[go: up one dir, main page]

US3589140A - Refrigerant feed control for centrifugal refrigeration machines - Google Patents

Refrigerant feed control for centrifugal refrigeration machines Download PDF

Info

Publication number
US3589140A
US3589140A US750A US3589140DA US3589140A US 3589140 A US3589140 A US 3589140A US 750 A US750 A US 750A US 3589140D A US3589140D A US 3589140DA US 3589140 A US3589140 A US 3589140A
Authority
US
United States
Prior art keywords
economizer
pressure
cooler
condenser
operable
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
US750A
Inventor
William T Osborne
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.)
Carrier Corp
Original Assignee
Carrier 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 Carrier Corp filed Critical Carrier Corp
Application granted granted Critical
Publication of US3589140A publication Critical patent/US3589140A/en
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
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle
    • F25B1/04—Compression machines, plants or systems with non-reversible cycle with compressor of rotary type
    • F25B1/053—Compression machines, plants or systems with non-reversible cycle with compressor of rotary type of turbine type
    • 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
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/13—Economisers
    • 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
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/23—Separators
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S62/00—Refrigeration
    • Y10S62/17—Condenser pressure control

Definitions

  • This invention has to do with refrigeration apparatus embodying a centrifugal compressor, a condenser, an economizer, and a cooler.
  • the compressor is equipped with the usual inlet guide vanes or throttling means at the inlet of the compressor operable to control the capacity of the machine.
  • the throttling means Upon shutdown of apparatus of this type, the throttling means is moved to closed position.
  • circumstances may be 'such that difficulty will be experienced in getting the machine into continuous operation.
  • the condenser cooling water may be at an unusually low temperature due to the cooling tower being subjected to a low ambient temperature.
  • the chilled water in the air conditioning system may, on startup, be at a high temperature.
  • a pressure differential actuator is connected to the economizer and the cooler.
  • this ac tuator effects operation of a switch connected to the float operated metering refrigerant valve for driving the valve to full open position regardless of the float actuator associated with the valve.
  • FIGURE is a schematic representation of refrigeration apparatus embodying my invention.
  • the apparatus includes a condenser llO connected by line 11 to an economizer 12.
  • the economizer is connected by refrigerant line 13 to the cooler 14.
  • the vapor space of the cooler 14 is connected by line 15 to the inlet side of the centrifugal compressor 16, the output of which is connected by line 21 to the condenser 10.
  • a metering valve 24 having an actuator 25 is operated by a v float 27 in the condenser.
  • the valve 24 and float 27 serve to maintain a liquid seal between the condenser and economizer as is conventional to prevent the passage of gaseous refrigerant through line 11 to the economizer.
  • the vapor space in the economizer 12 is connected by a line 31 to an intermediate pressure area of the compressor.
  • the line 31 may be connected to the housing enclosing the motor operating the compressor to provide refrigerant for cooling the motor with a return line to the cooler 14.
  • the line 31 may be connected to the gas flow passage intermediate the intake end of the impeller and the periphery thereof.
  • the compressor is of the two-stage type having first and second stage impellers 33,34, the line 31 being connected to the flow passage intermediate the impellers whereby suction is provided by the second impeller 34 for reducing the pressure in the economizer 12 to effect partial evaporation of the refrigerant therein to the end of lowering the temperature thereof as is well understood in the art.
  • the compressor is provided at the intake with throttling means as guide vanes 35.
  • the economizer pressure will drop below the cooler pressure. This is particularly true if the machine is started up with warm chilled water in the tube bundle 37 of the cooler 14 and, also, with the presence of low temperature water in the condenser coil 39. Under these conditions, the pressure in the cooler 14 may well exceed the pressure in the economizer 12, with the result that no refrigerant can flow through line 13 to the cooler 14.
  • the guide vanes 35 are under the control of a temperature sensor associated with the output line of the tube bundle 37; and upon elevation of the temperature of the water in that line, the guide vanes are moved to open position to establish the full capacity of the machine.
  • a temperature sensor associated with the output line of the tube bundle 37; and upon elevation of the temperature of the water in that line, the guide vanes are moved to open position to establish the full capacity of the machine.
  • control means operable upon the pressure in the economizer becoming equal to or less than the pressure in the cooler 14 to provide a full-flow passage from the condenser 10 to the economizer 12.
  • This full flow passage may be established by providing the valve 24 with an override actuator in the form of solenoid 45 which, when energized, will operate the valve 24 to full open position regardless of the position of the float .27.
  • the override actuator 45 is connected by a line 46 to a switch 47.
  • the switch 47 is operated by a pressure differential means 48 connected in a line 49 extending from the vapor area of the economizer 12 to the vapor area of the cooler 14.
  • the pressure differential device 48 functions to energize the override actuator 45 of valve 24 when the pressure in the cooler approaches or exceeds that in the economizer, in which event the valve 24 is operated to full open position permitting liquid and gaseous refrigerant to pass into the economizer 12. Due to the impedance in line 31 and the restriction and choking effect of opening 50, the pressure in the economizer is raised above the pressure then existing in the cooler 14, whereby the refrigerant in the economizer l2 flows to the cooler 14.
  • Refrigeration apparatus comprising a compressor, a con denser, an economizer, and a cooler, a line extending from said condenser to said economizer, metering valve means in said line operable to meter the flow of liquid refrigerant from said condenser to said economizer, a line connecting said economizer to said cooler, and control means operable upon the pressure in said cooler approaching the pressure in said economizer to provide an open flow passage for transmission of refrigerant gas from said condenser to said economizer.
  • Refrigeration apparatus as set forth in claim 1 wherein said control means is operable independently of said metering valve means.
  • Refrigeration apparatus as set forth in claim 1 wherein said control means includes an override actuator operable upon the pressure in said cooler approaching the pressure in said economizer to move said metering valve to open position.
  • Refrigeration apparatus as set forth in claim 1 wherein said metering valve means consists of a float-operated valve, said control means includes a solenoid connected to said valve tuating means operable upon the pressure in said cooler approaching the pressure in said economizer to actuate said switch to energize said circuit.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Control Of Positive-Displacement Air Blowers (AREA)
  • Safety Valves (AREA)
  • Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)

Abstract

In a refrigeration system including a centrifugal compressor, a condenser, an economizer, and a cooler, there is provided control means to establish a full-flow passage between the condenser and the economizer for transmitting liquid and gaseous refrigerant to the economizer to raise the pressure therein above the pressure in the cooler existing at startup under certain conditions and during certain part load conditions, thereby permitting refrigerant liquid to flow in a normal fashion through the system.

Description

United States Patent [72] Inventor William T. Osborne [56] References Cited East Syracuse UNITED STATES PATENTS P 750 3,315,482 4/1967 Kirtland 62/218 {22] Filed Jan. 5,1970
3,315,485 4/1967 Clark 62/218 Paemd 3 315 486 4/1967 LeChien 62/218 [73] Assignee Carrier Corp.
Syracuse, NY. Primary Examiner-Meyer Perlin Attorneys-Harry G. Martin, Jr. and J. Raymond Curtin REFRIGERANT FEED CONTROL FOR :SSTRACT: In a refrigeration system includciing a cintrifggal CENTRIFUGAL REFRIGERATION MACHINES pre ssor, a condenser, an economrzer, an a coo er, t ere 4 cm In 15 provided control means to establish a full-flow passage mung between the condenser and the eeonomizer for transmitting [S2] U.S. Cl 62/197, liquid and gaseous refrigerant to the economizer to raise the 62/218. 62/278, 62/510, 62/Dig. I7 pressure therein above the pressure in the cooler existing at [51] Int. Cl F25b 41/00 startup under certain conditions and during certain part load [50] Field of Search 62/196, conditions, thereby permitting refrigerant liquid to flow in a 197, 278, 209. 218, 510 normal fashion through the system.
PATENTEll-Jlmzs |97l INVENTOR. WILLIAM T. OSBORNE ATTORNEY REFRIGERANT FEED CONTROL FOR CENTRIFUGAL REFRIGERATION MACHINES BACKGROUND OF THE INVENTION This invention has to do with refrigeration apparatus embodying a centrifugal compressor, a condenser, an economizer, and a cooler. The compressor is equipped with the usual inlet guide vanes or throttling means at the inlet of the compressor operable to control the capacity of the machine.
Upon shutdown of apparatus of this type, the throttling means is moved to closed position. When the machine is started up, circumstances may be 'such that difficulty will be experienced in getting the machine into continuous operation. For example, the condenser cooling water may be at an unusually low temperature due to the cooling tower being subjected to a low ambient temperature. On the other hand, the chilled water in the air conditioning system may, on startup, be at a high temperature. Under these conditions, upon star tup of the machine, the pressure in the cooler will exceed the pressure in the economizer with the result that there will be no refrigerant flow from the economizer to the cooler, and any refrigerant in the cooler is quickly boiled off, whereby the cooler boils dry and the unit cuts out due to excessively low suction pressure. This action may take place quickly following startup of the machine and within the time lag established for the opening of the guide vanes at the inlet of the compressor. This situation may also prevail at low or part load operation withlow condensing water temperature.
This problem is to some extent solved by providing a buttertly valve or damper in the gas line extending from the economizer to the inlet of the second compressor stage. That valve is rigged to be modulated to closed position when a predetermined minimum pressure differential exists between the economizer and the evaporator. However, valves of that nature are expensive; they tend to be unreliable; and they are not readily serviceable.
SUMMARY OF THE INVENTION A pressure differential actuator is connected to the economizer and the cooler. When the pressure in the cooler approaches or exceeds the pressure in the economizer, this ac tuator effects operation of a switch connected to the float operated metering refrigerant valve for driving the valve to full open position regardless of the float actuator associated with the valve.
BRIEF DESCRIPTION OF THE DRAWING The FIGURE is a schematic representation of refrigeration apparatus embodying my invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the FIGURE, the apparatus includes a condenser llO connected by line 11 to an economizer 12. The economizer is connected by refrigerant line 13 to the cooler 14. The vapor space of the cooler 14 is connected by line 15 to the inlet side of the centrifugal compressor 16, the output of which is connected by line 21 to the condenser 10.
A metering valve 24 having an actuator 25 is operated by a v float 27 in the condenser. The valve 24 and float 27 serve to maintain a liquid seal between the condenser and economizer as is conventional to prevent the passage of gaseous refrigerant through line 11 to the economizer.
The vapor space in the economizer 12 is connected by a line 31 to an intermediate pressure area of the compressor. As is well understood, the line 31 may be connected to the housing enclosing the motor operating the compressor to provide refrigerant for cooling the motor with a return line to the cooler 14. Also, if the compressor is a singlc-stage machine, the line 31 may be connected to the gas flow passage intermediate the intake end of the impeller and the periphery thereof. In the form of the invention illustrated, the compressor is of the two-stage type having first and second stage impellers 33,34, the line 31 being connected to the flow passage intermediate the impellers whereby suction is provided by the second impeller 34 for reducing the pressure in the economizer 12 to effect partial evaporation of the refrigerant therein to the end of lowering the temperature thereof as is well understood in the art. The compressor is provided at the intake with throttling means as guide vanes 35.
At startup of the machine with the throttling means 35 closed, or with the throttling means closed at low or part load operation and with the economizer exposed to the inlet pressure at the intermediate pressure stage of the compressor, the economizer pressure will drop below the cooler pressure. This is particularly true if the machine is started up with warm chilled water in the tube bundle 37 of the cooler 14 and, also, with the presence of low temperature water in the condenser coil 39. Under these conditions, the pressure in the cooler 14 may well exceed the pressure in the economizer 12, with the result that no refrigerant can flow through line 13 to the cooler 14.
In normal operation, the guide vanes 35 are under the control of a temperature sensor associated with the output line of the tube bundle 37; and upon elevation of the temperature of the water in that line, the guide vanes are moved to open position to establish the full capacity of the machine. However, particularly at startup, there is a programmed time lag in the operation of the vanes 35. With no flow of refrigerant from the economizer to the cooler, any refrigerant remaining in the cooler is quickly vaporized under the: conditions stated, with the result that the cooler boils dry and the unit cuts out from excessively low suction pressure.
By my invention, there is provided control means operable upon the pressure in the economizer becoming equal to or less than the pressure in the cooler 14 to provide a full-flow passage from the condenser 10 to the economizer 12. This full flow passage may be established by providing the valve 24 with an override actuator in the form of solenoid 45 which, when energized, will operate the valve 24 to full open position regardless of the position of the float .27. The override actuator 45 is connected by a line 46 to a switch 47. The switch 47 is operated by a pressure differential means 48 connected in a line 49 extending from the vapor area of the economizer 12 to the vapor area of the cooler 14. The pressure differential device 48 functions to energize the override actuator 45 of valve 24 when the pressure in the cooler approaches or exceeds that in the economizer, in which event the valve 24 is operated to full open position permitting liquid and gaseous refrigerant to pass into the economizer 12. Due to the impedance in line 31 and the restriction and choking effect of opening 50, the pressure in the economizer is raised above the pressure then existing in the cooler 14, whereby the refrigerant in the economizer l2 flows to the cooler 14.
Iclaim:
l. Refrigeration apparatus comprising a compressor, a con denser, an economizer, and a cooler, a line extending from said condenser to said economizer, metering valve means in said line operable to meter the flow of liquid refrigerant from said condenser to said economizer, a line connecting said economizer to said cooler, and control means operable upon the pressure in said cooler approaching the pressure in said economizer to provide an open flow passage for transmission of refrigerant gas from said condenser to said economizer.
2. Refrigeration apparatus as set forth in claim 1 wherein said control means is operable independently of said metering valve means.
3. Refrigeration apparatus as set forth in claim 1 wherein said control means includes an override actuator operable upon the pressure in said cooler approaching the pressure in said economizer to move said metering valve to open position.
4. Refrigeration apparatus as set forth in claim 1 wherein said metering valve means consists of a float-operated valve, said control means includes a solenoid connected to said valve tuating means operable upon the pressure in said cooler approaching the pressure in said economizer to actuate said switch to energize said circuit.

Claims (4)

1. Refrigeration apparatus comprising a compressor, a condenser, an economizer, and a cooler, a line extending from said condenser to said economizer, metering valve means in said linE operable to meter the flow of liquid refrigerant from said condenser to said economizer, a line connecting said economizer to said cooler, and control means operable upon the pressure in said cooler approaching the pressure in said economizer to provide an open flow passage for transmission of refrigerant gas from said condenser to said economizer.
2. Refrigeration apparatus as set forth in claim 1 wherein said control means is operable independently of said metering valve means.
3. Refrigeration apparatus as set forth in claim 1 wherein said control means includes an override actuator operable upon the pressure in said cooler approaching the pressure in said economizer to move said metering valve to open position.
4. Refrigeration apparatus as set forth in claim 1 wherein said metering valve means consists of a float-operated valve, said control means includes a solenoid connected to said valve and operable upon energization to move said valve to open position independently of said float, an energizing circuit for said solenoid including a normally open switch and switch actuating means operable upon the pressure in said cooler approaching the pressure in said economizer to actuate said switch to energize said circuit.
US750A 1970-01-05 1970-01-05 Refrigerant feed control for centrifugal refrigeration machines Expired - Lifetime US3589140A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US75070A 1970-01-05 1970-01-05

Publications (1)

Publication Number Publication Date
US3589140A true US3589140A (en) 1971-06-29

Family

ID=21692867

Family Applications (1)

Application Number Title Priority Date Filing Date
US750A Expired - Lifetime US3589140A (en) 1970-01-05 1970-01-05 Refrigerant feed control for centrifugal refrigeration machines

Country Status (2)

Country Link
US (1) US3589140A (en)
DE (1) DE2061917C3 (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4014182A (en) * 1974-10-11 1977-03-29 Granryd Eric G U Method of improving refrigerating capacity and coefficient of performance in a refrigerating system, and a refrigerating system for carrying out said method
US4457768A (en) * 1982-12-13 1984-07-03 Phillips Petroleum Company Control of a refrigeration process
US4467621A (en) * 1982-09-22 1984-08-28 Brien Paul R O Fluid/vacuum chamber to remove heat and heat vapor from a refrigerant fluid
EP0123638A2 (en) * 1983-04-18 1984-10-31 Carrier Corporation A system for draining liquid refrigerant from a subcooler in a vapor compression refrigeration system
US4599873A (en) * 1984-01-31 1986-07-15 Hyde Robert E Apparatus for maximizing refrigeration capacity
US4615184A (en) * 1984-11-22 1986-10-07 Hitachi, Ltd. Compression refrigerating machine with vapor-liquid separator
US4748831A (en) * 1985-05-09 1988-06-07 Svenska Rotor Maskiner Ab Refrigeration plant and rotary positive displacement machine
US5749237A (en) * 1993-09-28 1998-05-12 Jdm, Ltd. Refrigerant system flash gas suppressor with variable speed drive
US20050120733A1 (en) * 2003-12-09 2005-06-09 Healy John J. Vapor injection system
US20070039347A1 (en) * 2005-08-22 2007-02-22 Gnanakumar Robertson Abel Compressor with vapor injection system
US20070039336A1 (en) * 2005-08-22 2007-02-22 Wu Man W Compressor with vapor injection system

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3940636A1 (en) * 1989-12-08 1991-06-13 Audi Ag Registering coolant quantity in heat or cold pump - using measuring float in fluid monitoring view chamber which changes in vol. according to temp. and pressure

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3315482A (en) * 1966-02-16 1967-04-25 Carrier Corp Refrigerant flow control for maintaining minimum head
US3315486A (en) * 1966-02-16 1967-04-25 Carrier Corp Refrigerant flow control for improving low capacity efficiency
US3315485A (en) * 1966-02-16 1967-04-25 Carrier Corp Refrigerant flow control including refrigerant agitation

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3315482A (en) * 1966-02-16 1967-04-25 Carrier Corp Refrigerant flow control for maintaining minimum head
US3315486A (en) * 1966-02-16 1967-04-25 Carrier Corp Refrigerant flow control for improving low capacity efficiency
US3315485A (en) * 1966-02-16 1967-04-25 Carrier Corp Refrigerant flow control including refrigerant agitation

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4014182A (en) * 1974-10-11 1977-03-29 Granryd Eric G U Method of improving refrigerating capacity and coefficient of performance in a refrigerating system, and a refrigerating system for carrying out said method
US4467621A (en) * 1982-09-22 1984-08-28 Brien Paul R O Fluid/vacuum chamber to remove heat and heat vapor from a refrigerant fluid
US4457768A (en) * 1982-12-13 1984-07-03 Phillips Petroleum Company Control of a refrigeration process
EP0123638A2 (en) * 1983-04-18 1984-10-31 Carrier Corporation A system for draining liquid refrigerant from a subcooler in a vapor compression refrigeration system
EP0123638A3 (en) * 1983-04-18 1986-02-19 Carrier Corporation A system for draining liquid refrigerant from a subcooler in a vapor compression refrigeration system
US4599873A (en) * 1984-01-31 1986-07-15 Hyde Robert E Apparatus for maximizing refrigeration capacity
US4615184A (en) * 1984-11-22 1986-10-07 Hitachi, Ltd. Compression refrigerating machine with vapor-liquid separator
US4748831A (en) * 1985-05-09 1988-06-07 Svenska Rotor Maskiner Ab Refrigeration plant and rotary positive displacement machine
US5749237A (en) * 1993-09-28 1998-05-12 Jdm, Ltd. Refrigerant system flash gas suppressor with variable speed drive
US20050120733A1 (en) * 2003-12-09 2005-06-09 Healy John J. Vapor injection system
US7299649B2 (en) 2003-12-09 2007-11-27 Emerson Climate Technologies, Inc. Vapor injection system
US20070039347A1 (en) * 2005-08-22 2007-02-22 Gnanakumar Robertson Abel Compressor with vapor injection system
US20070039336A1 (en) * 2005-08-22 2007-02-22 Wu Man W Compressor with vapor injection system
US7275385B2 (en) 2005-08-22 2007-10-02 Emerson Climate Technologies, Inc. Compressor with vapor injection system
US8037710B2 (en) 2005-08-22 2011-10-18 Emerson Climate Technologies, Inc. Compressor with vapor injection system
US8695369B2 (en) 2005-08-22 2014-04-15 Emerson Climate Technologies, Inc. Compressor with vapor injection system

Also Published As

Publication number Publication date
DE2061917C3 (en) 1975-05-07
DE2061917A1 (en) 1971-07-15
DE2061917B2 (en) 1974-09-26

Similar Documents

Publication Publication Date Title
US3589140A (en) Refrigerant feed control for centrifugal refrigeration machines
US5337574A (en) Heating and cooling system for a building
US3421339A (en) Unidirectional heat pump system
US3070972A (en) Automatic controls for room air conditioning unit
CN107477897A (en) A kind of computer-room air conditioning system and its control method
US3371500A (en) Refrigeration system starting
US2512758A (en) Combined refrigerant purifier and control apparatus
US2245454A (en) Refrigerating apparatus
US2061606A (en) Refrigerating apparatus
US2748572A (en) Air conditioning system
US2236058A (en) Refrigerating apparatus
US3315486A (en) Refrigerant flow control for improving low capacity efficiency
US2759333A (en) Air conditioning apparatus
JP2001033112A (en) Method for operating refrigerating cycle, and refrigerator
US3252295A (en) Refrigeration control system
US3315485A (en) Refrigerant flow control including refrigerant agitation
US2223725A (en) Control mechanism
US3315482A (en) Refrigerant flow control for maintaining minimum head
JPH03164661A (en) Air conditioner
JPS6463756A (en) Air conditioner
JPS6313429Y2 (en)
JPS6144123Y2 (en)
JPH08320161A (en) Air conditioner
GB1436169A (en) Airconditioning plant
US4187691A (en) Heat pump bypass valve arrangement