JP6282186B2

JP6282186B2 - Method for detecting refrigerant leakage in cooling system

Info

Publication number: JP6282186B2
Application number: JP2014136570A
Authority: JP
Inventors: 伊藤　潤一; 潤一伊藤; 田中　真; 真田中; 泰彦稲富; 康博頭島
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 2014-07-02
Filing date: 2014-07-02
Publication date: 2018-02-21
Anticipated expiration: 2034-07-02
Also published as: JP2016015010A

Description

本発明は、冷却システムの冷媒漏洩検知方法に関する。 The present invention relates to a refrigerant leakage detection method for a cooling system.

近年、情報処理技術の向上やインターネット環境の発達に伴って、情報処理量が増大している。そのため、各種の情報を大量に処理するためのデータ処理センタがビジネスとして脚光を浴びている。このデータ処理センタの例えば、サーバルームには、コンピュータやサーバ等の電子機器が集約された状態で多数設置され、昼夜にわたって連続稼働されている。 In recent years, the amount of information processing has increased with the improvement of information processing technology and the development of the Internet environment. For this reason, a data processing center for processing a large amount of various types of information has attracted attention as a business. For example, in a server room of this data processing center, a large number of electronic devices such as computers and servers are installed in an integrated state, and are continuously operated day and night.

一般的に、サーバルームにおける電子機器の設置は、ラックマウント方式が主流になっている。ラックマウント方式は、電子機器を機能単位別に分割して収納するラック(筺体)をキャビネットに段積みする方式であり、かかるキャビネットがサーバルームの床上に多数整列配置されている。 In general, the rack mount method is the mainstream for installing electronic devices in a server room. The rack mount system is a system in which racks (casings) for storing electronic devices divided into functional units are stacked in a cabinet, and a large number of such cabinets are arranged on the floor of a server room.

これら情報を処理する電子機器は、処理速度や処理能力が急速に向上してきており、そのため、電子機器からの発熱量も上昇の一途をたどっている。これらの電子機器は、動作に一定の温度環境が必要とされ、正常に動作するための温度環境が比較的低く設定されているため、電子機器が高温状態に置かれるとシステム停止等のトラブルを引き起こす。 Electronic devices that process these information have rapidly improved in processing speed and processing capacity, and the amount of heat generated from the electronic devices is steadily increasing. These electronic devices require a certain temperature environment for operation, and the temperature environment for normal operation is set to be relatively low. Therefore, if the electronic device is placed in a high temperature state, troubles such as system shutdown may occur. cause.

このため、サーバルーム内を冷却するための空調機を運転する空調動力(空調機の負荷)が大幅に増加しているのが実情であり、企業経営におけるコスト削減の観点のみならず、地球環境の保全の観点からも空調動力の削減が急務となっている。 For this reason, the actual situation is that air conditioning power (air conditioner load) for operating air conditioners to cool the server room has increased significantly, not only in terms of cost reduction in corporate management, but also in the global environment. From the viewpoint of maintenance, it is an urgent task to reduce air conditioning power.

一方、サーバルーム内で漏水が発生すると電子機器が破損する恐れがあるため、電子機器を冷却する際の熱搬送には水よりも熱輸送量が大きい冷媒の潜熱輸送を利用するのが一般的である。さらに、冷媒の搬送を削減するため、圧縮機を用いずに気液密度差を利用して搬送するシステムや圧縮機よりも省電力で冷媒を搬送できる冷媒ポンプを用いた冷却システムを採用することができる。 On the other hand, if water leakage occurs in the server room, the electronic device may be damaged. Therefore, it is common to use latent heat transport of a refrigerant having a larger heat transport amount than water for cooling the electronic device. It is. Furthermore, in order to reduce the transport of refrigerant, a system that transports refrigerant using a gas-liquid density difference without using a compressor or a cooling system that uses a refrigerant pump that can transport refrigerant with less power than the compressor should be adopted. Can do.

しかし、熱搬送に冷媒を使用する場合、冷媒は大気圧下ではガス化するため、少量の漏洩が発生した場合には冷媒漏洩が発生していることに気づかず、系内の冷媒量が減少していき冷却能力の低下が発生してしまう恐れがある。
このような背景から、特許文献１や特許文献２にみられるように、熱搬送に冷媒を用いた冷却システムの冷媒漏洩検知技術が提案されている。 However, when a refrigerant is used for heat transfer, the refrigerant is gasified under atmospheric pressure, so if a small amount of leakage occurs, the refrigerant will not be noticed and the amount of refrigerant in the system will decrease. However, there is a risk that the cooling capacity will decrease.
From such a background, as seen in Patent Document 1 and Patent Document 2, a refrigerant leakage detection technique for a cooling system using a refrigerant for heat transfer has been proposed.

特許文献１には、冷凍サイクルを構成する機器におけるエクセルギー損失量を測定し、漏洩した冷媒量に応じて変化する漏洩指標値を算出して冷媒漏洩が発生しているか否かを判定する方法が提案されている。 Patent Document 1 discloses a method for determining whether or not refrigerant leakage has occurred by measuring the amount of exergy loss in equipment constituting a refrigeration cycle, calculating a leakage index value that changes according to the amount of refrigerant that has leaked, and the like. Has been proposed.

特許文献２には、減圧装置出入口の差圧、冷媒循環量から冷媒密度を算出し、冷媒密度測定値と比較することで冷媒量減少を判断することが提案されている。 Patent Document 2 proposes that the refrigerant density is calculated from the differential pressure at the inlet / outlet of the decompression device and the refrigerant circulation amount, and compared with the refrigerant density measurement value to determine the refrigerant amount decrease.

特開２０１２−４７４４７号公報JP 2012-47447 A 特開２０１１−１０６７１４号公報JP 2011-106714 A

しかし、上記に示すような冷媒漏洩検知方法は、圧縮機と減圧装置を備えた冷凍サイクルを対象としており、圧縮機の過熱度、過冷却度で判断している。
圧縮機を用いない冷却システムでは、冷媒減少による変化量が小さく、冷媒漏洩を判定できない恐れがある。さらに、これらの測定値が冷媒漏洩を判定できるほど変化した場合、冷却能力の低下が発生し、電子機器の温度上昇を引き起こす恐れがある。 However, the refrigerant leakage detection method as described above is intended for a refrigeration cycle including a compressor and a decompression device, and makes a determination based on the degree of superheat and the degree of supercooling of the compressor.
In a cooling system that does not use a compressor, the amount of change due to a decrease in refrigerant is small, and refrigerant leakage may not be determined. Furthermore, when these measured values change to such an extent that refrigerant leakage can be determined, there is a risk that the cooling capacity will decrease and the temperature of the electronic device will increase.

本発明はこのような事情に鑑みてなされたものであり、冷媒の気液の密度差により熱搬送を行う冷却システムであっても冷却能力が低下する前に冷媒の漏洩が判定可能な冷却システムを提供することを目的とする。 The present invention has been made in view of such circumstances, and a cooling system capable of determining leakage of a refrigerant before the cooling capacity is lowered even in a cooling system that performs heat transfer due to a gas-liquid density difference of the refrigerant. The purpose is to provide.

上記目的を達成すべく、本発明に関わる冷却システムの冷媒漏洩検知方法は、電子機器から排出される高温排気を冷却する熱交換によって冷媒を気化する蒸発器と、前記蒸発器に供給される冷媒液の流量を調整する冷媒流量制御バルブと、前記蒸発器に前記高温排気を供給する送風機とを有する１または複数台設置された冷却装置と、前記蒸発器より高所に設置され前記蒸発器で気化した冷媒ガスを液化させる凝縮器と、前記蒸発器と前記凝縮器との間に設けられる冷媒ガス管と、前記凝縮器の入口の冷媒ガス圧力を測定する凝縮器ガス圧力センサと、前記蒸発器の出口の冷媒圧力を測定する蒸発器出口圧力センサと、前記冷却装置の冷却熱量を測定する冷却熱量測定手段と、制御装置とを備える冷却システムの冷媒漏洩検知方法である。 In order to achieve the above object, a refrigerant leakage detection method for a cooling system according to the present invention includes an evaporator that evaporates the refrigerant by heat exchange for cooling high-temperature exhaust discharged from an electronic device, and a refrigerant that is supplied to the evaporator. One or a plurality of cooling devices having a refrigerant flow control valve for adjusting the flow rate of the liquid, a blower for supplying the high-temperature exhaust to the evaporator, and an evaporator installed at a higher position than the evaporator A condenser for liquefying the vaporized refrigerant gas; a refrigerant gas pipe provided between the evaporator and the condenser; a condenser gas pressure sensor for measuring a refrigerant gas pressure at an inlet of the condenser; and the evaporation A refrigerant leakage detection method for a cooling system, comprising: an evaporator outlet pressure sensor for measuring a refrigerant pressure at the outlet of the evaporator; a cooling heat amount measuring means for measuring a cooling heat amount of the cooling device; and a control device.

該冷媒漏洩検知方法で前記制御装置は、前記冷媒流量制御バルブの開度を全開にして冷却運転を行い、前記蒸発器出口圧力センサと前記凝縮器ガス圧力センサで測定した圧力の差分をとることで前記冷媒ガス管の圧力損失を算出し、該算出した圧力損失が、前記冷媒の漏洩がない場合の前記蒸発器出口圧力センサと前記凝縮器ガス圧力センサで測定した圧力の差分で求められる前記冷媒ガス管の圧力損失より低い場合には、前記冷媒が漏洩していると判定し、前記冷却システムは、前記冷却装置の冷却熱量を測定する冷却熱量測定手段を備え、前記制御装置は、予め前記冷媒流量制御バルブの開度を全開にして前記冷却装置に様々な負荷条件で冷却運転を行い、前記蒸発器出口圧力センサと前記凝縮器ガス圧力センサで測定した圧力の差分をとることで前記冷媒ガス管の圧力損失を算出するとともに前記冷却熱量測定手段で前記冷却システムの冷却熱量を測定し、該算出した前記冷媒ガス管の圧力損失に基づき、前記冷却システムの冷却熱量に対する冷媒が漏洩しているか否か判定する冷媒ガス管圧力損失の閾値が設定され、実際に前記冷却システムを稼働させて前記冷媒流量制御バルブの制御による冷却運転を行い、前記冷媒の漏洩を検知する際に、前記冷媒流量制御バルブの開度を全開にして前記冷媒ガス管圧力損失と前記冷却熱量を測定し、該測定結果の前記冷媒ガス管圧力損失が、同じ冷却熱量での前記冷媒ガス管圧力損失の前記閾値未満である場合に前記冷媒が漏洩していると判定している。 In the refrigerant leakage detection method, the control device performs a cooling operation with the opening of the refrigerant flow control valve fully opened, and takes a difference in pressure measured by the evaporator outlet pressure sensor and the condenser gas pressure sensor. To calculate the pressure loss of the refrigerant gas pipe, and the calculated pressure loss is obtained by the difference in pressure measured by the evaporator outlet pressure sensor and the condenser gas pressure sensor when there is no leakage of the refrigerant. When the pressure loss of the refrigerant gas pipe is lower, it is determined that the refrigerant is leaking, and the cooling system includes a cooling heat amount measuring unit that measures the cooling heat amount of the cooling device, and the control device The refrigerant flow control valve is fully opened and the cooling device is cooled under various load conditions, and the difference in pressure measured by the evaporator outlet pressure sensor and the condenser gas pressure sensor is calculated. By calculating the pressure loss of the refrigerant gas pipe and measuring the cooling heat quantity of the cooling system by the cooling heat quantity measuring means, and based on the calculated pressure loss of the refrigerant gas pipe, A threshold value of a refrigerant gas pipe pressure loss for determining whether or not the refrigerant is leaking is set, and the cooling system is actually operated to perform a cooling operation under the control of the refrigerant flow control valve to detect the leakage of the refrigerant. The refrigerant flow rate control valve is fully opened to measure the refrigerant gas pipe pressure loss and the cooling heat quantity, and the refrigerant gas pipe pressure loss of the measurement result is the refrigerant gas pipe at the same cooling heat quantity. When the pressure loss is less than the threshold, it is determined that the refrigerant is leaking .

本発明に関わる冷却システムの冷媒漏洩検知方法によれば、冷媒の気液の密度差により熱搬送を行う冷却システムであっても冷却能力が低下する前に冷媒の漏洩が判定可能な冷却システムを実現できる。 According to the refrigerant leakage detection method for a cooling system according to the present invention, a cooling system capable of determining refrigerant leakage before cooling capacity is lowered even in a cooling system that performs heat transfer due to a difference in gas-liquid density of the refrigerant. realizable.

本発明の実施形態１に係る冷却システムを示す図。The figure which shows the cooling system which concerns on Embodiment 1 of this invention. 負荷(％)と冷媒ガス管圧力損失との関係を示す図。The figure which shows the relationship between load (%) and refrigerant gas pipe pressure loss. 冷却システムでの冷却熱量を用いた冷媒漏洩の検知の制御フローを示す図。The figure which shows the control flow of the detection of the refrigerant | coolant leakage using the cooling calorie | heat amount in a cooling system. 本発明の実施形態２に係る冷却システムを示す図。The figure which shows the cooling system which concerns on Embodiment 2 of this invention.

以下、本発明の実施形態について添付図面を参照して説明する。
＜＜実施形態１＞＞
図１に本発明の実施形態１に係る冷却システムを示す。
本発明は、熱搬送に冷媒を用いた冷却システムの冷媒の漏洩検知方法に係り、特に電子機器(図示せず)からの高温の排熱を効率的に冷却するために圧縮機を用いることなく冷媒の気液の密度差により熱搬送を行う冷却システムＳ１の冷媒の漏洩検知方法である。 Embodiments of the present invention will be described below with reference to the accompanying drawings.
<< Embodiment 1 >>
FIG. 1 shows a cooling system according to Embodiment 1 of the present invention.
The present invention relates to a refrigerant leakage detection method for a cooling system that uses a refrigerant for heat transfer, and in particular, without using a compressor to efficiently cool high-temperature exhaust heat from an electronic device (not shown). This is a refrigerant leakage detection method for the cooling system S1 that performs heat transfer by the difference in gas-liquid density of the refrigerant.

実施形態１の冷却システムＳ１は、冷却対象室８０内に載置される冷却対象のサーバなどの電子機器を所望の温度に冷却するシステムである。 The cooling system S1 according to the first embodiment is a system that cools an electronic device such as a server to be cooled placed in the cooling target chamber 80 to a desired temperature.

冷却システムＳ１は、冷却対象の電子機器を冷却するために用いられる冷媒の漏洩を検知することに特徴がある。
なお、冷却システムＳ１には、制御装置Ｃが設けられており、制御装置Ｃにより以下説明する冷却システムＳ１の機器の制御が遂行される。制御装置Ｃは、コンピュータと周辺回路とを有する、例えば、ＰＬＣ(programmable logic controller)などである。 The cooling system S1 is characterized in that it detects leakage of a refrigerant used for cooling an electronic device to be cooled.
The cooling system S1 is provided with a control device C, and the control device C controls equipment of the cooling system S1 described below. The control device C is, for example, a PLC (programmable logic controller) having a computer and peripheral circuits.

＜冷却装置２０ａ、２０ｂ＞
冷却対象室８０内には冷却対象であるサーバなどの電子機器(図示せず)が載置されている。電子機器は連続稼働されるため、電子機器からは高温の排気(高温排気２３ａ、２３ｂ)が、排出されている。
冷却システムＳ１には、冷却対象室８０内の冷却対象の電子機器からの高温排気２３ａ、２３ｂをそれぞれ冷却する冷却装置２０ａ、２０ｂが設置されている。 <Cooling devices 20a and 20b>
In the cooling target chamber 80, an electronic device (not shown) such as a server to be cooled is placed. Since the electronic device is continuously operated, high-temperature exhaust (high-temperature exhaust 23a, 23b) is discharged from the electronic device.
In the cooling system S1, cooling devices 20a and 20b for cooling the high-temperature exhausts 23a and 23b from the electronic devices to be cooled in the cooling target chamber 80 are installed.

冷却装置２０ａには、冷媒と高温排気２３ａとの熱交換を行う蒸発器２１ａと、蒸発器２１ａに高温排気２３ａを供給する送風機２２ａと、蒸発器２１ａ内部に供給される冷媒の流量を調整する冷媒流量制御バルブ２５ａとが組み込まれている。高温排気２３ａは、蒸発器２１ａで冷媒の蒸発に伴う蒸発潜熱により冷却される。 In the cooling device 20a, an evaporator 21a that performs heat exchange between the refrigerant and the high-temperature exhaust 23a, a blower 22a that supplies the high-temperature exhaust 23a to the evaporator 21a, and a flow rate of the refrigerant that is supplied into the evaporator 21a are adjusted. A refrigerant flow control valve 25a is incorporated. The high-temperature exhaust 23a is cooled by the evaporation latent heat accompanying the evaporation of the refrigerant in the evaporator 21a.

同様に、冷却装置２０ｂには、冷媒と高温排気２３ｂとの熱交換を行う蒸発器２１ｂと、蒸発器２１ｂに高温排気２３ｂを供給する送風機２２ｂと、蒸発器２１ｂ内部に供給される冷媒の流量を調整する冷媒流量制御バルブ２５ｂとが組み込まれている。高温排気２３ｂは、蒸発器２１ｂで冷媒の蒸発に伴う蒸発潜熱により冷却される。 Similarly, the cooling device 20b includes an evaporator 21b that exchanges heat between the refrigerant and the high-temperature exhaust 23b, a blower 22b that supplies the high-temperature exhaust 23b to the evaporator 21b, and a flow rate of the refrigerant that is supplied into the evaporator 21b. A refrigerant flow control valve 25b for adjusting the flow rate is incorporated. The high-temperature exhaust 23b is cooled by the evaporation latent heat accompanying the evaporation of the refrigerant in the evaporator 21b.

冷媒流量制御バルブ２５ａ、２５ｂは、それぞれ冷却の設定温度に対応して開度が自動的に制御される。つまり、冷却負荷が大きい場合には開度が大きく、冷却負荷が小さい場合には開度が小さく制御される。 The refrigerant flow control valves 25a and 25b are automatically controlled in opening degree corresponding to the set temperature for cooling. That is, when the cooling load is large, the opening degree is large, and when the cooling load is small, the opening degree is controlled small.

＜冷却装置２０ａ、２０ｂの冷却熱量測定手段＞
冷却装置２０ａには、高温排気２３ａの温度を測る冷却熱量測定手段の高温排気温度センサ２７ａと、蒸発器２１ａで高温排気２３ａを冷却した後の冷却空気２４ａの温度を測る冷却熱量測定手段の冷却空気温度センサ２６ａとが設けられている。 <Cooling heat quantity measuring means of cooling devices 20a and 20b>
The cooling device 20a includes a high-temperature exhaust gas temperature sensor 27a that measures the temperature of the high-temperature exhaust 23a, and a cooling heat-measuring device that measures the temperature of the cooling air 24a after the high-temperature exhaust gas 23a is cooled by the evaporator 21a. An air temperature sensor 26a is provided.

同様に、冷却装置２０ｂには、高温排気２３ｂの温度を測る冷却熱量測定手段の高温排気温度センサ２７ｂと、蒸発器２１ｂで高温排気２３ｂを冷却した後の冷却空気２４ｂの温度を測る冷却熱量測定手段の冷却空気温度センサ２６ｂとが設けられている。 Similarly, the cooling device 20b includes a high-temperature exhaust temperature sensor 27b serving as a cooling calorie measuring unit that measures the temperature of the high-temperature exhaust 23b, and a cooling calorific value measurement that measures the temperature of the cooling air 24b after the high-temperature exhaust 23b is cooled by the evaporator 21b. And a cooling air temperature sensor 26b.

＜凝縮器１０＞
冷却システムＳ１は、蒸発器２１ａ、２１ｂでガス化した冷媒を冷却して液化するため、冷水を作る冷熱源４０と該冷水を送る冷水ポンプ４１と凝縮器１０とを有している。ガス化した冷媒を冷却する熱媒体の水は、冷水配管４２を介して、冷熱源４０、冷水ポンプ４１、および凝縮器１０間を循環されている。 <Condenser 10>
The cooling system S1 includes a cold heat source 40 that produces cold water, a cold water pump 41 that sends the cold water, and a condenser 10 in order to cool and liquefy the refrigerant gasified by the evaporators 21a and 21b. The heat medium water that cools the gasified refrigerant is circulated between the cold heat source 40, the cold water pump 41, and the condenser 10 via the cold water pipe 42.

凝縮器１０は、蒸発器２１ａ、２１ｂよりも高所に設置されている。
蒸発器２１ａ、２１ｂでガス化した冷媒は、密度の減少により重量が周囲よりも軽くなり冷媒ガス管３０内を上昇して、冷媒ガス管３０を通過して凝縮器１０に供給される。凝縮器１０では、ガス化した冷媒が冷水と熱交換して、液化温度以下に冷却され液化し、冷媒液管３１に送られる。 The condenser 10 is installed at a higher position than the evaporators 21a and 21b.
The refrigerant gasified by the evaporators 21a and 21b becomes lighter than the surroundings due to a decrease in density, rises in the refrigerant gas pipe 30, passes through the refrigerant gas pipe 30, and is supplied to the condenser 10. In the condenser 10, the gasified refrigerant exchanges heat with cold water, is cooled to a temperature lower than the liquefaction temperature, is liquefied, and is sent to the refrigerant liquid pipe 31.

凝縮器１０で液化した冷媒は密度が大きくなることにより、重量が周囲よりも重くなり冷媒液管３１内を重力により落下して、冷媒ガス管３０を通過して蒸発器２１ａ、２１ｂに向けて供給される。 As the refrigerant liquefied in the condenser 10 increases in density, the refrigerant becomes heavier than the surroundings and falls in the refrigerant liquid pipe 31 due to gravity, passes through the refrigerant gas pipe 30, and toward the evaporators 21a and 21b. Supplied.

＜蒸発器２１ａ、２１ｂ＞
凝縮器１０で液化した冷媒は、冷媒流量制御バルブ２５ａ、２５ｂで、それぞれ高温排気２３ａ、２３ｂの温度に応じた冷却熱量に対応した流量に調整され蒸発器２１ａ、２１ｂに送られる。 <Evaporator 21a, 21b>
The refrigerant liquefied by the condenser 10 is adjusted to a flow rate corresponding to the amount of cooling heat corresponding to the temperature of the high temperature exhaust 23a, 23b by the refrigerant flow rate control valves 25a, 25b, respectively, and sent to the evaporators 21a, 21b.

例えば、高温排気２３ａ、２３ｂの温度が４０℃で冷却温度が２５℃に設定されている場合には、冷媒流量制御バルブ２５ａ、２５ｂの開度は相対的に大きく制御され、比較的多く冷媒が蒸発器２１ａ、２１ｂに供給される。これに対して、例えば、高温排気２３ａ、２３ｂの温度が３０℃で冷却温度が２５℃に設定されている場合には、冷媒流量制御バルブ２５ａ、２５ｂの開度は相対的に小さく制御され、比較的少ない冷媒が蒸発器２１ａ、２１ｂに供給される。 For example, when the temperature of the high-temperature exhausts 23a and 23b is set to 40 ° C. and the cooling temperature is set to 25 ° C., the openings of the refrigerant flow control valves 25a and 25b are controlled to be relatively large so that a relatively large amount of refrigerant is It is supplied to the evaporators 21a and 21b. On the other hand, for example, when the temperature of the high-temperature exhausts 23a and 23b is set to 30 ° C. and the cooling temperature is set to 25 ° C., the openings of the refrigerant flow control valves 25a and 25b are controlled to be relatively small, Relatively little refrigerant is supplied to the evaporators 21a and 21b.

そして、蒸発器２１ａ、２１ｂに供給される液状の冷媒は、それぞれ高温排気２３ａ、２３ｂと熱交換してガス化され、冷媒ガス管３０内に排出される。高温排気２３ａ、２３ｂはそれぞれ冷媒の蒸発潜熱により冷却され、冷却空気２４ａ、２４ｂとなり冷却装置２０ａ、２０ｂの外部に排出される。 The liquid refrigerant supplied to the evaporators 21a and 21b is gasified by exchanging heat with the high-temperature exhausts 23a and 23b, respectively, and discharged into the refrigerant gas pipe 30. The high-temperature exhausts 23a and 23b are cooled by the latent heat of vaporization of the refrigerant, respectively, and become cooling air 24a and 24b, which are discharged to the outside of the cooling devices 20a and 20b.

＜冷媒ガス管３０＞
前記したように、蒸発器２１ａ、２１ｂでガス化された冷媒は冷媒ガス管３０内に流入する。
ここで、冷媒ガス管３０内では冷媒が気液二相流状態となっている。つまり、蒸発器２１ａ、２１ｂでの冷却負荷が大きい場合には、ガス状態の冷媒が多く、蒸発器２１ａ、２１ｂでの冷却負荷が小さい場合には、液状態の冷媒が増加する。 <Refrigerant gas pipe 30>
As described above, the refrigerant gasified by the evaporators 21 a and 21 b flows into the refrigerant gas pipe 30.
Here, the refrigerant is in a gas-liquid two-phase flow state in the refrigerant gas pipe 30. That is, when the cooling load in the evaporators 21a and 21b is large, the refrigerant in the gas state is large, and when the cooling load in the evaporators 21a and 21b is small, the refrigerant in the liquid state increases.

このように、冷却システムＳ１では、ガス化された冷媒が冷媒ガス管３０内の上昇し、液化した冷媒が冷媒液管３１内を下降することにより冷媒が循環している。つまり、冷却システムＳ１では、冷媒の気液の密度差により熱搬送が遂行されている。 Thus, in the cooling system S1, the gasified refrigerant rises in the refrigerant gas pipe 30 and the liquefied refrigerant descends in the refrigerant liquid pipe 31 so that the refrigerant circulates. That is, in the cooling system S1, heat transfer is performed by the difference in the gas-liquid density of the refrigerant.

＜冷媒ガス管３０での圧力損失＞
ところで、冷媒ガス管３０における冷媒の圧力損失は、冷却システムＳ１の系内の冷媒量が同じであれば冷却装置２０ａ、２０ｂの冷却熱量により一意的に決まる。何故なら、系内の冷媒量が同じ、かつ、冷却装置２０ａ、２０ｂの冷却熱量が同じならば、冷媒ガス管３０における冷媒量と冷媒の気液状態とがそれぞれ同じになるからである。 <Pressure loss in refrigerant gas pipe 30>
By the way, the pressure loss of the refrigerant in the refrigerant gas pipe 30 is uniquely determined by the amount of cooling heat of the cooling devices 20a and 20b if the amount of refrigerant in the cooling system S1 is the same. This is because if the amount of refrigerant in the system is the same and the amount of cooling heat of the cooling devices 20a and 20b is the same, the amount of refrigerant in the refrigerant gas pipe 30 and the gas-liquid state of the refrigerant will be the same.

一方、系内の冷媒量が減少した場合には蒸発器２１ａ、２１ｂから、冷媒ガス管３０へ流出する冷媒液量が減少するため、冷媒ガス管３０内の冷媒の圧力は低下する。そのため、冷媒ガス管３０の圧力損失は小さくなる。 On the other hand, when the amount of refrigerant in the system decreases, the amount of refrigerant liquid flowing out from the evaporators 21a and 21b to the refrigerant gas pipe 30 decreases, so that the pressure of the refrigerant in the refrigerant gas pipe 30 decreases. Therefore, the pressure loss of the refrigerant gas pipe 30 is reduced.

＜冷媒ガス管３０での圧力損失と冷媒ガス管３０内の冷媒量との関係＞
そこで、冷媒ガス管３０での冷媒の圧力損失と冷媒ガス管３０内の冷媒量との関係を求めるため、下記のようにする。
蒸発器２１ａ、２１ｂの少なくとも１つの蒸発器２１ａ、２１ｂ近傍の冷媒ガス管３０に蒸発器２１ａ、２１ｂの出口の冷媒圧力を測定する蒸発器出口圧力センサ５１を設置する。そして、凝縮器１０内へ流入する冷媒ガスの圧力を測定する凝縮器ガス圧力センサ５０を設置する。 <Relationship Between Pressure Loss in Refrigerant Gas Pipe 30 and Refrigerant Amount in Refrigerant Gas Pipe 30>
Therefore, in order to obtain the relationship between the pressure loss of the refrigerant in the refrigerant gas pipe 30 and the amount of refrigerant in the refrigerant gas pipe 30, the following is performed.
An evaporator outlet pressure sensor 51 that measures the refrigerant pressure at the outlet of the evaporators 21a and 21b is installed in the refrigerant gas pipe 30 in the vicinity of at least one of the evaporators 21a and 21b. And the condenser gas pressure sensor 50 which measures the pressure of the refrigerant gas which flows in into the condenser 10 is installed.

これにより、蒸発器出口圧力センサ５１の冷媒の圧力の測定値と、冷媒ガス管３０を通過した後の冷媒の凝縮器ガス圧力センサ５０の圧力の測定値の差分から冷媒ガス管の圧力損失が算出される。同時に、冷却装置２０ａ、２０ｂの冷却熱量を測定することで、冷却システムＳ１の冷却熱量に対する(冷却熱量毎の)冷媒ガス管の圧力損失を求める。そして、当該圧力損失を同じ冷却熱量での冷媒の漏洩が発生しているか否かを判定する閾値と比較することで冷媒の漏洩を判定することが可能となる。 Thereby, the pressure loss of the refrigerant gas pipe is calculated from the difference between the measured value of the refrigerant pressure of the evaporator outlet pressure sensor 51 and the measured value of the pressure of the condenser gas pressure sensor 50 of the refrigerant after passing through the refrigerant gas pipe 30. Calculated. At the same time, by measuring the cooling heat quantity of the cooling devices 20a and 20b, the pressure loss of the refrigerant gas pipe (for each cooling heat quantity) with respect to the cooling heat quantity of the cooling system S1 is obtained. And it becomes possible to determine the leakage of the refrigerant by comparing the pressure loss with a threshold value for determining whether or not the leakage of the refrigerant with the same amount of cooling heat has occurred.

ここで、冷却装置２０ａ、２０ｂ内では冷媒流量制御バルブ２５ａ、２５ｂにより蒸発器２１ａ、２１ｂに供給される冷媒量が調整されており、系内の冷媒充填量が減少しても冷媒ガス管へ流出する冷媒量の変化量が小さいことから冷媒ガス管の圧力損失の変化量が小さくなり、冷媒の漏洩の判定が難しい。 Here, in the cooling devices 20a and 20b, the refrigerant amount supplied to the evaporators 21a and 21b is adjusted by the refrigerant flow rate control valves 25a and 25b, and even if the refrigerant charging amount in the system decreases, the refrigerant gas pipe is supplied. Since the change amount of the refrigerant flowing out is small, the change amount of the pressure loss of the refrigerant gas pipe is small, and it is difficult to determine the leakage of the refrigerant.

そこで、本冷却システムＳ１は冷媒の漏洩検知を行う場合、冷媒流量制御バルブ２５ａ、２５ｂの開度をそれぞれ全開にする。そして冷却装置２０ａ、２０ｂの冷却熱量と冷媒ガス管３０での圧力損失を測定する。これにより、系内の冷媒充填量が減少した場合、蒸発器出口圧力センサ５１の圧力測定値と凝縮器ガス圧力センサ５０の圧力測定値との差分で表わされる冷媒ガス管３０の圧力損失の測定値の変化量が大きくなり冷媒の漏洩の判定が可能になる。
従って、冷媒流量制御バルブ２５ａ、２５ｂの開度を全開にして冷却運転を行い、前記蒸発器出口圧力センサ５１と凝縮器ガス圧力センサ５０で測定した圧力の差分をとることで冷媒ガス管５０の圧力損失を算出し、該算出した圧力損失が、冷媒の漏洩がない場合の前記蒸発器出口圧力センサと凝縮器ガス圧力センサで測定した圧力の差分で求められる冷媒ガス管５０の圧力損失より低い場合には、冷媒が漏洩していると判定できる。 Therefore, the cooling system S1 fully opens the openings of the refrigerant flow control valves 25a and 25b when detecting leakage of the refrigerant. Then, the cooling heat quantity of the cooling devices 20a and 20b and the pressure loss in the refrigerant gas pipe 30 are measured. Thereby, when the refrigerant filling amount in the system decreases, the pressure loss of the refrigerant gas pipe 30 expressed by the difference between the pressure measurement value of the evaporator outlet pressure sensor 51 and the pressure measurement value of the condenser gas pressure sensor 50 is measured. The amount of change in the value becomes large, and it is possible to determine the leakage of the refrigerant.
Accordingly, the cooling operation is performed with the refrigerant flow control valves 25a and 25b fully opened, and the difference between the pressures measured by the evaporator outlet pressure sensor 51 and the condenser gas pressure sensor 50 is taken. The pressure loss is calculated, and the calculated pressure loss is lower than the pressure loss of the refrigerant gas pipe 50 obtained by the difference in pressure measured by the evaporator outlet pressure sensor and the condenser gas pressure sensor when there is no refrigerant leakage. In the case, it can be determined that the refrigerant is leaking.

＜冷却システムＳ１の冷却熱量毎の冷媒漏洩の検知の制御＞
次に、冷却システムＳ１における冷却熱量毎の冷媒漏洩の検知の制御について説明する。
始めに、冷媒漏洩の検知の制御に用いる冷却熱量の求め方を説明する。 <Control of detection of refrigerant leakage for each cooling heat quantity of cooling system S1>
Next, control of detection of refrigerant leakage for each cooling heat quantity in the cooling system S1 will be described.
First, how to obtain the amount of cooling heat used for control of detection of refrigerant leakage will be described.

＜冷却熱量＞
冷却装置２０ａでは、高温排気温度センサ２７ａにより高温排気２３ａの温度ｔ１１が検出される。そして、冷却空気温度センサ２６ａにより、高温排気２３ａの蒸発器２１ａでの冷却後の冷却空気２４ａの温度ｔ１２が検出される。高温排気２３ａを冷却した温度ΔＴ１は、次式で表わされる。 <Cooling heat amount>
In the cooling device 20a, the temperature t11 of the high temperature exhaust 23a is detected by the high temperature exhaust temperature sensor 27a. And the temperature t12 of the cooling air 24a after cooling in the evaporator 21a of the high temperature exhaust 23a is detected by the cooling air temperature sensor 26a. The temperature ΔT1 at which the high temperature exhaust 23a is cooled is expressed by the following equation.

ΔＴ１＝ｔ１１−ｔ１２ (１)
また、冷却装置２０ｂでは、高温排気温度センサ２７ｂで高温排気２３ｂの温度ｔ２１が検出される。そして、冷却空気温度センサ２６ｂでは、高温排気２３ｂの蒸発器２１ｂでの冷却後の冷却空気２４ｂの温度ｔ２２が検出される。高温排気２３ｂを冷却した温度 ΔＴ２は、次式で表わされる。
ΔＴ２＝ｔ２１−ｔ２２ (２) ΔT1 = t11−t12 (1)
In the cooling device 20b, the temperature t21 of the high temperature exhaust 23b is detected by the high temperature exhaust temperature sensor 27b. The cooling air temperature sensor 26b detects the temperature t22 of the cooling air 24b after being cooled by the evaporator 21b of the high temperature exhaust 23b. The temperature ΔT2 at which the high temperature exhaust 23b is cooled is expressed by the following equation.
ΔT2 = t21−t22 (2)

冷却熱量Ｑ(Ｊ)は、空気の熱容量Ｃとすると、
Ｑ＝ＣΔＴ (３)
と表わされる。
熱容量Ｃは、空気の質量ｍ(ｇ)、比熱ｃ(Ｊ／ｇ・Ｋ)とすると、
Ｃ＝ｍｃ (４)
と表わされる。 Assuming that the cooling heat quantity Q (J) is the heat capacity C of air,
Q = CΔT (3)
It is expressed as
The heat capacity C is defined as air mass m (g) and specific heat c (J / g · K).
C = mc (4)
It is expressed as

式(３)、(４)から、
Ｑ＝ｍｃΔＴ (５)
と表わされる。 From equations (3) and (4),
Q = mcΔT (5)
It is expressed as

次に、冷却する空気の質量を求める。
冷却装置２０ａでは、送風機２２ａが設けられており、送風機２２ａが、高温排気２３ａを蒸発器２１ａに送り冷却して、冷却空気２４ａとしている。
そこで、送風機２２ａの風量(Ｌ^３／Ｔ)から、体積＝風量×時間の関係から、時間Ｔの単位をなくす演算で空気の体積(Ｌ^３)が求められる。なお、Ｌは長さの単位を表わす次元である。 Next, the mass of air to be cooled is obtained.
In the cooling device 20a, a blower 22a is provided, and the blower 22a sends the high-temperature exhaust 23a to the evaporator 21a and cools it to form cooling air 24a.
Therefore, from the air volume (L ³ / T) of the blower 22a, the volume of air (L ³ ) is obtained by the calculation that eliminates the unit of time T from the relationship of volume = air volume × time. Note that L is a dimension representing a unit of length.

重さ＝比重・体積の関係より、空気の比重を用いて冷却空気２４ａの質量ｍ１が求められる。空気の比熱ｃ１(Ｊ／ｇ・Ｋ)とすると、式(５)から、式(１)の高温排気２３ａを冷却した温度ΔＴ１を用いて、蒸発器２１ａでの冷却熱量Ｑ１が、
Ｑ１＝ｍ１・ｃ１・ΔＴ１ (６)

と求められる。 From the relationship of weight = specific gravity / volume, the mass m1 of the cooling air 24a is obtained using the specific gravity of air. Assuming that the specific heat of air c1 (J / g · K) is given, the cooling heat quantity Q1 in the evaporator 21a is obtained from the equation (5) using the temperature ΔT1 of cooling the high temperature exhaust 23a of the equation (1).
Q1 = m1 ・ c1 ・ ΔT1 (6)

Is required.

同様に、冷却装置２０ｂには、送風機２２ｂが設けられており、送風機２２ｂが、高温排気２３ｂを蒸発器２１ｂに送り冷却して、冷却空気２４ｂとしている。
上述と同様にして、冷却空気２４ｂの質量をｍ２、空気の比熱ｃ１(Ｊ／ｇ・Ｋ)とすると、式(２)の高温排気２３ｂを冷却した温度ΔＴ２を用いて、蒸発器２１ｂでの冷却熱量Ｑ２が、式(５)より
Ｑ２＝ｍ２・ｃ１・ΔＴ２ (７)
と求められる。 Similarly, the cooling device 20b is provided with a blower 22b. The blower 22b sends the high-temperature exhaust 23b to the evaporator 21b and cools it to form cooling air 24b.
Similarly to the above, if the mass of the cooling air 24b is m2 and the specific heat c1 (J / g · K) of the air, the temperature ΔT2 at which the high-temperature exhaust 23b of the formula (2) is cooled is used in the evaporator 21b. Cooling heat quantity Q2 is calculated from equation (5)
Q2 = m2 ・ c1 ・ ΔT2 (7)
Is required.

冷却システムＳ１全体の冷却熱量Ｑｓは、式(６)、(７)より

Ｑｓ＝Ｑ１＋Ｑ２ (８)
と求められる。
こうして、高温排気温度センサ２７ａ、２７ｂ、冷却空気温度センサ２６ａ、２６ｂで各々測定される温度を用いて、冷却システムＳ１での冷却熱量Ｑｓが求められる。 The cooling heat quantity Qs of the entire cooling system S1 is obtained from the equations (6) and (7).

Qs = Q1 + Q2 (8)
Is required.
Thus, the amount of cooling heat Qs in the cooling system S1 is obtained using the temperatures measured by the high temperature exhaust temperature sensors 27a and 27b and the cooling air temperature sensors 26a and 26b, respectively.

＜負荷率(％)とガス管圧損＞
次に、冷却運転の負荷率(％)と冷媒ガス管３０の圧力損失(以下、冷媒ガス管圧力損失と称す)との関係について説明する。
図２に、負荷(％)と冷媒ガス管圧力損失との関係を示す。図２の横軸に冷却運転の負荷率(％)をとり、図２の縦軸に冷媒ガス管圧力損失(ｋＰａ)をとっている。 <Load factor (%) and gas pipe pressure loss>
Next, the relationship between the load factor (%) of the cooling operation and the pressure loss of the refrigerant gas pipe 30 (hereinafter referred to as refrigerant gas pipe pressure loss) will be described.
FIG. 2 shows the relationship between load (%) and refrigerant gas pipe pressure loss. The horizontal axis in FIG. 2 represents the load factor (%) of the cooling operation, and the vertical axis in FIG. 2 represents the refrigerant gas pipe pressure loss (kPa).

図２において、負荷率(％)が“０”とは、冷却システムＳ１で冷却運転が行われておらず冷却熱量が“０”である場合である。一方、負荷率(％)が“１００”とは、冷却システムＳ１で最大(maximum)の冷却運転が行われている場合である。つまり、冷媒流量制御バルブ２５ａ、２５ｂが全開であり、冷却装置２０ａ、２０ｂでの各負荷(冷却熱量)が最大であることを意味する。 In FIG. 2, the load factor (%) is “0” when the cooling operation is not performed in the cooling system S1 and the amount of cooling heat is “0”. On the other hand, the load factor (%) is “100” when the maximum cooling operation is performed in the cooling system S1. That is, it means that the refrigerant flow control valves 25a and 25b are fully opened and each load (cooling heat amount) in the cooling devices 20a and 20b is maximum.

図２に示すように、冷却システムＳ１において、冷却運転の負荷(冷却熱量)が“０”の場合には、冷却システムＳ１において冷却運転が行われていないので冷媒は流れない。そのため、冷媒ガス(３０)管圧力損失は“０”となる。そして、冷却運転の負荷(冷却熱量)が上昇するに従って、冷媒ガス管圧力損失は次第に上昇して、負荷率１００％で冷媒ガス管圧力損失は最大となる。つまり、冷媒の漏洩があるか否かを判定する閾値は、このような性質を有している。 As shown in FIG. 2, in the cooling system S1, when the cooling operation load (cooling heat amount) is “0”, the cooling operation is not performed in the cooling system S1, and thus the refrigerant does not flow. Therefore, the refrigerant gas (30) pipe pressure loss becomes “0”. The refrigerant gas pipe pressure loss gradually increases as the cooling operation load (cooling heat quantity) increases, and the refrigerant gas pipe pressure loss becomes maximum at a load factor of 100%. That is, the threshold value for determining whether or not there is refrigerant leakage has such a property.

一方、冷媒の漏洩が発生している場合には、冷却システムＳ１を循環する冷媒の量が減少し、管路内での圧力が低下するために、冷媒ガス管(３０)圧力損失は、冷却運転の各負荷率において閾値より低い。 On the other hand, when refrigerant leakage occurs, the amount of refrigerant circulating in the cooling system S1 decreases and the pressure in the pipe decreases, so the refrigerant gas pipe (30) pressure loss It is lower than the threshold at each load factor of operation.

＜冷媒漏洩の検知の制御＞
次に、冷却システムＳ１での冷却熱量Ｑｓ(冷却運転の負荷)を用いた冷媒漏洩の検知の制御について説明する。
図３に冷却システムでの冷却熱量を用いた冷媒漏洩の検知の制御フローを示す。 <Control of refrigerant leakage detection>
Next, control of detection of refrigerant leakage using the cooling heat quantity Qs (cooling operation load) in the cooling system S1 will be described.
FIG. 3 shows a control flow for detecting refrigerant leakage using the cooling heat quantity in the cooling system.

まず、冷却システムＳ１の系内に計画量の冷媒を充填する(図３のＳ１０１)。計画量の冷媒とは、冷却システムＳ１の蒸発器２１ａ、２１ｂに液状態の冷媒、冷媒液管３１に液状態の冷媒、冷媒ガス管３０にガス状態の冷媒がそれぞれ充填され安全率を見込んで、冷却システムＳ１が所定の冷却能力を発揮できるように冷媒が循環できる冷媒の量である。 First, a planned amount of refrigerant is charged into the cooling system S1 (S101 in FIG. 3). The planned amount of refrigerant means that the evaporators 21a and 21b of the cooling system S1 are filled with liquid refrigerant, the refrigerant liquid pipe 31 is filled with liquid refrigerant, and the refrigerant gas pipe 30 is filled with gas refrigerant so that a safety factor is expected. The amount of refrigerant that can be circulated so that the cooling system S1 can exhibit a predetermined cooling capacity.

続いて、予め冷媒流量制御バルブ２５ａ、２５ｂを全開にする (Ｓ１０２)。そして、冷却装置２０ａ、２０ｂに負荷(冷却熱量)を与えて冷却運転を行い、冷媒ガス管圧力損失を負荷毎(冷却熱量毎)に測定しておく。
具体的には、冷却熱量(負荷)として、例えば、ヒータなどで冷却装置２０ａ、２０ｂに熱を与え、例えば、冷却空気２４ａ、２４ｂが２５℃になるように冷却システムＳ１を運転する。 Subsequently, the refrigerant flow control valves 25a and 25b are fully opened in advance (S102). Then, a cooling operation is performed by applying a load (cooling heat amount) to the cooling devices 20a and 20b, and the refrigerant gas pipe pressure loss is measured for each load (each cooling heat amount).
Specifically, as the amount of cooling heat (load), for example, heat is applied to the cooling devices 20a and 20b with a heater or the like, and the cooling system S1 is operated so that the cooling air 24a and 24b becomes 25 ° C., for example.

冷却装置２０ａの高温排気温度センサ２７ａにより高温排気２３ａの温度ｔ１１を検出するとともに、冷却空気温度センサ２６ａにより冷却空気２４ａの温度ｔ１２を検出して、式(１)からΔＴ１を求める。 The temperature t11 of the high temperature exhaust 23a is detected by the high temperature exhaust temperature sensor 27a of the cooling device 20a, and the temperature t12 of the cooling air 24a is detected by the cooling air temperature sensor 26a to obtain ΔT1 from the equation (1).

同様に、冷却装置２０ｂの高温排気温度センサ２７ｂにより高温排気２３ｂの温度ｔ２１を検出するとともに、冷却空気温度センサ２６ａにより冷却空気２４ａの温度ｔ２２を検出して、式(２)からΔＴ２を求める。そして、式 (５)〜式 (８)を用いて、冷却システムＳ１での冷却熱量Ｑｓｉが求められる。 Similarly, the temperature t21 of the high temperature exhaust 23b is detected by the high temperature exhaust temperature sensor 27b of the cooling device 20b, and the temperature t22 of the cooling air 24a is detected by the cooling air temperature sensor 26a to obtain ΔT2 from the equation (2). And the amount of cooling heat Qsi in cooling system S1 is calculated | required using Formula (5)-Formula (8).

一方、冷媒ガス管圧力損失は、蒸発器出口圧力センサ５１の冷媒の圧力の測定値と、凝縮器ガス圧力センサ５０の圧力の測定値との差分で求められる。
この冷却熱量(負荷)の測定値を、または、測定値に幅をもたせて(マージンをとって)、冷媒が漏洩しているか否か判定する閾値として設定する(Ｓ１０３)。 On the other hand, the refrigerant gas pipe pressure loss is obtained by the difference between the measured value of the refrigerant pressure of the evaporator outlet pressure sensor 51 and the measured value of the pressure of the condenser gas pressure sensor 50.
The measured value of this cooling heat quantity (load) or a width of the measured value (with a margin) is set as a threshold for determining whether or not the refrigerant is leaking (S103).

続いて、実際の冷媒流量制御バルブ２５ａ、２５ｂの開度がそれぞれ冷却装置２０ａ、２０ｂの各設定温度になるように制御する冷却運転を行う(Ｓ１０４)。
そして、冷媒の漏洩を検知する場合には、通常の運転中やメンテナンス時などに、冷媒流量制御バルブ２５ａ、２５ｂを全開にする (Ｓ１０５)。 Subsequently, a cooling operation is performed to control the actual opening amounts of the refrigerant flow control valves 25a and 25b to the respective set temperatures of the cooling devices 20a and 20b (S104).
When detecting leakage of the refrigerant, the refrigerant flow control valves 25a and 25b are fully opened during normal operation or maintenance (S105).

続いて、冷媒ガス管圧力損失を蒸発器出口圧力センサ５１の冷媒の圧力の測定値と、凝縮器ガス圧力センサ５０の圧力の測定値との差分で測定する。また、冷却熱量(負荷)を、高温排気温度センサ２７ａ、冷却空気温度センサ２６ａと高温排気温度センサ２７ｂ、冷却空気温度センサ２６ｂとの各測定値を用いて、式 (５)〜式 (８)を用いて、冷却システムＳ１での冷却熱量Ｑｓｊを測定する (Ｓ１０６)。 Subsequently, the refrigerant gas pipe pressure loss is measured by the difference between the measured value of the refrigerant pressure of the evaporator outlet pressure sensor 51 and the measured value of the pressure of the condenser gas pressure sensor 50. In addition, the amount of cooling heat (load) is calculated using the measured values of the high temperature exhaust temperature sensor 27a, the cooling air temperature sensor 26a, the high temperature exhaust temperature sensor 27b, and the cooling air temperature sensor 26b. Is used to measure the cooling heat quantity Qsj in the cooling system S1 (S106).

続いて、実際の冷却熱量での冷媒ガス管圧力損失を、Ｓ１０３で求めた同じ冷却熱量(Ｑｓｉ＝Ｑｓｊ)でのＳ１０３で設定した冷媒ガス管圧力損失の閾値と比較し(Ｓ１０７)、実際の冷媒ガス管圧力損失が、冷媒ガス管圧力損失の閾値未満か否か判定する(Ｓ１０８)。
実際の冷媒ガス管圧力損失が、閾値未満の場合には(Ｓ１０８でＹｅｓ)、冷媒が漏洩していると判定する(Ｓ１０９)。 Subsequently, the refrigerant gas pipe pressure loss at the actual cooling heat quantity is compared with the threshold value of the refrigerant gas pipe pressure loss set at S103 at the same cooling heat quantity (Qsi = Qsj) obtained at S103 (S107). It is determined whether or not the refrigerant gas pipe pressure loss is less than a threshold value of the refrigerant gas pipe pressure loss (S108).
When the actual refrigerant gas pipe pressure loss is less than the threshold value (Yes in S108), it is determined that the refrigerant is leaking (S109).

一方、実際の冷媒ガス管圧力損失が、閾値以上の場合には(Ｓ１０８でＮｏ)、冷媒が漏洩していないと判定し(Ｓ１１０)、Ｓ１０４に移行する。
以上が、負荷毎(冷却熱量毎)に冷媒の漏洩があるか否かを判定する制御の流れである。 On the other hand, if the actual refrigerant gas pipe pressure loss is equal to or greater than the threshold (No in S108), it is determined that the refrigerant is not leaking (S110), and the process proceeds to S104.
The above is the flow of control for determining whether or not there is refrigerant leakage for each load (for each amount of cooling heat).

これにより、冷媒流量制御バルブ２５ａ、２５ｂの開度を全開にして冷却運転を行い、蒸発器出口圧力センサ５１と凝縮器ガス圧力センサ５０で測定した圧力の差分をとることで冷媒ガス管３０の圧力損失を算出するとともに冷却熱量測定手段の高温排気温度センサ２７ａ、２７ｂ、冷却空気温度センサ２６ａ、２６ｂで冷却システムＳ１の冷却熱量を、式(８)を用いて測定し、該冷却熱量の測定値に対する該冷媒ガス圧力損失算出値が、同じ冷却熱量での冷媒が漏洩しているか否か判定する閾値未満である場合に冷媒が漏洩していると判定することができる。
このように、電子機器の冷却運転中に冷媒漏洩を検知する場合に冷媒流量制御バルブ２５ａ、２５ｂをそれぞれ全開にして冷却装置２０ａ、２０ｂの冷却能力と冷媒ガス管圧力損失を測定し、測定結果が閾値以下であれば冷媒漏洩と判定することが本冷却システムＳ１の特徴である。 As a result, the refrigerant flow control valves 25a and 25b are fully opened and the cooling operation is performed, and the difference between the pressures measured by the evaporator outlet pressure sensor 51 and the condenser gas pressure sensor 50 is taken. While calculating the pressure loss, the cooling heat quantity of the cooling system S1 is measured by the high temperature exhaust temperature sensors 27a and 27b and the cooling air temperature sensors 26a and 26b of the cooling heat quantity measuring means using the equation (8), and the cooling heat quantity is measured. It can be determined that the refrigerant is leaking when the calculated value of the refrigerant gas pressure loss with respect to the value is less than the threshold value for determining whether or not the refrigerant with the same cooling heat quantity is leaking.
As described above, when refrigerant leakage is detected during the cooling operation of the electronic device, the refrigerant flow rate control valves 25a and 25b are fully opened to measure the cooling capacity and refrigerant gas pipe pressure loss of the cooling devices 20a and 20b, respectively. It is a feature of the present cooling system S1 that the refrigerant leak is determined to be less than the threshold value.

上記構成によれば、図１に示すように、圧縮機を用いず冷媒の気液密度差により冷媒を搬送する冷却システムＳ１で冷媒漏洩が発生した場合に、冷媒ガス管圧力損失を算出することで、冷媒の漏洩が検出できる。そのため、冷媒の漏洩の検出が簡単な構成で容易に行える。しかも、冷媒流量制御バルブ２５ａ、２５ｂの開度をそれぞれ全開にすることで行えるので、冷却性能に殆ど影響することなく、つまり一時的に冷却能力が上がるだけで、冷却運転の継続中に冷媒の漏洩が発生しているか否かの判定(検出)が行える。
以上のことから、冷却装置２０ａ、２０ｂの冷却能力が低下する前に冷媒漏洩を検知することが可能となり、信頼性の高い空調設備が提供可能である。 According to the above configuration, as shown in FIG. 1, when refrigerant leakage occurs in the cooling system S1 that conveys the refrigerant due to the gas-liquid density difference of the refrigerant without using the compressor, the refrigerant gas pipe pressure loss is calculated. Thus, refrigerant leakage can be detected. Therefore, detection of refrigerant leakage can be easily performed with a simple configuration. In addition, since the refrigerant flow rate control valves 25a and 25b can be opened by fully opening each of them, the cooling performance is hardly affected, that is, the cooling capacity is only temporarily increased. It is possible to determine (detect) whether or not a leak has occurred.
From the above, it becomes possible to detect refrigerant leakage before the cooling capacity of the cooling devices 20a and 20b is lowered, and it is possible to provide highly reliable air conditioning equipment.

＜＜実施形態２＞＞
実施形態１の冷却システムＳ１では、冷却熱量を測定する冷却熱量測定手段として蒸発器２１ａ、２１ｂに供給される高温排気２３ａ、２３ｂの温度を測定する高温排気温度センサ２７ａ、２７ｂと、高温排気２３ａ、２３ｂの冷却後の冷却空気２４ａ、２４ｂの温度を測定する冷却空気温度センサ２６ａ、２６ｂを備える場合を説明した。 << Embodiment 2 >>
In the cooling system S1 of the first embodiment, high-temperature exhaust gas temperature sensors 27a and 27b that measure the temperature of the high-temperature exhaust gas 23a and 23b supplied to the evaporators 21a and 21b as the cooling heat energy measurement unit that measures the cooling heat energy, and the high-temperature exhaust gas 23a The case where the cooling air temperature sensors 26a and 26b for measuring the temperature of the cooling air 24a and 24b after the cooling of the cooling air 23b are provided has been described.

ここで、冷却熱量測定手段は１または複数台設置された冷却装置２０ａ、２０ｂの冷却熱量が測定されればよい。
そこで、実施形態２の冷却システムＳ２では、熱源装置４０の冷水往・還温度差と冷水流量を測定して冷却熱量を算出している。ここで、冷却熱量測定手段は１または複数台設置された冷却装置２０ａ、２０ｂの冷却熱量が測定されていればよい。 Here, the cooling heat quantity measuring means only needs to measure the cooling heat quantity of one or more cooling devices 20a and 20b installed.
Therefore, in the cooling system S2 of the second embodiment, the amount of cooling heat is calculated by measuring the chilled water forward / return temperature difference and the chilled water flow rate of the heat source device 40. Here, the cooling calorie | heat amount measuring means should just measure the cooling calorie | heat amount of the cooling device 20a, 20b installed in one or more units.

図４に本発明の実施形態２に係る冷却システムを示す。
実施形態２の冷却システムＳ２では、冷媒ガス管３０を流れる冷媒を冷却する冷水が流れる凝縮器１０の一次側の冷水配管４２の上流側に冷水往温度センサ４３を設け、下流側に冷水還温度センサ４４を設けている。 FIG. 4 shows a cooling system according to Embodiment 2 of the present invention.
In the cooling system S2 of the second embodiment, a chilled water going temperature sensor 43 is provided on the upstream side of the chilled water pipe 42 on the primary side of the condenser 10 through which chilled water that cools the refrigerant flowing in the refrigerant gas pipe 30 flows, and the chilled water return temperature on the downstream side. A sensor 44 is provided.

実施形態２の冷却システムＳ２の制御は、実施形態１同様、制御装置Ｃで遂行される。その他の構成は、実施形態１と同様であるから、同様な構成要素には同一の符号を付して示し、詳細な説明は省略する。 Control of the cooling system S2 of the second embodiment is performed by the control device C as in the first embodiment. Since the other configuration is the same as that of the first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

＜冷却熱量＞
冷却システムＳ２では、凝縮器１０の２次側を流れる冷媒の出口での状態は同じ温度の液状態の冷媒となるように、熱源装置４０が制御されている。
冷却システムＳ２で冷却装置２０ａ、２０ｂの冷却熱量を測定するに際しては、まず、冷水往温度センサ４３の測定温度ｔ３１と冷水還温度センサ４４の測定温度ｔ３２との差から熱源装置４０の冷水往・還温度差ΔＴ２１を、
ΔＴ２１＝ｔ３２−ｔ３１ (９)
と求める。 <Cooling heat amount>
In the cooling system S2, the heat source device 40 is controlled such that the state at the outlet of the refrigerant flowing on the secondary side of the condenser 10 is a liquid refrigerant having the same temperature.
When measuring the cooling heat quantity of the cooling devices 20a and 20b in the cooling system S2, first, the cooling water flow of the heat source device 40 is determined from the difference between the measured temperature t31 of the cold water flow temperature sensor 43 and the measured temperature t32 of the cold water return temperature sensor 44. The return temperature difference ΔT21 is
ΔT21 = t32−t31 (9)
I ask.

また、冷水配管４２に設けた冷水流量計４５で冷水流量を測定する。
ここで、体積を体積＝冷水流量×時間の関係から求めて、重さ＝比重×体積の関係より、冷水の比重を用いて冷水の質量ｍ３を求める。冷水の比熱ｃ２(Ｊ／ｇ・Ｋ)とすると、式(５)から、冷水往・還温度差ΔＴ２１を用いて、冷却熱量Ｑ３が
Ｑ３＝ｍ３・ｃ２・ΔＴ２１
と求められる。
従って、熱源装置４０の冷水往・還温度差ΔＴ２１を用いて冷却熱量Ｑ３が求められる。 Further, the cold water flow rate is measured by a cold water flow meter 45 provided in the cold water pipe 42.
Here, the volume is obtained from the relationship of volume = cold water flow rate × time, and the mass m3 of cold water is obtained using the specific gravity of cold water from the relationship of weight = specific gravity × volume. Assuming that the specific heat of cold water c2 (J / g · K), the cooling heat quantity Q3 is calculated from the equation (5) using the cold water forward / return temperature difference ΔT21.
Q3 = m3 · c2 · ΔT21
Is required.
Therefore, the cooling heat quantity Q3 is obtained using the chilled water forward / return temperature difference ΔT21 of the heat source device 40.

＜冷媒の漏洩の判定＞
そして、冷媒が漏洩しているか否かの判定に際しては、まず、冷却システムＳ２において、予め、正常運転時(冷媒の漏洩がない場合)に、ある冷却熱量における(冷却熱量毎の)冷媒ガス管圧力損失を、蒸発器出口圧力センサ５１の冷媒の圧力の測定値と、凝縮器ガス圧力センサ５０の圧力の測定値との差分より測定する。 <Determination of refrigerant leakage>
When determining whether or not the refrigerant is leaking, first, in the cooling system S2, in the normal operation (when there is no refrigerant leakage), a refrigerant gas pipe at a certain amount of cooling heat (for each amount of cooling heat). The pressure loss is measured from the difference between the measured value of the refrigerant pressure of the evaporator outlet pressure sensor 51 and the measured value of the pressure of the condenser gas pressure sensor 50.

そして、各冷却熱量における冷媒ガス管圧力損失の測定値を、冷媒の漏洩があるか否かの判定を行うための閾値に設定する、或いは、該測定値に幅をもたせて(マージンをとって)、閾値を設定する。 Then, the measured value of the refrigerant gas pipe pressure loss at each cooling heat quantity is set as a threshold for determining whether or not there is refrigerant leakage, or the measured value is given a width (with a margin). ), Set the threshold.

そして、冷却システムＳ２の実際の運転において、ある冷却熱量における冷媒ガス管圧力損失を、蒸発器出口圧力センサ５１の冷媒の圧力の測定値と凝縮器ガス圧力センサ５０の圧力の測定値との差分より測定する。 Then, in the actual operation of the cooling system S2, the refrigerant gas pipe pressure loss at a certain amount of cooling heat is determined by the difference between the measured value of the refrigerant pressure of the evaporator outlet pressure sensor 51 and the measured value of the pressure of the condenser gas pressure sensor 50. Measure more.

そして、実際の運転時の冷媒ガス管圧力損失が、同じ冷却熱量における閾値未満であるか否かを測定することにより、冷媒の漏洩を判定することができる。つまり、図３と同様、実際の運転時の冷媒ガス管圧力損失が、閾値未満である場合には冷媒が漏洩していると判定され、閾値以上である場合には冷媒が漏洩していないと判定される。 The refrigerant leakage can be determined by measuring whether or not the refrigerant gas pipe pressure loss during actual operation is less than the threshold value for the same amount of cooling heat. That is, as in FIG. 3, if the refrigerant gas pipe pressure loss during actual operation is less than the threshold, it is determined that the refrigerant is leaking, and if it is greater than or equal to the threshold, the refrigerant is not leaking. Determined.

実施形態２によれば、冷却装置２０ａ、２０ｂの冷却熱量を、水還温度センサ４４の測定温度ｔ３２と冷水往温度センサ４３の測定温度ｔ３１との差から求める。そして、実際の運転時の冷媒ガス管圧力損失を測ることで、圧縮機を用いずに冷媒の気液密度差により冷媒を搬送する冷却システムＳ２で、冷媒漏洩が発生したことを検知できる。 According to the second embodiment, the cooling heat amount of the cooling devices 20 a and 20 b is obtained from the difference between the measured temperature t32 of the water return temperature sensor 44 and the measured temperature t31 of the chilled water temperature sensor 43. Then, by measuring the refrigerant gas pipe pressure loss during actual operation, it is possible to detect that the refrigerant leakage has occurred in the cooling system S2 that conveys the refrigerant by the gas-liquid density difference of the refrigerant without using the compressor.

従って、簡単な構成で容易に、冷却システムＳ２の冷媒の漏洩を検知することが可能である。
そのため、冷却装置２０ａ、２０ｂの冷却能力が低下する前に冷媒の漏洩を検知することが可能となり、信頼性が高い空調設備を提供できる。 Therefore, it is possible to easily detect the leakage of the refrigerant in the cooling system S2 with a simple configuration.
Therefore, it becomes possible to detect the leakage of the refrigerant before the cooling capacity of the cooling devices 20a and 20b decreases, and it is possible to provide a highly reliable air conditioning facility.

なお、上記構成に代えて、冷却装置２０ａ、２０ｂで冷却される電子機器の消費電力量を測定し、冷却熱量を推定しても構わない。
すなわち、冷却装置２０ａ、２０ｂで冷却される電子機器の消費電力量と発熱量を測定し、冷却運転中の温度から冷却熱量を推定して、冷却装置２０ａ、２０ｂの冷却負荷として求め、実際の運転時の冷媒ガス管圧力損失が、冷媒が漏洩しているか否か判定する閾値未満であるか否かを測定することにより、冷媒の漏洩を判定しても構わない。 Instead of the above configuration, the amount of power consumed by the electronic devices cooled by the cooling devices 20a and 20b may be measured to estimate the amount of cooling heat.
That is, the power consumption and the heat generation amount of the electronic devices cooled by the cooling devices 20a and 20b are measured, the cooling heat amount is estimated from the temperature during the cooling operation, and is obtained as the cooling load of the cooling devices 20a and 20b. The refrigerant leakage may be determined by measuring whether or not the refrigerant gas pipe pressure loss during operation is less than a threshold for determining whether or not the refrigerant is leaking.

＜＜その他の実施例＞＞
１．前記実施形態１、２で説明した蒸発器２１ａ、２１ｂの出口の冷媒圧力を測定する蒸発器出口圧力センサ５１は、蒸発器２１ａ、２１ｂの出口の冷媒圧力の少なくとも何れかの出口冷媒圧力を測ることができれば、その位置は他の位置に設けても構わない。 << Other Examples >>
1. The evaporator outlet pressure sensor 51 that measures the refrigerant pressure at the outlets of the evaporators 21a and 21b described in the first and second embodiments measures the outlet refrigerant pressure of at least one of the refrigerant pressures at the outlets of the evaporators 21a and 21b. If possible, the position may be provided at another position.

２．前記実施形態１、２では、冷却装置２０ａ、２０ｂが２台の場合を例示して説明したが、冷却装置は１台、或いは、３以上の複数台でも構わない。 2. In the first and second embodiments, the case where the number of the cooling devices 20a and 20b is two has been described as an example. However, the number of the cooling devices may be one or three or more.

なお、本発明は前記した実施形態に限定されるものでなく、様々な実施形態が含まれる。例えば、上記した実施形態は本発明を分り易く説明したものであり、必ずしも説明した全ての構成を備えるものに限定されるものではない。例えば、説明した構成の一部を含むものであってもよい。 In addition, this invention is not limited to above-described embodiment, Various embodiments are included. For example, the above-described embodiment is a description of the present invention in an easy-to-understand manner, and is not necessarily limited to one having all the configurations described. For example, a part of the configuration described may be included.

１０凝縮器
２０ａ、２０ｂ冷却装置
２１ａ、２１ｂ蒸発器
２２ａ、２２ｂ送風機(冷却熱量測定手段)
２３ａ、２３ｂ高温排気(高温の排気)
２５ａ、２５ｂ冷媒流量制御バルブ
２６ａ、２６ｂ冷却空気温度センサ(冷却熱量測定手段、冷却空気温度検出手段)
２７ａ、２７ｂ高温排気温度センサ(冷却熱量測定手段、高温排気温度検出手段)
３０冷媒ガス管
４３冷水往温度センサ(冷却熱量測定手段、熱媒体往温度検出手段)
４４冷水還温度センサ (冷却熱量測定手段、熱媒体還温度検出手段)
５０凝縮器ガス圧力センサ
５１蒸発器出口圧力センサ
Ｃ制御装置
Ｓ１、Ｓ２冷却システム 10 Condenser
20a, 20b Cooling device
21a, 21b Evaporator 22a, 22b Blower (cooling heat quantity measuring means)
23a, 23b High temperature exhaust (high temperature exhaust)
25a, 25b Refrigerant flow control valve
26a, 26b Cooling air temperature sensor (cooling heat quantity measuring means, cooling air temperature detecting means)
27a, 27b High temperature exhaust temperature sensor (cooling heat quantity measuring means, high temperature exhaust temperature detecting means)
30 Refrigerant gas pipe 43 Chilled water temperature sensor (cooling heat quantity measuring means, heat medium temperature detecting means)
44 Chilled water return temperature sensor (cooling heat quantity measuring means, heat medium return temperature detecting means)
50 Condenser gas pressure sensor 51 Evaporator outlet pressure sensor C Control devices S1, S2 Cooling system

Claims

An evaporator that vaporizes the refrigerant by heat exchange that cools the high-temperature exhaust discharged from the electronic device, a refrigerant flow control valve that adjusts the flow rate of the refrigerant liquid supplied to the evaporator, and the high-temperature exhaust that is supplied to the evaporator One or more installed cooling devices having a blower to supply;
A condenser which is installed at a higher position than the evaporator and liquefies the refrigerant gas vaporized by the evaporator;
A refrigerant gas pipe provided between the evaporator and the condenser;
A condenser gas pressure sensor for measuring the refrigerant gas pressure at the inlet of the condenser;
An evaporator outlet pressure sensor for measuring the refrigerant pressure at the outlet of the evaporator;
Cooling heat quantity measuring means for measuring the cooling heat quantity of the cooling device;
In a refrigerant leakage detection method for a cooling system comprising a control device,
The controller is
Performs cooling operation in the fully opened opening degree of the refrigerant flow rate control valve, to calculate the pressure loss of the refrigerant gas pipe by taking the difference between the pre-Symbol evaporator outlet pressure sensor and pressure measured in the condenser gas pressure sensor When the calculated pressure loss is lower than the pressure loss of the refrigerant gas pipe obtained by the difference in pressure measured by the evaporator outlet pressure sensor and the condenser gas pressure sensor when there is no leakage of the refrigerant Determining that the refrigerant is leaking ,
The cooling system includes a cooling heat quantity measuring unit that measures the cooling heat quantity of the cooling device,
The controller is
Preliminarily opening the refrigerant flow control valve and performing a cooling operation under various load conditions on the cooling device,
Calculating the pressure loss of the refrigerant gas pipe by taking the difference in pressure measured by the evaporator outlet pressure sensor and the condenser gas pressure sensor and measuring the cooling heat amount of the cooling system by the cooling heat amount measuring means;
Based on the calculated pressure loss of the refrigerant gas pipe, a threshold value of the refrigerant gas pipe pressure loss for determining whether or not the refrigerant is leaking with respect to the cooling heat amount of the cooling system is set,
The cooling system is actually operated to perform a cooling operation by controlling the refrigerant flow control valve,
When detecting the leakage of the refrigerant, fully open the refrigerant flow control valve, measure the refrigerant gas pipe pressure loss and the amount of cooling heat,
The refrigerant gas pipe pressure loss of the measurement results, cooling system that is characterized in that determines that the refrigerant when the is less than the threshold value of the refrigerant gas pipe pressure loss in the same cooling heat is leaking Refrigerant leakage detection method.