EP1929217A1 - Detection de fuite de frigorigene - Google Patents

Detection de fuite de frigorigene

Info

Publication number
EP1929217A1
EP1929217A1 EP06761870A EP06761870A EP1929217A1 EP 1929217 A1 EP1929217 A1 EP 1929217A1 EP 06761870 A EP06761870 A EP 06761870A EP 06761870 A EP06761870 A EP 06761870A EP 1929217 A1 EP1929217 A1 EP 1929217A1
Authority
EP
European Patent Office
Prior art keywords
refrigerant
receiver
pressure side
compressor
weight transducer
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.)
Withdrawn
Application number
EP06761870A
Other languages
German (de)
English (en)
Inventor
Finn Guldager Christensen
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.)
Knudsen Koling AS
Original Assignee
Knudsen Koling AS
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 Knudsen Koling AS filed Critical Knudsen Koling AS
Publication of EP1929217A1 publication Critical patent/EP1929217A1/fr
Withdrawn legal-status Critical Current

Links

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
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/005—Arrangement or mounting of control or safety devices of safety devices
    • 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—Component parts or details not otherwise provided for in this subclass
    • F25B2400/16—Receivers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2500/00—Problems to be solved
    • F25B2500/22—Preventing, detecting or repairing leaks of refrigeration fluids
    • F25B2500/222—Detecting refrigerant leaks
    • 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
    • F25B2600/05—Refrigerant levels

Definitions

  • the present invention relates to a refrigeration system capable of detecting leakage of the refrigerant, and in particular the present invention relates to a refrigeration system intended for a supermarket with many cooling sites.
  • refrigeration systems with several cooling sites such as refrigeration systems for a supermarket, have a receiver for accommodation of the refrigerant.
  • the amount of refrigerant in the receiver varies as a function of the load at the sites. The variation increases with the number of cooling sites.
  • the receiver is capable of accommodating the total amount of refrigerant in the system.
  • Maintenance of the refrigeration system requires monitoring of the amount of refrigerant in the system since the system requires a minimum amount of refrigerant for proper operation. Possible leakages should be detected since refilling of refrigerant ads to the cost of system operation, and leakage of refrigerant may contaminate the environment.
  • a conventional refrigeration system has a sight glass in the receiver allowing manual inspection of the liquid level in the receiver.
  • the pressure of the refrigerant is too high to allow a transparent sight glass in the flow system at a reasonable cost.
  • a refrigeration system comprising a flow circuit for recirculation of a refrigerant, the flow circuit comprising a compressor for generation of a refrigerant flow from a low- pressure side to a high-pressure side of the compressor and, in the order defined by the flow direction, connected in series with a condenser for cooling of the refrigerant towards the ambient temperature, a receiver for accommodation of refrigerant, a pressure reducing device separating the low-pressure side and the high pressure side of the compressor, and a first evaporator for evaporation of the refrigerant.
  • a weight transducer is mounted in operational contact with the receiver for generation of an output signal corresponding to the weight of the receiver.
  • the weight transducer may for example be mounted underneath the receiver supporting and simultaneously weighing the receiver.
  • the receiver is suspended by one or more wires with a weight transducer in each of the wires.
  • the one or more weight transducers may be installed substantially without changing the position of the receiver by suspension of the receiver.
  • modification of the tubing connected to the receiver is not required.
  • the system may further comprise a controller that is connected with the weight transducer for reception of the weight transducer signal and being further adapted for monitoring the transducer signal as a function of time and for detecting loss of refrigerant based on the signal.
  • the controller may further be adapted for detecting loss of refrigerant by comparison of actual weight transducer signal values with previous weight transducer signal values.
  • the controller may further be adapted for detecting loss of refrigerant by monitoring, e.g. the minimum, maximum, average, etc., weight transducer signal value as a function of time, e.g. as recorded at appropriate time intervals, such as daily, weekly, monthly, etc..
  • Utilization of a weight transducer for monitoring the amount of refrigerant may be particularly advantageous in a refrigeration system that is adapted for transcritical operation.
  • the high pressures of such a system e.g. 120 bar at the high-pressure side and 40 bar at the low- pressure side of the compressor, makes manual inspection of the amount of refrigerant tedious and costly.
  • the automatic detection of loss of refrigerant provides an early detection of a leakage so that the leakage may be found and repaired at an early stage before excessive loss of refrigerant. This saves the cost of running a less effective refrigerant system, saves the cost of refilling refrigerant, and protects the environment.
  • the weight transducer signal values may be recorded as a function of time, and the signal values of a day and night may be averaged over several days, e.g. a week. Significant negative deviations of the weight transducer signal value from the corresponding averaged values may trigger indication of loss of refrigerant to an operator of the system.
  • the minimum weight transducer signal value of a day may be recorded and compared with previous minimum values, and a minimum weight transducer signal value that is significantly smaller than previous values may trigger indication of loss of refrigerant to an operator of the system, or, a trend of minimum weight transducer signal values that shows a steadily decrease of the minimum values with time may trigger indication of loss of refrigerant to the operator.
  • the maximum weight transducer signal value of a day may be recorded and compared with previous maximum values, and a maximum weight transducer signal value that is significantly smaller than previous values may trigger indication of loss of refrigerant to an operator of the system, or, a trend of maximum weight transducer signal values that shows a steadily decrease of the maximum values with time may trigger indication of loss of refrigerant to the operator.
  • a sudden decrease in receiver content may be detected and trigger indication of loss of refrigerant to the operator. This may be used to detect e.g. a pipe breakdown, theft of refrigerant, etc.
  • the date and time of the sudden decrease is also recorded.
  • the controller may indicate loss of refrigerant by generation of an alarm signal, such as a visual display or an audible signal or a combination of a visual and an audible signal.
  • the refrigeration system according to the present invention may further comprise a remote monitoring system allowing an operator of the system to monitor various system parameters including one or more of the above-mentioned weight transducer signal values and a possible alarm signal from a remote location.
  • the refrigeration system and the remote monitoring system may for example be interconnected through a LAN network, a WAN network, such as the Internet, etc, etc.
  • an alarm signal may be communicated through a telephone network, such as a PSTN network, a mobile telephone network, e.g. utilizing SMS messaging, etc, to predetermined subscriber(s).
  • FIG. 1 is a blocked schematic of a first embodiment of a transcritical cooling system according to the present invention
  • Fig. 2 shows a suspended receiver
  • Fig. 3 is a plot of a subcritical cooling cycle
  • Fig. 4 is a plot of a transcritical cooling cycle
  • Fig. 5 is a plot illustrating control of gas cooler pressure.
  • Fig. 1 is a blocked schematic of a first embodiment 10 of a transcritical cooling system according to the present invention.
  • the system 10 comprises a refrigerant flow circuit for recirculation of CO 2 refrigerant 12, the flow circuit comprising a compressor 14 for generation of a refrigerant flow in the direction of the arrow 16 from a low-pressure side to a high- pressure side of the compressor 14 and, in the order defined by the flow direction, connected in series with a gas cooler 18 for cooling of the refrigerant 12 towards the ambient temperature, a valve 20 for pressure reduction as will be further explained below, a receiver 22 for accommodation of CO 2 refrigerant 12.
  • the receiver 22 is connected to an expansion valve 28 that cooperates with the compressor 14 for generation of the low-pressure side and the high-pressure side of the compressor 14, and a first evaporator 30 for evaporation of the CO 2 refrigerant.
  • a weight transducer 32 is mounted underneath and in operational contact with the receiver 22 for generation of an output signal 34 corresponding to the weight of the receiver 22.
  • the system 10 further comprises a controller 36 that is connected with the weight transducer 32 for reception of the weight transducer signal 34 and being further adapted for monitoring the transducer signal 34 as a function of time and for detecting loss of refrigerant based on the signal 34.
  • the controller is further adapted for detecting loss of refrigerant by comparison of actual weight transducer signal values with previous weight transducer signal values.
  • the controller is adapted for detecting loss of refrigerant by monitoring the daily minimum weight transducer signal value as a function of time.
  • the minimum weight transducer signal value of a day is recorded and compared with previous minimum values, and a minimum weight transducer signal value that is significantly smaller than previous values triggers indication of loss of refrigerant to an operator of the system.
  • the controller indicates loss of refrigerant by displaying an alarm signal 38 on a visual display 40 and forwarding an audio alarm signal 42 to a loud speaker 44 for emission of an audible alarm signal.
  • the refrigeration system 10 may further comprise a remote monitoring system 50 allowing an operator of the system 10 to monitor various system parameters including one or more of the above-mentioned weight transducer signal values and a possible alarm signal from a remote location.
  • the controller 36 and the remote monitoring system may for example be interconnected through a LAN network, a WAN network, such as the Internet, etc, etc. Further, the controller 36 may be adapted to communicate an alarm signal through a telephone network, such as a PSTN network, a mobile telephone network, e.g. utilizing SMS messaging, etc, to predetermined subscriber(s).
  • Fig. 2 shows the receiver 22 equipped with two S-shaped weight transducers 32, 33 inserted in two suspension wires 52, 54 suspending the receiver 22.
  • Refrigerant 12 enters the receiver 22 through tube 21 connected to the valve 20 shown in Fig. 1
  • refrigerant 12 leaves the receiver 22 through tube 27 connected to the expansion valve 28 shown in Fig. 1.
  • Suspension of the receiver 22 simplifies retrofitting of existing refrigeration systems in that minimum change of the mounting position of the receiver 22 is required in order to install the one or more weight transducers 32, 33 in the existing system.
  • Fig. 3 illustrates subcritical operation of the system 10 in a conventional Log (p), h (enthalpy) diagram.
  • the compressor 14 compresses the CO 2 refrigerant, and subsequently heat is released from the refrigerant from point 2 to 3 below the critical point 46 by condensation of the refrigerant in the gas cooler 18 at a constant pressure.
  • the expansion from point 3 to 4 takes place at constant specific enthalpy at passage of the expansion valve 28.
  • the heat absorption takes place in the evaporator 30 in the cooling furniture of the system 10 from point 4 to 1 at constant pressure.
  • the control valve 20 is fully open when the system 10 operates subcritically.
  • Fig. 4 illustrates transcritical operation of the system 10.
  • the most important difference between the plot of Fig. 4 and the plot of Fig. 3 is that the CO 2 refrigerant is above the critical point 46 at the high-pressure side of the compressor 14 and thus, heat is released from the refrigerant by CO 2 gas cooling in the gas cooler 18.
  • the coefficient of performance (COP) of the system 10 is less for transcritical cycles than for subcritical cycles due to the lacking phase transition, i.e. no condensation, during heat release.
  • the expansion from point 3 to 4 takes place in two steps, namely from point 3 to 5, and subsequently from point 5 to 4.
  • the valve 20 reduces the pressure from point 3 to point 5 so that CO 2 in the liquid phase enters the heat exchanger 22 and is collected in the receiver 22. Further, the valve 20 is controlled in such a way that the pressure in the gas cooler 18 attains a value that gives a high COP. This is further illustrated in Fig. 5. In addition to the transcritical cooling cycle, Fig. 5 shows two isotherms 34, 36.
  • the COP decreases for increased gas cooler pressure.
  • the valve 20 is adjusted in such a way that the gas cooler pressure attains, at least approximately, this optimum pressure value.
  • the gas cooler pressure is app. 120 bar while the pressure at the low-pressure side of the compressor 14 is app. 40 bar.

Landscapes

  • 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)
  • Examining Or Testing Airtightness (AREA)

Abstract

L'invention se rapporte à un système de réfrigération comprenant un détecteur qui permet de détecter et fuites de frigorigène. Ce système est doté d'un circuit de recirculation de frigorigène, et comprend un compresseur permettant de créer un flux de frigorigène entre le côté basse pression et le côté haute pression du compresseur, dans le sens défini par la direction d'écoulement, monté en série avec un condenseur servant à refroidir le frigorigène afin de rapprocher sa température de la température ambiante, un réservoir à frigorigène, un dispositif réducteur de pression séparant le côté basse pression et le côté haute pression du compresseur, et un premier évaporateur produisant l'évaporation du frigorigène, ainsi qu'un transducteur de masse installé en contact fonctionnel avec le réservoir, produisant un signal de sortie correspondant à la masse du réservoir.
EP06761870A 2005-08-25 2006-08-24 Detection de fuite de frigorigene Withdrawn EP1929217A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DKPA200501183 2005-08-25
PCT/DK2006/000460 WO2007022779A1 (fr) 2005-08-25 2006-08-24 Detection de fuite de frigorigene

Publications (1)

Publication Number Publication Date
EP1929217A1 true EP1929217A1 (fr) 2008-06-11

Family

ID=37137546

Family Applications (1)

Application Number Title Priority Date Filing Date
EP06761870A Withdrawn EP1929217A1 (fr) 2005-08-25 2006-08-24 Detection de fuite de frigorigene

Country Status (3)

Country Link
EP (1) EP1929217A1 (fr)
NO (1) NO20081408L (fr)
WO (1) WO2007022779A1 (fr)

Families Citing this family (10)

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US8973380B2 (en) * 2009-05-28 2015-03-10 Schneider Electric It Corporation Systems and methods for detecting refrigerant leaks in cooling systems
US8402816B2 (en) 2010-12-30 2013-03-26 Schneider Electric It Corporation Systems and methods for detecting leaks
CN104204697B (zh) 2012-02-10 2017-02-22 开利公司 检测制冷剂损失的方法
JP2013250038A (ja) 2012-06-04 2013-12-12 Daikin Industries Ltd 冷凍装置管理システム
US10054030B2 (en) * 2016-06-01 2018-08-21 GM Global Technology Operations LLC Engine cooling systems and methods
CN108775721B (zh) * 2018-07-27 2019-10-29 珠海格力电器股份有限公司 冷却系统及其控制方法
CN110887168B (zh) * 2018-09-10 2021-05-18 奥克斯空调股份有限公司 一种空调器冷媒不足的检测方法及其空调器
KR102422010B1 (ko) * 2020-09-23 2022-07-18 엘지전자 주식회사 냉난방 멀티 공기조화기
CN113531933B (zh) * 2021-07-05 2022-07-26 珠海格力电器股份有限公司 一种冷媒循环量调节方法、装置及空调系统
CN114980704B (zh) * 2022-07-08 2024-06-07 珠海格力电器股份有限公司 变频器冷却装置、冷却方法及空调设备

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Publication number Priority date Publication date Assignee Title
BR8700018A (pt) * 1987-01-06 1988-08-02 Consul Sa Dispositivo para dosagem de carga de gas frigorigeno em sistemas de refrigeracao
US4967567A (en) * 1987-12-10 1990-11-06 Murray Corporation System and method for diagnosing the operation of air conditioner systems
US5046322A (en) * 1989-05-08 1991-09-10 Kent-Moore Corporation Electronic refrigerant transfer scale
JP2997487B2 (ja) * 1989-12-13 2000-01-11 株式会社日立製作所 冷凍装置及び冷凍装置における冷媒量表示方法
US5253482A (en) * 1992-06-26 1993-10-19 Edi Murway Heat pump control system

Non-Patent Citations (1)

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Title
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Also Published As

Publication number Publication date
NO20081408L (no) 2008-03-18
WO2007022779A1 (fr) 2007-03-01

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