hybrid second effect of said hybrid double-effect sorption heat pump.   
     
     
         22 . The hybrid double-effect sorption chiller/heat pump system of  claim 21 ; further comprising at least one photo-voltaic solar array; wherein said at least one heat recovery heat source is a flow of air having thermal contact with a dark side of at least one panel of said photo-voltaic solar array. 
     
     
         23 . The hybrid double-effect sorption chiller/heat pump system of  claim 22 ; wherein said at least one external heat source is a condensing burner which burns a fuel selected from the group composed of natural gas, liquified petroleum gas (LPG, e.g. propane), and fuel oil; whereby said burner provides supplementary heat at times when the heat recovery is insufficient to drive the at least one solid adsorption chiller stage. 
     
     
         24 . The hybrid double-effect sorption chiller/heat pump system of  claim 23 ; wherein said first refrigerant is water, and said adsorbent material is selected from the group consisting of silica gel and silica zeolite. 
     
     
         25 . The hybrid double-effect sorption chiller/heat pump system of  claim 24 ; wherein said absorption-stage rectifier is cooled by a second flow of solution out of the absorber. 
     
     
         26 . A solar heat recovery-driven adsorption chiller/heat pump system; comprising
 at least one solar heat recovery heat source;   at least one external heat source;   at least one heat recovery recuperator in thermal communication with said at least one solar heat recovery heat source;   at least one solid adsorption chiller stage based on a first refrigerant, further comprising a housing with at least one pair of adsorber/desorber sections, each of said sections having at least one adsorber/desorber heat exchanger in thermal contact with a quantity of adsorbent material, and in refrigerant vapor communication with at least one adsorption-stage evaporator/condenser section by way of a thermal insulation layer permeable to vapor of said first refrigerant, said adsorption-stage evaporator/condenser section having a evaporator/condenser heat exchanger;   at least one hot thermo-fluid secondary loop having a pump and in thermal communication with said heat recovery recuperator, with said at least one solar heat recovery heat source, with said at least one adsorber/desorber heat exchanger and with said evaporator/condenser heat exchanger;   at least one thermal mass in thermal communication with said at least one hot thermo-fluid secondary loop;   at least one chilled thermo-fluid secondary loop in thermal communication with said at least one adsorption-stage evaporator, and operating simultaneously with said at least one hot thermo-fluid secondary loop;   at least one fan coil in thermal communication with said at least one hot thermo-fluid secondary loop, or in the alternative with said at least one chilled thermo-fluid secondary loop for heating or cooling respectively a flow of air from a living space;   and a DHW (domestic hot water) heat exchanger in thermal communication with said at least one hot thermo-fluid secondary loop;   wherein each of said pair of adsorber/desorber sections cycles alternately between an adsorption phase and a desorption phase with one section of said pair being in an adsorption phase while the other section is in a desorption phase, and the evaporator/condenser section operates as an evaporator when it is in vapor communication with an adsorber/desorber section in an adsorption phase, but operates as a condenser when it is in vapor communication with an adsorber/desorber section in an desorption phase.   
     
     
         27 . The solar heat recovery adsorption chiller/heat pump system of  claim 26 ; further comprising at least one photo-voltaic solar array; wherein said at least one solar heat recovery heat source is a flow of air having thermal contact with a dark side of at least one panel of said photo-voltaic solar array; whereby said at least one solid adsorption chiller stage is driven by heat recovered from the dark side of said photo-voltaic solar array. 
     
     
         28 . The solar heat recovery adsorption chiller/heat pump system of  claim 27 ; wherein said at least one external heat source is an on-demand domestic hot water heater with a condensing burner which burns a fuel selected from the group composed of natural gas, liquid petroleum gas (LPG, e.g. propane), and fuel oil; whereby said burner provides supplementary heat at times when the heat recovery is insufficient to drive the at least one solid adsorption chiller stage. 
     
     
         29 . The solar heat recovery adsorption chiller/heat pump system of  claim 28 ; wherein said first refrigerant is water, and said adsorbent material is selected from the group consisting of silica gel and silica zeolite.