JP5346343B2 - Two-stage compression heat pump cycle device - Google Patents

Description

The present invention uses NH ₃ as a heat medium, and is a device that constitutes a heat pump cycle that includes a two-stage compressor composed of a low-stage compression section and a high-stage compression section. 40 to 60 ° C.) and low temperature (−15 to 10 ° C.) three kinds of heat transfer media can be taken out at the same time, and the refrigeration capacity and COP are improved more than before.

  Japanese Patent Application Laid-Open No. 2000-249413 discloses a conventional two-stage compression refrigeration apparatus. This configuration will be described below. In FIG. 7, a refrigeration apparatus 010 is applied to a commercial refrigerator, a household refrigerator, an ice making apparatus, a showcase refrigeration apparatus, and the like. The refrigerant circuit 020 constitutes a two-stage compression refrigeration cycle in which the main circuit 02M includes two compressors, a high-stage compressor 021H and a low-stage compressor 021L. In addition, an intermediate cooler 022 is provided to reduce the discharge gas temperature.

  That is, the discharge side of the low stage compressor 021L is connected to the intermediate cooler 022 via the refrigerant pipe 023, and the intermediate cooler 022 is connected to the high stage compressor 021H via the refrigerant pipe 023. The discharge side of the high-stage compressor 021H is connected to the heat source side heat exchanger 024 via the refrigerant pipe 023. The heat source side heat exchanger 024 is, for example, an air-cooled condenser, and the outdoor air and the refrigerant exchange heat to condense the refrigerant. Alternatively, a heat transfer medium other than outdoor air may be introduced to heat the heat transfer medium.

  From the heat source side heat exchanger 024 to the heat exchanger 022a, the expansion valve 025, and the use side heat exchanger 026 of the intermediate cooler 022 are connected in series by a refrigerant pipe 023 in order. The use-side heat exchanger 026 is configured, for example, so that the inside air in the freezer and the refrigerant exchange heat and the refrigerant evaporates to cool the inside air. The use side heat exchanger 026 is connected to the suction side of the low-stage compressor 021L by a refrigerant pipe 023.

  A branch passage 030 is branched to the heat source side heat exchanger 024. The branch passage 030 includes an auxiliary expansion valve 031 and one end thereof is connected to the intermediate cooler 022. The intermediate cooler 022 supercools the liquid refrigerant in the main circuit 02M by evaporation of the liquid refrigerant flowing from the branch passage 030, and cools the discharged gas refrigerant discharged from the low-stage compressor 021L.

  The cooling operation of this two-stage compression refrigeration apparatus will be described based on the Mollier diagram of FIG. In FIG. 8, first, the low-pressure gas refrigerant flows into the low-stage compressor 021L from the state at the point A, and is compressed to the point B by the low-stage compressor 021L. The gas refrigerant discharged from the low-stage compressor 021L flows into the intermediate cooler 022 and is cooled to point C by the refrigerant described later.

  Thereafter, the cooled gas refrigerant flows into the high stage compressor 021H from the state of the C point, and is compressed to the D point by the high stage compressor 021H. The gas refrigerant discharged from the high stage compressor 021H flows into the heat source side heat exchanger 024, exchanges heat with another heat transfer medium, is cooled to the point E, and is condensed.

  The condensed high-pressure liquid refrigerant is divided into two, a main circuit 02M and a branch passage 030. The liquid refrigerant flowing through the branch passage 030 is decompressed to the point F by the auxiliary expansion valve 031 and flows to the intermediate cooler 022. On the other hand, the liquid refrigerant flowing through the main circuit 02M flows to the heat exchange unit 022a of the intermediate cooler 022. In the intermediate cooler 022, the liquid refrigerant from the branch passage 030 evaporates to cool the discharged gas refrigerant of the low-stage compressor 021 L (B → C), and supercool the liquid refrigerant in the heat exchange unit 022 a (E → G).

  On the other hand, the gas refrigerant in the branch passage 030 evaporated by the intermediate cooler 022 and the discharge gas refrigerant in the low-stage compressor 021L merge at point C. Thereafter, the gas refrigerant flows into the high stage compressor 021H. The liquid refrigerant in the main circuit 02M is depressurized from the point G of the heat exchanging part 022a to the point H by the expansion valve 025 and flows into the use side heat exchanger 026. In the use-side heat exchanger 026, for example, heat is exchanged with the freezer compartment air to evaporate, and the freezer air is cooled. Thereafter, the evaporative refrigerant returns to the point A and flows into the low-stage compressor 021L.

  As described above, the conventional extraction of a high-temperature or medium-temperature heat transfer medium has been performed mainly by heating the heat medium with the sensible heat and latent heat of condensation of the compressor discharge gas constituting the heat pump cycle. In this method, the amount of heat until liquefaction of the compressor discharge gas is divided between high temperature and medium temperature. Considering that high temperature extraction is mainly sensible heat utilization, the amount of heat obtained is about 20% or less from the discharge gas temperature to the condensation temperature range.

  Furthermore, since heat is exchanged by making the discharge gas and the heat transfer medium counter flow, when the discharge temperature decreases due to the operating conditions of the refrigeration cycle, sufficient heat exchange cannot be performed, resulting in insufficient heat. . For this reason, the problem that it becomes difficult to take out the high-temperature heat transfer medium occurs.

It is conventionally known that in a heat pump cycle apparatus, it is possible to take out a high-temperature heat transfer medium near 90 ° C. by operating CO ₂ as a refrigerant and operating in a supercritical state where the compressor discharge pressure is higher than the critical pressure.
However, when CO ₂ is operated in a supercritical state, the high pressure portion becomes a high pressure of about 10 to 12 MPa. Therefore, attention is required for operation, and the high pressure portion needs to have a pressure resistant structure. Furthermore, in the case of chasing in supercritical operation, the COP (coefficient of performance) is lowered, and there is a problem that the degree of freedom of operation is limited.
JP 2000-249413 A

  In view of the problems of the prior art, the present invention enables a high-temperature heat transfer medium to be stably generated in a two-stage compression heat pump cycle device, and simultaneously uses three types of heat transfer media of high temperature, medium temperature, and low temperature. An object of the present invention is to realize a heat pump cycle apparatus that can be taken out, can improve COP, and has a high degree of freedom in operation.

In order to achieve this object, the two-stage compression heat pump cycle device of the present invention,
NH ₃ is used as a heat medium, and the compressor is composed of a two-stage compressor composed of a low-stage compression section and a high-stage compression section with an intermediate cooler interposed therebetween,
Two-stage compression, in which the liquid heat medium discharged from the high-stage compression section and passed through the condenser exchanges heat with the gas heat medium discharged from the low-stage compression section in the intermediate cooler and then circulates to the low-stage compression section through the evaporator In heat pump cycle equipment,
The first heat transfer medium flow path is led to the condenser, and the first heat transfer medium is subjected to latent heat exchange with the gas heat medium in the condenser to generate a high-temperature heat transfer medium.
A second heat transfer medium flow path is led to the evaporator, and the second heat transfer medium is subjected to latent heat exchange with the liquid heat medium in the evaporator to generate a low-temperature heat transfer medium;
The first subcooler between the intercooler and the condenser, a second subcooler and respectively interposed between said evaporator and said intercooler,
The third heat transfer medium flow path is connected in series to the first subcooler via the second subcooler, and the third heat transfer medium is transferred to the liquid heat medium by the first and second subcoolers. And sensible heat exchange in the counter flow to produce an intermediate temperature heat transfer medium,
A first expansion valve is interposed between the first subcooler and the intermediate cooler, and a second expansion valve is interposed between the second subcooler and the evaporator, respectively. And

In the present invention, NH ₃ having advantages such as being friendly to the global environment, having a large heat transfer coefficient and heat absorption effect, high COP, and low price is used as a heat medium. As a result, the COP can be improved, and since the pressure in the high pressure portion is about 4 MPa, which is smaller than that of CO ₂ , a pressure resistant structure is not required and the operation is easy.
Further, since the high pressure portion does not become a supercritical pressure unlike the CO ₂ refrigerant, the COP does not decrease even when the reheating is performed. Therefore, there is an advantage that the degree of freedom of driving is wide.

Moreover, the condensation temperature in a condenser can be 65-80 degreeC, the intermediate temperature in an intermediate cooler can be 20-40 degreeC, and evaporation temperature can be -20-10 degreeC with an evaporator. By using the NH ₃ heat medium, a high heat medium temperature is obtained on the discharge side of the high-stage compression unit, and a high-temperature heat transfer medium is obtained by latent heat exchange between the heat medium and the heat transfer medium in the condenser. It can be taken out stably.

  The medium temperature heat transfer medium is taken out by the first subcooler and the second subcooler. That is, the third heat transfer medium flow path for taking out the intermediate temperature heat transfer medium passes through the second subcooler and then is connected in series to the first subcooler, so that the first and second subcoolers are provided. In sensible heat exchange with the liquid heat medium. Thereby, an intermediate temperature heat transfer medium of 40 to 60 ° C. can be generated.

Further, since the heat medium is supercooled by the first and second subcoolers, the amount of heat taken from the low-temperature heat transfer medium by the evaporator can be increased, thereby improving COP. In particular, compared to the conventional method, the amount of heat exchanged between the low-temperature heat transfer medium and the NH ₃ heat medium in the second subcooler is an increase in COP.

  In addition, when the degree of supercooling of the liquid heat medium increases, the dryness of the heat medium in the intermediate temperature range decreases. As a result, the flash gas during self-cooling of the heat medium is reduced, and the amount of gas heat medium generated in the intermediate pressure region is reduced, so that the intermediate pressure of the two-stage compression heat pump cycle is lowered. Therefore, there is an advantage that the power consumption of the high-stage compression section and the low-stage compression section is reduced. Furthermore, since the heat absorption capacity on the evaporator side is increased, the COP of the present apparatus is improved and the high-temperature heat transfer medium can be taken out more stably.

  As a use of the heat medium taken out at a high temperature, for example, the heat medium at 60 ° C. is heated to 70 ° C. and circulated, or used as a heat source for an adsorption refrigerator, or indirectly through a brine. It can also be used for hot water supply by exchanging heat. As an application of the generated intermediate temperature heat transfer medium, for example, the feed water at about 15 ° C. can be heated to 55 ° C. for hot water supply, or can be used for boiler feed water heating.

Applications of the heat transfer medium taken out at low temperatures include the use as a cooling process, an indirect system that supplies a brine such as CO ₂ brine by combining a low-pressure receiver and an evaporator, and the evaporator as a cascade capacitor. configured, the cascade condenser liquefies the CO ₂ refrigerant, a CO ₂ refrigerant can be used for _NH 3 -CO ₂ brine pump refrigeration system or the like for circulating a liquid pump.

In the device of the present invention, a first expansion valve is interposed between the first subcooler and the intercooler, and a second expansion valve is disposed between the second subcooler and the evaporator. By interposing, a two-stage compression heat pump cycle that forms an intermediate pressure region between the low-stage compression section and the high-stage compression section can be configured.

On the discharge side of the high-stage compression section, when the condensing temperature reaches about 80 ° C., the discharge pressure becomes around 4 MPa, so a structure without leakage of NH ₃ heating medium is required. Therefore, in the device of the present invention, it is preferable to provide a sealed motor or a sealed IPM motor that uses an aluminum wire as a stator winding to drive at least the high-stage compression section. As a result, the drive motor of the high-stage compression unit can be protected from corrosion by the NH ₃ heat medium, and the NH ₃ heat medium can be prevented from leaking outside the apparatus.

  In the device of the present invention, if the two-stage compressor is a single-unit two-stage compressor in which a high-stage compressor and a low-stage compressor are connected in series, the configuration of the two-stage compressor can be compactly combined. In addition, the installation space can be reduced and the power required for the compressor can be reduced. Furthermore, if the configuration of the hermetic motor and the configuration of a single-stage two-stage compressor are combined, a synergistic effect of each configuration can be obtained.

In the apparatus of the present invention, an oil separator is provided on the discharge side of the high-stage compression section, and NH ₃ discharged from the high-stage compression section is precooled by the condenser and then introduced into the oil separator. It is good to configure. With this configuration, the gas heat medium discharged at a high temperature from the high-stage compression section is once cooled by the condenser and then introduced into the oil separator, so that the durability of the elements constituting the oil separator is not deteriorated. In addition, by reducing the viscosity of the oil mist mixed in the gas heating medium, it is possible to improve the separation effect from the gas heating medium. In addition, by cooling the gas heating medium, the volume of the gas heating medium passing through the oil separator can be reduced, so that an appropriate passage flow rate can be ensured.

  Further, the oil separator is constituted by an oil separation element disposed so as to surround a flow inlet into which a mixed fluid composed of compressed gas and oil mist flows and is covered in a bag shape, and the oil separation element is formed from the inside. A rough separation prefilter element having a rough mesh diameter, a fine mesh diameter filter element capable of capturing oil mist, and a large number of gas heat medium passage holes, and the oil mist captured by the filter element facing outward. It is good to comprise from the three layers of the element for scattering prevention which prevents re-scattering.

In the NH ₃ heat medium, the temperature of the gas heat medium discharged from the high-stage compression unit is 100 ° C. or higher. On the other hand, a rough separation filter having a coarse mesh diameter is provided inside the filter element main body having a fine mesh diameter, and the filter element main body is up to 150 ° C. by separating scale and large oil mist in advance with the rough separation filter element. It is possible to ensure durability. Further, by providing a filter for preventing scattering on the outer peripheral side of the filter element body, it is possible to prevent the oil mist once separated from the gas heating medium from being scattered, so that the separation efficiency of the oil mist from the gas heating medium can be improved.

In addition, if an oil incompatible with the NH ₃ refrigerant is used as the lubricating oil for the two-stage compressor, the oil mist separation effect in the oil separator can be further improved.

It is a systematic diagram of the heat pump cycle device concerning a 1st embodiment of the present invention. It is a Mollier diagram of the heat pump cycle device concerning the 1st embodiment. It is a perspective view which cuts off a part and shows the hermetic motor used for the said 1st Embodiment. It is a schematic diagram of the compressor used in the said 1st Embodiment. It is a vertical elevation view of the oil separator used in the first embodiment. It is a partial systematic diagram of the heat pump cycle apparatus which concerns on 2nd Embodiment of this invention. It is a systematic diagram of the conventional two-stage compression refrigerator. It is a Mollier diagram of a conventional two-stage compression refrigerator.

Next, 1st Embodiment of this invention apparatus is described based on FIGS. FIG. 1 is a system diagram of a two-stage compression heat pump cycle apparatus using NH ₃ as a heat medium according to the present embodiment. In FIG. 1, an oil separator 12 is interposed in a discharge-side heat medium pipe 2 of a high-stage compressor 11 of a two-stage compression heat pump cycle apparatus 1, and the lubricating oil mixed with a gaseous heat medium in the high-stage compressor 11. Is separated by the oil separator 12, and the separated lubricating oil is returned to the high stage compressor 11 or the low stage compressor 19 described later via the return line 12a. In the present embodiment, a lubricating oil that is incompatible with the NH ₃ heating medium, for example, naphthenic mineral oil, alkylbenzene (synthetic oil), or the like is used.

A condenser 13 is interposed in the heat medium pipe 2 on the downstream side of the oil separator 12. A heat transfer medium line 14 is connected to the condenser 13 for exchanging heat with the gaseous NH ₃ heat medium to take out a high-temperature heat transfer medium, and a high-temperature take-out heat transfer medium a and a gas heat medium are connected to each other. Indirect latent heat exchange. In the condenser 13, the heat transfer medium a is subjected to latent heat exchange with a high-temperature gas heat medium so that the heat transfer medium a is heated and the gas heat medium is cooled and liquefied.

  A first subcooler 15 is interposed in the heat medium pipe 2 on the downstream side of the condenser 13. The first subcooler 15 is provided with a heat transfer medium line 16 for introducing the intermediate temperature extraction heat transfer medium b, where the heat transfer medium b and the liquid heat medium are subjected to sensible heat exchange, and the heat transfer medium b. While the heat medium b is heated, the liquid heat medium is supercooled. A first expansion valve 17 is interposed downstream of the first supercooler 15, and the liquid heat medium passes through the first expansion valve 17 and is depressurized, and then reaches the intermediate cooler 18.

The NH ₃ gas heat medium discharged from the low stage compressor 19 is supplied to the intermediate cooler 18 via the discharge side heat medium pipe 5 of the low stage compressor 19. A part of the liquid heat medium depressurized by the first expansion valve 17 evaporates by absorbing the heat of the gas heat medium supplied from the heat medium pipe 5 inside the intermediate cooler 18. Then, the gas heat medium n ₁ in the intermediate cooler 18 is introduced into the high stage compressor 11 through the heat medium pipe 3. The liquid heat medium n ₂ in the intermediate cooler 18 reaches the second subcooler 21 through the heat medium pipe 4.

  The second subcooler 21 is provided with an upstream side of the medium temperature extraction heat transfer medium line 16, and the medium temperature extraction heat transfer medium b is first exchanged with the liquid heat medium in the second subcooler 21. The liquid heat medium further increases the degree of supercooling. In this way, the intermediate temperature extraction heat medium line 16 is connected in series to the first subcooler 15 via the second subcooler 21, and the intermediate temperature extraction heat medium b is firstly connected to the second subcooler 21. After being preheated by the subcooler 21, the first supercooler 15 is further heated.

  A second expansion valve 22 is interposed in the downstream heat medium pipe 4 of the second subcooler 21, and the liquid heat medium is further depressurized through the second expansion valve 22. The depressurized heat medium reaches the evaporator 23. The evaporator 23 is provided with a low temperature take-out heat medium line 24. The low-temperature extraction heat medium c and the liquid heat medium are subjected to latent heat exchange in the evaporator 23, and the liquid heat medium takes the evaporative latent heat from the heat transfer medium c and evaporates to become a gas heat medium. And is compressed by the low-stage compressor 19. On the other hand, the heat transfer medium c is cooled and supplied to the application destination as a low-temperature heat transfer medium.

  In the present embodiment, the high-stage compressor 11 and the low-stage compressor 19 are configured as a single-stage two-stage compressor in which both rotary shafts are connected in series. That is, the high stage compressor 11 and the low stage compressor 19 are reciprocating compressors, and these pistons are connected to the same crankshaft via the piston rod and driven by the same crankshaft.

  Next, the operation of the heat pump cycle apparatus 1 of the present embodiment will be described with reference to the Mollier diagram of FIG. In FIG. 2, the symbols from A to H without a dash indicate the operating state of the conventional two-stage compression refrigeration apparatus 010 shown in FIG. 7, and this operating operation has already been explained in the Mollier diagram of FIG. is there. The operation operation of the heat pump cycle device 1 of the present embodiment is the same as the operation operation of the conventional two-stage compression refrigeration apparatus 010 from A to B, C, D, and to the point E.

That is, the low-pressure gas heating medium flows into the low stage compressor 19 from the state of the point A and is compressed to the point B by the low stage compressor 19. The gas heat medium discharged from the low-stage compressor 19 flows into the intermediate cooler 18 and is cooled by the liquid heat medium flowing into the intermediate cooler 18 from the heat medium pipe 2 and reaches the point C.

The gas heat medium n ₁ in the intermediate cooler 18 reaches the high stage compressor 11 and is compressed (point D), and the gas heat medium discharged from the high stage compressor 11 is cooled and condensed by the condenser 13. (Point E). The liquid refrigerant discharged from the condenser 13 is further cooled by the first supercooler 15 and reaches the supercooling zone (point E ′). The liquid refrigerant discharged from the first supercooler 15 is depressurized through the first expansion valve 17 and then reaches the intermediate cooler 18 (point F ′).

A part of the liquid heat medium depressurized through the first expansion valve 17 absorbs the heat held in the gas heat medium flowing from the discharge side heat medium pipe 5 of the low-stage compressor 19 by the intermediate cooler 18 and evaporates. (F ′ → C), and reaches the high stage compressor 11. On the other hand, the remaining liquid refrigerant n ₂ reaches the second subcooler 21 and is cooled by the intermediate temperature extraction heat medium b in the second subcooler 21 (F ′ → G ′). The liquid heat medium exiting the second subcooler 21 is depressurized through the second expansion valve 22 (G ′ → H ′), and then the latent heat of vaporization is removed from the low temperature extraction heat medium c by the evaporator 23. Evaporate (H '→ A). The evaporated gas heating medium is compressed again by the low-stage compressor 19 (A → B).

In the present embodiment, NH ₃ is used as a heat medium. However, NH ₃ is flammable and toxic, so it is necessary to prevent NH ₃ from leaking to the outside air. The high stage compressor 11 is required to have a structure with no NH ₃ leakage since the discharge pressure becomes about 4 MPa when the condensation temperature becomes about 80 ° C. Therefore, the driving device of the high-stage compressor 11 uses a hermetic motor using an aluminum wire that is not corroded by NH ₃ as a winding of the stator. Hereinafter, this structure will be described with reference to FIG.

  The hermetic motor 30 is coupled to a crankshaft that drives the pistons of the high-stage compressor 11 and the low-stage compressor 19, and drives the high-stage compressor 11 and the low-stage compressor 19. The hermetic motor 30 is, for example, a three-phase induction motor, and includes a substantially cylindrical pressure-resistant sealed casing 31, and a rotating shaft 33 is rotatably supported by a sealed ball bearing 32 on the casing 31. Yes. One end (right side of the drawing) of the rotating shaft 33 protrudes from the housing 31 and is coupled to the crankshafts of the high-stage compressor 11 and the low-stage compressor 19.

  A rotor 34 is attached to the rotary shaft 33, and a stator 35 is disposed inside a frame 31 a provided on the inner surface side of the housing 31 so as to surround the rotor 34. A winding 36 is attached to the stator 35. A terminal box 37 is connected to the casing 31, and the winding 36 is connected to the three-phase AC power source 43 from the terminal box 37 by a wiring 38 via a thermal relay 39, an electromagnetic contactor 41, and a circuit breaker 42. ing. The hermetic motor 30 is rotationally driven by this power supply mechanism.

As shown in FIG. 4, the compressor 50 used in the heat pump cycle apparatus 1 of the present embodiment is configured by a reciprocating high-stage compressor 11 and a low-stage compressor 19 arranged in parallel in a multi-cylinder type. Yes. In the crank chamber 51 of the compressor 50, pistons (not shown) of the high stage compressor 11 and the low stage compressor 19 are connected to a single crankshaft 52 via a piston rod.

  A rotary shaft 33 of the hermetic motor 30 is coupled by a crankshaft 52 and a coupling 53, and this coupled portion is between the compressor 50 and the hermetic between the crank chamber 51 and the housing 31 of the hermetic motor 30. It is located inside a connection casing 54 that completely integrates the mold motor 30 in an airtight state.

When the hermetic motor 30 rotates, the rotation is transmitted to the crankshaft 52 of the compressor 50 to drive the high-stage compressor 11 and the low-stage compressor 19. Although not shown, the housing 31 has inlet and outlet of the NH ₃ heating medium is provided by a portion of the NH ₃ heating medium is introduced from the conductor inlet in the casing 31, The hermetic motor 30 is cooled.

In FIG. 3, the rotor 34 is made of aluminum die cast, and the stator 35 has, for example, an insulating coating applied to the surface of a magnetic steel plate (JISC2522). The winding 36 is made of a high-purity aluminum wire, and the surface thereof is coated with a fluororesin perfluoroalkoxy (PFA). Aluminum wire has lower conductivity than copper wire, but it is not corroded by NH ₃ . Further, since the surface is coated with PFA having good insulation, followability to aluminum wire, crack resistance and heat deterioration resistance, durability against NH ₃ heat medium can be increased.

As the hermetic motor 30, an IPM motor (Interior Permanent Magnet Motor), which is a permanent magnet embedded synchronous motor, may be used instead of the three-phase induction motor. In the IPM motor, a permanent magnet is embedded in the rotor, and the stator is arranged so as to surround the rotor. By using the IPM motor, not only can the drive motor of the compressor 50 be made highly efficient and compact, but also the drive motor can be optimally controlled by rotational speed control such as so-called PAM rotational speed control ( the detailed structure of the case of applying a hermetic type motor or an IPM motor is used in a heat pump cycle device using NH ₃ heat medium as winding an aluminum wire lines, the applicant has previously filed JP 2004- No. 56990 publication).

Next, the structure of the oil separator 12 will be described with reference to FIG. In FIG. 5, an inlet opening 10a through which a mixed fluid d of NH ₃ heating medium and lubricating oil flows is provided in a partition wall 10 of the oil separator, and an oil separator 12 is attached to the lower part of the inlet opening 10a. The oil separator 12 includes an upper cover 122 having an opening 122a at the center, a cylindrical oil separation element structure 123, and a lower cover 124, and is screwed into a lower end portion of a mandrel 121 suspended from the center. The lower cover 124 is supported by the cylindrical large-diameter portion 121a, and is fixed to the inlet opening 10a of the oil separator 12.

  The oil separation element structure 123 has an upper opening. When the mixed fluid d flowing from the upper opening passes through the rough separation element 125 from the inside to the outside, that is, in the direction of the arrow e, the lubricating oil and dust are separated. The oil separation element structure 123 has a three-layer structure of a rough separation element 125, a regular separation element 126, and a scattering prevention element 127 from the inner peripheral side toward the outer peripheral side. A support member 128 for the regular separation element 126 is provided on the outer peripheral side of the regular separation element 126, and a guard member 129 for the scattering prevention element 127 is provided on the outer peripheral side of the scattering prevention element 127. The rough separation element 125 is composed of a metal rough wire mesh, and separates large oil mist and dust here.

  The regular separation element 126 is made of, for example, glass wool, has a porous sponge shape, has a fine mesh diameter, and fine oil mist is separated here. The scattering prevention element 127 has a large number of gas heat medium passage holes, and prevents the oil mist supplemented by the regular separation element 126 from re-scattering. By separating the oil mist in micron units by the oil separation element 123 having such a configuration, by providing the rough separation element 125, the possibility of damage to the regular separation element 126 due to dust can be reduced.

According to this embodiment having such a configuration, the NH ₃ heat medium having excellent heat medium characteristics is used, the discharge-side refrigerant temperature of the high stage compressor 11 is 100 ° C. or higher, and the condensation temperature in the condenser 13 is 65 to 80. It becomes ℃. Then, a high temperature extraction heat transfer medium line 14 is led to the condenser 13, and the heat transfer medium a flowing through the line 14 performs a latent heat exchange with the NH ₃ heat medium in a counter flow, and (D → E in FIG. 2). ), The high temperature heat transfer medium a of 60 to 75 ° C. can be taken out.

In addition, the intermediate temperature of the NH ₃ heat medium is 20 to 40 ° C. in the intermediate cooler 18, but the medium temperature extraction heat transfer medium line b is connected in series from the second subcooler 21 to the first subcooler 15. Since it is disposed and heated by sensible heat with the liquid heat medium in both the second subcooler 21 and the first subcooler 15, the amount of heat (E → G ′) in FIG. 2 is absorbed. The medium-temperature heat transfer medium b at 40 to 60 ° C. can be taken out. For example, when the temperature of the condensed heat medium liquid on the discharge side of the condenser 13 is 60 ° C., the heat transfer medium b at about 55 ° C. can be taken out.

  Then, in the evaporator 23, the heat transfer medium c for taking out at low temperature and the liquid heat medium perform latent heat exchange, whereby the amount of latent heat of evaporation for (H ′ → A) in FIG. 2 is obtained. Thereby, a low temperature heat transfer medium of −15 to 10 ° C. can be taken out.

  In the medium temperature extraction heat transfer medium line b, since the liquid heat medium is supercooled in two stages of the first subcooler 15 and the second subcooler 21, as shown in FIG. The refrigeration effect increases by Δh, and the amount of latent heat of evaporation in the evaporator 23 increases.

  For example, the enthalpy of the liquid heat medium whose intermediate temperature of the intermediate cooler 18 is 40 ° C. is 145.6 kcal / kg, and when it is subcooled to 15 ° C. by the second subcooler 21, the enthalpy of the liquid refrigerant is 117. Since it is .8 kcal / kg, the increase in the freezing effect is Δh = 145.6-117.8 = 27.8 kcal / kg. This increase corresponds to about 10% of the latent heat of evaporation absorbed when the liquid heat medium rises from −20 ° C. to 10 ° C. in the evaporator 23. From this, an increase in the heat absorption effect of about 10% at the maximum is expected.

  Further, by increasing the degree of supercooling of the liquid heat medium by the first subcooler 15 and the second subcooler 21, the dryness of the heat medium in the intermediate temperature range is decreased, and thereby the heat medium The self-cooled flash gas is reduced. Accordingly, since the circulation amount of the gas heat medium in the intermediate pressure region is reduced, the intermediate pressure is reduced, and the power consumption of the high stage compressor 11 and the low stage compressor 19 is reduced. Furthermore, the COP of the heat pump cycle apparatus 1 is improved by the improvement of the heat absorption capability in the evaporator 23, and the high-temperature heat transfer medium can be taken out stably.

Further, by using the NH3 heat medium, since the pressure of the high pressure section is smaller than in the case of 4MPa about and CO _2, without requiring a pressure-resistant structure, is easy operation. Further, since the high pressure portion does not become a supercritical pressure unlike the CO ₂ refrigerant, the COP does not decrease even when the reheating is performed. Therefore, there is an advantage that the degree of freedom of driving is wide.

  In addition, since the reciprocating compressor is used as the high stage compressor 11 of the compressor 50, the reciprocating compressor does not include a large amount of lubricating oil in the gas heat medium on the discharge side. Can be ensured, and the temperature of the gas heating medium can be increased. Incidentally, in the screw compressor, since a large amount of lubricating oil is interposed in the gas heat medium on the discharge side, the circulation amount of the heat medium is decreased, and the temperature of the gas heat medium is decreased.

Further, as a driving means of the compressor 50, a hermetic motor 30 using an aluminum wire is provided in the winding 36 of the stator 35, and the NH ₃ heat medium does not leak to the outside. There is no fear that NH ₃ that is toxic and highly corrosive leaks to the outside, and there is no concern that the drive motor of the compressor 50 is corroded by NH ₃ .

  In this embodiment, since the drive shafts of the high-stage compressor 11 and the low-stage compressor 19 have a single-machine two-stage structure in which the drive shafts are connected to a single crankshaft 52, the installation space for the heat pump cycle device 1 is reduced. The driving power of the high stage compressor 11 and the low stage compressor 19 can be reduced.

In the present embodiment, the oil separator 12 having the configuration shown in FIG. 5 is provided on the discharge side of the high stage compressor 11, so that the lubricating oil mixed in the gas heat medium discharged from the high stage compressor 11 can be supplied. Since the lubricating oil that can be separated with high accuracy and is incompatible with NH ₃ is used as the lubricating oil, the lubricating oil mixed in the NH ₃ heating medium can be separated in micron units.

Next, 2nd Embodiment of this invention apparatus is described based on FIG. In FIG. 6, in the present embodiment, in the discharge side heat medium pipe of the high stage compressor 11, the heat medium pipe 2 a that introduces the heat medium discharged from the high stage compressor 11 into the condenser 13 and the condenser 13 are manifested. A heat medium pipe 2b for introducing the refrigerant after heat heat exchange into the oil separator 12 is provided. Other configurations are the same as those in the first embodiment, including the use of NH ₃ as a heat medium, and thus the description of the same parts is omitted.

In the present embodiment, the high-temperature gas heat medium discharged from the high-stage compressor 11 is once guided to the condenser 13 and precooled by causing the condenser 13 to exchange sensible heat with the high-temperature extraction heat transfer medium a in a counterflow. Thereafter, a gas heating medium is introduced into the oil separator 12. The NH ₃ heating medium discharged from the high stage compressor 11 has a temperature of 100 ° C. or higher. Without introducing this high-temperature gas heating medium directly into the oil separator 12, the sensible heat is once exchanged in the condenser 13, precooled to a temperature of 100 ° C. or lower, and introduced into the oil separator 12. The durability of the separation element of the separator 12 can be prevented from being deteriorated by the high heat of the gas heating medium.

  In addition, by precooling the gas heat medium discharged from the high-stage compressor 11 and introducing it into the oil separator 12, the volume of the gas heat medium passing through the separation element of the oil separator 12 can be reduced. Therefore, an appropriate passage flow rate can be ensured. In addition, the same operational effects as those of the first embodiment can be obtained.

According to the present invention, in a two-stage compression heat pump cycle device using NH ₃ heat medium, heat transfer media in three temperature ranges of high temperature, medium temperature and low temperature can be taken out simultaneously, COP can be improved, and It is possible to realize a heat pump cycle device capable of separating the lubricating oil mixed in the gas heat medium with high accuracy on the discharge side of the high stage compressor.

Claims (6)

NH ₃ is used as a heat medium, and the compressor is composed of a two-stage compressor composed of a low-stage compression section and a high-stage compression section with an intermediate cooler interposed therebetween,
Two-stage compression, in which the liquid heat medium discharged from the high-stage compression section and passed through the condenser exchanges heat with the gas heat medium discharged from the low-stage compression section in the intermediate cooler and then circulates to the low-stage compression section through the evaporator In heat pump cycle equipment,
The first heat transfer medium flow path is led to the condenser, and the first heat transfer medium is subjected to latent heat exchange with the gas heat medium in the condenser to generate a high-temperature heat transfer medium.
A second heat transfer medium flow path is led to the evaporator, and the second heat transfer medium is subjected to latent heat exchange with the liquid heat medium in the evaporator to generate a low-temperature heat transfer medium;
The first subcooler between the intercooler and the condenser, a second subcooler and respectively interposed between said evaporator and said intercooler,
The third heat transfer medium flow path is connected in series to the first subcooler via the second subcooler, and the third heat transfer medium is transferred to the liquid heat medium by the first and second subcoolers. And sensible heat exchange in the counter flow to produce an intermediate temperature heat transfer medium,
A first expansion valve is interposed between the first subcooler and the intermediate cooler, and a second expansion valve is interposed between the second subcooler and the evaporator, respectively. A two-stage compression heat pump cycle device. 2. The two-stage compression heat pump cycle apparatus according to claim 1, further comprising a hermetically sealed motor or a hermetically sealed IPM motor using an aluminum wire as a stator winding for driving at least the high-stage compression unit. 2. The two-stage compression heat pump cycle apparatus according to claim 1, wherein the two-stage compressor is a single-stage two-stage compressor in which a high-stage compression section and a low-stage compression section are connected in series. An oil separator is provided on the discharge side of the high-stage compression section, and the NH ₃ heat medium discharged from the high-stage compression section is precooled by the condenser and then introduced into the oil separator. The two-stage compression heat pump cycle device according to claim 1 . The oil separator is composed of an oil separation element disposed so as to surround a flow inlet into which a mixed fluid composed of compressed gas and oil mist flows and covers the bag.
The oil separation element has, from the inside toward the outside, a rough separation pre-filter element having a coarse mesh diameter, a fine mesh diameter filter element capable of capturing oil mist, and a large number of gas heat medium passage holes. 5. The two-stage compression heat pump cycle device according to claim 4 , wherein the two-stage compression heat pump cycle device comprises three layers of anti-scattering elements that prevent re-entrainment of oil mist captured by the filter element. The two-stage compression heat pump cycle device according to claim 4 or 5 , wherein oil that is incompatible with NH ₃ refrigerant is used as lubricating oil for the two-stage compressor.

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