JP2012042088A - Refrigerating apparatus using triple-tube type heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerating apparatus using a triple-tube type heat exchanger that can improve refrigerating capacity by supercooling of a high pressure liquid refrigerant.SOLUTION: The refrigerating apparatus includes a refrigerant circulating circuit of closed loop formed by series-connecting at least a compressor 1, a capacitor 2, the triple-tube type heat exchanger 3, an expansion valve (a pressure reducer) 4, a gas-liquid separator 5 and an evaporator 6 by refrigerant piping L1-L6. The refrigerant apparatus is constituted to allow a liquid refrigerant flowing toward the expansion valve 4 from the capacitor 2, to pass through a first outer passage of the triple-tube type heat exchanger 3, to allow a gas refrigerant separated by the gas-liquid separator 5, to pass through an inner passage of the triple-tube type heat exchanger 3 from refrigerant piping L9, to allow a gas refrigerant evaporated by the evaporator 6, to pass through a second outer passage of the triple-tube type heat exchanger 3 from the refrigerant piping L5 and to allow the gas refrigerant having passed through the second outer passage and the gas refrigerant having passed through the inner passage, to join in the refrigerant piping L6, L10 to be introduced into the compressor 1.

Description

  The present invention relates to a refrigeration apparatus that is a triple-pipe heat exchanger that exchanges heat between fluids flowing through three independent flow paths, and that supercools liquid refrigerant condensed by a condenser to increase the refrigeration capacity. .

  In general, a refrigeration system connects a compressor, a condenser, a decompressor, and an evaporator in series by a refrigerant pipe to form a closed-loop refrigerant circulation circuit. The high-pressure gas refrigerant compressed by the compressor is radiated by heat dissipation in the condenser. The liquid refrigerant is liquefied, and the high-pressure liquid refrigerant is expanded by a decompressor such as an expansion valve to reduce the pressure. Then, the low-pressure liquid refrigerant having a lowered boiling point is evaporated in an evaporator, and the latent heat of vaporization at this time is The inside of the cabinet is cooled by taking it away.

  As a method for improving the refrigeration capacity or coefficient of performance (COP) of such a refrigeration apparatus, for example, in Patent Document 1, a gas-liquid heat exchanger is provided, and a high-pressure liquid refrigerant liquefied by a condenser and a part thereof are extracted and decompressed. There has been proposed a method of supercooling the high-pressure liquid refrigerant by exchanging heat with the low-pressure gas refrigerant.

  In Patent Document 2, a gas-liquid heat exchanger (auxiliary heat exchanger) and a gas-liquid separator are provided, and the high-pressure liquid refrigerant liquefied by the condenser and the low-pressure gas refrigerant separated in the gas-liquid separator are gas-liquid. A method of supercooling the high-pressure liquid refrigerant by exchanging heat in a heat exchanger has been proposed.

Japanese Utility Model Publication No. 1-167972 Japanese Patent Laid-Open No. 11-014167

  However, in the method proposed in Patent Document 1, since the gas refrigerant sucked into the compressor is overheated and the discharge temperature of the compressor rises, a part of the high-pressure liquid refrigerant liquefied by the condenser is extracted and injected into the gas refrigerant. However, it is necessary to lower the discharge temperature of the compressor. Then, when a portion of the high-pressure liquid refrigerant liquefied by the condenser is extracted and injection is performed, there is a problem that the refrigerating capacity is lowered because the refrigerant circulation amount in the evaporator is reduced.

  Further, in the method proposed in Patent Document 2, the low-temperature and low-pressure gas refrigerant separated in the gas-liquid separator bypasses the evaporator and flows into the compressor. Separation performance of the separator deteriorates, a liquid back phenomenon occurs in which part of the liquid refrigerant is sucked into the compressor, and problems such as an increase in the load on the compressor occur.

  The present invention has been made in view of the above problems, and the object of the present invention is to improve the refrigeration capacity by supercooling the high-pressure liquid refrigerant and prevent the occurrence of liquid back due to the inflow of the liquid refrigerant into the compressor. An object of the present invention is to provide a refrigeration apparatus that can perform the above.

In order to achieve the above object, the invention described in claim 1 includes at least a compressor, a condenser, a triple-pipe heat exchanger, a decompressor, a gas-liquid separator, and an evaporator connected in series by a refrigerant pipe. A refrigeration system comprising a closed-loop refrigerant circulation circuit,
The liquid refrigerant traveling from the condenser to the decompressor is passed through the first outer flow path of the triple tube heat exchanger, and the gas refrigerant separated by the gas-liquid separator is disposed inside the triple tube heat exchanger. The gas refrigerant passed through the flow path and evaporated by the evaporator is allowed to pass through the second outer flow path of the triple tube heat exchanger, and the gas refrigerant and the inner flow path that have passed through the second outer flow path. The gas refrigerant that has passed through is combined and introduced into the compressor.

  Invention of Claim 2 set the cross-sectional area of the inner side flow path of the said triple tube type heat exchanger smaller than each cross-sectional area of the 1st and 2nd outer side flow path in invention of Claim 1 in invention. It is characterized by.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, a part of the liquid refrigerant from the condenser to the pressure reducer is separated from the gas-liquid separator and the inner passage of the triple tube heat exchanger. It is characterized in that it is injected into a refrigerant pipe connecting the.

  According to the first aspect of the present invention, the high-pressure liquid refrigerant that is liquefied by condensation in the condenser and goes to the decompressor passes through the first outer flow path of the triple-pipe heat exchanger in the course of passing through the inner flow path. Is efficiently subcooled by heat exchange between the gas refrigerant passing through the gas refrigerant (gas refrigerant separated by the gas-liquid separator) and the gas refrigerant passing through the second outer flow path (gas refrigerant evaporated by the evaporator), The latent heat of vaporization in the evaporator is increased by the amount of heat of the supercooling, and the refrigeration capacity and coefficient of performance (COP) of the refrigeration apparatus are increased.

  According to the second aspect of the present invention, since the cross-sectional area of the inner flow path of the triple-pipe heat exchanger is set smaller than the cross-sectional areas of the first and second outer flow paths, gas-liquid separation is caused by load fluctuations and the like. Even if liquid refrigerant flows into the inner flow path of the triple-pipe heat exchanger from the vessel, the liquid refrigerant evaporates by heat exchange with the high-pressure liquid refrigerant flowing in the first outer flow path. Occurrence of liquid back due to inflow of water is prevented.

  According to the invention of claim 3, the temperature rise of the gas refrigerant (gas refrigerant separated by the gas-liquid separator and passing through the inner passage) used for supercooling of the high-pressure liquid refrigerant in the triple pipe heat exchanger Is cooled by the evaporation of the liquid refrigerant injected into the refrigerant pipe connecting the gas-liquid separator and the inner passage of the triple-pipe heat exchanger, so that the compressor can be controlled without affecting the temperature control of the decompressor. An increase in the temperature of the sucked gas refrigerant can be suppressed. For this reason, an increase in the discharge temperature of the compressor is suppressed, and deterioration of the oil in the compressor is prevented. Note that the amount of refrigerant circulating in the evaporator is reduced by the amount of liquid refrigerant that is injected, but the decrease in refrigeration capacity that accompanies this decrease in refrigerant circulation is the effective excess of high-pressure liquid refrigerant in the triple-pipe heat exchanger. Compensated by cooling.

It is a refrigerant circuit figure of the refrigerating device concerning the present invention. It is a connection diagram of the triple pipe heat exchanger of the refrigeration apparatus according to the present invention. FIG. 3 is a sectional view taken along line XX in FIG. 2. It is a Mollier diagram which shows the state change of the refrigerant | coolant in the freezing apparatus which concerns on this invention. It is a figure which shows the gas-liquid heat exchange amount with respect to the refrigerant | coolant flow rate of the triple pipe type heat exchanger of the freezing apparatus which concerns on this invention compared with that of the conventional helical heat exchanger.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a refrigerant circuit diagram of a refrigeration apparatus according to the present invention, FIG. 2 is a connection diagram of a triple-pipe heat exchanger of the refrigeration apparatus, and FIG. 3 is a sectional view taken along line XX of FIG.

  As shown in FIG. 1, the refrigeration apparatus according to the present invention basically includes a compressor 1, a condenser 2, a triple pipe heat exchanger 3, an expansion valve 4 as a decompressor, a gas-liquid separator 5, an evaporator 6, and the like. Main devices are connected by refrigerant pipes L1, L2, L3, L4, L5, and L6.

  And the refrigerant | coolant piping L1 connects the discharge side of the compressor 1, and the inlet side of the capacitor | condenser 2, The oil separator 7 and the electromagnetic on-off valve V1 are connected to this refrigerant | coolant piping L1. A receiver tank 8, a dryer (D) 9 and a sight glass (SG) 10 are connected to a refrigerant pipe L 2 extending from the outlet side of the condenser 2 and connected to the inlet side of the triple-pipe heat exchanger 3. ing. Furthermore, the expansion valve 4 is provided in the refrigerant pipe L3 connecting the outlet side of the triple-pipe heat exchanger 3 and the gas-liquid separator 5, and the refrigerant pipe L5 extending from the outlet side of the evaporator 6 is a triple pipe. An intake pressure adjusting valve (ZSP valve) V2 and an accumulator 11 are connected to a refrigerant pipe L6 that is connected to the heat exchanger 3 and extends from the triple pipe heat exchanger 3 to the suction side of the compressor 1. .

  An oil return pipe L7 extending from the oil separator 7 is connected between the suction pressure adjusting valve V2 of the refrigerant pipe L6 and the accumulator 11, and an oil cooler 12 is provided in the middle thereof.

  An injection pipe L8 branches from between the sight glass 10 of the refrigerant pipe L2 and the triple pipe heat exchanger 3, and this injection pipe L8 extends from the upper part of the gas-liquid separator 5 and is triple pipe type. Connected in the middle of the refrigerant pipe L9 connected to the heat exchanger 3, an electromagnetic on-off valve V3 and a capillary tube 13 for flow rate adjustment are provided in the middle of the refrigerant pipe L8. The refrigerant pipe L10 extending from the triple pipe heat exchanger 3 is connected to a portion of the refrigerant pipe L6 immediately after exiting from the triple pipe heat exchanger 3.

  Here, the structure of the triple-pipe heat exchanger 3 and the connection structure of the refrigerant pipes L2, L3, L5, L6, L9, and L10 to this will be described with reference to FIGS.

  As shown in FIG. 3, the triple-pipe heat exchanger 3 has a circular radial cross section (a petal shape) in the circumferential direction on the outer periphery of a circular tubular first tube 14 arranged in the center in the direction perpendicular to the paper surface of FIG. A second tube 15 formed by continuously deforming the tube wall into an uneven shape is disposed, and a large-diameter circular tubular third tube 16 is disposed on the outer periphery of the second tube 15. An inner flow path S 1 is formed inside the first pipe 14, a first outer flow path S 2 is formed inside the second pipe 15, and the gap between the second pipe 15 and the third pipe 16 is formed. A second outer flow path S3 is formed in the space. Here, in the present embodiment, the cross-sectional area of the inner flow path S1 is set smaller than the cross-sectional areas of the first and second outer flow paths S2 and S3.

  Thus, as shown in FIG. 2, the refrigerant pipe L2 extending from the condenser 2 (see FIG. 1) is connected to the inlet of the first outer flow path S2 (see FIG. 3) of the triple pipe heat exchanger 3. The refrigerant pipe L3 extending from the outlet of the first outer flow path S2 is connected to the gas-liquid separator 5, and the expansion valve 4 is provided in the middle thereof. The refrigerant pipe L5 extending from the evaporator 6 is connected to the inlet of the second outer flow path S3 (see FIG. 3) of the triple pipe heat exchanger 3, and the compressor 1 is connected to the outlet of the second outer flow path S3. A refrigerant pipe L6 connected to (see FIG. 1) is connected.

  Further, the refrigerant pipe L9 extending from the gas-liquid separator 5 is connected to the inlet of the inner flow path S1 (see FIG. 3) of the triple pipe heat exchanger 3, and an injection pipe L8 branched from the refrigerant pipe L2 in the middle thereof. Are connected, and the electromagnetic on-off valve V3 and the capillary tube 13 for flow rate adjustment are provided in the middle of the injection pipe L8. And the refrigerant | coolant piping L10 extended from the exit of inner side flow path S1 is connected to the refrigerant | coolant piping L6 extended from the exit of 2nd outer side flow path S3.

  Next, the operation of the refrigeration apparatus configured as described above will be described below with reference to the Mollier diagram (Pi diagram) shown in FIG.

When the compressor 1 is driven by an unillustrated engine or the like as a drive source, the gas refrigerant in the state (pressure P ₁ , enthalpy i ₁ ) shown in FIG. 4A is compressed by the compressor 1 and b in FIG. (Pressure P ₂ , enthalpy i ₂ ) in a high-temperature and high-pressure gas refrigerant (compression stroke), and this gas refrigerant is introduced into the capacitor 2 through the refrigerant pipe L1. Note that the compression power W (in terms of heat) of the compressor 1 at this time is represented by (i ₂ −i ₁ ).

In the capacitor 2, liquefied high-temperature high-pressure gas refrigerant is changed state (phase change) to b → c in FIG. 4 by releasing heat of condensation Q ₂ to the outside air (condensation stroke), indicated by c in FIG. 4 It becomes a high-pressure liquid refrigerant in a state (pressure P ₂ , enthalpy i ₃ ). Incidentally, the heat radiation amount of time (condensation heat) _{Q 2} is represented by _(i 2 -i _3).

A part of the high-pressure liquid refrigerant liquefied in the capacitor 2 as described above is injected into the refrigerant pipe L9 through the injection pipe L8, but this liquid refrigerant is decompressed by passing through the capillary tube 13. Adiabatic expansion (equal enthalpy expansion) results in the state indicated by d in FIG. 4 (pressure P ₁ , enthalpy i ₃ ), part of which is gasified and separated in the gas-liquid separator 5 as described later. The refrigerant pipe L9 joins the low-pressure gas refrigerant in the state d ′ (pressure P ₁ , enthalpy i ₃ ′) in FIG. 4 flowing in the direction of the arrow in FIG.

On the other hand, most of the other high-pressure liquid refrigerant flows from the refrigerant pipe L2 to the triple pipe heat exchanger 3, and the first outer flow path S2 (see FIG. 3) of the triple pipe heat exchanger 3 is shown in FIG. In the process of flowing in the direction of the arrow, the inner flow path of the triple-pipe heat exchanger 3 is joined with the low-pressure liquid refrigerant (partially gasified) that flows through the refrigerant pipe L9 and is injected from the injection pipe L8 on the way. S1 (see FIG. 3) is vaporized by the low pressure gas refrigerant flowing in the direction of the arrow in FIG. 2 and evaporation in the evaporator 6, and the second outer flow path S3 of the triple heat exchanger 3 from the refrigerant pipe L5 (see FIG. 3). ) In the state a ′ (pressure P ₁ , enthalpy i ₁ ′) in FIG. 4 flowing in the direction of the arrow in FIG. 2 is supercooled by heat exchange with the low pressure gas refrigerant. That is, the high-pressure liquid refrigerant heading from the condenser 2 toward the expansion valve 4 is supercooled by passing through the triple-pipe heat exchanger 3 and is in the state of c → c ′ in FIG. 4 (pressure P ₂ , enthalpy i ₃ ′). The state is changed to, and it is supercooled by ΔQ ₂ (= i ₃ −i ₃ ′) shown in the figure. In the triple-pipe heat exchanger 3, as indicated by an arrow in FIG. 2, the direction in which the high-pressure liquid refrigerant flows through the first outer flow path S2 and the inner flow paths S1 of the two low-pressure gas refrigerants The directions flowing through the second outer flow path S3 are opposite to each other (opposite flow).

Thus, the high-pressure liquid refrigerant supercooled in the triple-pipe heat exchanger 3 is reduced in pressure by passing through the expansion valve 4 and adiabatically expanded (isenthalpy expansion) (expansion stroke), and c ′ of FIG. → The state changes to the state of d ′ (pressure P ₁ , enthalpy i ₃ ′), and a part thereof is gasified. The partially gasified refrigerant is introduced into the gas-liquid separator 5 through the refrigerant pipe L3 to separate the gas and liquid, and the low-pressure gas refrigerant is discharged from the refrigerant pipe L9 as described above. In the middle of flowing toward the exchanger 3, the low-pressure liquid refrigerant (partially gasified) merged from the injection pipe L <b> 8 is merged, and the merged gas refrigerant flows inside the triple-pipe heat exchanger 3. In the process of flowing through the passage S1, the high-pressure liquid refrigerant flowing through the first outer passage S2 is used for supercooling. The low-pressure gas refrigerant that flows through the inner passage S1 of the triple-pipe heat exchanger 3 and is discharged to the refrigerant pipe L10 is a low-pressure gas refrigerant (evaporator 6) that flows through the refrigerant pipe L6 as shown in FIGS. Evaporated and joined to the low-pressure gas refrigerant used for supercooling the high-pressure liquid refrigerant in the triple-pipe heat exchanger 3.

Further, the low-pressure liquid refrigerant in the state d ′ (pressure P ₁ , enthalpy i ₃ ′) in FIG. 4 in the gas-liquid separator 5 is introduced into the evaporator 6 through the refrigerant pipe L 4 and passes through the evaporator 6. Then, the heat of evaporation Q ₁ is taken from the surroundings and the state changes from d ′ → a ′ (pressure P ₁ , enthalpy i ₁ ′) to evaporate (evaporation process) to become a gas refrigerant in the state a ′. The amount of heat of vaporization (latent heat of vaporization) Q _{1 at} this time is represented by (i ₁ ′ −i ₃ ′). As described above, the high-pressure liquid refrigerant is converted into ΔQ ₂ (= i ₃ − − in the gas-liquid heat exchanger 3. Since i ₃ ′) is supercooled, the amount of heat of evaporation Q ₁ is increased by the amount of heat ΔQ _{2 of the} supercooled portion, and the refrigerating capacity is increased by that amount.

Thereafter, the low-pressure gas refrigerant evaporated in the evaporator 6 is supplied to the triple-pipe heat exchanger 3 through the refrigerant pipe L5, and the second outer flow path S3 of the triple-pipe heat exchanger 3 as described above. In the process of flowing, the high-pressure liquid refrigerant flowing in the first outer flow path S2 is used for supercooling. The low-pressure gas refrigerant used for supercooling of the high-pressure liquid refrigerant in this way rises in temperature due to heat exchange with the high-pressure liquid refrigerant and the gas refrigerant from the refrigerant pipe L10, and is sucked into the compressor 1. At the stage, the state changes from a ′ → a (pressure P ₁ , enthalpy i ₁ ) shown in FIG. 4 and is heated by the illustrated amount of heat ΔQ ₁ (= i ₁ −i ₁ ′). This gas refrigerant is compressed again by the compressor 1 and thereafter the same state change (refrigeration cycle) as above is repeated. However, the oil contained in the high-pressure gas refrigerant discharged from the compressor 1 is The separated oil is separated from the refrigerant, and the separated oil is returned from the oil return pipe L6 to the refrigerant pipe L6, mixed with the gas refrigerant in the accumulator 11, sucked into the compressor 1, and used for lubrication of each part in the compressor 1. .

  Thus, in the refrigeration apparatus according to the present invention, the refrigeration cycle described above is repeated, and the required refrigeration is performed by the endothermic heat accompanying the evaporation of the low-pressure liquid refrigerant in the evaporator 6, but according to the refrigeration apparatus according to the present invention. The following effects can be obtained.

  That is, the high-pressure liquid refrigerant that is liquefied by condensation in the condenser 2 and travels toward the expansion valve 4 passes through the first outer flow path S2 of the triple pipe heat exchanger 3 and passes through the inner flow path S1. Refrigerant (gas refrigerant separated by the gas-liquid separator 5), low-pressure liquid refrigerant (partially gasified) injected from the injection pipe L8, and gas refrigerant (evaporator 6) passing through the second outer flow path S3 Therefore, the latent heat of vaporization in the evaporator 6 is increased by the amount of heat of the supercooling, and the refrigerating capacity and the coefficient of performance (COP) are increased. In the present embodiment, the pull-down time of the refrigeration apparatus is shortened by 3%, and the heat exchange efficiency of the triple tube heat exchanger 3 is improved by about 30% to 70% as will be described later.

  In the triple-pipe heat exchanger 3, the heat transfer area of the second pipe 15 formed by continuously deforming the pipe wall in the circumferential direction in a radial cross section is expanded, so that high heat exchange efficiency is ensured. Is done. Further, heat exchange is performed between the high-pressure liquid refrigerant flowing through the first outer flow path S2 in the second pipe 15 and the two low-pressure gas refrigerants flowing through the inner flow path S1 and the second outer flow path S3. Since the high-pressure liquid refrigerant flowing through the first outer flow path S2 can be supercooled, the high-pressure liquid refrigerant flowing through the first outer flow path S2, the inner flow path S1, and the second outer flow path S3 flow. The amount of heat exchange with the two low-pressure gas refrigerants is increased, and the high-pressure liquid refrigerant flowing through the first outer flow path S2 is effectively subcooled to increase the refrigeration capacity of the refrigeration apparatus.

  Further, according to the refrigeration apparatus according to the present invention, the cross-sectional area of the inner flow path S1 of the triple-pipe heat exchanger 3 is set smaller than the cross-sectional areas of the first and second outer flow paths S2, S3. Even if the liquid refrigerant flows from the gas-liquid separator 5 into the inner flow path S1 of the triple-pipe heat exchanger 3 due to load fluctuation or the like, the liquid refrigerant is in contact with the high-pressure liquid refrigerant flowing through the first outer flow path S2. Since it evaporates by heat exchange, the occurrence of liquid back due to the inflow of liquid refrigerant into the compressor 1 is prevented.

  Furthermore, according to the refrigeration apparatus according to the present invention, the gas refrigerant used for supercooling of the high-pressure liquid refrigerant in the triple tube heat exchanger 3 (separated by the gas-liquid separator 5 and passes through the inner flow path S1). The temperature rise of the gas refrigerant is cooled by the evaporation of the liquid refrigerant injected into the refrigerant pipe L9 that connects the gas-liquid separator 5 and the inner flow path S1 of the triple pipe heat exchanger 3, so the expansion valve 4 The temperature rise of the gas refrigerant sucked into the compressor 1 can be suppressed without affecting the temperature control. For this reason, the rise of the discharge temperature of the compressor 1 is suppressed, and the effect that deterioration of the oil in the compressor 1 is prevented can be obtained. Note that the refrigerant circulation amount in the evaporator 6 is reduced by the amount of liquid refrigerant to be injected. The decrease in the refrigeration capacity accompanying the reduction in the refrigerant circulation amount is the efficiency of the high-pressure liquid refrigerant in the triple-pipe heat exchanger 3. Compensated for by supercooling.

  Here, the gas-liquid heat exchange amount with respect to the refrigerant flow rate of the triple-pipe heat exchanger of the refrigeration apparatus according to the present invention and the conventional spiral heat exchanger is shown by curves A and B in FIG. 5, respectively. Then, it turns out that the amount of gas-liquid heat exchange of the triple-pipe heat exchanger of the refrigeration apparatus according to the present invention is larger than that of the conventional spiral heat exchanger.

上表からも本発明に係る冷凍装置の三重管式熱交換器の気液熱交換量の方が従来の螺旋式熱交換器のそれよりも大きく、本発明に係る冷凍装置の三重管式熱交換器の著しい性能向上が図られることが分かる。 Moreover, each gas-liquid heat exchange amount with respect to various chamber temperatures (−20 ° C., −10 ° C., 0 ° C., 10 ° C.) of the triple pipe heat exchanger of the refrigeration apparatus according to the present invention and the conventional spiral heat exchanger. (W) is shown in the table below.

Also from the above table, the gas-liquid heat exchange amount of the triple pipe heat exchanger of the refrigeration apparatus according to the present invention is larger than that of the conventional spiral heat exchanger, and the triple pipe heat of the refrigeration apparatus according to the present invention is larger. It can be seen that the performance of the exchanger is significantly improved.

  In the present embodiment, an expansion valve is used as the pressure reducer, but any other pressure reducer such as a capillary tube or a vortex tube can be used.

1 Compressor 2 Condenser 3 Triple tube heat exchanger 4 Expansion valve (pressure reducer)
5 Gas-liquid separator 6 Evaporator 7 Oil separator 8 Receiver tank 9 Dryer 10 Sight glass 11 Accumulator 12 Oil cooler 13 Capillary tube 14 First pipe 15 Second pipe 16 Third pipe L1 to L6 Refrigerant pipe L7 Oil return pipe L8 Injection pipe L9, L10 Refrigerant piping S1 Inner flow path S2 First outer flow path S3 Second outer flow path V1 Electromagnetic switching valve V2 Suction pressure adjustment valve (ZSP valve)
V3 solenoid valve

According to a second aspect of the invention, at least a compressor, a condenser, triple tube heat exchanger, a pressure reducer, the gas-liquid separator and the evaporator are connected in series by a refrigerant pipe formed by constituting a refrigerant circuit of a closed loop refrigeration Equipment
The liquid refrigerant traveling from the condenser to the decompressor is passed through the first outer flow path of the triple tube heat exchanger, and the gas refrigerant separated by the gas-liquid separator is disposed inside the triple tube heat exchanger. The gas refrigerant passed through the flow path and evaporated by the evaporator is allowed to pass through the second outer flow path of the triple tube heat exchanger, and the gas refrigerant and the inner flow path that have passed through the second outer flow path. The gas refrigerant that has passed through is combined and introduced into the compressor.

To achieve the above object, the invention according to claim 1, wherein at least a compressor, a condenser, triple tube heat exchanger, a pressure reducer, the gas-liquid separator and the refrigerant circulation loop by connecting an evaporator in series by a refrigerant pipe A refrigeration system comprising a circuit,
The liquid refrigerant traveling from the condenser to the decompressor is passed through the first outer flow path of the triple tube heat exchanger, and the gas refrigerant separated by the gas-liquid separator is disposed inside the triple tube heat exchanger. The gas refrigerant passed through the flow path and evaporated by the evaporator is allowed to pass through the second outer flow path of the triple tube heat exchanger, and the gas refrigerant and the inner flow path that have passed through the second outer flow path. The gas refrigerant that has passed through is combined and introduced into the compressor.

It is a refrigerant circuit figure of the refrigerating device concerning the present invention. It is a connection diagram of the triple pipe heat exchanger of the refrigeration apparatus according to the present invention. FIG. 3 is a sectional view taken along line XX in FIG. 2. It is a Mollier diagram which shows the state change of the refrigerant | coolant in the freezing apparatus which concerns on this invention. It is a figure which shows the gas-liquid heat exchange amount with respect to the refrigerant | coolant flow rate of the triple pipe type heat exchanger of the freezing apparatus which concerns on this invention compared with that of the conventional helical heat exchanger.

Claims (3)

A refrigeration system comprising at least a compressor, a condenser, a triple tube heat exchanger, a decompressor, a gas-liquid separator and an evaporator connected in series by a refrigerant pipe to form a closed-loop refrigerant circulation circuit,
The liquid refrigerant traveling from the condenser to the decompressor is passed through the first outer flow path of the triple tube heat exchanger, and the gas refrigerant separated by the gas-liquid separator is disposed inside the triple tube heat exchanger. The gas refrigerant passed through the flow path and evaporated by the evaporator is allowed to pass through the second outer flow path of the triple tube heat exchanger, and the gas refrigerant and the inner flow path that have passed through the second outer flow path. A refrigerating apparatus using a triple-pipe heat exchanger, characterized in that the gas refrigerant that has passed through is combined and introduced into the compressor.   The triple-tube heat exchanger according to claim 1, wherein the cross-sectional area of the inner flow path of the triple-tube heat exchanger is set smaller than the cross-sectional areas of the first and second outer flow paths. The refrigeration equipment used. 3. A part of the liquid refrigerant heading from the condenser to the decompressor is injected into a refrigerant pipe connecting the gas-liquid separator and an inner passage of the triple pipe heat exchanger. A refrigeration apparatus using the triple-pipe heat exchanger described.

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