JP2006017350A - Refrigeration device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigeration device capable of reducing the quantity of discharged heat of a system as a whole, reducing the power consumption and improving a coefficient of performance. <P>SOLUTION: This refrigeration device comprises an absorption refrigeration cycle 100 comprising a regenerator 1, a condenser 3, an evaporator 5 and an absorber 7, and a vapor compression refrigeration cycle 200 comprising a compressor 31, heat source-side heat exchangers 33, 35, a decompressing device 39 and a use-side heat exchanger 47. The refrigerant circulated in the devices of the absorption refrigeration cycle 100 is made to recover the exhaust heat of the heat source-side heat exchangers of the vapor compression refrigeration cycle 200, and a refrigerant at an outlet side, of the heat source-side heat exchangers of the vapor compression refrigeration cycle 200 is cooled by the evaporator 5 of the absorption refrigeration cycle 100. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a refrigeration apparatus including a vapor compression refrigeration cycle using a refrigerant such as carbon dioxide.

In general, a refrigeration apparatus including a vapor compression refrigeration cycle having a compressor, a heat source side heat exchanger, a decompression device, and a use side heat exchanger is known (see, for example, Patent Document 1). In this type, the heat source side heat exchanger is water-cooled or air-cooled. In either case, the exhaust heat of the heat source-side heat exchanger is dissipated to water or air. .
JP 2002-228229 A

  However, in the conventional configuration, the exhaust heat of the heat source side heat exchanger is not effectively used, the exhaust heat is wasted, and the heat source side heat exchanger is water-cooled type or air-cooled type. Was not so good, and there was a limit to improving the coefficient of performance.

  Accordingly, an object of the present invention is to provide a refrigeration apparatus that can solve the above-described problems of the conventional technology, reduce the amount of heat released as a whole system, reduce power consumption, and improve the coefficient of performance. is there.

  The present invention includes an absorption refrigeration cycle including a regenerator, a condenser, an evaporator, and an absorber, and a vapor compression refrigeration cycle including a compressor, a heat source side heat exchanger, a decompression device, and a use side heat exchanger. And using the exhaust heat of the heat source side heat exchanger of the vapor compression refrigeration cycle as a heat source of the absorption refrigeration cycle, and heat source side heat exchange of the vapor compression refrigeration cycle by the evaporator of the absorption refrigeration cycle The outlet side refrigerant of the vessel is cooled.

  In this case, the heat source side heat exchanger of the vapor compression refrigeration cycle may be configured to include a first heat source side heat exchanger disposed in the regenerator of the absorption refrigeration cycle. Further, the heat source side heat exchanger of the vapor compression refrigeration cycle may be configured to include a second heat source side heat exchanger disposed in the evaporator of the absorption refrigeration cycle. The heat source side heat exchanger of the vapor compression refrigeration cycle is a third heat source side heat exchanger comprising an air-cooled radiator connected between the first heat source side heat exchanger and the second heat source side heat exchanger. It may be provided with. The exhaust heat of the first heat source side heat exchanger of the vapor compression refrigeration cycle may be directly recovered by the refrigerant of the absorption refrigeration cycle.

  A gas phase separated by this intermediate cooler is provided between the use side heat exchanger of the vapor compression refrigeration cycle and the decompression device of the vapor compression refrigeration cycle by providing a second expansion device and an intermediate cooler. The refrigerant may be introduced into the intermediate pressure portion of the compressor of the vapor compression refrigeration cycle. The compressor of the vapor compression refrigeration cycle may be a two-stage compressor, and the introduction means may introduce a gas phase refrigerant between the first stage and the second stage of the two-stage compressor. Carbon dioxide refrigerant may be enclosed in the vapor compression refrigeration cycle.

  In the present invention, the refrigerant circulating through each device of the absorption refrigeration cycle recovers the exhaust heat of the heat source side heat exchanger of the vapor compression refrigeration cycle, so that the exhaust heat can be used effectively, and the absorption type Since the refrigerant on the outlet side of the heat source side heat exchanger of the vapor compression refrigeration cycle is cooled by the evaporator of the refrigeration cycle, the coefficient of performance can be improved.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  In FIG. 1, 100 indicates an absorption refrigeration cycle based on the principle of a single-effect absorption refrigeration machine, and 200 indicates a vapor compression refrigeration cycle using a carbon dioxide refrigerant.

  The absorption refrigeration cycle 100 is, for example, an absorption refrigeration cycle using water as a refrigerant of the absorption refrigeration cycle and lithium bromide (LiBr) as an absorbent, and includes a regenerator 1, a condenser 3, and an evaporator 5. And an absorber 7, a solution cooler 9, and a solution heat exchanger 11. In the regenerator 1, by using the exhaust heat of the vapor compression refrigeration cycle 200, which will be described later, the dilute liquid (hereinafter referred to as dilute liquid) is heated, whereby the dilute liquid is concentrated. To concentrate.)

  The refrigerant vapor of the absorption refrigeration cycle generated in the regenerator 1 enters the condenser 3, where it condenses by exchanging heat with the cooling water from the cooling tower 13. 14 is a cooling water pump. The refrigerant liquid of the absorption refrigeration cycle condensed by the condenser 3 enters the evaporator 5 via the control valve 15 and evaporates here. The refrigerant vapor of the absorption refrigeration cycle evaporated by the evaporator 5 enters the adjacent absorber 7. On the other hand, the concentrated liquid concentrated in the regenerator 1 is cooled through the solution heat exchanger 11 and then enters the absorber 7. In the absorber 7, the concentrated liquid is evaporated in the evaporator 5. Absorbs refrigerant vapor in the absorption refrigeration cycle. A part of the concentrated liquid accumulated in the lower part of the absorber 7 enters the solution cooler 9 via the first pump 17, where it is cooled and enters the absorber 7. The remainder enters the solution heat exchanger 11 via the second pump 19, where it is heated by the concentrated liquid from the regenerator 1 toward the absorber 7 and returned to the regenerator 1. Reference numeral 21 denotes a third pump. The third pump 21 causes the refrigerant of the absorption refrigeration cycle, which has not been completely evaporated by the evaporator 5, to flow back to the evaporator 5.

  Next, a vapor compression refrigeration cycle 200 using a carbon dioxide refrigerant will be described. The vapor compression refrigeration cycle 200 includes a two-stage compressor 31. The two-stage compressor 31 is connected to a first heat source side heat exchanger 33 for regeneration of an absorption refrigeration cycle provided inside the regenerator 1 via a refrigerant pipe 32, and this first heat source A third heat source side heat exchanger (air-cooled radiator) 35 is connected to the side heat exchanger 33 via a refrigerant pipe 34. A second heat source side heat exchanger (additional cooler) 37 provided inside the evaporator 51 is connected to the third heat source side heat exchanger 35 via the refrigerant pipe 36, and the second heat source side A decompression device (second expansion device) 39 and an intermediate cooler 41 are connected in series to the side heat exchanger 37 in this order via a refrigerant pipe 38. The first to third heat source side heat exchangers 33, 35, and 37 constitute a heat source side heat exchanger of the vapor compression refrigeration cycle.

  The intercooler 41 separates the carbon dioxide refrigerant of the vapor compression refrigeration cycle into a gas phase refrigerant and a liquid phase refrigerant, and the gas phase carbon dioxide refrigerant is a refrigerant pipe 42 (introducing means). To the intermediate pressure part 31C between the first stage 31A and the second stage 31B of the second stage compressor 31. Further, the liquid phase carbon dioxide refrigerant of the vapor compression refrigeration cycle separated by the intermediate cooler 41 is supplied with a decompression device 45 and a carbon dioxide evaporator (use side heat exchanger) 47 through a refrigerant pipe 43. In this case, after evaporating and vaporizing, it is returned to the suction pipe 48 of the first stage 31A of the two-stage compressor 31. The carbon dioxide evaporator 47 of the vapor compression refrigeration cycle cools the inside of the refrigeration warehouse 47A.

  In this configuration, the exhaust heat of the first heat source side heat exchanger 33 of the vapor compression refrigeration cycle 200 is heated by the refrigerant circulating through the devices 1, 3, 5, 7, 9, and 11 of the absorption refrigeration cycle 100. The refrigerant is recovered and the inlet-side refrigerant of the carbon dioxide evaporator 47 of the vapor compression refrigeration cycle 200 is cooled by the evaporator 5 of the absorption refrigeration cycle 100 via the second heat source side heat exchanger 37.

  FIG. 2 is an enthalpy / pressure diagram. When the carbon dioxide refrigerant is sealed, the high-pressure pipe is operated at a supercritical pressure during operation, as shown in FIG. In addition to the carbon dioxide refrigerant, for example, ethylene, diborane, ethane, nitrogen oxide and the like can be cited as the refrigerant of the vapor compression refrigeration cycle in which the inside of the high-pressure pipe is operated at a supercritical pressure.

  In FIG. 2, the state of the refrigerant of the vapor compression refrigeration cycle at the outlet of the second stage 31B of the two-stage compressor 31 is indicated by a state a. The refrigerant of this vapor compression refrigeration cycle circulates through the first heat source side heat exchanger 33, the third heat source side heat exchanger 35, and the second heat source side heat exchanger (cooler) 37, Then, it is cooled in order through the state b and the state c to the state d, and the heat is released to the absorption refrigerant in the regenerator 1, to the cooling air, and further to the absorption refrigerant in the evaporator 51. Next, the refrigerant of the vapor compression refrigeration cycle reaches the state e due to the pressure drop in the decompression device 39, where a gas phase / liquid phase two-phase mixture is formed and reaches the intercooler 41.

  In the intercooler 41, the refrigerant of the vapor compression refrigeration cycle undergoes gas-liquid separation. In this case, the ratio of the gas phase / liquid phase corresponds to the line segment length of m1 / m2. The gas phase portion of the refrigerant is in the state 1 in the intercooler 41. The gas phase portion is introduced into the intermediate pressure portion 31C between the first stage 31A and the second stage 31B of the second stage compressor 31.

  The state k is the state of the inlet of the second stage 31B in the two-stage compressor 31. On the other hand, in the intercooler 41, the liquid phase portion of the refrigerant of the vapor compression refrigeration cycle is in the state f. This liquid phase portion reaches the state g due to the pressure drop in the decompression device 45. Further, the liquid phase portion of the refrigerant in the vapor compression refrigeration cycle evaporates in the carbon dioxide evaporator 47 and absorbs heat. The refrigerant of the vapor compression refrigeration cycle that has become a gas phase by the evaporator 47 is heated to the state i and returned to the suction pipe 48 of the first stage 31A of the two-stage compressor 31. The state j is the discharge of the first stage 31A of the two-stage compressor 31.

  In the supercritical cycle, the high pressure gas phase refrigerant of the vapor compression refrigeration cycle discharged from the compressor 31 is not condensed, but the first heat source side heat exchanger 33, the third heat source side heat exchanger 35, and A temperature drop occurs in the second heat source side heat exchanger (cooler) 37. The final temperature of the refrigerant in the vapor compression refrigeration cycle in the third heat source side heat exchanger 35 (state c) is several degrees higher than the temperature of the cooling air. The high-pressure gas-phase refrigerant is cooled to a state d that is several degrees lower in the second heat source side heat exchanger 37.

  In the above configuration, the refrigerant in the vapor compression refrigeration cycle is gas-liquid separated in the intermediate cooler 41, and the gas phase portion of the refrigerant is introduced into the intermediate pressure portion 31 </ b> C of the two-stage compressor 31. Even if this gas phase portion is supplied to the carbon dioxide evaporator 47, there is little refrigeration effect there. In this configuration, this gas phase portion is introduced into the intermediate pressure portion 31C of the two-stage compressor 31 by bypassing the carbon dioxide evaporator 47, and the liquid after the gas-liquid separation is supplied to the carbon dioxide evaporator 47. Compared with a configuration in which only the phase portion is supplied and the refrigerant evaporated here is returned to the suction pipe 48 of the first stage 31A of the two-stage compressor 31 and all the gas phase / liquid phase refrigerant is returned to the suction pipe 48. In this case, the work amount of the two-stage compressor 31 can be reduced.

  By the way, in this type of refrigeration apparatus, in a supercritical cycle using a carbon dioxide refrigerant that uses an air-cooled heat exchanger as the heat source side heat exchanger, the ambient temperature of the heat source side heat exchanger is high during cooling operation. And heat exchange in the said heat source side heat exchanger becomes inadequate, and cooling capacity and a coefficient of performance fall remarkably.

  In the present embodiment, in the second heat source side heat exchanger (additional cooler) 35, the absorption refrigeration cycle 100 cools the refrigerant on the outlet side of the heat source side heat exchanger in the vapor compression refrigeration cycle 200. The specific enthalpy of the refrigerant at the heat source side heat exchanger outlet can be reduced, and as a result, the specific enthalpy at the evaporator inlet can be reduced and the refrigeration effect can be increased. Therefore, for example, even during a cooling operation where the outside air temperature is high, the cooling operation capability and the coefficient of performance can be improved.

  Moreover, since the heat source of the absorption refrigeration cycle 100 according to this configuration is covered by the exhaust heat of the heat source side heat exchanger in the vapor compression refrigeration cycle 200, it is possible to realize an energy saving operation by effectively using the exhaust heat. .

  FIG. 3 shows the performance of a so-called “hybrid cycle” according to the present embodiment, in which the absorption refrigeration cycle 100 and the vapor compression refrigeration cycle 200 are combined. In the vapor compression refrigeration cycle 200 which is the basis of this “hybrid cycle”, as shown in FIG. 3B, the evaporation temperature in the carbon dioxide evaporator (use side heat exchanger) 47 is −35 ° C., and the refrigeration capacity is 25 kW. , Assuming that the power consumption of the compressor 31 and the air cooling fan is 17.5 kW, the coefficient of performance is 1.43, the outside air temperature is 35 ° C., and the amount of heat released from the heat source side heat exchanger is 16.2 kW. Then, the evaporation temperature in the evaporator 5 is 20 ° C., the refrigerating capacity is 9.30 kW, the power consumption of various pumps and fans is 0.82 kW, the coefficient of performance is 0.840, the cooling water temperature is 32 ° C., and the amount of heat released is 20. Assuming that it is .3 kW, the entire “hybrid cycle” has an evaporation temperature of −35 ° C., a refrigeration capacity of 25 kW, a power consumption of 18.32 kW, a coefficient of performance of 1.36, and an outside temperature. But 35 ° C., releasing heat is 43.3KW.

  On the other hand, in a conventional vapor compression refrigeration cycle, that is, in a general vapor compression refrigeration cycle using a carbon dioxide refrigerant using an air-cooled heat exchanger for the heat source side heat exchanger, the use side heat exchange is performed. Evaporation temperature at the cooler is -35 ° C, refrigeration capacity is 25 kW, power consumption of the compressor 31 and the air cooling fan is 21.42 kW, coefficient of performance is 1.17, outside air temperature is 35 ° C, and the heat released from the heat source side heat exchanger Is 46.4 kW.

  When these are compared, as shown in FIG. 3A, a “hybrid cycle” improves the coefficient of performance by 16.2%, further reduces power consumption by 14.5%, and releases heat by 6.7%. It has been reduced.

  As mentioned above, although this invention was demonstrated based on one Embodiment, this invention is not limited to this, A various deformation | transformation is possible within the range which does not deviate from the meaning of this invention.

  For example, the combination of the 1st heat source side heat exchanger 33 and the 3rd heat source side heat exchanger 35 is not limited to this. The third heat source side heat exchanger 35 may be omitted, or another radiator may be provided in the cooling tower 13 instead of the third heat source side heat exchanger 35. The compressor 31 is not limited to a two-stage compressor, and may be a single-stage compressor. In this case, the intermediate pressure part is provided in the middle of the first stage compression.

It is a circuit diagram showing one embodiment of the present invention. It is an enthalpy and pressure diagram showing one embodiment of the present invention. A and B are diagrams showing the performance of the “hybrid cycle” according to the present embodiment, in which an absorption refrigeration cycle and a vapor compression refrigeration cycle are combined.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Absorption-type refrigeration cycle 200 Vapor compression-type refrigeration cycle 1 Regenerator 3 Condenser 5 Evaporator 7 Absorber 9 Solution cooler 11 Solution heat exchanger 31 Two-stage compressor 31C Intermediate pressure part 33 1st heat source side heat exchanger 35 3rd heat source side heat exchanger 37 2nd heat source side heat exchanger 39 Pressure reducing device 41 Intermediate cooler 47 Carbon dioxide evaporator (use side heat exchanger)

Claims (8)

  An absorption refrigeration cycle comprising a regenerator, a condenser, an evaporator, and an absorber; and a vapor compression refrigeration cycle comprising a compressor, a heat source side heat exchanger, a decompression device, and a utilization side heat exchanger, The exhaust heat of the heat source side heat exchanger of the vapor compression refrigeration cycle is used as a heat source of the absorption refrigeration cycle, and the outlet side of the heat source side heat exchanger of the vapor compression refrigeration cycle by the evaporator of the absorption refrigeration cycle A refrigeration apparatus for cooling a refrigerant.   The heat source side heat exchanger of the vapor compression refrigeration cycle is configured to include a first heat source side heat exchanger disposed in a regenerator of the absorption refrigeration cycle. The refrigeration apparatus described.   2. The heat source side heat exchanger of the vapor compression refrigeration cycle is configured to include a second heat source side heat exchanger disposed in the evaporator of the absorption refrigeration cycle. Or the refrigeration apparatus of 2.   The heat source side heat exchanger of the vapor compression refrigeration cycle is a third heat source side heat exchanger comprising an air-cooled radiator connected between the first heat source side heat exchanger and the second heat source side heat exchanger. The refrigeration apparatus according to any one of claims 1 to 3, wherein the refrigeration apparatus is configured to include:   The refrigeration according to any one of claims 1 to 4, wherein exhaust heat of the first heat source side heat exchanger of the vapor compression refrigeration cycle is directly recovered by the refrigerant of the absorption refrigeration cycle. apparatus. A second expansion device and an intercooler are provided between the use side heat exchanger of the vapor compression refrigeration cycle and the decompression device of the vapor compression refrigeration cycle,
6. An introduction means for introducing a gas-phase refrigerant separated by the intermediate cooler into an intermediate pressure portion of a compressor of the vapor compression refrigeration cycle is provided. The refrigeration apparatus described. The compressor of the vapor compression refrigeration cycle is a two-stage compressor;
The refrigerating apparatus according to any one of claims 1 to 6, wherein the introducing means introduces a gas-phase refrigerant between the first stage and the second stage of the two-stage compressor. The refrigeration apparatus according to any one of claims 1 to 7, wherein a carbon dioxide refrigerant is sealed in the vapor compression refrigeration cycle.

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