US3797266A - Air conditioning control system - Google Patents

Air conditioning control system Download PDF

Info

Publication number
US3797266A
US3797266A US00269638A US3797266DA US3797266A US 3797266 A US3797266 A US 3797266A US 00269638 A US00269638 A US 00269638A US 3797266D A US3797266D A US 3797266DA US 3797266 A US3797266 A US 3797266A
Authority
US
United States
Prior art keywords
pressure
temperature
refrigerant
evaporator
air
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00269638A
Other languages
English (en)
Inventor
A Newton
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
York International Corp
Original Assignee
Borg Warner Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Borg Warner Corp filed Critical Borg Warner Corp
Application granted granted Critical
Publication of US3797266A publication Critical patent/US3797266A/en
Assigned to YORK INTERNATIONAL CORPORATION, 631 SOUTH RICHLAND AVENUE, YORK, PA 17403, A CORP. OF DE reassignment YORK INTERNATIONAL CORPORATION, 631 SOUTH RICHLAND AVENUE, YORK, PA 17403, A CORP. OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: BORG-WARNER CORPORATION
Assigned to CANADIAN IMPERIAL BANK OF COMMERCE reassignment CANADIAN IMPERIAL BANK OF COMMERCE SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: YORK INTERNATIONAL CORPORATION
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/30—Expansion means; Dispositions thereof
    • F25B41/31—Expansion valves
    • F25B41/33—Expansion valves with the valve member being actuated by the fluid pressure, e.g. by the pressure of the refrigerant
    • F25B41/335—Expansion valves with the valve member being actuated by the fluid pressure, e.g. by the pressure of the refrigerant via diaphragms
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2500/00—Problems to be solved
    • F25B2500/26—Problems to be solved characterised by the startup of the refrigeration cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/25—Control of valves
    • F25B2600/2513—Expansion valves

Definitions

  • the constant pressure expansion device at system start up, is operated at a relatively high pressure to maximize the refrigeration effect and increase cooling capacity.
  • a temperature sensing element which is sensitive to a variable indicative of air temperature within the cooled space, is operative to reset the control point of the expansion device to reduce the temperature and pressure of the evaporator.
  • the improvement of the subject invention is directed to a system in which the temperature sensing element comprises a temperature responsive bulb and capillary charged with a fluid having a pressure difference over its temperature range which approximately matches the pressuredifference of the system refrigerant over its range of operating conditions.
  • the critical part of the system is in the compressor.
  • the efficiency of the compressor is materially reduced in that the refrigeration taken in the suction side of the compressor is in a smaller quantity and less work can be performed on the refrigerant.
  • Automotive applications also present a problem with respect to start-up conditions. For example, the temperature of the air in an enclosed vehicle space, if the auto is parked in the sun with the airconditioning off, is often 145 F. and may be as high as 180 F.
  • the system should be operated in such a manner as to reduce this temperature as fast as possible to minimize discomfort of the occupants.
  • the evaporator pressure should be kept relatively high. This allows more refrigerant to be taken into the compressor suction and provides for effective use of the entire evaporator coil surface.
  • the refrigerant will completely evaporate in the first section of the evaporator coil. Beyond this point the temperature of the refrigerant vapor rises (is superheated) and then passes to the compressor suction port.
  • the pressure can be raised to effectively increase thecapacity of the compressor and utilize most of the evaporator coil surface.
  • the evaporator pressure should then be lowered to a point slightly above the temperature at which ,coil freeze up can occur.
  • the thermal bulb capillary system which, for the pull-down temperature range, matches the pressure-temperature characteristics of the refrigerant employed in the system. For example, if it is desired to operate the evaporator at 55 F. upon initiation of the refrigeration system and at 28 F. after the desired air temperature in the control space has been reached, this is effectively a 15.2 psi difference in refrigeration pressure. If the thermal bulb is placed in contact with the air circulating in the passenger compartment, the temperature drop from 145 to F. should be about equal to the previously mentioned pressure difference i.e., 15.2 psi.
  • 15.2 psi One advantage flowing from this is that further decrease in the temperature of air within the vehicle space would have very little effeet on the thermal bulb-capillary system.
  • FIG. 1 is a schematic or diagrammatic view of the air conditioning system constructed in accordance with the present invention.
  • FIG. 2 is a graph in which refrigeration'system capacity(Q) is plotted against evaporator temperature (T).
  • the airconditioning system of the present invention includes a compressor 10, a condenser 12, an expansion device 14 and an evaporator 16 all connected to provide a closed circuit refrigeration system.
  • Refrigerant compressed by the compressor 10 is delivered to the condenser through line 18.
  • the liquified refrigerant is then passed through line 28 to expansion device 14, which will be discussed in more detail below.
  • expansion device 14 which will be discussed in more detail below.
  • the refrigerant passes through the expansion device from high pressure side to low pressure side, it flows through line 22 to the evaporator 16 which cools the air circulated over it by fan 17.
  • the refrigerant then flows through line 24, commonly referred to as the suction gas line, to the suction connection of compressor 10.
  • a superheat regulating valve 25 is located between the evaporator and the compressor in line 24. Since the construction and operation is described in detail in the above-identified Newton application it is incorporated by reference.
  • Expansion device 14 comprises a valve having a casing 30, a valve member 32 adapted to be seated on valve seat 34, inlet 36 and outlet 37.
  • Valve member 32 is connected to a stem 38 which is secured at its opposite end to an actuating diaphragm 40.
  • Spring 42 is seated upon a spring support member 43 and tends to urge the valve member toward a closed position against seat 34.
  • Spring 44 located in the upper portion of the casing 30 engages the diaphragm 40 and biases the same in a downward position tending to open the valve by urging valve member 32 away from the seat.
  • an important feature of the inven tion is the provision of means for establishing a control signal indicative of the interior air temperature and using such signal to vary the control point of the expansion device 14.
  • a fluid connection by means of capillary tube 50, to thermal bulb 52.
  • FIG. 2 shows a plot of temperature in the evaporator vs. capacity of a system using refrigerant R-12
  • the two lines running across the graph with a downward slope indicate the characteristics of the 90 F. wet bulb condition and the 65 F. wet bulb condition, as indicated by the legends.
  • the two curves with the positive slope identified as A and B respectively indicate the compressor capacity pressure conditions at maximum discharge pressure and at normal discharge pressure.
  • the intersection (C) of the 90 F. wet bulb line and capacity curve A approximates the conditions at initiation of the pull-down phase and results in a 55 F. evaporator pressure.
  • wet bulb line is the desired operating point on the assumption that the air temperature and humidity have been adjusted to this value after several minutes of operation. This produces the desired evaporator temperature of about 28 F. It is obvious from inspection of FIG. 2 that the compressor must shift operation between points C and D along the dashed line C-D. In order to establish this shift it is desirable to use a fluid in the thermal bulb-capillary system which has the same pressure drop between an assumed high interior vehicle space condition, about 145 F. and the desired air temperature, about 75 F. It can be seen that whil jhgevaporator pressure is being shifted from 66.7 psia (corresponding to 55Fij and 41.5 psia (corresponding to 28 F.) the bulbcapillary system must operate over an appreciably larger temperature range.
  • a desirable fluid for use in the bulb-capillary system would be refrigerant R-l 13.
  • this refrigerant has a pressure of 23.9 psia and at 75 F. a pressure of 6.2'psia resulting in a difference of 17.7 psi.
  • R-l or R-216 can be used in the bulb-capillary system. The net result of this matching of pressures within the control system forces the shift of operating conditions along a line approximating line C-D on FIG. 2.
  • the bulb 50 which as previously noted may be located in a position to sense interior air temperature, will be relatively warm. Accordingly, the fluid charge in the bulb and capillary will be at a high pressure, tending to establish arelatively high pressure. not only within the bulb itself but also in chamber 56 which is part of the same closed system. This pressure acting against the upper surface of diaphragm 40 will tend to bias the valve member to its open position and establish a control point effecting a relatively high pressure on the downstream side of the valve, and in the evaporator itself. After the system has been operating for a few minutes the pressure on the downstream side will be maintained constant by the pressure acting against the under side of the diaphragm 40.
  • the bulb temperature will be reduced tending to reduce the pressure in chamber 56 to relieve the pressure on the upper surface of the diaphragm. This will gradually shift control point at lower and lower pressures until such time as the pull-down phase has been completed.
  • the evaporator pressure will be established at a point slightly above the temperature at which freeze up can occur but at a low enough temperature to effect the desired dehumidification of air passing through the evaporator coil.
  • the fluid to be used for the thermal bulb fill it is preferred that such fluid have a pressure change between 145 and 75 F. of between 75 and 125 percent of the pressure change of the system refrigerant between 55 and 28 F.
  • a fluid for the thermal bulb-capillary system which exhibits little pressure change upon further change in the temperature of the compartment.
  • refrigerant R-113 for a system utilizing refrigerant R-l2 meets this need.
  • the average pressure change from 145 F. bulb temperature to 75 F. bulb temperature is approximately 0.25 psi/ F., whereas for the next 10 F. (down to F.) there would be only 0.12 psi/ F. pressure change for further reduction in temperature.
  • An air conditioning system comprising a compressor, a condenser, a constant pressure expansion device, and an evaporator all connected to provide a closed, vapor cycle refrigeration circuit through which a refrigerant is circulated; means for circulating air within a cooled space through said evaporator; a control system including a thermal bulb-capillary unit for establishing a control signal which is a function of the temperature of air within said cooled space; means for applying said signal to said constant pressure expansion device to vary the control point thereof, and the corresponding evaporator pressure, whereby the evaporator pressure is established at a lower value when the temperature of the cooled space is below some predetermined value, said thermal bulb-capillary unit being filled with an expansible, halocarbon fluid having a pressure change in the range of 145 and F of between 75 and percent of the pressure change of said refrigerant in the range between 55 and 28 F, whereby the temperature range of air within the controlled space during normal operation matches the temperature-pressure characteristics of said refrigerant over the range

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Air-Conditioning For Vehicles (AREA)
  • Temperature-Responsive Valves (AREA)
US00269638A 1972-07-07 1972-07-07 Air conditioning control system Expired - Lifetime US3797266A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US26963872A 1972-07-07 1972-07-07

Publications (1)

Publication Number Publication Date
US3797266A true US3797266A (en) 1974-03-19

Family

ID=23028070

Family Applications (1)

Application Number Title Priority Date Filing Date
US00269638A Expired - Lifetime US3797266A (en) 1972-07-07 1972-07-07 Air conditioning control system

Country Status (5)

Country Link
US (1) US3797266A (enrdf_load_stackoverflow)
JP (2) JPS4951654A (enrdf_load_stackoverflow)
CA (1) CA990087A (enrdf_load_stackoverflow)
GB (1) GB1429873A (enrdf_load_stackoverflow)
IT (1) IT990887B (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3866430A (en) * 1973-12-17 1975-02-18 Robert C Webber Method and apparatus for controlling refrigerant flow in cryogenic systems
US7076964B2 (en) * 2001-10-03 2006-07-18 Denso Corporation Super-critical refrigerant cycle system and water heater using the same
FR2905633A1 (fr) * 2006-09-08 2008-03-14 Valeo Systemes Thermiques Boucle de climatisation d'un vehicule automobile dont le fluide refrigerant est a base de 1,1,1,2-tetrafluoroproprene et de trifluoroiodomethane
CN110953401A (zh) * 2019-12-17 2020-04-03 天津商业大学 一种热力执行装置
US20210180842A1 (en) * 2016-10-28 2021-06-17 Mitsubishi Electric Corporation Air conditioner

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1408744A (en) * 1920-01-09 1922-03-07 Keen Harold Perot Thermostatically-operated ammonia expansion valve
US1618815A (en) * 1922-08-11 1927-02-22 Cash A W Co Refrigerating system and appliance

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5219433B2 (enrdf_load_stackoverflow) * 1971-08-16 1977-05-27

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1408744A (en) * 1920-01-09 1922-03-07 Keen Harold Perot Thermostatically-operated ammonia expansion valve
US1618815A (en) * 1922-08-11 1927-02-22 Cash A W Co Refrigerating system and appliance

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3866430A (en) * 1973-12-17 1975-02-18 Robert C Webber Method and apparatus for controlling refrigerant flow in cryogenic systems
US7076964B2 (en) * 2001-10-03 2006-07-18 Denso Corporation Super-critical refrigerant cycle system and water heater using the same
FR2905633A1 (fr) * 2006-09-08 2008-03-14 Valeo Systemes Thermiques Boucle de climatisation d'un vehicule automobile dont le fluide refrigerant est a base de 1,1,1,2-tetrafluoroproprene et de trifluoroiodomethane
US20210180842A1 (en) * 2016-10-28 2021-06-17 Mitsubishi Electric Corporation Air conditioner
CN110953401A (zh) * 2019-12-17 2020-04-03 天津商业大学 一种热力执行装置

Also Published As

Publication number Publication date
JPS4951654A (enrdf_load_stackoverflow) 1974-05-20
GB1429873A (en) 1976-03-31
CA990087A (en) 1976-06-01
IT990887B (it) 1975-07-10
JPS57172376U (enrdf_load_stackoverflow) 1982-10-29

Similar Documents

Publication Publication Date Title
US5195331A (en) Method of using a thermal expansion valve device, evaporator and flow control means assembly and refrigerating machine
US3389576A (en) System for controlling refrigerant condensing pressures by dynamic hydraulic balance
JP6338019B2 (ja) 冷凍サイクル装置
US3667247A (en) Refrigeration system with evaporator outlet control valve
JP4179231B2 (ja) 圧力制御弁と蒸気圧縮式冷凍サイクル
US5634350A (en) Refrigeration system
US2774220A (en) Control for a refrigeration system
US3797266A (en) Air conditioning control system
JPH10288411A (ja) 蒸気圧縮式冷凍サイクル
US3803864A (en) Air conditioning control system
JP2001147048A (ja) 冷凍回路の過熱度制御装置
US3054273A (en) Thermal expansion valve
US3388558A (en) Refrigeration systems employing subcooling control means
US3803865A (en) Refrigeration control system
US3786650A (en) Air conditioning control system
JP2009019847A (ja) 冷凍サイクル装置
US3688517A (en) Air conditioning control system
US2752760A (en) Expansion valve with bulb control
US2748571A (en) Defrosting system for refrigeration evaporators
US3738119A (en) Head pressure operated suction throttling valve
EP0378933A2 (en) Evaporator and flow control means assembly for a refrigerating machine
JPH1163687A (ja) エアコンサイクル
JP4676166B2 (ja) 冷凍サイクルの安全弁装置
JPH09133436A (ja) 温度式膨脹弁およびこれを用いた車両用空調装置
JP6485256B2 (ja) 冷凍サイクル装置

Legal Events

Date Code Title Description
AS Assignment

Owner name: YORK INTERNATIONAL CORPORATION, 631 SOUTH RICHLAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST. EFFECTIVE;ASSIGNOR:BORG-WARNER CORPORATION;REEL/FRAME:004676/0360

Effective date: 19860609

AS Assignment

Owner name: CANADIAN IMPERIAL BANK OF COMMERCE

Free format text: SECURITY INTEREST;ASSIGNOR:YORK INTERNATIONAL CORPORATION;REEL/FRAME:005156/0705

Effective date: 19881215