US 2690656 A
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BY KIM-fp@ ATTORNEYS Martell [lm W. W. CUMMINGS METHOD OF AIR CONDITIONING Filed March 24, 1949 Patented Oct. 5, 1954 UNITED STATES PATENT OFFICE 3 Claims.
This invention relates to improvements in methods of air conditioning, and has for its object to increase the capacity of standard refrigeration systems without materially adding to their operating costs.
In the standard refrigeration system used for cooling air, for instance, as is well known, the refrigerant in low pressure gaseous form, of any standard and known type, is rst compressed by a standard compressor to a gas of high pressure. This compression of the gas generates heat. The high pressure gas then passes to the condenser, where it is condensed, or changed to liquid form through the use of a cooling medium, which is frequently cold water, and some times air, and in the condensation process the high pressure gas loses heat and the cooling medium gains heat. The heat thus acquired by the cooling medium is normally wasted. The high pressure saturation refrigerant then usually passes to a receiver or storage tank, from which it is released through an expansion or regulating valve to an evaporating coil, Where the liquid refrigerant changes back to a gas of low pressure. In this process the refrigerant drops rapidly in temperature and there is an exchange of heat between the refrigerant and a cooling medium, which may be brine, which in turn is recirculated about the area being refrigerated. Or the exchange of heat may be between the refrigerant in the evaporating coil across which air is passed to be cooled, or it may be the substance being refrigerated itself which loses heat to the refrigerant. The gas is then again compressed as before and the cycle is repeated.
Heretofore, the only practical way of materially increasing the capacity of such a standard refrigeration system has involved increasing the physical facilities, as by duplicating the existing plant or by replacing it with one of greater capacity. This of necessity has involved increasing the operating costs, or doubling them, if the plant is duplicated. I have discovered, however, that the capacity of the standard refrigeration system may be greatly increased or even doubled, without materially increasing the operating costs, by combining with it a uid sorbent system (such as triethylene glycol, or lithium chloride) for dehumidifying the air, and regenerating the sorbent, by using the liquid sorbent, after passing through the dehumidifier, as the cooling or condensing medium for the refrigerant. At the same time, the sorbent, which has thus gained heat in the condensing process, can be used for preheating the air stream in the sorbent regeneration system for regenerating or restoring the sorbent by extracting from it the moisture previously absorbed from the air in the dehumidication process. The air stream in the uid sorbent regeneration system is normally separately heated from an outside or additional heat source. The heat thus normally thrown away on the refrigeration side is thus utilized for preheating the air stream in the sorbent regeneration cycle, and as the heat normally thrown away on the refrigeration side usually equals that required for sorbent regeneration (per yton of accomplishment) great savings in operating costs can be achieved. Thus for any desired refrigeration tonnage, by thus combining the standard refrigeration system with a uid sorbent regeneration system, the refrigerating capacity can be doubled, without appreciably increasing the operating costs, in either power or water consumption. When the uid sorbent regeneration system also includes the use of a diffusing tower, as described in my copending patent application Serial No. 63,358, filed December 3, 1948, now abandoned, where the warm high vapor pressure air is passed through the diffusing tower and equalization of the vapor pressure to that of the surrounding atmosphere is elected, with consequent loss of water vapor without appreciable loss of heat, additional savings in operating costs can be achieved.
In the drawings:
The iigure is a diagrammatic showing of my invention, in which a standard refrigeration system is combined with a fluid sorbent regeneration system.
As shown in the drawings, A represents the standard refrigeration system or cycle, and B represents the sorbent regeneration system or cycle. In the refrigeration system of standard form the compresser unit is indicated at l0, where the low pressure saturated gas of a refrigerant, of any well known type such as Freon 11 or 12 (which chemically is dichloro-difiuoro-methane, CClzFz) is compressed to a high pressure saturated gas, and in the process heat is generated. A condenser unit is indicated at I2, and again is of standard type, where the high pressure Saturated gas of a superheated temperature is cooled and condensed to a high pressure saturated liquid. The usual cooling medium is, of course, -cold water and occasionally air, which is passed through a heat exchanger, whereby the heat of the high pressure saturated gas is removed and carried away by the cooling medium. The heat thus acquired by the cooling medium in the condensing processis normally wasted. A novel feature of the present invention, however, is that the dilute liquid sorbent from the dehumidifying unit 20 in the sorbent regeneration system B is used as the cooling or condensing medium in the condenser I2 of the refrigeration system A. The high pressure saturated liquid refrigerant then passes to the receiver or tank I4, where it is retained until it passes through the expansion valve I5. In passing through the expansion valve l5 the high pressure liquid refrigerant passes to the evaporator or cooler i6 and expands to a low pressure gas. is required, and as well known, the heat is drawn from the substances to be cooled; which may be of any nature, and where the evaporator or cooler IB is located at a distance from the substance to be cooled, brine, ammonia, cold water. or other suitable cooling medium is nrst cooled in the evaporator I6 and then pumped to the cooling chamber as in central refrigeration plants.
As previously stated; the sorbent regeneration system B- is connected to the refrigeration system A through utilizing the-dilute liquid sorbent from the dehumidier 2G as the cooling medium in the condenser l2` of the refrigeration system A. The sorbent regeneration system B may be of any standardl type, but for greatest emciency the form shown inthe drawings at B- is preferred. It will be understood that the Warm moist air passes through the dehumidier 2e which takes-out'most of` the moisture and removes latent heat or heat of the moisture from the air. The warm dry air may then beV passed through a cooling coil 22 which receives cooling medium through the pipe I- from the evaporator or cooler i6 and which cooling medium is then returned to the cooler I6A through thepipe I9. Passing the warm dry air through the-coolingV coil 22 removes aportion of the sensible heat content of that air. The cool dry air then passes intothe controlled zone. By thus combiningthe-sorbent' regeneration system BA with the refrigeration system-A, the latent heat removal is accomplished in great part by the use of heat formerly wasted.
The sorbent regeneration system B rst conducts the concentrated liquid sorbent, of any standardl or suitable type, such as triethylene glycol, lithium chlorideY and the like, to the dehumidier 2d through the conduit l-B. As is Well known an air stream is forced through the dehumidifier 2t' by a fan (not shown), where it passes through' a spray or cascade of theA concentrated sorbent which absorbs moisture from the air stream, thus dehumidifying it. Asprevi'- ously stated, liquid sorbent thus dilutedis conducted through'the condenser l2 of the refrigeration systemA A, where it acts as the cooling medium for the refrigerant inl the condenser l2. Inthe process the dilute liquid sorbent acquires considerable heat, and it is then conducted to the'pre-heat exchanger 24 in the air stream 26 of the closed sorbent regeneration system B. The diluteliquid sorbent there gives up its heat to thev air stream andV thus preheats the latterfor subsequent use. The sorbent may be further cooled in the sorbent cooler 2B, which is cooled by anyv suitable cooling medium, chilled Water or the like, or from the cooling medium of the evaporator or cooler I6 of the refrigeration cycle A. The sorbent cooler 28, however, may be omitted entirely if the sorbent is sufficiently cooledwithout it, and the cooled dilute sorbent then passes to the spray nozzle 3U, where the sorbent is regenerated and the moisture extracted. from it by passing the heated. air stream from conduit 26 During this change of state heat.
4 through the spray of the dilute sorbent. The regenerated and concentrated sorbent then passes again through pipe I8 back to the dehumidier 20. The heated moisture containing air after passing through the spray Sil may then be wasted to atmosphere where its heat is entirely lost. But I prefer to conduct it through conduit 32 to the diirusing tower 34 having porous, permeable or pervious walls 35. The side Walls. 3.5 of the diffusion tower are made of" a porous, permeable or pervious material, relatively densely packed but having fine interstices therethrough which permits the moisture content in the air, in vapor or gaseous form and or" relatively high vapor pressure to escape through the walls 35, until the vapor pressure within the diiusion tower 34 equalizes withy that of the air surrounding the tower se. The interstices or passages through the Walls 35 are so small that they oier frictional resistance to the passage of air therethrough both from the' inside out and from the inside in. The walls 35 thusvineiect act as a lter in permitting the high pressure watervapor to escape, but retaining the relatively low pressure heated air therein. The ltered walls- 2li may be made of any suitable material, which is preferably rustless, and will not absorb or soak up moisture, such as spun glass, or fine metal wire wool such as stainless steel, copper or brass. The sorbent regeneration system B', with its diffusing tower 3G is more fully described' in my copending application Serial No. 53,358, filed December, 3, 194:8. By conductingv the heated and moisture containing air through my diffusion tower 3ft, at least fifty percent of the heat therein normally lost ii exhausted toatmosphere, can be saved by the method and apparatus embodying my sorbent regeneration system B and disclosed in my above mentioned patent application. The air stream with a large portion of its moisture content removed is then re-circulated through the closed sorbent regeneration system B by means of the circulating fan 3S, where the' air is again passed through the preheat exchanger 24, to repeat the sorbent regeneration cycle. It will thus be seen that by utilizing the warmed dilute liquid sorbent after passing through the condenser |25 of the' refrigeration system A, to preheat the air in the closed sorbent regeneration system B, no separater or additional heat source is necessary for preheating the air, as is required in a standardsorbent regeneration system.
It will thus be seen that by combining a standard refrigeration system with a liquidV sorbent regeneration system the capacity ofl a standard refrigeration system, the refrigeratingv capacity can be doubled, without materially increasing the operating costs, either in power or water consumption.
1. The process of air conditioning which combines cooling and dehumidifying the air in a controlled area which consists in' combining a refrigeration system for cooling the air wherein a refrigerant in gas form is compressed to high pressure, and then condensed to liquid formI with a liquid sorbent regeneration system for dehumidifying the air, and' usingthe dilute liquid sorbent from the dehumidifier of the controlled air stream in the liquid? sorbent regeneration system as the cooling medium for condensingv the refrigerant inthe refrigeration system, and using ther dilute; liquid. sorbent as. heatedi in condensing the refrigerant in: the refrigeration system'V for preheating the air stream usedzin regenerating the liquid sorbent in the liquid sorbent regeneration system.
2. The process of air conditioning which combines cooling and dehumidifying the air in a controlled area which consists in combining a refrigeration system for cooling the air wherein a refrigerant in gas form is compressed to high pressure, and then condensed to liquid form, with a liquid sorbent regeneration system for dehumidifying the air, and using the dilute liquid sorbent from the dehumidifier of the controlled air stream in the liquid sorbent regeneration system as the cooling medium for condensing the refrigerant in the refrigeration system, using the dilute liquid sorbent as heated in condensing the refrigerant in the refrigeration system for preheating the air stream used in regenerating the liquid sorbent in the liquid sorbent regeneration system, and regenerating the dilute liquid sorbent by passing said preheated air stream through it.
3. The process of air conditioning which combines cooling and dehumidifying the air in a controlled area which consists in combining a refrigeration system for cooling the air wherein a refrigerant in gas form is compressed to high pressure, and then condensed to liquid form, with a liquid sorbent regeneration system for dehumidifying the air, and using the dilute liquid sorbent from the dehumidifier of the controlled air stream in the liquid sorbent regeneration system as the cooling medium for condensing the refrigerant in the refrigeration system, using the dilute liquid sorbent as heated in condensing the refrigerant in the refrigeration system for preheating the air stream used in regenerating the liquid sorbent in the liquid sorbent regeneration system, and regenerating the dilute liquid sorbent by passing said preheated air stream through it. and conducting the heated air stream through an equalizer chamber exposed on its outer surface to normal atmospheric pressure and having porous walls permeable to the passage of high pressure water vapor in said preheated air stream, but resistant to the passage of air therethrough.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,937,984 Scherer Dec. 5, 1933 1,943,908 Woods Jan. 16, 1934 2,223,586 Thomas Dec. 3, 1940 2,269,053 Crawford Jan. 6, 1942 2,355,828 Taylor Aug. 15, 1944 2,421,121 Haagen-Smit May 27, 1947