US20080196426A1 - System Reheat Control by Pulse Width Modulation - Google Patents

System Reheat Control by Pulse Width Modulation Download PDF

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Publication number
US20080196426A1
US20080196426A1 US11/995,128 US99512805A US2008196426A1 US 20080196426 A1 US20080196426 A1 US 20080196426A1 US 99512805 A US99512805 A US 99512805A US 2008196426 A1 US2008196426 A1 US 2008196426A1
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US
United States
Prior art keywords
refrigerant
reheat
set forth
condenser
valve
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.)
Abandoned
Application number
US11/995,128
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English (en)
Inventor
Michael F. Taras
Alexander Lifson
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
Assigned to CARRIER CORPORATION reassignment CARRIER CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: LIFSON, ALEXANDER, TARAS, MICHAEL F.
Publication of US20080196426A1 publication Critical patent/US20080196426A1/en
Abandoned legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
    • F24F3/12—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling
    • F24F3/14—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification
    • F24F3/153—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification with subsequent heating, i.e. with the air, given the required humidity in the central station, passing a heating element to achieve the required temperature
    • 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
    • F25B2400/04—Refrigeration circuit bypassing means
    • F25B2400/0403—Refrigeration circuit bypassing means for the condenser
    • 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
    • F25B2600/2521—On-off valves controlled by pulse signals

Definitions

  • This application relates to a pulse width modulation control that allows for continuous or precise stepwise reheat capacity to be provided by a refrigerant system.
  • Refrigerant systems are utilized in many applications such as to condition an environment. Air conditioners and heat pumps are used to cool and/or heat the air entering an environment. The cooling or heating load on the environment may change with ambient conditions, and as the temperature and/or humidity levels demanded by an occupant of the environment vary. Obviously, the refrigerant system operation and control have to adequately reflect these changes to maintain stable temperature and humidity conditions within the environment.
  • the temperature level of the indoor air stream to provide a comfortable environment in a conditioned space may need to be higher than the temperature that would provide the ideal humidity level.
  • the temperature of the air stream may need to be higher than the temperature that would provide the ideal humidity level.
  • by lowering the temperature of the air stream more moisture can be removed from the air.
  • controls can be programmed to optionally actuate the reheat function.
  • the capacity provided by the reheat circuit is increased or decreased in steps. It would be desirable to provide the ability to vary the reheat capacity and overall system performance between these discrete steps.
  • pulse width modulation controls have been provided for various purposes in refrigerant systems, they have not been utilized to provide varying steps in a reheat capacity.
  • a pulse width modulation control is provided for selectively varying capacity provided by a reheat circuit and thus overall system performance.
  • the “on/off” cycle time interval is selected such that the overall effect on the system in terms of external operational characteristics, due to system thermal inertia, is negligible. That is, an occupant of an environment being conditioned would not recognize that the flow of refrigerant to the reheat circuit is being periodically turned on and off.
  • control is operable to vary the width of the pulse to achieve a desired time interval for a flow control device such as a valve being opened to direct refrigerant to the reheat heat exchanger.
  • a flow control device such as a valve being opened to direct refrigerant to the reheat heat exchanger.
  • the present invention may also be provided in combination with a circuit that allows for bypass of refrigerant around a condenser to allow for additional operational flexibility in the reheat functionality and control.
  • FIG. 1 shows a first schematic
  • FIG. 2 shows a second schematic
  • a refrigerant system 20 is illustrated in FIG. 1 including a compressor 22 compressing refrigerant and delivering it to a downstream condenser 24 .
  • a fan 25 blows air over the condenser 24 .
  • Refrigerant passes from the condenser 24 to a downstream expansion device 26 , then to an evaporator 28 , and finally returns to compressor 22 .
  • a three-way valve 30 is placed on a discharge refrigerant line, and as illustrated, between the compressor 22 and the condenser 24 .
  • the three-way valve 30 is controlled by a control 38 for a purpose that will be described below.
  • the three-way valve When the three-way valve is in an open position, it will deliver refrigerant through a reheat heat exchanger 34 and a check valve 35 , and then return the refrigerant back to a position 31 still upstream of the condenser 24 .
  • a fan 36 blows air over the evaporator 28 , and the reheat heat exchanger 34 is placed such that it is in the path of that air stream behind the evaporator 28 .
  • the purpose of the reheat heat exchanger 34 is to allow the evaporator 28 to cool the air passing over it to a level that is lower than may be desired by an occupant of an environment and requested through a thermostat 32 in order to remove sufficient amount of moisture from the air and maintain desired humidity level in the environment. Lower temperatures of air passing over the evaporator 28 result in more moisture been removed from the air. The air then passes over the reheat heat exchanger 34 , and is reheated back towards the desired temperature. In this manner, utilization of a reheat circuit provides both desired temperature and humidity levels in the conditioned environment.
  • the control 38 sends a pulse width modulation signal to the valve 30 .
  • the valve 30 is of a three-way type that is typically in a normally open position (during a cooling mode of operation) communicates refrigerant from the compressor 22 directly to the condenser 24 , and may be driven to an alternate position (during a reheat mode of operation) at which it allows refrigerant to flow from the compressor 22 through the reheat heat exchanger 34 to the condenser 24 .
  • a pulse width modulation signal is provided by the control 38 to the valve 30 , it moves the valve to this alternate position.
  • control 38 Since the control 38 is determining the required reheat capacity, the control can then determine the width of the pulse and the time interval between the pulses sent to the valve 30 , such that the valve 30 can be in the open position precisely for an amount of time to provide this required reheat capacity. In this manner, just the right reheat capacity is provided, and temperature and humidity in a conditioned environment are precisely controlled.
  • the present invention thus offers a relatively inexpensive and efficient method of providing a variable reheat function with essentially an infinite number of reheat stages.
  • FIG. 2 shows another embodiment 37 , which is similar to the FIG. 1 embodiment, however, rather than having a three-way valve, conventional on/off solenoid valves 38 and 40 are controlled by the pulse width modulation signal.
  • a reheat branch is active, the valve 40 is opened and the refrigerant is tapped from a point 100 and is returned to point 102 of the main circuit.
  • the pulse width modulation is controlled in a manner similar to that described with the FIG. 1 embodiment.
  • Valve 40 may be opened and closed to achieve a variable reheat capacity similar to the three-way valve 30 in FIG. 1 .
  • Valve 38 may also be operated by the pulse width nodulation signal and allows control over the refrigerant flow in a main refrigerant circuit in conjunction with the valve 40 .
  • FIG. 2 schematic also provides the option of including a condenser bypass line 42 passing through a bypass valve 44 to allow rerouting of at least a portion of refrigerant around the condenser 24 .
  • the bypass valve 44 is activated when dehumidification is desired with little or no cooling of the air.
  • the operation and control of the bypass valve 44 is as known in the art, however the provision of the condenser bypass function that can also be operated by the pulse width modulation signal along with the variable pulse modulation control for the reheat circuit itself provides increased flexibility in operation to precisely achieve desired parameters (in terms of temperature and humidity) in an environment conditioned by the refrigerant system 37 .
  • FIGS. 1 and 2 may be configured either with a three-way valve or a pair of solenoid valves. Further, although only two reheat concepts are disclosed, any known reheat schematic can benefit from the invention.
  • Pulse width modulation controls are known, and valves operated by the pulse width modulation signal are known.
  • the present invention utilizes this known technology in a unique manner to achieve goals and benefits as set forth above.
US11/995,128 2005-08-23 2005-08-23 System Reheat Control by Pulse Width Modulation Abandoned US20080196426A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US2005/030603 WO2007024237A1 (en) 2005-08-23 2005-08-23 System reheat control by pulse width modulation

Publications (1)

Publication Number Publication Date
US20080196426A1 true US20080196426A1 (en) 2008-08-21

Family

ID=37771893

Family Applications (1)

Application Number Title Priority Date Filing Date
US11/995,128 Abandoned US20080196426A1 (en) 2005-08-23 2005-08-23 System Reheat Control by Pulse Width Modulation

Country Status (5)

Country Link
US (1) US20080196426A1 (de)
EP (1) EP1938026A4 (de)
CN (1) CN101248319A (de)
CA (1) CA2616279A1 (de)
WO (1) WO2007024237A1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160305696A1 (en) * 2013-12-02 2016-10-20 Samsung Electronics Co., Ltd. Cooling device
US10955149B2 (en) 2016-07-25 2021-03-23 Carrier Corporation Dehumidification system for heat pump

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2318997B1 (es) * 2006-10-17 2010-03-01 Merak Sistemas Integrados De Climatizacion, S.A. Sistema de climatizacion.
ES2688420T3 (es) * 2008-06-13 2018-11-02 Carrier Corporation Procedimiento de arranque para sistemas refrigerantes que tienen condensador de microcanales y ciclo de recalentamiento
CN102997517B (zh) * 2011-09-09 2015-08-12 珠海格力电器股份有限公司 空调器恒温除湿系统
CN103791652B (zh) * 2014-01-13 2016-01-20 浙江理工大学 一种双温热源热泵系统
CN106500378A (zh) * 2016-09-29 2017-03-15 同济大学 基于高温制冷剂混合再热模式的高效空调机组及控制方法

Citations (9)

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Publication number Priority date Publication date Assignee Title
US5651258A (en) * 1995-10-27 1997-07-29 Heat Controller, Inc. Air conditioning apparatus having subcooling and hot vapor reheat and associated methods
US6047556A (en) * 1997-12-08 2000-04-11 Carrier Corporation Pulsed flow for capacity control
US6055818A (en) * 1997-08-05 2000-05-02 Desert Aire Corp. Method for controlling refrigerant based air conditioner leaving air temperature
US6286327B1 (en) * 1996-12-09 2001-09-11 Valeo Climatisation Refrigerant fluid circuit including an air conditioning loop and a heating loop, in particular for a motor vehicle
US6422308B1 (en) * 1997-04-09 2002-07-23 Calsonic Kansei Corporation Heat pump type air conditioner for vehicle
US6449972B2 (en) * 1995-06-07 2002-09-17 Copeland Corporation Adaptive control for a refrigeration system using pulse width modulated duty cycle scroll compressor
US6826921B1 (en) * 2003-07-03 2004-12-07 Lennox Industries, Inc. Air conditioning system with variable condenser reheat for enhanced dehumidification
US6931867B2 (en) * 2002-07-15 2005-08-23 Copeland Corporation Cooling system with isolation valve
US20060086115A1 (en) * 2004-10-22 2006-04-27 York International Corporation Control stability system for moist air dehumidification units and method of operation

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US1837798A (en) * 1928-09-19 1931-12-22 York Ice Machinery Corp Apparatus for conditioning air
US2515842A (en) * 1947-07-16 1950-07-18 Carrier Corp System for providing reheat in bus air conditioning
US2844946A (en) * 1955-03-16 1958-07-29 Donald A Bauer Air conditioning device with reheat means
AT305354B (de) * 1970-10-06 1973-02-26 Friedmann Kg Alex Klimaanlage für Eisenbahnfahrzeuge
US4548047A (en) * 1981-11-11 1985-10-22 Hitachi, Ltd. Expansion valve
JP3233447B2 (ja) * 1992-06-02 2001-11-26 東芝キヤリア株式会社 空気調和機
JP3151310B2 (ja) * 1992-10-27 2001-04-03 東芝キヤリア株式会社 空気調和機
JP2002221280A (ja) * 2001-01-26 2002-08-09 Saginomiya Seisakusho Inc 流体制御弁の駆動装置
US6672087B1 (en) * 2002-10-30 2004-01-06 Carrier Corporation Humidity and temperature control in vapor compression system
US20040089015A1 (en) * 2002-11-08 2004-05-13 York International Corporation System and method for using hot gas reheat for humidity control

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6449972B2 (en) * 1995-06-07 2002-09-17 Copeland Corporation Adaptive control for a refrigeration system using pulse width modulated duty cycle scroll compressor
US5651258A (en) * 1995-10-27 1997-07-29 Heat Controller, Inc. Air conditioning apparatus having subcooling and hot vapor reheat and associated methods
US6286327B1 (en) * 1996-12-09 2001-09-11 Valeo Climatisation Refrigerant fluid circuit including an air conditioning loop and a heating loop, in particular for a motor vehicle
US6422308B1 (en) * 1997-04-09 2002-07-23 Calsonic Kansei Corporation Heat pump type air conditioner for vehicle
US6055818A (en) * 1997-08-05 2000-05-02 Desert Aire Corp. Method for controlling refrigerant based air conditioner leaving air temperature
US6047556A (en) * 1997-12-08 2000-04-11 Carrier Corporation Pulsed flow for capacity control
US6931867B2 (en) * 2002-07-15 2005-08-23 Copeland Corporation Cooling system with isolation valve
US6826921B1 (en) * 2003-07-03 2004-12-07 Lennox Industries, Inc. Air conditioning system with variable condenser reheat for enhanced dehumidification
US20060086115A1 (en) * 2004-10-22 2006-04-27 York International Corporation Control stability system for moist air dehumidification units and method of operation

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160305696A1 (en) * 2013-12-02 2016-10-20 Samsung Electronics Co., Ltd. Cooling device
US10203139B2 (en) * 2013-12-02 2019-02-12 Samsung Electronics Co., Ltd. Cooling device
US10955149B2 (en) 2016-07-25 2021-03-23 Carrier Corporation Dehumidification system for heat pump

Also Published As

Publication number Publication date
WO2007024237A1 (en) 2007-03-01
EP1938026A4 (de) 2011-12-14
CN101248319A (zh) 2008-08-20
CA2616279A1 (en) 2007-03-01
EP1938026A1 (de) 2008-07-02

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Legal Events

Date Code Title Description
AS Assignment

Owner name: CARRIER CORPORATION, NEW YORK

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:TARAS, MICHAEL F.;LIFSON, ALEXANDER;REEL/FRAME:020340/0422

Effective date: 20050819

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION