JP2015048983A - Over-cooler and steam compression type refrigeration cycle having the over-cooler incorporated - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide equipment or a steam compression type refrigeration cycle that has higher capacity and saves energy by increasing refrigeration capacity by sending a refrigerant having lower temperature and lower pressure to an expansion process prior to a vaporization process, and can sufficiently exhibit capabilities of heating and defrosting in a cold district.SOLUTION: An over-cooler comprises a heat exchanger which is incorporated between a condenser and an expansion valve of a steam compression type refrigeration cycle, integrally has a primary side and a secondary side through which a refrigerant having passed through the primary side flows in and passes in series, the primary side and secondary side being partitioned off by one heat conduction plate to have the same heat conduction area and capacity. The heat exchanger is equipped with a one-stage pressure reduction valve at a primary-side intake and with a two-stage pressure reduction valve at a secondary-side intake so as to overcool the refrigerant by a two-stage pressure reduction system.

Description

  The present invention relates to a supercooler and a vapor compression refrigeration cycle incorporating the supercooler, and relates to a refrigerant for an expansion valve that performs expansion (low-pressure low-temperature) that is a pre-evaporation step in the refrigeration cycle process. The present invention relates to a supercooler for supercooling and feeding in advance to achieve a significant improvement in refrigeration capacity and energy saving, and a vapor compression refrigeration cycle incorporating the supercooler.

  Conventionally, it is known in Patent Documents 1 to 8 that a thermal self-equilibrium heat exchanger is incorporated as an element for improving the cooling or heating effect in a refrigeration cycle using refrigerant gas. In these Patent Documents 1 to 8, the primary side and the secondary side are integrated, introduced to the primary side, and the refrigerant gas that has passed through the primary side is sent to the secondary side via the expansion valve, and the primary side The heat energy is condensed and evaporated as a heat source through the heat transfer plate on the secondary side and the heat energy is synergistically enhanced to enhance the functions of the primary and secondary sides. A heat exchanger that is stable is described.

  Patent Document 9 discloses a heat exchange mechanism provided with a capillary tube instead of an expansion valve.

  However, conventionally, even in a refrigeration cycle incorporating the above-described heat exchanger, there is a limit to the defrost that can be said to be complete, and excessive work and cost are applied to the defrost. In particular, in cold regions, there is a limit to the efficient and safe operation as a heating device, and it has become practical to rely on heaters that use electricity for defrost.

Application documents for Japanese Patent Application No. 2013-028699 JP 2003-214731 A Japanese Patent Laid-Open No. 2004-361033 Japanese Patent Application No. 2005-98817 JP 2005-114267 A JP 2006-64331 A JP 2009-156563 A JP 2011-58652 A Microfilm of Japanese Utility Model Sho 56-155277

  The problem to be solved by the present invention is that the refrigerant having a lower temperature and lower pressure is fed into the expansion process, which is the previous stage of the evaporation process, thereby increasing its refrigerating capacity, improving its capacity and saving energy. In other words, there was no equipment or vapor compression refrigeration cycle that can sufficiently exhibit the effects of heating and defrosting in cold regions.

  In order to solve this problem, a supercooler according to the present invention is incorporated between a condenser and an expansion valve of a vapor compression refrigeration cycle, and a refrigerant passing through the primary side and the primary side flows in, and is connected in series. It has a secondary side that passes through, and the primary side and the secondary side are partitioned by a single heat transfer plate and are configured by a heat exchanger having the same heat transfer area and capacity. The inlet is provided with a single-stage pressure reducing valve, and the secondary side inlet is provided with a two-stage pressure reducing valve, which is a two-stage pressure reducing type, and the refrigerant is supercooled. It becomes a production | generation part, a secondary side turns into a low temperature part for primary side cooling, and the temperature of the refrigerant | coolant which passed the secondary side is lower than the temperature of the refrigerant | coolant which passed the primary side, It is characterized by the above-mentioned.

  Further, the supercooler according to the present invention is characterized in that the above-described supercooler has a configuration in which the outer surface is encapsulated with a heat insulating material to prevent heat dissipation and heat absorption. It is characterized by using urethane foam.

  Furthermore, the vapor compression refrigeration cycle according to the present invention is characterized by incorporating the supercooler described in claims 1 to 4, and includes two of the cooling time, freezing time, heating time, and defrosting time. A refrigerant circuit incorporating the supercooler according to any one of claims 1 to 4 is formed.

  The supercooler according to the present invention and the vapor compression refrigeration cycle incorporating the supercooler are configured as described above. Therefore, before the refrigerant is introduced into the expansion process (expansion valve), the refrigerant is made into a low pressure and low temperature in two stages by the subcooler in a state where the pressure is lowered by the condensation process. Therefore, in combination with the subsequent expansion valve, three stages of low pressure and low temperature are achieved, and a low temperature supercooling state up to the saturated liquid line in the Ph diagram is obtained, and an unprecedented refrigeration capacity can be obtained.

  Also, by insulating the outer surface of the subcooler, heat dissipation and heat absorption from the subcooler are suppressed to a very small amount, and energy is transferred only between the primary side and secondary side refrigerants, The efficiency will be greatly improved, increasing the latent heat of condensation and increasing the latent heat of evaporation. For this reason, it is possible to improve the refrigeration efficiency by 20 to 30%, and most preferably by 50% compared to the conventional case.

  Furthermore, by arranging this supercooler in two circuits and switching between cooling, freezing and heating, and defrosting, the cycle efficiency of each of them will be greatly improved.

It is a figure which shows the supercooler made into the two-stage pressure reduction type | mold which implemented this invention. It is a fragmentary sectional view. It is a Ph diagram which shows transfer of latent heat in a subcooler made into a two-stage decompression type. It is a Ts diagram in the conventional refrigeration cycle. It is a Ts diagram of a refrigerating cycle using a two-stage decompression type supercooler. It is a cycle circuit diagram at the time of cooling and freezing. It is a cycle circuit diagram at the time of heating and defrosting.

  This was realized by configuring as illustrated in the drawings and described in the examples.

  Next, an example of a preferred embodiment of the present invention will be described with reference to the drawings. In the figure, reference numeral 1 denotes a two-stage depressurizing subcooler according to the present invention. This two-stage depressurization type subcooler 1 is incorporated on a cycle circuit between a condensation step (condenser) and an expansion step (expansion valve) of a vapor compression refrigeration cycle.

  The two-stage pressure-reducing supercooler 1 is composed of an integral casing. The primary side 2 into which the refrigerant from the condenser is introduced and the secondary side 3 into which the refrigerant that has passed through the primary side is introduced and passed are one sheet. It is partitioned by the heat transfer plate 4 and integrated. Therefore, the heat transfer areas of the primary side 2 and the secondary side 3 are the same, and the capacities are also the same.

  The primary side 2 refrigerant inlet is provided with a first-stage pressure reducing valve 5, and the refrigerant inlet having passed the primary side 2 of the secondary side 3 is provided with a second-stage pressure reducing valve 6. The refrigerant sent out from the refrigerant is passed in series, and the refrigerant that has passed through the secondary side 3 is sent to the expansion valve 7 that is arranged in the previous stage of the evaporation step (evaporator).

  Further, the supercooler 1 is controlled so that the outer surface of the supercooler 1 is encapsulated by the heat insulating material 8 while leaving the inlet and outlet portions of the refrigerant, and heat radiation and heat absorption from the supercooler 1 are minimized. Here, a foam material type urethane foam is used as the heat insulating material 8, and it is designed so that it can cope with external impacts.

  Here, the operation of the two-stage decompression supercooler 1 will be described. The refrigerant that has passed through the condenser is in a gas-liquid two-phase uncondensed state (refrigerant temperature T3), passes through the first-stage pressure reducing valve 5, and is introduced to the primary side 2. At this time, the refrigerant is depressurized by the passage of the first stage pressure reducing valve 5 and becomes low temperature (refrigerant temperature T4). The refrigerant whose pressure has been reduced and discharged is discharged from the primary side 2 (refrigerant temperature T5), passes through the two-stage pressure reducing valve 6 (refrigerant temperature T6), and is introduced to the secondary side 3. At the time of introduction to the secondary side 3, the refrigerant is decompressed as compared with the state of the primary side 2, and discharged at a much lower temperature (refrigerant temperature T7). In the two-stage decompression-type supercooler 1, the refrigerant cools each other on the primary side 2 and the secondary side 3, and becomes a low-temperature supercooling liquid.

  Here, the temperature relationship of the refrigerant will be described using inequalities. The above-described T3 passes through the first stage pressure reducing valve 5 to become a low temperature T4, and the high temperature condensed refrigerant liquid is evaporated by the first stage pressure reducing valve 5 to change the refrigerant toward low temperature and low pressure. That is, T4 is cooler than T3. The refrigerant of T4 is introduced into the primary side 2 and becomes Ta (T4 = Ta). Since Ta does not have an evaporation heat source (a heat source higher in temperature than Ta), it cannot evaporate. After the cycle progresses, Ta becomes lower than T4. When the primary side 2 passes, the refrigerant dissipates heat to the secondary side 3, and cooling and condensation proceed. At this time, the refrigerant on the secondary side 3 becomes Tb.

  The refrigerant Ta on the primary side 2 and the refrigerant on the secondary side 3 exchange heat with a single heat transfer plate 4. The refrigerant T5 discharged from the primary side 2 is a gas-liquid two-phase one having a temperature lower than that of the refrigerant T3 discharged from the condenser, and T5 is lower in temperature than T3. This refrigerant T5 passes through the two-stage pressure reducing valve 6 to become a lower temperature refrigerant T6, and T6 becomes lower in temperature than T5.

  The refrigerant T6 is introduced into the secondary side 3 and becomes Tb. T6 = Tb. As the cycle progresses, heat exchange is performed in which the refrigerant complements the primary side 2 and the secondary side 3 of the two-stage depressurization subcooler 1 where T6 ≧ Tb and the temperature changes. The refrigerant Ta on the primary side 2 obtains a condensation heat source (low temperature) because the refrigerant Tb on the secondary side 3 has a low temperature. That is, Tb is lower than Ta.

  Since the refrigerant Ta on the primary side 2 obtains a condensation heat source (lower temperature than Ta) from the refrigerant Tb on the secondary side 3, it becomes a condensate without evaporating, increasing the latent heat of condensation, and the latent heat of evaporation also increases. The refrigerant Ta on the primary side 2 is cooled at a lower temperature than the refrigerant Tb on the secondary side 3 and the temperature is lowered, so that T5 is also lowered in temperature. Correspondingly, T6 = Tb also becomes a low temperature, and Ta that exchanges heat with Tb further advances the low temperature to advance the condensation.

The above thermal relationship is
T7 is lower than Tb, Tb is lower than or equal to T6, T6 is lower than T5, T5 is lower than Ta, Ta is lower than T4, and T4 is lower than T3.

  The refrigerant Tb on the secondary side 3 is in a condensate state. Although the refrigerant Tb on the secondary side 3 also slightly evaporates, the subcooling is maintained because there is no latent heat of evaporation (heat lower than Tb) obtained from the refrigerant Ta on the primary side 2. Due to the evaporation heat source of the refrigerant Ta on the primary side 2 that remains slightly, the refrigerant T7 that is discharged by evaporating the refrigerant Tb on the secondary side 3 has the lowest temperature.

  In the secondary side 3, the refrigerant T <b> 5 cooled to the condensate on the primary side 2 is not allowed to evaporate due to the lack of evaporation heat source in the refrigerant Ta on the primary side 2 even after passing through the two-stage pressure reducing valve 6. Cooling is advanced and maintained, resulting in a low-temperature, low-pressure 100% supercooled liquid, increasing latent heat of vaporization and correlation latent heat of condensation.

  Further, since the outer surface of the two-stage depressurization type subcooler 1 is encapsulated by the heat insulating material 8 except for the refrigerant inlet and outlet portions, the heat radiation from the two-stage depressurization subcooler 1 or The heat absorption from the outside is suppressed to a very small amount of heat, and the energy is transferred only between the refrigerant on the primary side 2 and the secondary side 3.

  The refrigerant passing through the primary side 2 increases the latent heat of condensation by the refrigerant on the secondary side 3 and simultaneously increases the latent heat of vaporization. The primary side 2 lowers the temperature of the refrigerant supplied to the secondary side 3. It can be said that it is a preparation room.

During the passage of the primary side 2 and the secondary side 3, the refrigerant exchanges heat with each other and changes with time. During the passage of the two-stage decompression supercooler 1, the refrigerant becomes an analog low pressure, and the Ph diagram It becomes a supercooled liquid at a low temperature up to the upper point of the saturated liquid line (the hatched portion of the chain line in the Ph diagram), and at the same time, the latent heat of condensation is increased and the latent heat of vaporization is also increased in correlation. In FIG. 3, 11 is a refrigerant sucked into the compressor, 12 is a refrigerant introduced into the condenser, 13 is introduced into the first stage pressure reducing valve 5, 14 is introduced into the two stage pressure reducing valve 6, and 15 is Introduction to the expansion valve 7, 16 indicates introduction into the evaporator through the expansion valve 7,
Δh1 The pressure is reduced by one stage, becomes a low temperature, is cooled by the secondary refrigerant, and the amount of condensation latent heat is increased.
Δh2 two-stage depressurization, the temperature becomes low, and the condensation latent heat is increased by being cooled by the primary refrigerant.
The latent heat of vaporization and latent heat of condensation increased by the Δh3 two-stage depressurization subcooler 1,
Total condensation latent heat increased by the Δhh two-stage decompression supercooler 1,
The total evaporation latent heat increased by the ΔhC two-stage decompression type subcooler 1 is shown.

  Next, the performance of a conventional circuit and a circuit incorporating the two-stage decompression supercooler 1 will be compared with reference to a Ts diagram (FIGS. 4 and 5). In FIG. 4 showing a conventional example, 21 is a compressor suction refrigerant, 22 is a compressor discharge refrigerant state, 23 is a condenser outlet refrigerant, 24 is an expansion valve inlet refrigerant, 25 is an evaporator inlet refrigerant, and 26 is an evaporator outlet. Refrigerant is shown.

  A refrigerant circuit incorporating the two-stage depressurization type supercooler 1 is shown in FIG. 5 and compared with FIG. In FIG. 5, 31 is a compressor suction refrigerant, 32 is a compressor discharge refrigerant state, 33 is an inlet refrigerant of the first-stage pressure reducing valve 5, 34 is an inlet refrigerant of the two-stage pressure reducing valve 6, and 35 is an inlet of the expansion valve 7. A refrigerant 36 passes through the expansion valve 7 and indicates an inlet refrigerant to the evaporator. In FIG. 5, ΔS3 indicates the latent heat of condensation, ΔS4 indicates the latent heat of evaporation, and it is clear that both increase, and Δ7 indicates the refrigerant discharge temperature, which is also increased.

  Next, a circuit incorporating the two-stage depressurization type subcooler 1 according to the present invention will be described with reference to FIGS. FIG. 6 specifically shows a circuit during freezing and cooling, and a system indicated by a chain line is a circuit during heating and defrosting. In this circuit, reference numeral 40 denotes a compressor, and the refrigerant discharged from the compressor 40 is introduced into the condenser 41. The uncondensed refrigerant that has passed through the condenser 41 passes through the supercooler 1 that performs the above-described configuration and action, passes through the expansion valve 7, and passes through the indoor unit 42 (a radiator as an evaporator). After returning to the room, the air is returned to the compressor 40. In this circuit, the three-stage pressure reducing action is performed by passing through the first-stage pressure reducing valve 5, the two-stage pressure reducing valve 6, and the expansion valve 7.

  Moreover, the system shown by a solid line in FIG. 7 is a circuit during heating and defrosting. In the case of this circuit, the refrigerant discharged from the compressor 40 switches the flow path by the switching valve and flows into the hot gas pipe 43. The high-temperature and high-pressure refrigerant that has passed through the hot gas pipe 43 causes the indoor unit 42 described above to act as a condenser in this case, and discharges warm air into the room. The refrigerant that has passed through the indoor device 42 is switched to the flow path returning to the compressor 40 by the switching valve, and is introduced into the second subcooler 1 a of the hot gas defrost unit 44. The second subcooler 1a is also provided with a first-stage pressure reducing valve 5a and a two-stage pressure reducing valve 6a at the inlets of the primary side 2a and the secondary side 3a, respectively. However, in this case, the first-stage pressure reducing valve 5a on the primary side 2a can be bypassed to pass through the first-stage pressure reducing valve 5a.

  The refrigerant that has passed through the second subcooler 1a in the hot gas unit 44 passes through the expansion valve 7a in this unit 44, passes through the evaporator 42a, and returns to the compressor 40. This cycle will be circulated.

  As can be seen from the description of each circuit described above, the refrigeration cycle according to the present invention is configured to circulate through the five steps of compression, condensation, supercooling, expansion, and evaporation, much more than the conventional decompression using only the expansion valve. The operation of the heating and defrost circuit that is evaporated to the outside air is easy to obtain a heat source of evaporation from the outside air temperature, and the low temperature operation in a cold region is excellent.

1, 1a Supercooler 2, 2a Primary side 3, 3a Secondary side 4 Heat transfer plate 5, 5a First stage pressure reducing valve 6, 6a Two stage pressure reducing valve 7, 7a Expansion valve 8 Heat insulating material 11, 22, 32 To compressor Refrigerant sucked 12 Refrigerant introduced into the condenser 13, 33 Refrigerant introduced into the first stage pressure reducing valve 14, 34 Refrigerant introduced into the second stage pressure reducing valve 15, 24, 35 Refrigerant introduced into the expansion valve 16, 25 , 36 Refrigerant introduced into the evaporator 22, 32 Compressor discharged refrigerant 23 Condenser outlet refrigerant 40 Compressor 41 Condenser 42 Indoor unit 42a Evaporator 43 Hot gas pipe 44 Hot gas defrost unit 45 Bypass

Claims (6)

  Built-in between the condenser and expansion valve of the vapor compression refrigeration cycle, the primary side and the refrigerant that has passed through the primary side flow in, and the secondary side that passes in series is integrated with the primary side and the secondary side. The side of the heat exchanger is divided by a single heat transfer plate and has the same heat transfer area and capacity, the primary inlet of this heat exchanger is provided with a single pressure reducing valve, and the secondary inlet has two A subcooler comprising a stage pressure reducing valve, having a two-stage pressure reducing type, and supercooling the refrigerant.   In the above-described supercooler, the primary side serves as a supercooling liquid generator, the secondary side serves as a low temperature part for primary side cooling, and the temperature of the refrigerant passing through the secondary side is lower than the temperature of the refrigerant passing through the primary side. The subcooler according to claim 1, wherein:   The supercooler according to claim 1 or 2, wherein an outer surface of the supercooler is encapsulated with a heat insulating material to prevent heat dissipation and heat absorption.   4. The supercooler according to claim 3, wherein the heat insulating material uses foamed urethane which is a foam material type.   A vapor compression refrigeration cycle incorporating the supercooler according to claim 1.   6. The steam according to claim 5, wherein a refrigerant circuit incorporating the supercooler according to any one of claims 1 to 4 is formed during cooling, freezing, heating, and defrosting. Compression refrigeration cycle.

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