US3520146A - Refrigeration system - Google Patents

Refrigeration system Download PDF

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US3520146A
US3520146A US741621A US3520146DA US3520146A US 3520146 A US3520146 A US 3520146A US 741621 A US741621 A US 741621A US 3520146D A US3520146D A US 3520146DA US 3520146 A US3520146 A US 3520146A
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refrigeration
heat exchange
load
condenser
exchange medium
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US741621A
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Richard S Arnold Sr
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Carrier Corp
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Carrier Corp
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24FAIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F5/00Air-conditioning systems or apparatus not covered by F24F1/00 or F24F3/00, e.g. using solar heat or combined with household units such as an oven or water heater
    • F24F5/0007Air-conditioning systems or apparatus not covered by F24F1/00 or F24F3/00, e.g. using solar heat or combined with household units such as an oven or water heater cooling apparatus specially adapted for use in air-conditioning
    • F24F5/001Compression cycle type
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B1/00Compression machines, plants or systems with non-reversible cycle
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B7/00Compression machines, plants or systems, with cascade operation, i.e. with two or more circuits, the heat from the condenser of one circuit being absorbed by the evaporator of the next circuit
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28HEAT EXCHANGE IN GENERAL
    • F28CHEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA COME INTO DIRECT CONTACT WITHOUT CHEMICAL INTERACTION
    • F28C1/00Direct-contact trickle coolers, e.g. cooling towers
    • F28C1/02Direct-contact trickle coolers, e.g. cooling towers with counter-current only
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02BCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Definitions

  • Cooling towers In a comfort cooling installation to satisfy an air conditioning load, it is common practice to utilize a cooling tower to provide water to condense the compressed refrigerant in the condenser portion of the refrigeration machine. Cooling towers normally maintain a water temperature of approximately 95 F. and therefore the condensing temperature in the machine would normally be approximately 105 F. To provide chilled Water to satisfy the air conditioning load, the desired evaporator temperature would ordinarily be maintained at approximately 35 F. These conditions would give a temperature differential across the machine of 70.
  • a condenser temperature of approximately 105 would be common. These conditions would give a temperature differential across the machine of 105. For economical compressor operation over this wide temperature range, multiple stage compressors would be required which add to the cost of the system.
  • both intermediate temperature refrigeration for comfort cooling and low temperature refrigeration for manufacturing processes, food storage, etc. are required.
  • a stadium may require chilled water for air conditioning and a low temperature heat exchange medium for maintaining an ice rink.
  • This invention relates to a multitemperature refrigeration system employing single stage compressors wherein a first portion of the system is utilized to satisfy a first cooling load and to condense refrigerant for a second portion of the system which is adapted to satisfy a second cooling load at a temperature substantially lower than the temperature of the first cooling load.
  • FIG. 1 is a schematic illustration of a refrigeration system embodying the present invention.
  • the air-conditioning load is satisfied by a centrifugal refrigeration machine having a centrifugal compressor 3, an evaporator 5 and a condenser 7.
  • Refrigerant vapor from evaporator 5 is compressed by centrifugal compressor 3.
  • the high pressure refrigerant vapor from the compressor is passed through condenser 7 in heat exchange relationshp with water or other heat exchange 3,520,146 Patented July 14, 1970 medium from a suitable source such as a cooling tower 9.
  • the Water from the cooling tower is provided to the condenser 7 through line 11 by pump 12 and returns to the cooling tower from the condenser through a line 13.
  • Suitable expansion means 15 are provided for regulating the quantity of refrigerant passed from the high pressure condenser 7 to the low pressure evaporator 5.
  • a suitable heat exchange medium such as water is passed through evaporator 5 in heat exchange relationship with the refrigerant therein and is cooled thereby.
  • the chilled water from evaporator 5 is circulated by pump 14 through supply line 16 and return line 18 for satisfying an air conditioning load represented by heat exchangers 19 or any other medium temperature refrigeration load.
  • a second refrigeration machine 17 is provided to satisfy a low temperature refrigeration load, for example, to produce ice for a skating rink.
  • the refrigeration machine 17 employs a centrifugal compressor 20 to compress low pressure gaseous refrigerant from an avaporator 21 and provide high pressure referigerant to a condenser 23.
  • Refrigerant is passed through condenser 23 in heat exchange relationship with the cooled heat exchange medium from evaporator 5 which is supplied to condenser 23 by pump 14 through line 24.
  • the heat exchange medium is returned from condenser 23 through line 26 to return line 18.
  • Suitable expansion means 25 are provided for regulating the quantity of refrigerant passed from condenser 23 to evaporator 21.
  • a heat exchange medium such as inhibited ethylene glycol is passed through evaporator 21 in heat exchange relationship with the refrigerant therein and is cooled thereby.
  • the chilled ethylene glycol is circulated by pump 27 through supply line 29 and return line 31 to satisfy a low temperature refrigeration load such as an ice skating rink 32.
  • Valves 33 and 35 are provided in lines 16 and 18 respectively to prevent flow of heat exchange medium from evaporator 5 through heat exchangers 19 when there is no air conditioning demand.
  • Valves 37 and 39 are provided in lines 24 and 26 respectively to prevent flow of chilled water from evaporator 5 to refrigeration machine 17 when there is no low temperature refrigeration requirement.
  • the disclosed system is especially suited for air conditioning a stadium and providing refrigeration for an ice ring in the stadium.
  • the low temperature refrigeration machine could be employed for initially producing the ice for the skating rink when the stadium is not in use and therefore the air conditioning load is at a minimum.
  • the intermediate temperature refrigeration machine is capable of handling the normal air conditioning load and the load imposed thereon by condenser 23 for maintaining the ice rink.
  • the disclosed system utilizes standard single stage refrigeration compressors to provide a staged refrigeration system by employing the excess capacity of the intermediate temperature refrigeration machine to provide a low condensing temperature in the low temperature re frigeration machine.
  • This allows the use of a much smaller low temperature refrigeration machine, resulting in lower initial and operating costs for the complete system.
  • a refrigeration system utilized to provide comfort cooling is operated below its rated capacity for the majority of the year since the machine must be sized to provide suflicient cooling for the warmest days of the year when the building is in use.
  • the intermediate temperature refrigeration machine can be operated near capacity year around. Further, the size of the low temperature refrigeration machine can be drastically reduced.
  • the intermediate temperature refrigeration system at or near its rated capacity the operating eificiency of the machine is optimized.
  • the disclosed system employs a single compressor to satisfy the intermediate temperature load and a single compressor to satisfy the low temperature refrigeration load. It should be understood that a plurality of refrigeration machines could be used to satisfy the intermediate temperature refrigeration load and a plurality of refrigeration machines could be employed to satisfy the low temperature refrigeration load. This would allow a portion of the intermediate temperature refrigeration machines and the low temperature refrigeration machines to be shut down when the refrigeration loads are reduced to provide for more economical operation of the system.
  • a refrigeration system to provide multi-temperature refrigeration comprising:
  • a first compressor, condenser and evaporator connected in refrigerant flow relationship to cool a low tempera ture heat exchange medium
  • a second compressor, condenser and evaporator connected in refrigerant flow relationship to cool an intermediate temperature heat exchange medium
  • a refrigeration system further including pump means for circulating the intermediate temperature heat exchange medium, said means to satisfy an intermediate temperature refrigeration load including:
  • said means to condense refrigerant in said first condenser including:
  • a second supply line to provide communication between said first supply line and said first condenser to pro vide intermediate temperature heat exchange medium to said first condenser
  • a second return line communicating between said first condenser and said first return line to return the intermediate temperature heat exchange medium from said first condenser to said first return line
  • said pump means being adapted to circulate intermediate temperature heat exchange medium through said 4 lines to satisfy said refrigeration load and condense refrigerant in said first condenser.
  • a refrigeration system wherein said means to provide a portion of the intermediate temperature heat exchange medium to satisfy an intermediate temperature heat exchange load includes:
  • said means to provide intermediate temperature heat exchange medium to condense refrigerant in said first condenser including:
  • shutoff valves in said second supply line and a fourth shutoff valve in said second return line, said third and fourth shutoff valves being adapted to prevent flow of heat exchange medium to said first condenser when said first compressor is inoperative.
  • a method for providing multitemperature refrigeration comprising the steps of:

Description

July 14, 1970. R. s. ARNOLD, SR
. REFRIGERATION SYSTEM Filed July 1, 1968 INVENTOR. RICHARD 5. ARNQLD,SR. BY
yaw 5 M6 ATTORNEY.
United States Patent 3,520,146 REFRIGERATION SYSTEM Richard S. Arnold, Sn, De Witt, N.Y., assignor to Carrier Corporation, Syracuse, N.Y., a corporation of Delaware Filed July 1, 1968, Ser. No. 741,621 Int. Cl. F25b 1/00 US. Cl. 62115 4 Claims ABSTRACT OF THE DISCLOSURE A refrigeration system to simultaneously satisfy an intermediate temperature cooling load and a low temperature cooling load or to satisfy either an intermediate temperature cooling load or a low temperature cooling load exclusively.
BACKGROUND OF THE INVENTION In a comfort cooling installation to satisfy an air conditioning load, it is common practice to utilize a cooling tower to provide water to condense the compressed refrigerant in the condenser portion of the refrigeration machine. Cooling towers normally maintain a water temperature of approximately 95 F. and therefore the condensing temperature in the machine would normally be approximately 105 F. To provide chilled Water to satisfy the air conditioning load, the desired evaporator temperature would ordinarily be maintained at approximately 35 F. These conditions would give a temperature differential across the machine of 70.
In a low temperature cooling installation where it is desired to maintain evaporator temperatures around 0 F. and a cooling tower is utilized for condenser cooling, a condenser temperature of approximately 105 would be common. These conditions would give a temperature differential across the machine of 105. For economical compressor operation over this wide temperature range, multiple stage compressors would be required which add to the cost of the system.
In some instances, both intermediate temperature refrigeration for comfort cooling and low temperature refrigeration for manufacturing processes, food storage, etc., are required. For example, a stadium may require chilled water for air conditioning and a low temperature heat exchange medium for maintaining an ice rink.
SUMMARY OF THE INVENTION This invention relates to a multitemperature refrigeration system employing single stage compressors wherein a first portion of the system is utilized to satisfy a first cooling load and to condense refrigerant for a second portion of the system which is adapted to satisfy a second cooling load at a temperature substantially lower than the temperature of the first cooling load.
BRIEF DESCRIPTION OF THE DRAWINGS The figure is a schematic illustration of a refrigeration system embodying the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing there is illustrated a multitemperature refrigeration system for satisfying an airconditioning load and to provide low temperature cooling. The air-conditioning load is satisfied by a centrifugal refrigeration machine having a centrifugal compressor 3, an evaporator 5 and a condenser 7. Refrigerant vapor from evaporator 5 is compressed by centrifugal compressor 3. The high pressure refrigerant vapor from the compressor is passed through condenser 7 in heat exchange relationshp with water or other heat exchange 3,520,146 Patented July 14, 1970 medium from a suitable source such as a cooling tower 9. The Water from the cooling tower is provided to the condenser 7 through line 11 by pump 12 and returns to the cooling tower from the condenser through a line 13.
Suitable expansion means 15 are provided for regulating the quantity of refrigerant passed from the high pressure condenser 7 to the low pressure evaporator 5. A suitable heat exchange medium such as water is passed through evaporator 5 in heat exchange relationship with the refrigerant therein and is cooled thereby. The chilled water from evaporator 5 is circulated by pump 14 through supply line 16 and return line 18 for satisfying an air conditioning load represented by heat exchangers 19 or any other medium temperature refrigeration load.
A second refrigeration machine 17 is provided to satisfy a low temperature refrigeration load, for example, to produce ice for a skating rink.
The refrigeration machine 17 employs a centrifugal compressor 20 to compress low pressure gaseous refrigerant from an avaporator 21 and provide high pressure referigerant to a condenser 23. Refrigerant is passed through condenser 23 in heat exchange relationship with the cooled heat exchange medium from evaporator 5 which is supplied to condenser 23 by pump 14 through line 24. The heat exchange medium is returned from condenser 23 through line 26 to return line 18. Suitable expansion means 25 are provided for regulating the quantity of refrigerant passed from condenser 23 to evaporator 21. A heat exchange medium such as inhibited ethylene glycol is passed through evaporator 21 in heat exchange relationship with the refrigerant therein and is cooled thereby. The chilled ethylene glycol is circulated by pump 27 through supply line 29 and return line 31 to satisfy a low temperature refrigeration load such as an ice skating rink 32. Valves 33 and 35 are provided in lines 16 and 18 respectively to prevent flow of heat exchange medium from evaporator 5 through heat exchangers 19 when there is no air conditioning demand. Valves 37 and 39 are provided in lines 24 and 26 respectively to prevent flow of chilled water from evaporator 5 to refrigeration machine 17 when there is no low temperature refrigeration requirement.
The disclosed system is especially suited for air conditioning a stadium and providing refrigeration for an ice ring in the stadium.
In such an installation, the low temperature refrigeration machine could be employed for initially producing the ice for the skating rink when the stadium is not in use and therefore the air conditioning load is at a minimum. Once the ice is produced the intermediate temperature refrigeration machine is capable of handling the normal air conditioning load and the load imposed thereon by condenser 23 for maintaining the ice rink.
The disclosed system utilizes standard single stage refrigeration compressors to provide a staged refrigeration system by employing the excess capacity of the intermediate temperature refrigeration machine to provide a low condensing temperature in the low temperature re frigeration machine. This allows the use of a much smaller low temperature refrigeration machine, resulting in lower initial and operating costs for the complete system. Ordinarily, a refrigeration system utilized to provide comfort cooling is operated below its rated capacity for the majority of the year since the machine must be sized to provide suflicient cooling for the warmest days of the year when the building is in use. By utilizing this excess capacity to provide condensing water for the low temperature refrigeration system, the intermediate temperature refrigeration machine can be operated near capacity year around. Further, the size of the low temperature refrigeration machine can be drastically reduced. By operating the intermediate temperature refrigeration system at or near its rated capacity the operating eificiency of the machine is optimized.
The disclosed system employs a single compressor to satisfy the intermediate temperature load and a single compressor to satisfy the low temperature refrigeration load. It should be understood that a plurality of refrigeration machines could be used to satisfy the intermediate temperature refrigeration load and a plurality of refrigeration machines could be employed to satisfy the low temperature refrigeration load. This would allow a portion of the intermediate temperature refrigeration machines and the low temperature refrigeration machines to be shut down when the refrigeration loads are reduced to provide for more economical operation of the system.
While I have described a preferred embodiment of my invention it is to be understood that the invention is not limited thereto but may be otherwise embodied within the scope of the following claims.
I claim:
1. A refrigeration system to provide multi-temperature refrigeration comprising:
a first compressor, condenser and evaporator connected in refrigerant flow relationship to cool a low tempera ture heat exchange medium;
means to circulate the cooled low temperature heat exchange medium to satisfy a low temperature refrigeration load;
a second compressor, condenser and evaporator connected in refrigerant flow relationship to cool an intermediate temperature heat exchange medium;
means to provide a portion of the cooled intermediate temperature heat exchange medium to satisfy an intermediate temperature refrigeration load; and
means to provide the remaining portion of the cooled intermediate temperature heat exchange medium to condense refrigerant in said first condenser.
2. A refrigeration system according to claim 1 further including pump means for circulating the intermediate temperature heat exchange medium, said means to satisfy an intermediate temperature refrigeration load including:
a supply line communicating between said second evaporator and the intermediate temperature refrigeration load to supply cooled intermediate temperature heat exchange medium thereto,
a return line communicating with said second evaporator to return heat exchange medium from the refrigeration load, said means to condense refrigerant in said first condenser including:
a second supply line to provide communication between said first supply line and said first condenser to pro vide intermediate temperature heat exchange medium to said first condenser, and
a second return line communicating between said first condenser and said first return line to return the intermediate temperature heat exchange medium from said first condenser to said first return line, said pump means being adapted to circulate intermediate temperature heat exchange medium through said 4 lines to satisfy said refrigeration load and condense refrigerant in said first condenser.
3. A refrigeration system according to claim 2 wherein said means to provide a portion of the intermediate temperature heat exchange medium to satisfy an intermediate temperature heat exchange load includes:
a first shutoff valve in said first supply line and a second shutoff valve in said first return line to prevent flow of heat exchange medium to the intermediate temperature refrigeration load, said means to provide intermediate temperature heat exchange medium to condense refrigerant in said first condenser including:
a third shutoff valve in said second supply line and a fourth shutoff valve in said second return line, said third and fourth shutoff valves being adapted to prevent flow of heat exchange medium to said first condenser when said first compressor is inoperative.
4. A method for providing multitemperature refrigeration comprising the steps of:
compressing refrigerant vapor in a first refrigeration cycle,
passing the compressed refrigerant vapor in heat exchange relationship with a high temperature heat exchange medium to condense the refrigerant vapor,
passing the condensed refrigerant in heat exchange relationship with an intermediate temperature heat exchange medium to evaporate the refrigerant, thereby cooling the intermediate temperature heat exchange medium,
utilizing a portion of the cooled intermediate temperature heat exchange medium to satisfy an intermediate temperature cooling load,
compressing refrigerant vapor in a second refrigeration cycle,
passing the compressed refrigerant vapor in the second refrigeration cycle in heat exchange relationship with the remaining portion of the cooled intermediate temperature heat exchange medium to condense the refrigerant vapor,
passing the condensed refrigerant vapor in the second refrigeration cycle in heat exchange relationship with a low temperature heat exchange medium to evaporate the refrigerant, thereby cooling the low temperature heat exchange medium, and
utilizing the cooled low temperature heat exchange medium to satisfy a low temperature cooling load.
References Cited UNITED STATES PATENTS LLOYD L. KING, Primary Examiner U.S. c1. X.R. 62-175, 510
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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4144723A (en) * 1976-03-15 1979-03-20 General Atomic Company Power plant secondary coolant circuit
USRE30630E (en) * 1976-03-15 1981-06-02 General Atomic Company Power plant secondary coolant circuit
EP0340115A1 (en) * 1988-04-28 1989-11-02 Société Anonyme ELECTROLUX CR Central refrigeration plant supplying enclosures with at least two temperatures, and defrosting method for such a central plant
US5440894A (en) * 1993-05-05 1995-08-15 Hussmann Corporation Strategic modular commercial refrigeration
US20120198872A1 (en) * 2009-10-28 2012-08-09 Mitsubishi Electric Corporation Air-conditioning apparatus
US20120204585A1 (en) * 2009-10-28 2012-08-16 Mitsubishi Electric Corporation Air-conditioning apparatus
US20120304675A1 (en) * 2010-02-10 2012-12-06 Mitsubishi Electric Corporation Air-conditioning apparatus
US20180356130A1 (en) * 2013-03-15 2018-12-13 Trane International Inc. Cascading heat recovery using a cooling unit as a source

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2680956A (en) * 1951-12-19 1954-06-15 Haskris Co Plural stage refrigeration system
US2739453A (en) * 1953-04-17 1956-03-27 Robert C Webber Explosion-proof low-high temperature system
US3199304A (en) * 1963-01-18 1965-08-10 Air Prod & Chem Methods for producing low temperature refrigeration
US3322188A (en) * 1965-07-08 1967-05-30 Carrier Corp Heating and cooling apparatus and method
US3392541A (en) * 1967-02-06 1968-07-16 Larkin Coils Inc Plural compressor reverse cycle refrigeration or heat pump system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2680956A (en) * 1951-12-19 1954-06-15 Haskris Co Plural stage refrigeration system
US2739453A (en) * 1953-04-17 1956-03-27 Robert C Webber Explosion-proof low-high temperature system
US3199304A (en) * 1963-01-18 1965-08-10 Air Prod & Chem Methods for producing low temperature refrigeration
US3322188A (en) * 1965-07-08 1967-05-30 Carrier Corp Heating and cooling apparatus and method
US3392541A (en) * 1967-02-06 1968-07-16 Larkin Coils Inc Plural compressor reverse cycle refrigeration or heat pump system

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4144723A (en) * 1976-03-15 1979-03-20 General Atomic Company Power plant secondary coolant circuit
USRE30630E (en) * 1976-03-15 1981-06-02 General Atomic Company Power plant secondary coolant circuit
EP0340115A1 (en) * 1988-04-28 1989-11-02 Société Anonyme ELECTROLUX CR Central refrigeration plant supplying enclosures with at least two temperatures, and defrosting method for such a central plant
FR2630816A1 (en) * 1988-04-28 1989-11-03 Electrolux Cr Sa REFRIGERATING CENTER SUPPLYING SPEAKERS AT AT LEAST TWO TEMPERATURES AND METHOD OF DEFROSTING SUCH A PLANT
US5440894A (en) * 1993-05-05 1995-08-15 Hussmann Corporation Strategic modular commercial refrigeration
EP0936421A3 (en) * 1993-05-05 1999-09-01 Hussmann Corporation Strategic modular commercial refrigeration
US20120198872A1 (en) * 2009-10-28 2012-08-09 Mitsubishi Electric Corporation Air-conditioning apparatus
US20120204585A1 (en) * 2009-10-28 2012-08-16 Mitsubishi Electric Corporation Air-conditioning apparatus
US9303904B2 (en) * 2009-10-28 2016-04-05 Mitsubishi Electric Corporation Air-conditioning apparatus
US9335074B2 (en) * 2009-10-28 2016-05-10 Mitsubishi Electric Corporation Air-conditioning apparatus
US20120304675A1 (en) * 2010-02-10 2012-12-06 Mitsubishi Electric Corporation Air-conditioning apparatus
US9353958B2 (en) * 2010-02-10 2016-05-31 Mitsubishi Electric Corporation Air-conditioning apparatus
US20180356130A1 (en) * 2013-03-15 2018-12-13 Trane International Inc. Cascading heat recovery using a cooling unit as a source
US10767908B2 (en) * 2013-03-15 2020-09-08 Trane International Inc. Cascading heat recovery using a cooling unit as a source

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