JP5009530B2 - Non-azeotropic refrigerant for ultra-low temperature - Google Patents

Non-azeotropic refrigerant for ultra-low temperature Download PDF

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JP5009530B2
JP5009530B2 JP2006011745A JP2006011745A JP5009530B2 JP 5009530 B2 JP5009530 B2 JP 5009530B2 JP 2006011745 A JP2006011745 A JP 2006011745A JP 2006011745 A JP2006011745 A JP 2006011745A JP 5009530 B2 JP5009530 B2 JP 5009530B2
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refrigerant
isobutane
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low
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JP2007191597A (en
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進 栗田
宣義 栗田
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Nihon Freezer Co Ltd
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Description

本発明は、−50℃以下の超低温用冷媒に関し、特に超低温度を達成するための低沸点の冷媒と室温環境で運転可能とするための特性を付与する高沸点冷媒とを組合わせて混合した非共沸冷媒に関する。   The present invention relates to a refrigerant for ultra-low temperature of −50 ° C. or less, and in particular, a low-boiling refrigerant for achieving ultra-low temperature and a high-boiling refrigerant that imparts characteristics for enabling operation in a room temperature environment are mixed and mixed. It relates to a non-azeotropic refrigerant.

現在、冷凍装置用に用いられる冷媒について、オゾン層の破壊原因となるいわゆる特定フロンの使用が禁止され、また温室効果ガスとして影響の大きいフロン類の使用が制限されつつある。このため、これら特定フロン以外のフロンや炭化水素系の冷媒を用いるべく種々検討されているが、−50℃以下の超低温度を達成する冷凍装置用として使用可能な冷媒の種類には限りがある。
このため、2種以上の冷媒を用いてそれぞれ独立に作動する冷凍装置システムを組合わせたり、混合した2種以上の冷媒を多段階に気化させてその気化熱により目的とする超低温度を達成する低沸点の冷媒を凝縮させる、などの手法が試みられているが複雑な構造とならざるを得ない。
これに対して2種以上の冷媒を混合して目的とする特性に調整して単純な単一の凝縮・気化プロセスにより作動する冷凍装置システムに適用する手法もあるが、これらの混合冷媒の多くは非共沸特性を有するため、連続して安定な運転を継続することが困難である。
これらの非共沸特性は、圧力、温度の広い範囲にわたって液相と気相とが共存し、また温度・圧力の変化と共にこれら各相の組成が変化するなど、特有の性質を有するため、これらの冷凍装置に適用すると冷凍装置システム内のそれぞれの過程に相当する温度・圧力下でそれぞれに組成の異なる液相と気相とが共存する状態を生じる。
このため、エバポレータやコンプレッサーに至る過程で気液分離手段を設ける必要があり、また、その気液平衡条件も冷却対象や外気温の変化などの冷凍機の運転条件に応じた負荷によって変動するため、一層複雑な制御が必要とされるためその普及に到っていない。
特開平8−166172号公報 特開平6−317358号公報
Currently, for refrigerants used for refrigeration equipment, the use of so-called specific chlorofluorocarbons, which cause destruction of the ozone layer, is prohibited, and the use of chlorofluorocarbons, which have a large effect on greenhouse gases, is being restricted. For this reason, various studies have been made to use chlorofluorocarbons and hydrocarbon refrigerants other than these specific chlorofluorocarbons, but there are limits to the types of refrigerants that can be used for refrigeration systems that achieve ultra-low temperatures of -50 ° C or lower. .
For this reason, a refrigeration system that operates independently using two or more kinds of refrigerants is combined, or two or more kinds of mixed refrigerants are vaporized in multiple stages to achieve the desired ultra-low temperature by the heat of vaporization. Attempts have been made to condense low-boiling refrigerants, but the structure must be complicated.
On the other hand, there is also a technique that is applied to a refrigeration system that operates by a simple single condensation / vaporization process by mixing two or more refrigerants and adjusting them to the desired characteristics. Has non-azeotropic characteristics, and it is difficult to continue stable operation continuously.
These non-azeotropic characteristics have unique properties such as the coexistence of the liquid phase and gas phase over a wide range of pressure and temperature, and the composition of each phase changes with changes in temperature and pressure. When applied to the refrigeration apparatus, a liquid phase and a gas phase having different compositions coexist at temperatures and pressures corresponding to the respective processes in the refrigeration system.
For this reason, it is necessary to provide gas-liquid separation means in the process leading to the evaporator and compressor, and the gas-liquid equilibrium conditions also vary depending on the load depending on the operating conditions of the refrigerator such as the object to be cooled and changes in the outside air temperature. However, since more complicated control is required, it has not been widely used.
JP-A-8-166172 JP-A-6-317358

これに対し、本発明者らは、目的とする低温度を達成するための、一般に低沸点となるほど臨界温度も低く、かつ高蒸気圧となる超低温度用冷媒に対して、
室温環境で凝縮可能な高沸点、かつ低蒸気圧の冷媒を組合せた非共沸冷媒を使用し、
冷凍装置システムの構成を、
冷凍庫(エバポレータ)からコンプレッサーに送られる高沸点冷媒の凝縮相を含む低温度冷媒とコンデンサーを経てキャピラリなどの絞り弁に向かう低沸点冷媒の気相を含む高温度の冷媒との間で熱交換し、
この熱交換によって、絞り弁に向かう冷媒中の気相状態にある低沸点冷媒を凝縮させると共に、コンプレッサーに向かう冷媒中の高沸点冷媒を気化することにより、
非共沸冷媒の絞り弁に向かう冷媒をその圧力下での液相線以下、
コンプレッサーに向かう冷媒をその圧力下で気相線以上の温度となる条件を実現し、これら非共沸冷媒の特性を利用して気液分離手段を必要とせず、共沸冷媒と同様の安定した運転を可能とした。
WO2004/051155号公報
On the other hand, the present inventors, in order to achieve the target low temperature, in general, the lower the boiling point, the lower the critical temperature and the higher the vapor pressure.
Use a non-azeotropic refrigerant that combines a high boiling point and low vapor pressure refrigerant that can be condensed in a room temperature environment.
The configuration of the refrigeration system
Heat exchange is performed between the low-temperature refrigerant containing the condensed phase of the high-boiling refrigerant sent from the freezer (evaporator) to the compressor and the high-temperature refrigerant containing the gas phase of the low-boiling refrigerant going to the throttle valve such as the capillary through the condenser. ,
By this heat exchange, while condensing the low boiling point refrigerant in the gas phase state in the refrigerant going to the throttle valve, and evaporating the high boiling point refrigerant in the refrigerant going to the compressor,
The refrigerant going to the throttle valve of the non-azeotropic refrigerant is below the liquidus under the pressure,
Realizes the condition that the refrigerant going to the compressor has a temperature higher than the gas-phase line under the pressure, uses the characteristics of these non-azeotropic refrigerants, does not require gas-liquid separation means, and is stable like azeotropic refrigerants Operation was possible.
WO 2004/051155

このシステムによれば、超低温度を実現する低沸点冷媒と室温環境下で凝縮可能な冷媒とを混合して非共沸特性を呈する冷媒により、室温環境下で単純な一元単段式冷凍装置システムにより、超低温度が達成可能となるのであって、コンプレッサーとして実用可能な圧力範囲で運転できるように圧力条件を考慮して、冷媒の特性、組成を選択すればよい。
また、本発明者らは先に目的とする超低温度を達成する冷媒としてR−23(トリフルオロメタン:CHF3)及びR−116(パーフルオロエタン:C26) を選び、これに対して室温環境下で凝縮可能な高沸点冷媒としてノルマルブタンを組合わせた非共沸混合冷媒を提案した。
特開2001−99498号公報 WO1999/064536号公報
According to this system, a simple single-stage refrigeration system in a room temperature environment by mixing a low boiling point refrigerant that realizes an ultra-low temperature and a refrigerant that can be condensed in a room temperature environment and exhibiting non-azeotropic characteristics. Therefore, it is possible to achieve an ultra-low temperature, and it is only necessary to select the characteristics and composition of the refrigerant in consideration of the pressure conditions so that the compressor can be operated in a pressure range practical for use as a compressor.
Further, the present inventors previously selected R-23 (trifluoromethane: CHF 3 ) and R-116 (perfluoroethane: C 2 F 6 ) as refrigerants that achieve the intended ultra-low temperature, and against this, A non-azeotropic refrigerant mixture combining normal butane was proposed as a high-boiling point refrigerant that can condense in a room temperature environment.
JP 2001-99498 A WO 1999/064536

R−23及びR−116は、いわゆるフロンであるが、塩素を含まないことからオゾン層を破壊することなく、温暖化係数が高いためフロン回収破壊法の対象となって回収義務が課せられているものの使用可能なガスであり、表1にも示すように−50℃以下の超低温度を達成するために優れた特性を発揮する。
これらと組合わせるノルマルブタンは、表−1に示すように標準沸点が室温近傍にあり、冷媒を凝縮させる圧力下では室温で容易に凝縮する。更に、ノルマルブタンは、その蒸気圧が極めて低く、低沸点冷媒と組合わせることによって混合冷媒の蒸気圧を低下させることが期待できるためであった。
特に、R−116及びR−23とがいずれも蒸気圧が非常に高いため、いずれにせよその凝縮過程ではコンプレッサーの実用限界を超える圧力となることが予想されることか
ら、混合冷媒の蒸気圧を低下させなければ実用化は望めないため、この蒸気圧を低減することは重要である。
R-23 and R-116 are so-called chlorofluorocarbons, but since they do not contain chlorine, they do not destroy the ozone layer and are subject to the chlorofluorocarbon recovery and destruction law because of their high global warming potential. However, as shown in Table 1, it exhibits excellent characteristics in order to achieve an ultra-low temperature of −50 ° C. or lower.
Normal butane combined with these has a normal boiling point near room temperature as shown in Table 1, and easily condenses at room temperature under pressure to condense the refrigerant. Further, normal butane has an extremely low vapor pressure, and it can be expected to reduce the vapor pressure of the mixed refrigerant when combined with a low boiling point refrigerant.
In particular, since the vapor pressure of both R-116 and R-23 is very high, it is expected that the pressure in the condensation process will exceed the practical limit of the compressor anyway. It is important to reduce the vapor pressure because practical use cannot be expected without reducing the pressure.

非共沸混合冷媒として上記冷凍システムに適用するためには、室温20℃以上という温度条件と1.数MPa 以下という実用可能なコンプレッサーの吐出圧条件下でこの冷凍システムを稼動するに充分な熱量を大気中に放出して高沸点成分のリッチな凝縮相を形成しなければならないのであって、この高沸点成分のリッチな凝縮相はその後のエバポレータを経由した圧力下でも残存して熱交換においてその気化により、1.数MPaの圧力下にある低沸点成分のリッチな気相を完全に凝縮することが必要である。
ノルマルブタンは、上記の冷凍システムに適合するものとして、その標準沸点はマイナスであるが室温に近く、混合冷媒としてその低沸点成分由来の高い蒸気圧に対してコンプレッサーの実用限界近傍の吐出圧力でシステムを稼動するものであった。
ところで、ノルマルブタンは、上記のような観点から採用したものであるが、一般に市販されているガスとしては燃料用などを含め、ブタンの異性体であるイソブタンが一般的であり、冷媒調達の便宜上もコスト上も有利である。 しかしながら両者は化学式は同じであるが、異性体としての化学構造の相違から、イソブタンの標準沸点は表−1に示すようにノルマルブタンに比して約11℃も低く、それに連れて臨界温度も約18℃低いうえ、蒸気圧もまた約2倍の0.22MPaである。
このため、これら非共沸混合系冷媒の特性は、成分組成の算術和として予測できないこと、ノルマルブタンについては上記したとおり標準沸点が室温近傍とはいえ、マイナスであって余裕のあるものではないから、ノルマルブタンを用いた結果からイソブタンの採否は判断できない。
In order to be applied to the refrigeration system as a non-azeotropic refrigerant mixture, a temperature condition of room temperature of 20 ° C. or higher and 1. A sufficient condensed phase of high-boiling components must be formed by releasing a sufficient amount of heat into the atmosphere to operate the refrigeration system under a practical compressor discharge pressure condition of several MPa or less. The condensed phase rich in high-boiling components remains even under pressure via a subsequent evaporator, and is vaporized in the heat exchange. It is necessary to completely condense the gas phase rich in low-boiling components under a pressure of several MPa.
Normal butane is compatible with the above refrigeration system, and its normal boiling point is negative, but it is close to room temperature. As a mixed refrigerant, normal butane has a discharge pressure near the practical limit of the compressor against a high vapor pressure derived from its low-boiling components. The system was to operate.
By the way, normal butane is adopted from the above viewpoints, but as a commercially available gas, isobutane, which is an isomer of butane, is generally used, including for fuel, etc. This is also advantageous in terms of cost. However, both have the same chemical formula, but due to the difference in chemical structure as an isomer, the normal boiling point of isobutane is about 11 ° C. lower than that of normal butane as shown in Table 1, and the critical temperature is accordingly increased. In addition to being about 18 ° C. lower, the vapor pressure is also about twice that of 0.22 MPa.
For this reason, the characteristics of these non-azeotropic refrigerants cannot be predicted as the arithmetic sum of the component composition, and for normal butane, the normal boiling point is near room temperature as described above, but it is negative and not marginal. Therefore, it is not possible to judge whether or not isobutane is adopted from the results of using normal butane.

Figure 0005009530
Figure 0005009530

解決しようとする問題点は、−50℃以下の超低温度を達成する冷媒であるR−23及びR−116を用いて上記冷凍システムの室温環境下での運転を可能とする冷媒として、ノルマルブタンに替わって広く市販されているイソブタンとの組合せを検討し、上記冷凍装置システムの室温環境下での運転を可能とする冷媒の特性と組成条件を解明する。   The problem to be solved is normal butane as a refrigerant that enables operation of the refrigeration system in a room temperature environment using R-23 and R-116, which are refrigerants that achieve an extremely low temperature of −50 ° C. or less. Instead, the combination with commercially available isobutane is studied, and the characteristics and composition conditions of the refrigerant that enables the refrigeration system to operate in a room temperature environment are elucidated.

本発明は、コンプレッサー、凝縮器、キャピラリー(絞り弁)、及び蒸発器からなる冷凍装置において、凝縮器からキャピラリーに至る冷媒と蒸発器からコンプレッサーに至る冷媒との間で熱交換を行い、
該熱交換によって、キャピラリーに至る冷媒の凝縮過程を冷媒状態図の液相線以下、コンプレッサーに至る冷媒の気化過程を気相線以上で作動するシステム構成とするため、
室温で冷凍装置を作動可能な高沸点冷媒とー50℃以下の低温度を達成する低沸点冷媒とを組み合わせてなる非共沸混合冷媒において、
低沸点冷媒としてのR−23に対し、高沸点冷媒としてのイソブタンを40〜60wt%としてなることを特徴とする、超低温用非共沸混合冷媒であり、
また、上記冷凍装置のシステム構成に適用する超低温用非共沸混合冷媒として、
低沸点冷媒としてのR−116に対し、高沸点冷媒としてのイソブタンを50〜80wt%としたことを特徴とする、
超低温用非共沸混合冷媒である。
In the refrigeration apparatus comprising a compressor, a condenser, a capillary (throttle valve), and an evaporator, the present invention performs heat exchange between the refrigerant from the condenser to the capillary and the refrigerant from the evaporator to the compressor,
In order to achieve a system configuration in which the condensation process of the refrigerant reaching the capillary is operated below the liquidus in the refrigerant phase diagram and the vaporization process of the refrigerant reaching the compressor is performed above the gas phase line by the heat exchange,
In a non-azeotropic refrigerant mixture comprising a combination of a high-boiling refrigerant capable of operating a refrigeration system at room temperature and a low-boiling refrigerant that achieves a low temperature of −50 ° C. or lower,
A non-azeotropic refrigerant mixture for ultra-low temperature, characterized in that the isobutane as a high boiling point refrigerant is 40 to 60 wt% relative to R-23 as a low boiling point refrigerant,
In addition, as a non-azeotropic refrigerant mixture for ultra-low temperature applied to the system configuration of the refrigeration apparatus,
With respect to R-116 as a low boiling point refrigerant, isobutane as a high boiling point refrigerant is 50 to 80 wt%,
It is a non-azeotropic refrigerant mixture for ultra-low temperatures.

本発明の冷媒は、上記の冷凍装置システムに適用して、室温環境下において−50℃以下の超低温度を容易に且つ安定して達成することができる。   The refrigerant of the present invention can be applied to the above refrigeration system and can easily and stably achieve an ultra-low temperature of −50 ° C. or lower in a room temperature environment.

本発明においては、R−23及びR−116に対して、室温で使用可能な特性を付与する冷媒としてイソブタンを加えた非共沸混合冷媒を調整し、上記した熱交換器を備えた超低温度用冷凍システムに適用して、室温以上の温度環境とコンプレッサーの吐出圧力の能力範囲で稼動するための条件を検証し、
超低温度用非共沸混合冷媒としての特性を確認した。
実機運転に使用した冷凍装置システムの構成模式図を図1に示す。これらのシステム構成は、上記した本発明者らによる先行出願の発明におけるものと基本的に変わらない。
コンプレッサー1で圧縮された冷媒は、ファン3によって冷却される凝縮器(コンデンサー)2、ドライヤー20、熱交換器4、キャピラリーチューブ(絞り弁)5を経て断熱材で囲まれた冷凍庫7の蒸発器6に送られ、再び熱交換器4を経てコンプレッサーに送られる。
図中、10、11、12、15、16及び17は、温度センサー及び圧力計などの配置を示す。 それぞれ、10はコンプレッサー吐出圧力及び温度、11及び12は高圧側冷媒の熱交換器入口及び出口の温度、15は冷凍庫温度、16,17はエバポレーターから出た低圧冷媒の温度を測定した。
In the present invention, a non-azeotropic mixed refrigerant in which isobutane is added as a refrigerant that imparts characteristics usable at room temperature to R-23 and R-116 is prepared, and an ultra-low temperature provided with the above-described heat exchanger Applied to an industrial refrigeration system, verifying the conditions for operating in a temperature environment above room temperature and the compressor discharge pressure capacity range,
The characteristics as a non-azeotropic refrigerant mixture for ultra-low temperature were confirmed.
FIG. 1 shows a schematic configuration diagram of a refrigeration system used for actual machine operation. These system configurations are basically the same as those in the invention of the prior application by the present inventors.
The refrigerant compressed by the compressor 1 passes through a condenser (condenser) 2 cooled by a fan 3, a dryer 20, a heat exchanger 4, and a capillary tube (throttle valve) 5, and an evaporator of a freezer 7 surrounded by a heat insulating material. 6 is sent to the compressor via the heat exchanger 4 again.
In the figure, 10, 11, 12, 15, 16, and 17 indicate the arrangement of a temperature sensor and a pressure gauge. 10 is the compressor discharge pressure and temperature, 11 and 12 are the heat exchanger inlet and outlet temperatures of the high-pressure refrigerant, 15 is the freezer temperature, and 16 and 17 are the low-pressure refrigerant temperatures coming from the evaporator.

実験条件:
冷凍装置:リーペヘル社製(ドイツ:形式名GS-360)
冷凍庫内容積: 300リットル
外気温:27.3〜32.5℃
充填冷媒総量(標準装備):165g
熱交換は、コンデンサーからキャピラリーに至る高圧の冷媒とエバポレーターからコンプレッサーに至る低圧の冷媒間で行い、それぞれの冷媒の通る銅管をロウ付けによりサイド・バイ・サイドで結合した約2mのものを使用した。
この構造の熱交換器は、従来より冷凍装置における凝縮効率を向上するため小規模のものが使用されているが、本発明においては上記冷凍システムの熱交換条件を達成するため約2mとして使用した。
なお、コンプレッサー圧力は、ゲージ圧である。
Experimental conditions:
Refrigeration equipment: manufactured by Liebherr (Germany: model name GS-360)
Freezer internal volume: 300 liters Outside temperature: 27.3-32.5 ° C
Filling refrigerant total amount (standard equipment): 165g
Heat exchange is performed between the high-pressure refrigerant from the condenser to the capillary and the low-pressure refrigerant from the evaporator to the compressor, and the copper pipes through which each refrigerant is used are joined by side by side by brazing. did.
The heat exchanger having this structure is conventionally used in a small scale in order to improve the condensation efficiency in the refrigeration apparatus. In the present invention, the heat exchanger is used as about 2 m in order to achieve the heat exchange conditions of the refrigeration system. .
The compressor pressure is a gauge pressure.

以上のシステム構成により、R−23及びとR−116に対してイソブタンを加えた非共沸混合冷媒の特性を確認した。これらの非共沸混合冷媒の特性を確認するため、まずイソブタン単体の冷媒により実機運転を行い、そのデータに基づいてR−23及びR−116との非共沸混合冷媒の特性を確認する。
なお、R−23及びR−116はそれぞれ臨界温度25.9℃及び19.7℃であって、冷媒の特性上室温環境下では使用できないので、イソブタンを冷媒として冷凍装置を運転し、順次これらの低沸点冷媒を添加・増量して混合冷媒としての特性を確認した。
With the above system configuration, the characteristics of the non-azeotropic refrigerant mixture in which isobutane was added to R-23 and R-116 were confirmed. In order to confirm the characteristics of these non-azeotropic refrigerant mixtures, first, actual operation is performed with a refrigerant of isobutane alone, and the characteristics of the non-azeotropic refrigerant mixture with R-23 and R-116 are confirmed based on the data.
Since R-23 and R-116 have critical temperatures of 25.9 ° C. and 19.7 ° C., respectively, and cannot be used in a room temperature environment due to the characteristics of the refrigerant, the refrigeration apparatus is operated using isobutane as the refrigerant, The characteristics of a mixed refrigerant were confirmed by adding and increasing the low boiling point refrigerant.

(1)上記冷凍装置システムによるイソブタン単体冷媒の特性。
イソブタン充填量と実機運転による結果を表−2及び図−2に示す。
なお、表中コンプレッサー圧力の「高圧」はコンプレッサー吐出圧、「低圧」はコンプレッサー吸入口における圧力で、「−」は大気圧よりも低いゲージ圧となっていることを示す(以下、各表において同じ。)。
また、コンプレッサー入口温度は、熱交換器を経てコンプレッサーに吸引される冷媒配管の温度で測定しているため、コンプレッサーからの熱伝導により若干温度が上昇しており、配管内を通る冷媒の温度よりも数℃以上高めと考えられる。さらに、キャピラリー入口温度も熱交換器を経てキャピラリー(絞り弁)に送られる冷媒の通る配管の温度であるため、熱交換器とキャピラリーの双方からの伝熱の影響があるが、熱交換器からの影響が大きく、冷媒温度よりも若干高めに表れると思われる。
(1) Characteristics of isobutane simple substance refrigerant by the refrigeration system.
Table 2 and Fig. 2 show the results of isobutane loading and actual machine operation.
In the table, the compressor pressure “High” indicates the compressor discharge pressure, “Low pressure” indicates the pressure at the compressor inlet, and “−” indicates that the gauge pressure is lower than the atmospheric pressure. the same.).
In addition, the compressor inlet temperature is measured by the temperature of the refrigerant pipe sucked into the compressor through the heat exchanger. Is considered to be higher than several degrees Celsius. Furthermore, the capillary inlet temperature is also the temperature of the piping through which the refrigerant sent to the capillary (throttle valve) passes through the heat exchanger, so there is an influence of heat transfer from both the heat exchanger and the capillary, but from the heat exchanger It seems that the effect is slightly higher than the refrigerant temperature.

Figure 0005009530
Figure 0005009530

図−2において、充填量40g近傍で庫内温度−30℃でほぼ一定となり、圧力も吐出圧(高圧)及びコンプレッサー吸引側(低圧)側共に安定した状態となる。このことから、実機運転における最低充填容量は、ほぼ40g以上とみられるが、コンプレッサー吸引側で負圧となり、イソブタンの標準沸点−11.7℃よりも低い庫内温度を達成している。
イソブタンの充填量がさらに増加して、120gを越えると却って庫内温度が上昇し、同時にコンプレッサー吐出圧の低下と吸入圧の上昇が連動する。
このとき、備考に摘記したように熱交換器の著しい温度低下を生じており、エバポレータで気化しきれない状態となって、コンプレッサー吸入側で気化して吸入圧の上昇を生じ、またコンデンサーでの凝縮促進のため吐出圧が低下するものと思われる。
これらの結果から、実機運転の条件において、最低充填容量40gであって、充填量120gで冷却能力上充填量が飽和、すなわち冷却能力に余裕が生じると考えられる。
以上の結果から、R−23の凝縮にはこの余剰の冷却能力を利用するため、イソブタン100gからR−23との混合比率を確認する。
In FIG. 2, the inside temperature is approximately −30 ° C. near the filling amount of 40 g, and the pressure is stable on both the discharge pressure (high pressure) side and the compressor suction side (low pressure) side. From this, the minimum charging capacity in actual machine operation seems to be approximately 40 g or more, but the negative pressure is obtained on the compressor suction side, and the internal temperature lower than the normal boiling point of isobutane of −11.7 ° C. is achieved.
When the filling amount of isobutane further increases and exceeds 120 g, the internal temperature rises, and at the same time, the decrease in the compressor discharge pressure and the increase in the suction pressure are linked.
At this time, as noted in the remarks, the temperature of the heat exchanger has dropped significantly, and the evaporator cannot be completely vaporized, vaporizing on the compressor suction side, increasing the suction pressure, and in the condenser It is thought that the discharge pressure decreases due to the acceleration of condensation.
From these results, it is considered that under the conditions of actual machine operation, the minimum filling capacity is 40 g and the filling amount is saturated with a filling amount of 120 g, that is, there is a margin in the cooling capacity.
From the above results, in order to utilize this excess cooling capacity for the condensation of R-23, the mixing ratio of 100 g of isobutane to R-23 is confirmed.

(2)R−23とイソブタンとの非共沸混合冷媒の特性
そこで、イソブタン充填量100gを基準として、R−23を10g刻みで添加した効果を表−3に示す。
(2) Characteristics of non-azeotropic refrigerant mixture of R-23 and isobutane Therefore, Table 3 shows the effect of adding R-23 in increments of 10 g with an isobutane filling amount of 100 g as a reference.

Figure 0005009530
Figure 0005009530

これらの結果を図−3に示す。
R−23の添加による効果は、添加量増加と共に表れ、R-23:30wt%近傍で−65℃に達し、ほぼ−65℃近傍で一定となる。
それ以上は充填量の増加に伴なって、60%近傍まで庫内温度など温度条件はほぼ一定であるが、圧力が若干上昇気味であり、特に低圧側の圧力上昇が見られるのは、冷媒充填量の増加によるものと考えられ、冷凍システムは稼動するが、R−23充填量を増す効果はほぼ飽和し、他方イソブタンの冷却能力の不足があると考えられる。
なお、これらの現象と共にコンプレッサーの吐出圧力の上昇と熱交換後のキャピラリ入口温度の低下が見られ、R−23の増加により凝縮温度の低下とその凝縮のための圧力上昇が連動していることがわかる。
そこでこれらの混合冷媒の冷却効果は、室温環境で凝縮するイソブタンの熱交換作用によることから、イソブタンの冷却効果を確認するため、R−23含有量を最大限の150g一定とし、さらにイソブタンの含有量を100g以上で増加してその効果を確認した。その条件及び結果を表−4及び図−4に示す。
These results are shown in FIG.
The effect of the addition of R-23 appears with an increase in the amount of addition, and reaches R65: -65 ° C in the vicinity of 30 wt%, and becomes constant in the vicinity of -65 ° C.
Above that, the temperature condition such as the internal temperature is almost constant up to around 60% as the filling amount increases, but the pressure seems to rise slightly, and especially the pressure increase on the low pressure side is seen in the refrigerant The refrigeration system is considered to be due to an increase in the filling amount, but the effect of increasing the R-23 filling amount is almost saturated, while it is thought that there is a lack of cooling capacity for isobutane.
Along with these phenomena, an increase in the discharge pressure of the compressor and a decrease in the capillary inlet temperature after heat exchange are observed, and an increase in R-23 is linked to a decrease in the condensation temperature and an increase in pressure for the condensation. I understand.
Therefore, since the cooling effect of these mixed refrigerants is due to the heat exchange action of isobutane condensed in a room temperature environment, in order to confirm the cooling effect of isobutane, the R-23 content is made constant at a maximum of 150 g, and the isobutane content is further increased. The effect was confirmed by increasing the amount above 100 g. The conditions and results are shown in Table-4 and FIG.

Figure 0005009530
Figure 0005009530

図−4に示すとおり、イソブタンの増加は庫内温度を低下するがその効果は小さく、むしろ熱交換によるコンプレッサー入口温度、キャピラリー入口温度の低下が著しい。
すなわち、イソブタンの冷却容量は充分にあるが、庫内温度を低下させる低沸点冷媒であるR−23の凝縮に活かされないこと、総充填量から見ても限界である、ということができる。
そこで、この非共沸冷媒の能力を見極めるため、イソブタン含有量を先に最低庫内温度となった60wt%として、最適総充填量を確認した。
その結果を表−5及び図−5に示す。
As shown in FIG. 4, an increase in isobutane lowers the internal temperature, but its effect is small. Rather, the compressor inlet temperature and capillary inlet temperature are significantly reduced due to heat exchange.
That is, although the cooling capacity of isobutane is sufficient, it can be said that it is not utilized for the condensation of R-23, which is a low-boiling point refrigerant that lowers the internal temperature, and that it is a limit from the viewpoint of the total filling amount.
Therefore, in order to determine the capability of this non-azeotropic refrigerant, the optimum total filling amount was confirmed by setting the isobutane content to 60 wt%, which was the lowest internal temperature.
The results are shown in Table-5 and FIG.

Figure 0005009530
Figure 0005009530

表−5及び図−5から、イソブタン60wt%近傍で最も低い庫内温度を達成でき、また総充填量にはかなりの許容幅があることから、これらの条件を実機の容量に合わせる上で有利であることがわかる。
以上の結果から、R−23とイソブタンの非共沸混合冷媒は、上記の冷凍システムに適しており、広い組成範囲においてこの冷凍装置システムを稼動可能であることがわかる。
実機運転であるため、個別の装置固有の性能や熱交換器の能力、冷媒充填量などにより左右されるが、上記の結果から一般的に好適な組成範囲は、R−23に対してイソブタンは広い比率の組成範囲で適用可能であって、超低温度用冷媒としてイソブタン40wt%からほぼ80wt%までが実用範囲と考えられる。
又、以上の実験結果から、R−23・イソブタン系非共沸冷媒の特性は、先に確認されたR−23・ノルマルブタン系非共沸冷媒と比較してなんら遜色はなく、意外なことに前述した標準沸点がノルマルブタンより低く、蒸気圧が高いことによる支障はなく、むしろ沸点の低いことが冷却効果において有利に作用していることがわかった。
From Table-5 and Fig.5, the lowest internal temperature can be achieved in the vicinity of 60% by weight of isobutane, and the total filling amount has a considerable tolerance, so it is advantageous for adjusting these conditions to the actual capacity. It can be seen that it is.
From the above results, it can be seen that the non-azeotropic refrigerant mixture of R-23 and isobutane is suitable for the above refrigeration system and can operate the refrigeration system in a wide composition range.
Because it is an actual machine operation, it depends on the performance unique to each device, the capacity of the heat exchanger, the refrigerant charge amount, etc., but from the above results, the generally preferred composition range is that of isobutane relative to R-23. The composition can be applied in a wide range of composition, and the practical range is from 40 wt% to 80 wt% of isobutane as an ultra-low temperature refrigerant.
From the above experimental results, the characteristics of the R-23 / isobutane non-azeotropic refrigerant are not inferior to the R-23 / normal butane non-azeotropic refrigerant previously confirmed, and are surprising. In addition, it was found that the above-mentioned normal boiling point is lower than that of normal butane and there is no problem due to the high vapor pressure, but rather the low boiling point has an advantageous effect on the cooling effect.

(3)R−116とイソブタンとの非共沸混合冷媒の特性
R−116に対するイソブタン添加の効果を確認するため、イソブタン(100g)に対してR−116を10g刻みで順次添加した結果を表−6及び図−6に示す。
(3) Characteristics of non-azeotropic refrigerant mixture of R-116 and isobutane In order to confirm the effect of addition of isobutane to R-116, the results of sequentially adding R-116 in increments of 10 g to isobutane (100 g) It is shown in -6 and Fig.-6.

Figure 0005009530
Figure 0005009530

図から明らかなように、R−116とイソブタンの組み合わせにおいても、R−23とイソブタンとの混合冷媒とほぼ同様な傾向を有するが、コンプレッサー吐出圧は、R−23の場合に比較してR−116ではかなり低い。
庫内温度は、R−116が20wt%(充填量:130g)近傍でー60℃近傍に達し、R−116が50wt%(充填量:200g)、庫内温度−65℃程度まで安定して低下するが、それ以上では不安定となり、庫内温度低下効果も飽和する傾向にある。
そこで、イソブタン130gにR−116を漸次増量して加えて実験した結果を表−7及び図7に示す。
As is apparent from the figure, the combination of R-116 and isobutane also has a tendency similar to that of the mixed refrigerant of R-23 and isobutane, but the compressor discharge pressure is R compared with that of R-23. At -116 it is quite low.
The temperature inside the chamber reaches about −60 ° C. when R-116 is about 20 wt% (filling amount: 130 g), and is stable until the temperature inside the chamber is about 50 wt% (filling amount: 200 g) and the temperature inside the chamber is about −65 ° C. Although it decreases, it becomes unstable above that, and the effect of lowering the internal temperature tends to be saturated.
Accordingly, Table 7 and FIG. 7 show the results of experiments in which R-116 was gradually increased in amount to 130 g of isobutane.

Figure 0005009530
Figure 0005009530

図−7に示すように、R−116:10wt%から増加するに従って庫内温度が低下し、
その効果が表れるが、30wt%近傍で(イソブタン70wt%)のその効果が低下し、むしろR−116の増量に伴なう吐出圧の上昇とこれに対するキャピラリー入口温度の低下などからイソブタン:70wt%近傍でイソブタンによる冷却効果は飽和しているものと考えられる。
そこで、イソブタンの冷却容量を若干見込んでR-116:30wt%(イソブタン70wt%)とした冷媒の総充填量の変化と効果を以下に確認した。(表−8及び図−8)
As shown in Fig.7, the internal temperature decreases as R-116 increases from 10 wt%,
The effect appears, but the effect of isobutane decreases in the vicinity of 30 wt% (isobutane 70 wt%). Rather, the increase in the discharge pressure accompanying the increase in R-116 and the decrease in the capillary inlet temperature with respect to this, isobutane: 70 wt% The cooling effect by isobutane is considered to be saturated in the vicinity.
Therefore, the change and effect of the total charge amount of the refrigerant with R-116: 30 wt% (isobutane 70 wt%) with some expectation of the cooling capacity of isobutane were confirmed below. (Table-8 and Figure-8)

Figure 0005009530
Figure 0005009530

表−8及び図−8から、冷媒総充填量の140g以上の増加は、あまり庫内温度降下に寄与していない。むしろ、R−116との組み合わせにおいては、コンプレッサーの吐出圧を低く抑制することに特徴が見られる。
一方、冷媒の総充填量と庫内温度との関係では、これらのほぼ全域においてフラットな特性を有しており、図−6に表されるイソブタン50〜80wt%の範囲において幅広く安定した冷媒特性を発揮し、安定して−50℃以下の超低温度を維持できる事と相俟って、冷媒として優れた特性を有することが解る。
以上から、R−116とイソブタン混合冷媒においては、上記の冷凍システムに適用するイソブタン含有量の実用範囲は、50〜80wt%ということができる。
また、R−116とイソブタン系非共沸混合冷媒においても、室温環境で稼動する上でイソブタンの低沸点沸点及び高い蒸気圧による支障は見られず、ノルマルブタンに劣らない優れた添加成分であることがわかった。
From Table-8 and FIG.-8, the increase of 140 g or more of the refrigerant total charge amount does not contribute much to the temperature drop in the refrigerator. Rather, the combination with R-116 is characterized by suppressing the discharge pressure of the compressor low.
On the other hand, the relationship between the total charging amount of the refrigerant and the internal temperature has a flat characteristic in almost all of these areas, and a wide and stable refrigerant characteristic in the range of 50 to 80 wt% of isobutane shown in FIG. In combination with the fact that it can stably maintain an ultra-low temperature of −50 ° C. or less, it is understood that it has excellent characteristics as a refrigerant.
From the above, in the R-116 and isobutane mixed refrigerant, the practical range of the isobutane content applied to the refrigeration system can be said to be 50 to 80 wt%.
In addition, R-116 and isobutane-based non-azeotropic mixed refrigerants are excellent additive components that are not inferior to normal butane, and are not affected by the low boiling point and high vapor pressure of isobutane when operating in a room temperature environment. I understood it.

本発明の非共沸混合冷媒は、上記した室温環境下で運転可能な単純なシステムからなる冷凍装置によって容易に−50℃以下の超低温度を達成することができ、医療用や食品用を始めとする多くの用途に対して実用的な冷凍装置を提供することができる。
これらの用途は、バイオ医療を始めとして著しい発展を遂げており、これらの需要に対して容易に且つ適切に応えることができる。
The non-azeotropic refrigerant mixture of the present invention can easily achieve an ultra-low temperature of −50 ° C. or less by a refrigeration apparatus composed of a simple system that can be operated in a room temperature environment as described above. A practical refrigeration apparatus can be provided for many uses.
These applications have undergone remarkable development including biomedical medicine, and can easily and appropriately meet these demands.

本発明を適用する冷凍装置システム模式図。1 is a schematic diagram of a refrigeration system to which the present invention is applied. イソブタン単体による冷媒の特性。Characteristics of refrigerant by isobutane alone. イソブタン100gに対するR−23添加の効果。Effect of R-23 addition on 100 g of isobutane. R−23:150gに対するイソブタン添加量を120〜160gに増加した効果。R-23: The effect of increasing the amount of isobutane added to 120 to 160 g with respect to 150 g. イソブタン:60wt%R−23系混合冷媒の充填量と冷却効果。Isobutane: 60 wt% R-23 mixed refrigerant charge amount and cooling effect. イソブタン100gに対してR-116を添加した効果。Effect of adding R-116 to 100 g of isobutane. イソブタン:130gに対してR−116を添加した効果。Effect of adding R-116 to 130 g of isobutane. イソブタン:70wt%R−116系混合冷媒の充填量と冷却効果。Isobutane: filling amount of 70 wt% R-116 mixed refrigerant and cooling effect.

符号の説明Explanation of symbols

1 コンプレッサー
2 凝縮器(コンデンサー)
3 ファン
4 熱交換器
5 キャピラリーチュ
6 蒸発器(エバポレーター)
7 冷凍庫
10 温度、圧力センサー
11、12、15、16、17 温度センサー
20 ドライヤー
1 Compressor 2 Condenser
3 Fan 4 Heat exchanger 5 Capillary tube 6 Evaporator
7 Freezer 10 Temperature, pressure sensor 11, 12, 15, 16, 17 Temperature sensor 20 Dryer

Claims (2)

コンプレッサー、凝縮器、キャピラリー(絞り弁)、及び蒸発器からなる冷凍装置において、凝縮器からキャピラリーに至る冷媒と蒸発器からコンプレッサーにいたる冷媒との間で該熱交換を行い、
該熱交換によって、キャピラリーに至る冷媒の凝縮過程を冷媒状態図の液相線以下、コンプレッサーに至る冷媒の気化過程を気相線以上で作動するシステム構成とするための、室温で冷凍装置を作動可能な高沸点冷媒とー50℃以下の低温度を達成する低沸点冷媒とを組み合わせてなる非共沸混合冷媒において、
上記高沸点冷媒がイソブタン、上記低沸点冷媒がR−23であって、それらの比率がそれぞれイソブタンが40〜60wt%、R−23が残部であることを特徴とする、
超低温用非共沸混合冷媒。
In a refrigeration system comprising a compressor, a condenser, a capillary (throttle valve), and an evaporator, the heat exchange is performed between the refrigerant from the condenser to the capillary and the refrigerant from the evaporator to the compressor,
By this heat exchange, the refrigeration system is operated at room temperature so that the condensation process of the refrigerant reaching the capillaries is configured to operate below the liquidus in the refrigerant phase diagram and the vaporization process of the refrigerant reaching the compressor above the gas phase line. In a non-azeotropic refrigerant mixture comprising a combination of a possible high boiling point refrigerant and a low boiling point refrigerant that achieves a low temperature of −50 ° C. or lower,
The high-boiling refrigerant is isobutane, the low boiling point refrigerant is a R-23, their ratio isobutane 40~60Wt% respectively, and wherein the this R-23 is the balance,
Non-azeotropic refrigerant mixture for ultra-low temperatures.
コンプレッサー、凝縮器、キャピラリー(絞り弁)、及び蒸発器からなる冷凍装置において、凝縮器からキャピラリーに至る冷媒と蒸発器からコンプレッサーにいたる冷媒との間で該熱交換を行い、
該熱交換によって、キャピラリーに至る冷媒の凝縮過程を冷媒状態図の液相線以下、コンプレッサーに至る冷媒の気化過程を気相線以上で作動するシステム構成とするための、室温で冷凍装置を作動可能な高沸点冷媒とー50℃以下の低温度を達成する低沸点冷媒とを組み合わせてなる非共沸混合冷媒において、
上記高沸点冷媒がイソブタン、上記低沸点冷媒がR−116であって、それらの比率がそれぞれイソブタンが50〜80wt%、R−116が残部であることを特徴とする、
超低温用非共沸混合冷媒。
In a refrigeration system comprising a compressor, a condenser, a capillary (throttle valve), and an evaporator, the heat exchange is performed between the refrigerant from the condenser to the capillary and the refrigerant from the evaporator to the compressor,
By this heat exchange, the refrigeration system is operated at room temperature so that the condensation process of the refrigerant reaching the capillaries is configured to operate below the liquidus in the refrigerant phase diagram and the vaporization process of the refrigerant reaching the compressor above the gas phase line. In a non-azeotropic refrigerant mixture comprising a combination of a possible high boiling point refrigerant and a low boiling point refrigerant that achieves a low temperature of −50 ° C. or lower,
The high boiling point refrigerant is isobutane, the low boiling point refrigerant is R-116, and the ratio thereof is 50 to 80 wt% of isobutane and R-116 is the balance ,
Non-azeotropic refrigerant mixture for ultra-low temperatures.
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WO2014156190A1 (en) 2013-03-29 2014-10-02 パナソニックヘルスケア株式会社 Dual refrigeration device

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KR102409357B1 (en) * 2022-02-08 2022-06-16 유니셈(주) Cryogenic cooling device based on mixed refrigerant

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US5049296A (en) * 1989-01-28 1991-09-17 Chujun Gu Working media for a thermodynamic engineering device operating in accordance with the Gu thermodynamic cycle

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014156190A1 (en) 2013-03-29 2014-10-02 パナソニックヘルスケア株式会社 Dual refrigeration device
US10731898B2 (en) 2013-03-29 2020-08-04 Phc Holdings Corporation Binary refrigerating apparatus

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