US20050274133A1 - Refrigeration plant - Google Patents

Refrigeration plant Download PDF

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Publication number
US20050274133A1
US20050274133A1 US10/956,297 US95629704A US2005274133A1 US 20050274133 A1 US20050274133 A1 US 20050274133A1 US 95629704 A US95629704 A US 95629704A US 2005274133 A1 US2005274133 A1 US 2005274133A1
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US
United States
Prior art keywords
valve
refrigerant
overheating
evaporator
compressor
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
US10/956,297
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English (en)
Inventor
Emidio Barsanti
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.)
MICHELETTI IMPIANTI Srl LLC
Original Assignee
MICHELETTI IMPIANTI Srl LLC
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 MICHELETTI IMPIANTI Srl LLC filed Critical MICHELETTI IMPIANTI Srl LLC
Assigned to MICHELETTI IMPIANTI SRL LLC reassignment MICHELETTI IMPIANTI SRL LLC ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: BARSANTI, EMIDIO
Publication of US20050274133A1 publication Critical patent/US20050274133A1/en
Abandoned legal-status Critical Current

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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
    • F25B41/34—Expansion valves with the valve member being actuated by electric means, e.g. by piezoelectric actuators
    • F25B41/345—Expansion valves with the valve member being actuated by electric means, e.g. by piezoelectric actuators by solenoids
    • F25B41/347—Expansion valves with the valve member being actuated by electric means, e.g. by piezoelectric actuators by solenoids with the valve member being opened and closed cyclically, e.g. with pulse width modulation
    • 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
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/19—Pressures
    • F25B2700/193—Pressures of the compressor
    • F25B2700/1933—Suction pressures
    • 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
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2115—Temperatures of a compressor or the drive means therefor
    • F25B2700/21151—Temperatures of a compressor or the drive means therefor at the suction side of the compressor
    • 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
    • F25B47/00—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
    • F25B47/02—Defrosting cycles
    • F25B47/022—Defrosting cycles hot gas defrosting
    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Definitions

  • the present invention relates the field of the refrigeration plants or systems, with particular—but not exclusive—reference to those of middle-great dimensions.
  • the invention refers to a solenoid valve without orifice which is periodically energized (opened) and de-energized (closed) by a control system that, in response to some parameters of the refrigeration plant (e.g. overheating), varies the ratio between the energizing time (opening) and the de-energizing time (closing) of the solenoid valve during each period of operation of the valve so that to regulate the flow of refrigerant that goes through the valve itself.
  • some parameters of the refrigeration plant e.g. overheating
  • a refrigeration plant typically includes a compressor, a condensing coil and a evaporating coil.
  • Refrigerant vapor is compressed to high pressure by the compressor and supplied to the condenser where the high pressure refrigerant vapor is condensed to a high pressure liquid.
  • An expansion valve is provided between the condenser and the evaporator so that the liquid refrigerant from the condenser can be adiabatically expanded before entering in the evaporator.
  • the low pressure refrigerant absorbs heat from the surrounding environment and it is transformed, at least partially, in a vapor which returns to the inlet of the compressor through a suction line.
  • the expansion valve is a so-called thermostatic expansion valve.
  • the common thermostatic expansion valve as for instance the known “Danfoss TE2” model, has an expansion port therein with a metering orifice and a valve member to regulate the flow of refrigerant through the expansion port.
  • a spring biases the valve member toward its closing position, and it is provided a diaphragm actuator having a side of the diaphragm exposed to the pressure of the suction gas while the other side is connected, through a capillary pipe, to a thermostatic bulb which exchanges heat with the refrigerant vapor (also called “suction gas”) exhausted by the evaporator.
  • the bulb which is loaded with a suitable volatile fluid (e.g.
  • a refrigerant exerts a pressure force on the valve member on the diaphragm actuator opposing the force of the spring and the pressure of the suction gas.
  • the thermostatic bulb detects an increase in the suction gas temperature with respect to its pressure, the clean pressure force exerted on the diaphragm actuator is correspondingly increased, thereby obtaining to increase the opening of the valve so as to allow to a greater quantity of refrigerant to flow through the evaporator, resulting in a drop in temperature of the suction gas.
  • the thermostatic bulb decreases the pressure force exerted on the diaphragm actuator and thereby allows the spring to close at least partially the valve, reducing the flow of refrigerant in the evaporator and, in turn, increasing the temperature of the suction gas.
  • the expansion valve regulates the overheating at the evaporator outlet, the overheating being defined as the difference between the temperature of the refrigerant vapor and the temperature of a saturated vapor of the same refrigerant to the same pressure.
  • the expansion valves of known type have generally the following limitations:
  • the U.S. Pat. No. 4,112,703 discloses an electromechanical valve working also as expansion device in the refrigeration circuit, wherein the refrigerant expands while it flows through the valve, going out of the valve in the form of a two-phase mixture of liquid and gas in which the preponderant phase is the liquid phase.
  • the valve is used for furnishing a varying orifice correspondingly to the applied control.
  • the expansion valve known with the commercial name of “Danfoss AKV” is conceptually similar to the U.S. Pat. No. 4,459,819: in substance, it concerns a solenoid valve incorporating a metering orifice which is activated every six seconds and subsequently deactivated after a suitable time calculated by a proportional, differential and integral electronic controller.
  • the patent DE3419666 discloses the same simple solenoid incorporating a metering orifice, used as expansion valve for air conditioning for generic use and for heat pumps.
  • a refrigeration plant comprising a compressor having an inlet and an outlet, a condenser connected to the outlet of the compressor, an evaporator connected to the condenser and the compressor inlet, and a regulation valve situated between the condenser and the evaporator.
  • the condenser provides the high pressure refrigerant to the regulation valve, which is constituted by a solenoid valve having a solenoid actuator that, when is activated (energized), moves the valve member to its open position while when is deactivated (de-energized) it allows the valve member to move itself in its closed position by means of a suitable return spring.
  • the solenoid valve doesn't have any metering orifice through which the refrigerant fluid could be expanded.
  • the solenoid actuator is periodically activated/deactivated by a suitable electronic controller with the purpose to regulate the flow of refrigerant that goes through the regulation valve to obtain the desired overheating for the refrigerant at the evaporator outlet.
  • Said overheating control is carried out by the electronic controller which analyzes the signals coming from a pressure probe and from a temperature probe positioned between the evaporator outlet and the compressor inlet.
  • a pipeline for the refrigerant which is in warm gaseous-state is provided between the compressor outlet and the evaporator inlet.
  • this pipeline that by-passes the condenser and the regulation valve, is controlled by an additional solenoid valve with the purpose to carry out the defrosting and the heating of the evaporator.
  • said regulation solenoid valve without metering orifice can be constituted by a common refrigerant solenoid valve (as the EVR of the Danfoss), that is advantageously more cheap than an solenoid expansion valve having a metering orifice (as the AKV of the Danfoss).
  • said lacking of metering orifice allows to avoid the installation of a liquid receiver in many situations for which it would be necessary to use a solenoid expansion valve with metering orifice.
  • the size of the pipeline between the condenser and the evaporator can be reduced, because a relevant part of the expansion happens in the same pipeline, thereby further reducing the total quantity of refrigerant needed by the plant.
  • a reduction up to 80% of the total quantity of needed refrigerant is obtained.
  • FIG. 1 schematically shows the main components of a refrigeration plant, for instance of the semi-hermetic type with hot-gas defrost, to refrigerate a cold-room.
  • the outlet 3 of the semi-hermetic compressor 1 is connected to the inlet 10 of the condenser 9 through a pipeline 6 .
  • the outlet 11 of the condenser 9 is connected to the inlet 13 of the solenoid regulation valve 12 through a pipeline 15 .
  • the solenoid valve 12 is preferably placed near to the outlet of the condenser 11 or near to the inlet of the compressor 1 , with the advantage to simplify the installation and to facilitate the maintenance.
  • the outlet 14 of the valve 12 is connected to the inlet 18 of the evaporator 17 through a pipeline 16 , while the outlet 19 of the evaporator 17 is connected to the inlet 2 of the compressor 1 through the pipeline 20 .
  • the pressure probe 4 is preferably connected to the low pressure cap of the compressor 1 , while the temperature probe 5 is preferably positioned in contact with the low part of the pipeline 20 immediately before the inlet 2 of the compressor 1 .
  • the hot gas bypass pipeline 7 connects the high-pressure pipeline 6 outgoing from the compressor 1 with the pipeline 16 downstream the regulation valve 12 , by means of the hot gas solenoid valve 8 .
  • the electronic controller 21 calculates with a microprocessor the overheating of the refrigerant entering in the compressor 1 , by using the information coming from the pressure and temperature probes 4 and 5 .
  • the hot gas valve 8 is kept close (off) and the desired overheating is kept and controlled by switching off and on the solenoid regulation valve 12 .
  • the “ON time” is firstly fixed to an interval of about 2 seconds, then it is gradually increased or decreased by the controller to control the overheating, preferably by means of a proportional, integral and/or differential control method.
  • the regulation valve 12 is maintained closed and the hot gas valve 8 is opened, while the compressor 1 is on, thereby supplying hot gas to the evaporator 17 without by-passing the inlet 18 to the evaporator.
  • the controller 21 monitors the value of the overheating at the compressor and, when such overheating is below a preset value, for instance of about 4° C., it closes the hot gas valve 8 until the preset minimum value of the overheating is reached again.
  • All the components of the refrigeration system can be designed according to traditional methods, with exception of the regulation valve 12 and of the pipeline 15 and 16 , respectively upstream and downstream of such valve.
  • the pipeline 15 and 16 are so small that refrigerant completely liquid starts to outflow from the outlet 11 of the condenser 9 but the flow resistance of the pipeline it is so high that OH is still greater than OH 0 .
  • the further filling of refrigerant simply floods the condenser 9 resulting in a small improvement of the overheating.
  • the pipelines 15 and 16 are so big that, before that completely liquid refrigerant starts to outflow from the outlet 11 of the condenser 9 , the overheating OH is already equal to OH 0 . This involve that part of the refrigerant from the outlet 11 of the condenser 9 is gaseous and consequently the capacity and the efficiency of the refrigeration system are reduced, since the gaseous part does not undergo evaporation during the refrigeration cycle. If the efficiency is the main concern, the quantity of refrigerant can be increased until completely liquid refrigerant outflows from the outlet 11 of the condenser 9 , allowing the regulation valve 12 to be activated/deactivated for controlling the flow of the fluid in order to maintain the desired overheating.
  • the natural flow resistance between the outlet 11 of the condenser 9 and the inlet 18 of the evaporator 17 can be smaller than required and consequently, if the regulation valve 12 would be completely open, an excessive quantity of refrigerant would be furnished to the evaporator, thereby resulting in an insufficient overheating (too low). For this reason the regulation valve 12 is activated and deactivated for limiting the flow of refrigerant and to obtain the desired overheating.
  • a bigger regulation valve 12 has a smaller flow resistance when it is completely open and it allows a greater flow resistance in the pipelines 15 and 16 , thereby reducing the quantity of refrigerant which is really necessary to the plant itself.
  • the sizing of the regulation valve appears rather simple. However, it should be noted that said sizing it is limited by the costs and by practical reasons.
  • a common on-off solenoid valve without metering orifice (as the EVR Danfoss), used as regulation valve, is advantageously simple, reliable and cheap with respect to more sophisticated valves.
  • the EVR Danfoss used as regulation valve
  • valve 12 is to regulate the refrigerant flow in order to get the desired working conditions and not that to expand the refrigerant fluid.
  • said valve without metering orifice is characterized by its own natural flow resistance and it does not provide any other flow limitation device when said valve is completely open.
  • Part of the refrigerant that is furnished to said valve is already in a gaseous form when said valve it is completely open, while the expansion of said refrigerant occurs primarily in the part of pipeline between the condenser and the evaporator.
  • the regulation valve 12 can be sized to perform a remarkable part of the expansion, this sizing would be deleterious since it would determine a flow resistance through the valve itself, thereby reducing acceptable flow resistance through the pipelines 15 and 16 , increasing the quantity of refrigerant needed by the plant.
  • a refrigerant which can be used in the plant herein disclosed is, for instance, a HFC as the R134a or the R404A or the R407A or the R410A or the R507A.
  • the regulation valve 12 without metering orifice is preferably an on/off direct controlled solenoid valve.
  • the valve is preferably energized (open) and de-energized (close) as a function of a parameter of the refrigeration system (e.g. the overheating), in such a way that the ratio between the energizing time and the de-energizing time during every period of operation of the valve is varied in response to the system parameter(s) and in such a way that the on/off solenoid valve works as a modulated refrigerant flow control expansion valve.
  • a parameter of the refrigeration system e.g. the overheating
  • the system has a quantity of refrigerant strongly reduced. In most conditions, the circuit does not need any liquid receiver and the hot-gas defrost can be performed without by-passing the distributor of the evaporator.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Devices That Are Associated With Refrigeration Equipment (AREA)
  • Magnetically Actuated Valves (AREA)
  • Air Conditioning Control Device (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
US10/956,297 2004-06-10 2004-10-01 Refrigeration plant Abandoned US20050274133A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP04425426.6 2004-06-10
EP04425426A EP1607699B1 (fr) 2004-06-10 2004-06-10 Appareil frigorifique

Publications (1)

Publication Number Publication Date
US20050274133A1 true US20050274133A1 (en) 2005-12-15

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US10/956,297 Abandoned US20050274133A1 (en) 2004-06-10 2004-10-01 Refrigeration plant

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US (1) US20050274133A1 (fr)
EP (1) EP1607699B1 (fr)
AT (1) ATE395566T1 (fr)
DE (1) DE602004013749D1 (fr)
WO (1) WO2005121663A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090031738A1 (en) * 2005-05-06 2009-02-05 Tomoichiro Tamura Refrigerating machine
US20100243202A1 (en) * 2009-03-30 2010-09-30 Han Wang Kuk Hot water circulation system associated with heat pump
US20170065931A1 (en) * 2014-05-09 2017-03-09 Atlas Copco Airpower, Naamloze Vennootschap Method and device for cool-drying a gas with circulating cooling liquid with bypass line
US20170128879A1 (en) * 2014-05-09 2017-05-11 Atlas Copco Airpower, Naamloze Vennootschap Method and device for cool-drying a gas using a heat exchanger with closed cooling circuit
US20170144103A1 (en) * 2014-05-09 2017-05-25 Atlas Copco Airpower, Naamloze Vennootschap Method for cool drying a gas
US20170151529A1 (en) * 2014-05-09 2017-06-01 Atlas Copco Airpower, Naamloze Vennootschap Method and device for cool drying a gas

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5867998A (en) * 1997-02-10 1999-02-09 Eil Instruments Inc. Controlling refrigeration

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6006544A (en) * 1995-12-11 1999-12-28 Matsushita Electric Industrial Co., Ltd. Refrigeration cycle
JPH11118202A (ja) * 1997-08-13 1999-04-30 Toshiba Corp スプリットエアコン
US6701729B2 (en) * 2001-05-16 2004-03-09 Bbc Enterprises, Inc. Device and method for operating a refrigeration cycle without evaporator icing
US6668570B2 (en) * 2001-05-31 2003-12-30 Kryotech, Inc. Apparatus and method for controlling the temperature of an electronic device under test
ITMI20011918A1 (it) * 2001-09-14 2003-03-14 Domnick Hunter Hiross S P A Sistema di controllo per essicatori di gas compresso a refrigerazione
ITTO20030792A1 (it) * 2002-10-08 2004-04-09 Danfoss As Dispositivo e procedimento di controllo di una valvola

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5867998A (en) * 1997-02-10 1999-02-09 Eil Instruments Inc. Controlling refrigeration

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090031738A1 (en) * 2005-05-06 2009-02-05 Tomoichiro Tamura Refrigerating machine
US7886550B2 (en) * 2005-05-06 2011-02-15 Panasonic Corporation Refrigerating machine
US20100243202A1 (en) * 2009-03-30 2010-09-30 Han Wang Kuk Hot water circulation system associated with heat pump
US20170065931A1 (en) * 2014-05-09 2017-03-09 Atlas Copco Airpower, Naamloze Vennootschap Method and device for cool-drying a gas with circulating cooling liquid with bypass line
US20170128879A1 (en) * 2014-05-09 2017-05-11 Atlas Copco Airpower, Naamloze Vennootschap Method and device for cool-drying a gas using a heat exchanger with closed cooling circuit
US20170144103A1 (en) * 2014-05-09 2017-05-25 Atlas Copco Airpower, Naamloze Vennootschap Method for cool drying a gas
US20170151529A1 (en) * 2014-05-09 2017-06-01 Atlas Copco Airpower, Naamloze Vennootschap Method and device for cool drying a gas
US9914092B2 (en) * 2014-05-09 2018-03-13 Atlas Copco Airpower Naamloze Vennootschap Method and device for cool drying a gas
US9914091B2 (en) * 2014-05-09 2018-03-13 Atlas Copco Airpower, Naamloze Vennootschap Method for cool drying a gas
US9950294B2 (en) * 2014-05-09 2018-04-24 Atlas Copco Airpower, Naamloze Vennootschap Method and device for cool-drying a gas using a heat exchanger with closed cooling circuit
US10232309B2 (en) * 2014-05-09 2019-03-19 Atlas Copco Airpower, Naamloze Vennootschap Method and device for cool-drying a gas with circulating cooling liquid with bypass line

Also Published As

Publication number Publication date
EP1607699A1 (fr) 2005-12-21
WO2005121663A1 (fr) 2005-12-22
EP1607699B1 (fr) 2008-05-14
DE602004013749D1 (de) 2008-06-26
ATE395566T1 (de) 2008-05-15

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Owner name: MICHELETTI IMPIANTI SRL LLC, ITALY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:BARSANTI, EMIDIO;REEL/FRAME:015890/0056

Effective date: 20040917

STCB Information on status: application discontinuation

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