US 3257822 A
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Description (OCR text may contain errors)
June 28, 1966 w, BB 3,257,822
AIR CONDITIONING APPARATUS FOR COOLING OR DEHUMIDIFYING OPERATION Filed Sept. 4, 1964 INVENTOR. ROY W ABBOTT BYW H \s TTORNEY United States Patent r 3,257,822 AIR CONDITIONING APPARATUS FOR COOLING 0R DEHUMIDIFYING OPERATION Roy W. Abbott, Jeffersontown, Ky., assignor to General Electric Company, a corporation of New York Filed Sept.4, 1964, Ser. No. 394,411 3 Claims. (Cl. 62-428) tion as an evaporator and the other as a reheat coil during operation of the apparatus as a dehumidifier.
Further objects and advantages of the invention will become apparent from the following description and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming part of this specification.
In accordance with the present invention there is provided air conditioning apparatus for cooling or dehumidifying air from an enclosure comprising a refrigeration system including a compressor, a condenser, a fixed flow restrictor, first and second heat exchanger coils and unitary valve means for controlling the flow of refrigerant through the system so that both of the coils will operate in series as an evaporator or one of the coils will operate as a cooling or evaporating element and the other as a reheat coil. To this end, means are provided for connecting the compressor, the condenser, a fixed flow restrictor, the first coil and the second coil in series connection to form a closed circuit for refrigerant fi-ow during cooling operation of the apparatus and valve means including a first portion having a normally closed valve opening or port connecting the compressor outlet to a portion of the circuit ahead of the first coil section and a second portion in the circuit between the first and second coils or coil sections. The valve includes a piston separating the first and second portion and is so constructed that when the valve port is opened to permit flow of high pressure refrigerant from the compressor discharge to the inlet end of the first coil section, high pressure conditions within the valve operate the piston which includes means for restricting the flow of refrigerant from the first coil section to the second coil section thereby causing the first coil section to operate as a condenser or reheat coil and the second c-oil section to continue to operate as an evaporator. Fan means are provided for directing a stream of air through the second coil section and then through the first coil section so that the air is either cooled by both of the coil sections when the apparatus is operating on the cooling cycle or is cooled for dehumidification and reheated during operation of the apparatus as a dehumidifier.
For a better understanding of the invention reference may be had to the accompanying drawing in which the single figure illustrates somewhat schematically a refrigeration system of the present invention and electrical control circuitry for controlling the operation of the system either as a cooling unit or as a dehumidifier.
It will be understood that the refrigeration system shown in the accompanying drawing forms part of air conditioning apparatus which may be either a room air conditioning unit or a central air conditioning unit.
The refrigeration system includes a compressor 1 connected by a discharge line 2 to an outdoor heat exchanger or condenser 3 in which hot compressed refrigerant from "ice the compressor is cooled and condensed by means of a stream of air passed through a duct 4 enclosing the condenser by means of a fan 5. The condensed or liquid refrigerant flows from the condenser through a strainer or filter 6 and expansion means in the form of a capillary flow restrictor 7 to an indoor heat exchanger 8 comprising a first coil or coil section 9 and a second coil or coil section 10 in series connection. Air from within the enclosure is conditioned by being passed through a duct 14 by means of a fan 11 so that the air passes in series flow first over the second coil section 10 and then over the first coil section 9. Refrigerant evaporated in the heat exchanger 8 is withdrawn from the heat exchanger through a suction line 12 by the compressor 1.
In order that the air conditioning. apparatus may be operated either as a cooling unit or as a dehumidifying unit means are provided for operation of the coil section 9 either as an evaporator component or as a condenser or reheat coil. This flow control means includes a bypass line 15 connecting the compressor discharge line 2 to the inlet end 16 of the coil section 9. A valve generally indicated by the numeral 17 includes a first or upper portion 18 containing a valve port 19 and connected in the bypass line 15 and a second lower portion 20 connected between the two coil sections 9 and 10. A movable piston 21 separates the upper and lower portions of the valve and includes a circumferential slot or groove 22. A spring 23 normally biases the piston 21 to an upper position to provide unrestricted flow of refrigerant from the first coil section 9 to the second coil section 10 through the low pressure chamber 24 in the lower portion of the valve 17. When the port 19 is opened by energization of the solenoid 26, the passage'of high pressure refrigerant from the high pressure inlet chamber 25 above the port 19 through the port 19 into the intermediate outlet chamber 27 above the piston 21 raises the pressure in the chamber and causes the piston 21 to move downwardly to a position between the inlet 28 to the low pressure chamber 24 and the outlet 29 from this chamber thereby placing the slot or groove 22 between the inlet and outlet and restricting the flow of refrigerant from the coil section 9 to the coil section 10.
The specific construction of this valve forms no part I of the present invention and for a more detailed desctiption of the structure and operation thereof, reference is made to Patent 3,132,491 issued May 12, 1964 in the name of F. A. Schumacher and assigned to the same assignee as the present invention.
For cooling operation of the air conditioning apparatus, the port 19 of the valve 17 is closed so that the compressor 1, the condenser 3, the capillary flow restrictor 7, the first coil section 9, the low pressure chamber 23 coil sections 9 and 10 which may be separate heat ex-U changers or parts of the same heat exchanger operate as series-connected evaporator components.
When the valve 17 is operated by the solenoid 26 to open the valve port 19, warm and high pressure refrigerant from the compressor 1 is bypassed around the condenser and the restricting means 7 and is introduced directly into the inlet end of the coil section 9. At the same time piston 21 is forced downwardly between inlet 28 and outlet 29. The flow restriction provided by the groove or slot 22 in the piston 21is designed to provide a fiow restriction such that the refrigerant introduced into the first coil section 9 will be condensed in that coil section while the liquid refrigerant introduced into the Patented June 28, 1966 second coil section 10 through the slot or groove 22 will be evaporated therein thereby absorbing heat from the air passing over this coil section by means of the fan 11. Thus when the apparatus is operated as a dehumidifier unit air passing through the duct 14 is first cooled so that moisture in the air stream 8 condenses out on the coil 10 after which the cooled air is reheated to substantially its original temperature by means of the coil 9 functioning as a condenser or reheat coil.
The selective operation of the air conditioning apparatus as either a cooling unit or as a dehumidifier may be either manually or automatically controlled. The control circuitry illustrated schematically in the drawing is intended to provide for either manual or automatic operation whereby the apparatus will operate as a cooling unit whenever the temperature of the air in the enclosure is above a predetermined temperature and as a dehumidifying unit when the temperature of that air is below the predetermined temperature.
More specifically, the air conditioner apparatus is provided with a thermostat 33 arranged to be responsive to the temperature of the air in the enclosure as for example the air withdrawn from the enclosure through the duct 14 by the fan 11. The thermostat 33 contains a first bimetal switch 36 connected across lines L1 and L2 for energizing the compressor Whenever the temperature rises above a predetermined temperature such as 70 F. and to de-energize the compressor when the temperature falls below that temperature. A second bimetal switch 37 connected in series with the bimetal switch 36 is adapted to be closed to energize the solenoid 26 whenever dehumidification rather than cooling of the air within the enclosure is desirable, as for example at temperatures below 75 F. A switch 33 is provided for manual control thereby making it possible to operate the air conditioning apparatus to provide cooling without reheat that is as a dehumidifier over the entire temperature range of operation controlled by the switch 36.
By this control arrangement the apparatus operates to cool the enclosure air at all temperatures above a predetermined temperature as for example a temperature 75 F. while at any temperature between 75 F. and a lower temperature such as 70 F. closing of the bimetal switch 37 causes the unit to operate as a dehumidifier due to the opening of the valve 17 to bypass refrigerant through the bypass line 15. At temperatures below 70 F. opening of the bimetal switch 36 tie-energizes both the compressor and the solenoid operated valve 17 thereby interrupting the operation of the apparatus either as a cooling unit or as a dehumidifying unit.
It is to be noted that during operation of the apparatus as a dehumidifier, most of the refrigerant flow from the compressor is bypassed through the bypass line 15 to the inlet end of the coil 9. However, a slight flow of refrigerant can take place through the condenser 3 and the capillary 7 thereby eliminating any possibility of trapping oil or refrigerant in this portion of the sys-' tem. In other words, this portion of the system is opened to the remaining portion of the system during operation of the apparatus as a dehumidifier so that any liquid refrigerant stored therein at the beginning of the dehumidifying cycle will be transferred to the active dehumidification portion of the circuit.
While there has been shown and described a particular embodiment of the present invention it is to be understood that it is not restricted thereto and it is intended by the appended claims to cover all such modifications as fall within the true spirit and scope of the invention.
What I claim as new and desire to secure by Letters Patent of the United States is:
1. An air conditioning apparatus for cooling and dehumidifying air from an enclosure comprising a refrigeration system including a compressor, condenser, a fixed flow restrictor, first evaporator section and second evaporator section series connected to form a closed normal cooling circuit,
means for circulating a stream of air from said enclosure in series flow over said second and first evaporator sections,
flow control means for operating said first evaporator section as a reheat coil for operation of said apparatus as a dehumidifier,
said flow control means comprising a unitary valve including an inlet connected in said refrigerant circuit between said compressor and said condenser and an outlet connected to said circuit between said flow restrictor and said first evaporator section and a valve port between said inlet and outlet connections and means operable upon opening of said valve port for restricting flow of refrigerant from said first evaporator section to said second evaporator section whereby said first evaporator section functions as a reheat coil when said valve port is open.
2. An air conditioning apparatus for cooling and dehumidifying air from an enclosure comprising a refrigeration system including a compressor, condenser, 21 fixed flow restrictor, first evaporator section and second evaporator section series connected to form a closed normal cooling circuit,
means for circulating a stream of air from said enclosure in series flow over said second and first evaporator sections,
flow control means for operating said first evaporator section as a reheat coil for operation of said apparatus as a dehumidifier, said flow control means comprising a unitary valve including a first portion and a second portion,
said first portion having an inlet connected to said refrigerant circuit between said compressor and said condenser, and an outlet connected to said circuit between said flow restrictor and said first evaporator section and a valve port bet-ween said inlet and outlet connections,
said second portion being connected in said circuit between said evaporator sections,
solenoid means for opening said valve port for the flow of hot compressed refrigerant gas from said compressor to said first evaporator section, said valve including means operable upon opening of said valve port for restricting flow of refrigerant from said first evaporator section to said second evaporator section through said second portion whereby said first evaporator section functions as a reheat coil when said valve port is open. 3. An air conditioning apparatus for cooling or dehumidifying air from an enclosure comprising a refrigeration system including a compressor, condenser, a fixed flow restrictor, a first coil and a second coil and unitary valve means for operating said apparatus either as a cooling unit or as a dehumidifying unit,
said valve including a valve body comprising a high pressure inlet chamber at one end of said body, a low pressure chamber at the other end of said body and having spaced inlet and outlet ports, an intermediate outlet chamber between said high pressure chamber and said low pressure chamber and normally closed valve means between said high pressure and intermediate chambers, a movable piston within said valve body between said intermediate chamber and said low pressure chamber,
means for normally positioning said piston within said valve body between said valve means and said low pressure chamber inlet and outlet and for permitting movement of said piston downwardly to a second position overlying said inlet and outlet,
means for connecting said compressor, condenser, flow restricting means, first coil section, low pressure chamber, second coil section in series connection to form a closed refrigerant circuit for operation of said piston is in said second position whereby said said apparatus as a cooling unit, first coil section operates as a condenser and said means connecting said compressor, said high pressure second coil section operates as an evaporator when chamber, said intermediate outlet chamber, said first 7 said valve means is open.
coil section, said low pressure chamber, said second 5 coil section in closed series flow refrigerant circuit, References Cited y the Examine! and means for opening said valve means whereby hot UNITED STATES PATENTS compressed refrigerant from the compressor flows v through said high pressure chamber and said outlet gig? chamber to said first coil section and said piston 10 3105366 10/1963 62 moves downwardly to its second position overlying I said inlet and outlet to said low pressure chamber, 3139735 7/1964 Malkofi 62173 said piston including means defining a restricted com- MEYER PERLIN, primary Examiner munication between said inlet and said outlet when