Vehicular absorption air conditioning process and system utilizing engine coolant waste heat

Claim 2

In combination with a vehicle having a recirculating liquid engine coolant, an absorption cycle air-conditioning process for cooling the passenger compartment of said vehicle, said process utilizing a refrigerant consisting essentially of water and an absorbent consisting essentially of lithium bromide, said absorbent and said refrigerant being intermiscible to form working solutions of variable concentration, said process comprising the steps of: (a) at relatively low pressure, contacting at least a portion of said refrigerant with a first working solution to absorb at least a portion of said refrigerant into said first working solution, said refrigerant being initially in vapor phase; (b) pumping said first working solution to an area of intermediate pressure; (c) utilizing a portion of the heat available from said engine coolant to desorb as vapor at least a portion of said refrigerant from said first working solution; (d) passing said first working solution resulting from step (c) through a first pressure reduction valve and a first heat exchanger, thereby reducing pressure and temperature to the operating conditions of step (a); (e) returning said first working solution to step (a) to complete the first working solution circuit; (f) at said intermediate pressure, contacting at least a portion of the refrigerant vapor from step (c) with a second working solution to absorb at least a portion of said refrigerant vapor into said second working solution; (g) pumping said second working solution to an area of relatively high pressure; (h) utilizing a portion of the heat available from said engine coolant to desorb as vapor at least a portion of said refrigerant from said second working solution; (i) passing said second working solution resulting from step (h) through a second expansion valve and a second heat exchanger, thereby reducing pressure and temperature to the operating conditions of step (f); (j) returning said second working solution to step (f) to complete the second working solution circuit; (k) condensing at least a portion of the refrigerant vapor from step (h) at relatively high pressure; (l) passing the resultant liquid refrigerant to an area of relatively low pressure; (m) directing a flow of relatively warm air past said liquid refrigerant thereby cooling said air flow and vaporizing at least a portion of said liquid refrigerant, and; (n) passing the resultant refrigerant vapor to step (a).

Claim 3

An absorption cycle air conditioning process according to claim 1 wherein the operating pressure of steps (a), (m) and (n) is approximately 0.14 psia (7 mm Hg), the operating pressure of steps (c) and (f) is approximately 0.25 psia (13 mm Hg), and the operating pressure of steps (h) and (k) is approximately 0.66 psia (34 mm Hg).

Claim 4

An absorption cycle air conditioning process according to claim 1, further comprising the steps of: storing in a reservoir a portion of said liquid refrigerant resulting from step (k), and; storing in a reservoir a portion of said first working solution resulting from steps (a) and (b); whereby a stored volume of said liquid refrigerant and a stored volume of said working solution are available to enable the cooling operation of said air conditioning process under conditions where the heat available from said engine coolant is insufficient to produce desorption of said refrigerant in steps(c) and (h).

Claim 5

In combination with a vehicle having a recirculating liquid engine coolant, an absorption cycle air-conditioning system for cooling the passenger compartment of said vehicle, said system utilizing a refrigerant consisting essentially of water and an absorbent consisting essentially of lithium bromide, said absorbent and said refrigerant being intermiscible to form working solutions of variable concentration, said system comprising: first absorber means for absorbing at least a portion of said refrigerant into a first working solution, said first absorber means operating at relatively low pressure; first generator means connected to said first absorber means for desorbing as vapor at least a portion of said refrigerant from said first working solution produced in said first absorber means; first pumping means interposed between said first absorber means and said first generator means for raising said first working solution to an intermediate pressure; means for returning said first working solution produced in said first generator means to said first absorber means at reduced pressure and temperature; second absorber means connected to said first generator means for absorbing at least a portion of the refrigerant vapor produced in said first generator means into a second working solution; second generator means connected to said second absorber means for desorbing as vapor at least a portion of said refrigerant from said second working solution produced in said second absorber means; second pumping means interposed between said second absorber means and said second generator means for raising said second working solution to a relatively high pressure; means for returning said second working solution produced in said second generator means to said second absorber means at reduced pressure and temperature; condenser means connected to said second generator means for condensing at relatively high pressure the refrigerant vapor produced in said second generator means; pressure reduction means connected to said condenser means for reducing the liquid refrigerant produced by said condenser means to a relatively low pressure; evaporator means for evaporating at relatively low pressure the liquid refrigerant flowing from said pressure reduction means, said evaporator means including means for transferring the heat available from a flowing air stream to said liquid refrigerant thereby causing its evaporation; means for connecting said evaporator means to said first absorber means, and; means for transferring the heat available from said engine coolant to said first and second generator means.

Claim 6

In combination with a vehicle having a recirculating liquid engine coolant, an absorption cycle air-conditioning system for cooling the passenger compartment of said vehicle, said system utilizing a refrigerant consisting essentially of water and an absorbent consisting essentially of lithium bromide, said absorbent and said refrigerant being intermiscible to form working solutions of variable concentration, said system comprising: first absorber means for absorbing at least a portion of said refrigerant into a first working solution, said first absorber means operating at relatively low pressure; first generator means connected to said first absorber means for desorbing as vapor at least a portion of said refrigerant from said first working solution produced in said first absorber means; first pumping means interposed between said first absorber means and said first generator means for raising said first working solution to an intermediate pressure; means for returning said first working solution produced in said first generator means to said first absorber means at reduced pressure and temperature; second absorber means connected to said first generator means for absorbing at least a portion of the refrigerant vapor produced in said first generator means into a second working solution; second generator means connected to said second absorber means for desorbing as vapor at least a portion of said refrigerant from said second working solution produced in said second absorber means; second pumping means interposed between said second absorber means and said second generator means for raising said second working solution to a relatively high pressure; means for returning said second working solution produced in said second generator means to said second absorber means at reduced pressure and temperature; condenser means connected to said second generator means for condensing at relatively high pressure the refrigerant vapor produced in said second generator means; pressure reduction means connected to said condenser means for reducing the liquid refrigerant produced by said condenser means to a relatively low pressure; evaporator means for evaporating at relatively low pressure the liquid refrigerant flowing from said pressure reduction means, said evaporator means including means for transferring the heat available from a flowing air stream to said liquid refrigerant thereby causing its evaporation; means for connecting said evaporator means to said first absorber means, and; means for transferring the heat available from said engine coolant to said first and second generator means.

Claim 7

A vehicular absorption air conditioning system according to claim 4 wherein said condenser means includes a reservoir for storing a predetermined volume of liquid refrigerant, and said first generator means includes a reservoir for storing a predetermined volume of concentrated working solution whereby predetermined volumes of said liquid refrigerant and of said concentrated working solution are available to enable the cooling operation of said air conditioning system under conditions where insufficient heat is available from said engine coolant to thermally drive said first and second generator means.

Claim 8

A vehicular absorption air conditioning system according to claim 4 wherein said means for transferring the heat available from said engine coolant to said first and second generator means comprises: at least one tube containing said engine coolant disposed within said first generator means and having its outer surface in contact with said first working solution contained within said first generator means, said tube being fabricated from thermally conductive material enabling the transfer of heat from said engine coolant to said first working solution, and; at least one tube containing said engine coolant disposed within said second generator means and having its outer surface in contact with said second working solution contained within said second generator means, said tube being fabricated from thermally conductive material enabling the transfer of heat from said engine coolant to said second working solution, and; means for passing said engine coolant from the engine to said tubes and returning it to said engine.

Claim 9

A vehicular air conditioning system according to claim 5 further comprising means for remotely actuating the operation of said air conditioning system so as to enable pre-cooling of said vehicle prior to starting the engine of said vehicle.

Claim 10

A vehicular air conditioning system according to claim 5 further comprising timer means in electrical association with said air conditioning system for automatically actuating the operation of said air conditioning system at a predetermined time.