Abstract:
The invention provides a heat pump/engine system having a water/brine flash evaporator in fluid communication with a first air/brine heat exchanger, a brine condenser in fluid communication with a second air/brine heat exchanger, and a vapor compressor/turbine connected on a fluid conduit leading from the flash evaporator to the brine condenser. Heat/pump methods are also provided herein.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a heat pump/engine system and method, in particular to a heat pump/engine system and method for the air-conditioning of enclosed spaces. 
     BACKGROUND OF THE INVENTION 
     Conventional air-conditioners are effective in removing Sensible Heat (SH) and less effective in removing Latent Heat (LH). To remove heat, the evaporator of the air-conditioner must be cold compared with the ambient air which is normally about 26° C. Yet to remove vapor, the evaporator should be cold compared with the dew point temperature, which is about 15° C. 
     It can be shown that when the LH exceeds the SH, the humidity in a conventionally conditioned enclosed space exceeds 60%, which humidity is the maximum humidity recommended for maintaining a comfortable environment. For this reason, in humid climate air-conditioning systems require an absorption machine which, while removing humidity, heats the enclosed space, and thus, reduces the efficiency of the conditioning system. 
     In PCT Application Publication No. WO96/33378, there is disclosed a heat pump system and method for air-conditioning utilizing a refrigerant evaporation and a refrigerant condenser for exchanging heat with brine solution. The refrigerant is considered to have an adverse effect on the ozone, and thus, it is recommended to avoid the use thereof. 
     SUMMARY OF THE INVENTION 
     Hence, it is a general object of the present invention to provide an environmental friendly heat pump/engine system and method utilizing a water/brine flash evaporator and air/brine heat exchangers. 
     It is a further object of the present invention to provide a heat pump/engine system and a method for air-conditioning an enclosed space by controlling the heat load in the enclosed space, by regulating the water/brine concentration of a flash evaporator. 
     It is still a further object of the present invention to provide a heat pump/engine method and a system for air-conditioning an enclosed space by controlling the temperature of the water and or the brine of said flash evaporator. 
     According to the present invention there is therefore provided a heat pump/engine system, comprising a water/brine flash evaporator in fluid communication with a first air/brine heat exchanger, a brine condenser in fluid communication with a second air/brine heat exchanger, and a vapor compressor/turbine connected on a fluid conduit leading from said flash evaporator to said brine condenser. 
     The invention further provides a heat pump/engine method, comprising a flash water/brine evaporator in fluid communication with a first air/brine heat exchanger, a brine condenser in fluid communication with a second air/brine heat exchanger, and a vapor compressor/turbine connected on a fluid conduit leading from said flash evaporator to said brine condenser, and regulating the heat load in an enclosed space by controlling the water flow in said flash evaporator in accordance with humidity and heat load in said space. 
     The invention will now be described in connection with certain preferred embodiments with reference to the following illustrative figures, so that it may be more fully understood. 
     With specific reference now to the figures in detail, it is stressed that the particulars shown are by way of example and for the purposes of illustrative discussion of the preferred embodiments of the present invention only and are presented in the cause of providing what is s believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to shown structural details of the invention in more detail that is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic illustration of a heat pump/engine system according to the present invention; 
     FIG. 2 is a schematic illustration of a further embodiment of a heat pump/engine system, and 
     FIG. 3 is a schematic illustration of still a further embodiment of a heat pump/engine system, according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1 there is seen a heat pump/engine system, including a water/brine flash evaporator  2  having a housing  4 , a water inlet  6  and a brine outlet conduit  8  leading from the bottom portion of the housing to a drip-type air-brine heat exchanger  10 . The top portion of the housing  4  constituting a vapor chamber  12  communicating with via conduit  14  and vapor compressor  16  with a vapor chamber  18  of a brine condenser  20 . To the vapor chamber  18  there is attached a vacuum pump  22 . The output from brine condensor  20  leads via conduit  24  to a second, air/brine heat exchanger  26 . Both heat exchangers  10  and  26  are similarly structured and are advantageously composed of an inlet  28  in the form of drip or spray nozzles, a brine/air heat exchanging means  30 , e.g., densely folded carton paper or packed particles. The lower portion of the heat exchangers constitute a brine reservoir  32 . For a more effective operation, there is installed an air blower  34  for introducing forced ambient air in the drip portion  35 . 
     The cold brine accumulated at the reservoirs  32  are recycled back to the brine flash evaporator  2  and to the condensor  20 , via conduits  36 , 38 , respectively, by means of pumps  40 , 42 . 
     In dry climate areas, the environmental vapor pressure may be lower than the vapor pressure inside the air-conditioned enclosed space. In such a case, the compressor  16  becomes a turbine, i.e., supplies, instead of consumes, energy. 
     In humid areas where the LH is dominant, ventilation will merely introduce more vapor into the enclosed space. When, however, the water is used to further cool down the brine at the flash evaporator  2  and heat exchanger  10 , dehumidifying and cooling of air at the air/brine heat exchangers  26 , is achieved. 
     In the event that most of the heat load is SH, the brine will reach a point where it will no longer absorb water vapor. Since the compressor  16  continues to suck vapor from the vapor chamber  12 , for the purpose of cooling, fresh water should be supplied through water inlet  6 . 
     Referring to FIG. 2, there is illustrated a further embodiment in which there is provided a flash evaporator  44  having two chambers, a brine flash chamber  46  and a water flash chamber  48 . A water conduit  50  having an inlet port  52  located adjacent to the bottom of the chamber  48  leads into the brine flash chamber  46 , meanders therealong, and exits adjacent to the water level  54  in the water chamber  48 . A pump  56  effects the circulation of water through the conduit  50 . Instead of the illustrated conduit  50 , other types of heat exchangers could just as well be used. 
     Such a two-chamber flash evaporator has a thermodynamic advantage, in that the brine/water solution is only partly cooled by water, having a vapor pressure which is high relative to the solution and therefore the compressor  16  invests relatively less energy in compressing the vapor. 
     Otherwise, the system operates similarly to the system of FIG.  1 . 
     In order to avoid excessive dilution of the brine and to improve performance, a per-se known brine concentrator  58  can be added to the system shown in FIG.  3 . 
     The brine concentrator  58  communicates via conduit  60  with the reservoir  32  of the heat exchanger  26  to receive the diluted brine accumulated therein. The water extracted by the concentrator  58  is driven into the water flash chamber  48  of the water/brine heat exchanger  44  via conduit  62  and pump  64 . 
     In cold climate areas, the system according to the present invention can be used for space heating by providing a heat source. Accordingly, as further seen in FIG. 3, the water in the water flash chamber  48  of flash evaporator  44  originates from a heated source  66 , e.g., a water aquifer, and is circulated between the heated source  66  and the chamber  48  via conduits  68  and  70 , by means of a pump  72 . 
     Alternatively, or in addition, the brine in heat exchanger  10  absorbs heat and vapor from outside air and part of this heat is used for flushing the brine and part is transmitted via conduit  50  to the water where it is used for water evaporation. There may also be provided a further heat exchanger  74 , abutting the blower  34  for cooling the air by means of this heat exchanger, communicating via conduits  76 ,  78  and circulating pump  80  with the water chamber  48 . 
     It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrated embodiments and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof the present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.