JP2017161182A - Heat pump device - Google Patents

Abstract

A heat storage amount of a heat medium is increased by suppressing a decrease in evaporation capacity of a first refrigeration circuit when the degree of superheat of the first refrigerant increases at the evaporator outlet of the first refrigeration circuit, and the flow rate of the second refrigerant is increased. To provide a heat pump device with high energy saving performance by suppressing a decrease in heat exchange efficiency due to stagnation of refrigerating machine oil in an evaporator due to a decrease. A compressor, a condenser, a throttling means, and an evaporator are connected in a ring shape with a pipe to circulate a first refrigerant, and the condenser and the throttling means. A bypass circuit 8 connected between the evaporator 4 and the compressor 1, a bypass throttling means 9 disposed in the bypass circuit 8, and a second refrigerant are circulated, and the evaporator 4, a second refrigeration circuit 19 that performs heat exchange with the first refrigeration circuit 5, and a control unit 20, wherein the control unit 20 has a temperature of the first refrigerant sucked into the compressor 1 at a predetermined value. In the above case, the bypass throttling means 9 is adjusted so that the flow rate of the first refrigerant flowing through the bypass circuit 8 is increased. [Selection] Figure 1

Description

  The present invention relates to a heat pump device that bypasses a refrigerant that has flowed out of a condenser between a compressor and an evaporator in a high-stage side cycle of a dual refrigeration cycle.

Conventionally, as shown in FIG. 9, this type of heat pump apparatus includes an refrigeration cycle 59 for air conditioning and a refrigeration cycle 63 for hot water supply.
The air-conditioning refrigeration cycle 59 includes an air-conditioning compressor 50, an outdoor heat exchanger 51, and outdoor heat exchanger opening / closing means 52a and 52b, an outdoor heat exchanger throttle means 53, an indoor heat exchanger 54, and an indoor heat exchange. Opening / closing means 55a and 55b and the indoor heat exchanger throttle means 56 are connected in series, and the refrigerant-refrigerant heat exchanger 57 and the hot water supply heat source throttle means 58 are connected in series to connect the indoor heat exchanger 54 and the indoor The heat exchanger opening / closing means 55a, 55b and the indoor heat exchanger throttle means 56 are connected in parallel to circulate the air conditioning refrigerant.
The hot water supply refrigeration cycle 63 includes a hot water supply compressor 60, a heat medium-refrigerant heat exchanger 61, a hot water supply throttling means 62, and a refrigerant-refrigerant heat exchanger 57 connected in series. Circulate.
The refrigeration cycle 59 for air conditioning and the refrigeration cycle 63 for hot water supply are connected by the refrigerant-refrigerant heat exchanger 57 so as to exchange heat between the air conditioning refrigerant and the hot water supply refrigerant. There is one that can perform the cooling or heating operation and the heating operation of the hot water supply heat medium in the hot water supply refrigeration cycle 63 at the same time.

International Publication WO2009 / 098751

However, in the conventional configuration, when the heating load is high in the air-conditioning refrigeration cycle 59 or when the condensing temperature is high (for example, 50 ° C.) as in the cooling operation under a condition where the outside air temperature is high. When the evaporating temperature of the hot water supply refrigeration cycle 63 is increased by the air-conditioning refrigeration cycle 59 in the refrigerant-refrigerant heat exchanger 57 and the enthalpy difference equivalent to that when the evaporating temperature is low is secured, the refrigerant-refrigerant heat exchange is performed. The degree of superheat of the hot water supply refrigerant at the outlet of the heater 57 tends to increase.
In such a case, since the suction density of the hot water supply refrigerant in the hot water supply compressor 60 decreases and the flow rate of the first refrigerant decreases, the capacity of the hot water supply refrigeration cycle 63 decreases as compared with the case where the degree of superheat is small. .

By the way, when the temperature of the heat medium (for example, water) flowing into the heat medium-refrigerant heat exchanger 61 in the hot water supply refrigeration cycle 63 increases, the temperature of the hot water supply refrigerant at the outlet of the heat medium-refrigerant heat exchanger 61 also increases. The enthalpy increases.
Accordingly, the enthalpy of the hot water supply refrigerant at the inlet of the refrigerant-refrigerant heat exchanger 57 that becomes equal enthalpy also increases, the enthalpy difference of the hot water supply refrigerant in the refrigerant-refrigerant heat exchanger 57 decreases, and the refrigeration cycle 63 for hot water supply Evaporation capacity decreases.
In particular, under conditions where the temperature of the heat medium flowing into the heat medium-refrigerant heat exchanger 61 is highest,
The evaporation capacity of the hot water supply refrigeration cycle 63 is minimized.

On the other hand, the air-conditioning refrigerant cycle 59 that covers both air-conditioning and hot-water supply capacities has a higher rated capacity than the hot-water supply refrigeration cycle 63, but also has a minimum capacity.
When the condensing capacity of the air-conditioning refrigeration cycle 59 exceeds the evaporation capacity of the hot water supply refrigeration cycle 63 in the refrigerant-refrigerant heat exchanger 57, the air-conditioning refrigeration cycle 59 becomes overheated and the high pressure rises. Exceeds the usable range.

  Therefore, the heat pump device is stopped before the temperature of the heat medium flowing into the heat medium-refrigerant heat exchanger 61 becomes the highest so that the condensation capacity of the air-conditioning refrigeration cycle 59 does not exceed the evaporation capacity of the hot water supply refrigeration cycle 63. There is a need to.

  When storing the heat medium, the amount of heat stored in the heat medium when the heat pump device is stopped before the temperature of the heat medium flowing into the heat medium-refrigerant heat exchanger 61 becomes the highest becomes the highest temperature of the heat medium. Therefore, the amount of heat medium that can be used by the user is reduced.

  In order to solve the above-described conventional problems, the heat pump device of the present invention includes a first refrigeration circuit that circulates a first refrigerant by connecting a compressor, a condenser, a throttle means, and an evaporator in a ring shape, and the condensation. A bypass circuit connected between the evaporator and the compressor, a bypass throttle means disposed in the bypass circuit, and a second refrigerant are circulated from between the condenser and the throttle means, and the evaporation A second refrigeration circuit for exchanging heat with the first refrigeration circuit in a cooler, and a control unit, wherein the control unit is configured such that when the temperature of the first refrigerant sucked into the compressor is equal to or higher than a predetermined value, The bypass throttling means is adjusted so that the flow rate of the first refrigerant flowing through the bypass circuit is increased.

As a result, the first refrigerant from the evaporator having a large degree of superheat and the first refrigerant from the condenser outlet having a low degree of dryness are mixed at the outlet of the evaporator, and the first refrigerant sucked into the compressor is mixed. The degree of superheat decreases.
Therefore, compared with the case where the superheat degree of the 1st refrigerant | coolant suck | inhaled by a compressor is large, the suction density of a 1st refrigerant | coolant is improved, the flow volume of a 1st refrigerant | coolant increases, and the evaporation capability fall of a 1st freezing circuit is suppressed. It will be.

Moreover, by suppressing the evaporation capability fall of a 1st freezing circuit, the condensation capacity fall of the 2nd freezing circuit which performs heat exchange with an evaporator is suppressed, and the fall of the flow volume of a 2nd refrigerant | coolant is suppressed.
Therefore, stagnation of refrigeration oil due to insufficient flow rate of the second refrigerant in the second refrigeration circuit in the evaporator is prevented, and heat transfer inhibition by the refrigeration oil is prevented.

  The heat pump device of the present invention reduces the evaporation capacity of the first refrigeration circuit even when the second refrigeration circuit has a high load and the condensation temperature increases and the degree of superheat of the first refrigerant increases at the evaporator outlet of the first refrigeration circuit. The heat pump device can be operated until the temperature of the heat medium flowing into the condenser rises, and the heat storage amount of the heat medium can be increased, and the decrease in heat exchange efficiency due to the stagnation of refrigeration oil in the evaporator is suppressed. , Energy saving can be improved.

FIG. 3 is a refrigerant circuit diagram of the heat pump device in Embodiment 1 of the present invention. Refrigerant circuit diagram in the case where the second refrigeration circuit of the heat pump device according to Embodiment 1 of the present invention is operated for heating and the first refrigeration circuit is also operated. Refrigerant circuit diagram when cooling the second refrigeration circuit of the heat pump device in Embodiment 1 of the present invention and operating the first refrigeration circuit as well Refrigerant circuit diagram in the case where the second refrigeration circuit of the heat pump device according to Embodiment 1 of the present invention is operated simultaneously with cooling and heating, and the first refrigeration circuit is also operated. Refrigerant circuit diagram in the case where the indoor heat exchanger of the second refrigeration circuit of the heat pump device according to Embodiment 1 of the present invention is changed to perform the cooling and heating simultaneous operation and the first refrigeration circuit is also operated. Control flow diagram in the embodiment of the present invention Refrigerant circuit diagram of heat pump device in Embodiment 2 of the present invention Refrigerant circuit diagram when the branch position of bypass circuit 8 of the heat pump device in Embodiment 2 of the present invention is different Refrigerant circuit diagram of a conventional heat pump device

According to a first aspect of the present invention, a compressor, a condenser, a throttle means, and an evaporator are connected in a ring shape with a pipe, and one end is provided between the first refrigeration circuit for circulating the first refrigerant, and the condenser and the throttle means. A bypass circuit connected at the other end between the evaporator and the compressor, a bypass throttling means disposed in the bypass circuit, and a second refrigerant circulated. A second refrigeration circuit for exchanging heat with one refrigeration circuit, and a control unit, wherein the control unit is configured to switch the bypass circuit when the temperature of the first refrigerant sucked into the compressor is equal to or higher than a predetermined value. By adjusting the opening degree of the bypass throttling means so that the flow rate of the flowing first refrigerant increases, the first refrigerant from the evaporator having a large superheat degree and the outlet of the condenser having a low dryness can be obtained at the evaporator outlet. The first refrigerant is mixed and sucked into the compressor 1 degree of superheat of the refrigerant is reduced.
Therefore, compared with the case where the superheat degree of the 1st refrigerant | coolant suck | inhaled by a compressor is large, the suction density of a 1st refrigerant | coolant is improved, the flow volume of a 1st refrigerant | coolant increases, and the evaporation capability fall of a 1st freezing circuit is suppressed. It will be.

Moreover, by suppressing the evaporation capability fall of a 1st freezing circuit, the condensation capacity fall of the 2nd freezing circuit which performs heat exchange with an evaporator is suppressed, and the fall of the flow volume of a 2nd refrigerant | coolant is suppressed.
Therefore, stagnation of refrigeration oil due to insufficient flow rate of the second refrigerant in the second refrigeration circuit in the evaporator is prevented, and heat transfer inhibition by the refrigeration oil is prevented.
Therefore, even when the second refrigeration circuit has a high load and the condensation temperature becomes high and the superheat degree of the first refrigerant increases at the evaporator outlet of the first refrigeration circuit, the decrease in the evaporation capacity of the first refrigeration circuit is suppressed. The heat pump device can be operated until the temperature of the heat medium flowing into the chamber rises, and the heat storage amount of the heat medium can be increased, and the decrease in heat exchange efficiency due to refrigeration oil stagnation in the evaporator is improved, improving energy savings it can.

According to a second aspect of the present invention, a supercooling heat exchanger is provided between the condenser and the throttling means, and the supercooling heat exchanger flows out of the first refrigerant that has flowed out of the condenser and the bypass throttling means. The first refrigeration circuit and the bypass circuit are connected so as to exchange heat with the first refrigerant, and the control unit is configured when the temperature of the first refrigerant sucked into the compressor is equal to or higher than a predetermined value. The temperature of the first refrigerant at the outlet of the supercooling heat exchanger of the first refrigeration circuit is lowered and the evaporator is adjusted by adjusting the bypass throttling means so that the flow rate of the first refrigerant flowing through the bypass circuit is increased. At the outlet, the first refrigerant from the evaporator having a high degree of superheat and the first refrigerant from the bypass circuit having a low degree of dryness are mixed, and the degree of superheat of the first refrigerant sucked into the compressor is reduced. To do.
Accordingly, the enthalpy difference of the first refrigeration circuit in the evaporator is increased, and the refrigerant density on the high pressure side of the first refrigeration circuit is decreased to lower the high pressure.
Further, the suction density of the first refrigerant is improved and the flow rate of the first refrigerant is increased as compared with the case where the degree of superheat of the first refrigerant sucked into the compressor is large.
Therefore, even when the degree of superheat is increased in the evaporator and the high pressure of the first refrigeration circuit is increased, the rotational speed is reduced due to the high pressure restriction of the compressor, and the enthalpy difference of the first refrigeration circuit in the evaporator is reduced. In addition, the flow rate of the first refrigerant is increased, and the decrease in the evaporation capacity of the first refrigeration circuit is suppressed.

Moreover, the temperature of the 1st refrigerant | coolant of the evaporator entrance of a 1st freezing circuit falls by reducing the temperature of the 1st refrigerant | coolant of the supercooling heat exchanger exit of a 1st freezing circuit, and heat exchange is carried out with an evaporator. The temperature on the low temperature side of the second refrigerant in the second refrigeration circuit to be performed also decreases.
Therefore, the enthalpy difference of the 2nd freezing circuit in an evaporator is increased.
As a result, the second refrigeration circuit is heavily loaded and the condensing temperature is increased, the degree of superheat of the first refrigerant is increased at the evaporator outlet of the first refrigeration circuit, and the heat medium flowing out from the condenser is at a high temperature. Even when the high pressure of the circuit is high, that is, even when high temperature water is discharged, the heat pump device can be operated until the temperature of the heat medium flowing into the condenser becomes high. The heat storage amount can be increased, and the condensing capacity can be increased without increasing the flow rate of the second refrigerant in the second refrigeration circuit, thereby improving the energy saving performance.

In a third aspect based on the second aspect, the bypass circuit has one end connected between the condenser and the supercooling heat exchanger, and the other end between the evaporator and the compressor. By being connected, the temperature of the first refrigerant at the outlet of the supercooling heat exchanger of the first refrigeration circuit is lowered and the evaporator having a high degree of superheat is provided at the outlet of the evaporator as in the second invention. The first refrigerant from the bypass circuit having a low dryness is mixed, and the degree of superheat of the first refrigerant sucked into the compressor is reduced.
Accordingly, the enthalpy difference of the first refrigeration circuit in the evaporator is increased, and the refrigerant density on the high pressure side of the first refrigeration circuit is decreased to lower the high pressure.
Further, the suction density of the first refrigerant is improved and the flow rate of the first refrigerant is increased as compared with the case where the degree of superheat of the first refrigerant sucked into the compressor is large.
Therefore, even when the degree of superheat is increased in the evaporator and the high pressure of the first refrigeration circuit is increased, the rotational speed is reduced due to the high pressure restriction of the compressor, and the enthalpy difference of the first refrigeration circuit in the evaporator is reduced. In addition, the flow rate of the first refrigerant is increased, and the decrease in the evaporation capacity of the first refrigeration circuit is suppressed.

In a fourth aspect based on the second aspect, the bypass circuit has one end connected between the supercooling heat exchanger and the throttling means, and the other end between the evaporator and the compressor. By being connected, the temperature of the first refrigerant at the outlet of the supercooling heat exchanger of the first refrigeration circuit is lowered and the evaporator having a high degree of superheat is provided at the outlet of the evaporator as in the second invention. The first refrigerant from the bypass circuit having a low dryness is mixed, and the degree of superheat of the first refrigerant sucked into the compressor is reduced.
Accordingly, the enthalpy difference of the first refrigeration circuit in the evaporator is increased, and the refrigerant density on the high pressure side of the first refrigeration circuit is decreased to lower the high pressure.
Further, the suction density of the first refrigerant is improved and the flow rate of the first refrigerant is increased as compared with the case where the degree of superheat of the first refrigerant sucked into the compressor is large.
Therefore, even when the degree of superheat is increased in the evaporator and the high pressure of the first refrigeration circuit is increased, the rotational speed is reduced due to the high pressure restriction of the compressor, and the enthalpy difference of the first refrigeration circuit in the evaporator is reduced. In addition, the flow rate of the first refrigerant is increased, and the decrease in the evaporation capacity of the first refrigeration circuit is suppressed.

According to a fifth aspect of the present invention, a compressor suction temperature detecting means for detecting the temperature of the first refrigerant sucked into the compressor is provided, so that the temperature of the first refrigerant sucked into the compressor is directly controlled. By adjusting the opening of the bypass throttling means so that the flow rate of the first refrigerant flowing through the bypass circuit is increased when the temperature of the first refrigerant is greater than or equal to a predetermined value, at the evaporator outlet, The first refrigerant from the evaporator with a high degree of superheat and the first refrigerant at the outlet of the condenser with a low degree of dryness are mixed, and the degree of superheat of the first refrigerant drawn into the compressor is reduced.
Therefore, compared with the case where the superheat degree of the 1st refrigerant | coolant suck | inhaled by a compressor is large, the suction density of a 1st refrigerant | coolant is improved, the flow volume of a 1st refrigerant | coolant increases, and the evaporation capability fall of a 1st freezing circuit is suppressed. It will be.

According to a sixth aspect of the present invention, the control unit is detected by the compressor suction temperature detecting means by including a compressor suction pressure detecting means for detecting the pressure of the first refrigerant sucked into the compressor. The degree of opening of the bypass throttle means can be adjusted based on the degree of superheat determined from the difference between the temperature and the saturation temperature calculated based on the pressure detected by the compressor suction pressure detection means. As in the above invention, the first refrigerant from the evaporator having a high degree of superheat and the first refrigerant from the condenser outlet having a low dryness are mixed at the outlet of the evaporator and sucked into the compressor. The superheat degree of the 1st refrigerant | coolant made falls.
Therefore, compared with the case where the superheat degree of the 1st refrigerant | coolant suck | inhaled by a compressor is large, the suction density of a 1st refrigerant | coolant is improved, the flow volume of a 1st refrigerant | coolant increases, and the evaporation capability fall of a 1st freezing circuit is suppressed. It will be.

According to a seventh aspect of the present invention, the controller is provided with first refrigeration circuit evaporator inlet temperature detection means for detecting the inlet temperature of the evaporator, so that the control unit detects the temperature detected by the compressor suction temperature detection means, The degree of opening of the bypass throttling means can be adjusted based on the degree of superheat determined from the difference between the temperature detected by the first refrigeration circuit evaporator inlet temperature detecting means, At the evaporator outlet, the first refrigerant from the evaporator having a large degree of superheat and the first refrigerant at the outlet of the condenser having a low degree of dryness are mixed, and the degree of superheat of the first refrigerant sucked into the compressor. Decreases.
Therefore, compared with the case where the superheat degree of the 1st refrigerant | coolant suck | inhaled by a compressor is large, the suction density of a 1st refrigerant | coolant is improved, the flow volume of a 1st refrigerant | coolant increases, and the evaporation capability fall of a 1st freezing circuit is suppressed. It will be.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a refrigerant circuit diagram of a heat pump device 100 according to the first embodiment of the present invention. In FIG. 1, the heat pump device includes two refrigeration circuits, a first refrigeration circuit 5 and a second refrigeration circuit 19.

The first refrigeration circuit 5 is configured by connecting the compressor 1, the condenser 2, the throttling means 3, and the evaporator 4 in series with a refrigerant pipe. In the first refrigeration circuit 5, the first refrigerant is circulated. The first refrigeration circuit 5 includes a bypass circuit 8 that connects a liquid pipe 50 between the condenser 2 and the throttling means 3 and a gas pipe 60 between the evaporator 4 and the compressor 1. That is, the bypass circuit 8 has one end connected to the liquid pipe 50 and the other end connected to the gas pipe 60. A connection location between the bypass circuit 8 and the liquid pipe 50 is defined as a bypass circuit liquid pipe connection port 51. Further, a connection point between the bypass circuit 8 and the gas pipe 60 is a bypass circuit gas pipe connection port 61.
The bypass circuit 8 includes bypass throttling means 9 that adjusts the flow rate of the first refrigerant flowing through the bypass circuit 8. Between the bypass throttle means 9 and the gas pipe 60, a bypass throttle means outlet temperature detection means 22 is provided.

A compressor discharge temperature detection means 6 is provided between the compressor 1 and the condenser 2. The compressor discharge temperature detection means 6 detects the temperature of the first refrigerant discharged from the compressor 1.
A condenser outlet temperature detecting means 31 is provided between the condenser 2 and the bypass circuit liquid pipe connection port 51. The condenser outlet temperature detection means 31 detects the temperature of the first refrigerant at the outlet of the condenser 2.
A first refrigeration circuit evaporator inlet temperature detection means 23 is provided between the first throttling means 3 and the evaporator 4. The first refrigeration circuit evaporator inlet temperature detection means 23 detects the temperature of the first refrigerant at the inlet of the evaporator 4.

A compressor suction temperature detecting means 7 is provided between the bypass circuit gas pipe connection port 61 and the compressor 1. The compressor suction temperature detection means 7 detects the temperature of the first refrigerant discharged from the compressor 1.
Further, a compressor suction pressure detection means 21 is provided between the bypass circuit gas pipe connection port 61 and the compressor 1. The compressor suction pressure detection means 21 is provided between the compressor 1 and the compressor suction temperature detection means 7.

  The evaporator 4 is a refrigerant-refrigerant heat exchanger that exchanges heat between the first refrigerant and the second refrigerant, and a plate heat exchanger or a double-pipe heat exchanger is used.

  On the other hand, the second refrigeration circuit 19 is an indoor unit disposed at one inlet of the second compressor 11, indoor heat exchangers 12a and 12b for exchanging heat with room air, and indoor heat exchangers 12a and 12b. Heat exchanger opening / closing means 13a, 13b, 13c, 13d, indoor heat exchanger throttle means 14a, 14b, arranged at the other inlet of the indoor heat exchangers 12a, 12b, exchanges heat with outdoor air. Outdoor heat exchanger 15, outdoor heat exchanger opening / closing means 16 a, 16 b disposed at one inlet of outdoor heat exchanger 15, outdoor heat exchanger throttle disposed at the other inlet of outdoor heat exchanger 15 The means 17 is connected in series by the refrigerant pipe, and the evaporator 4 and the evaporator throttle means 18 are connected in series to be connected to the indoor heat exchangers 12a and 12b and the indoor heat exchanger open / close means 13a, 13b, 13c, and 13d. , Inner heat exchanger throttle means 14a, 14b and is constructed by connecting in parallel by refrigerant pipes, for circulating the second refrigerant.

  The heat pump apparatus 100 includes a control unit 20 as a control unit for the first refrigeration circuit 5 and the second refrigeration circuit 19. The control unit 20 centrally controls each part of the heat pump apparatus, and includes a CPU, a ROM that stores an executable basic control program and data related to the basic control program, and a program executed by the CPU. And RAM for temporarily storing predetermined data, and other peripheral circuits.

  Further, as the first refrigerant and the second refrigerant, natural refrigerants such as carbon dioxide (CO2) are used in addition to chlorofluorocarbon refrigerants such as R22, R410A, R407C, R32, and R134a. R407C, R134a and carbon dioxide (CO2) widely used for high temperature applications are desirable.

About the heat pump apparatus 100 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.
First, when the second refrigeration circuit 19 is heated using the indoor heat exchangers 12a and 12b as condensers and the first refrigeration circuit 5 is also operated, the air is discharged from the second compressor 11 as shown in FIG. The second refrigerant flows into the indoor heat exchanger 12a through the open indoor heat exchanger opening / closing means 13b and dissipates heat to the indoor air. In this case, the second refrigerant discharged from the second compressor 11 flows into the indoor heat exchanger 12b through the open indoor heat exchanger opening / closing means 13d and radiates heat to the indoor air. In this case, the second refrigerant discharged from the second compressor 11 flows into the evaporator 4 and is absorbed by the first refrigerant.

In the first refrigeration circuit 5, the first refrigerant discharged from the compressor 1 dissipates heat in the condenser 2 and is throttled by the throttle means 3 based on the temperature detected by the compressor discharge temperature detection means 6. It flows into the evaporator 4, absorbs heat from the second refrigerant, and is sucked into the compressor 1. The first refrigerant that has passed through the condenser 2 flows through the bypass circuit 8 according to the opening degree of the bypass throttling means 9, and merges with the first refrigerant that has absorbed heat from the second refrigerant in the evaporator 4.
The opening degree of the throttle means 3 is adjusted based on the temperature detected by the compressor discharge temperature detecting means 6.

  And the 2nd refrigerant | coolant absorbed into the 1st refrigerant | coolant in the evaporator 4 passes through the throttle means 18 for evaporators substantially without being squeezed. The second refrigerant that has flowed out of the indoor heat exchangers 12a and 12b passes through the indoor heat exchanger throttle means 14a and 14b without being substantially throttled. The second refrigerant that has passed through the evaporator throttle means 18, the indoor heat exchanger throttle means 14 a, and the indoor heat exchanger throttle means 14 b merges and is throttled by the outdoor heat exchanger throttle means 17 to the outdoor heat exchanger 15. It flows in, absorbs heat from the outdoor air, and is sucked into the second compressor 11 through the open outdoor heat exchanger opening / closing means 16a. In this case, the indoor heat exchanger opening / closing means 13a, 13c and the outdoor heat exchanger opening / closing means 16b are closed so that the second refrigerant does not flow.

  Next, when the second refrigeration circuit 19 is cooled using the indoor heat exchangers 12a and 12b as evaporators and the first refrigeration circuit 5 is also operated, the discharge from the second compressor 11 is performed as shown in FIG. The second refrigerant thus passed flows into the outdoor heat exchanger 15 through the open / close means 16b for the outdoor heat exchanger, and dissipates heat to the outdoor air. In this case, the second refrigerant discharged from the second compressor 11 flows into the evaporator 4 and is absorbed by the first refrigerant.

In the first refrigeration circuit 5, as in the heating operation of the second refrigeration circuit 19, the first refrigerant discharged from the compressor 1 radiates heat in the condenser 2 and is detected by the compressor discharge temperature detection means 6. Based on the temperature, it is squeezed by the squeezing means 3 and flows into the evaporator 4 where it absorbs heat from the second refrigerant and is sucked into the compressor 1. The first refrigerant that has passed through the condenser 2 flows through the bypass circuit 8 according to the opening degree of the bypass throttling means 9, and merges with the first refrigerant that has absorbed heat from the second refrigerant in the evaporator 4.
The opening degree of the throttle means 3 is adjusted based on the temperature detected by the compressor discharge temperature detecting means 6.

  And the 2nd refrigerant | coolant absorbed into the 1st refrigerant | coolant in the evaporator 4 passes through the throttle means 18 for evaporators substantially without being restrict | squeezed. The second refrigerant that has flowed out of the outdoor heat exchanger 15 passes through the outdoor heat exchanger throttling means 17 almost without being throttled. The second refrigerant that has passed through the evaporator throttle means 18 and the outdoor heat exchanger throttle means 17 is throttled by the indoor heat exchanger throttle means 14a and 14b, flows into the indoor heat exchangers 12a and 12b, and absorbs heat from the room air. The air is drawn into the second compressor 11 through the open / close means 13a and 13c for the indoor heat exchanger in the open state. In this case, the indoor heat exchanger opening / closing means 13b, 13d and the outdoor heat exchanger opening / closing means 16a are closed so that the second refrigerant does not flow.

  Next, FIG. 4 shows a case where the second refrigeration circuit 19 is operated simultaneously with cooling and heating and the first refrigeration circuit 5 is operated using the indoor heat exchanger 12a as a condenser and the indoor heat exchanger 12b as an evaporator. As described above, the second refrigerant discharged from the second compressor 11 flows into the indoor heat exchanger 12a through the open indoor heat exchanger opening / closing means 13b and radiates heat to the indoor air. In this case, the second refrigerant discharged from the second compressor 11 flows into the evaporator 4 and is absorbed by the first refrigerant.

In the first refrigeration circuit 5, the first refrigerant discharged from the compressor 1 dissipates heat in the condenser 2 and is throttled by the throttle means 3 based on the temperature detected by the compressor discharge temperature detection means 6. Then, it flows into the evaporator 4, absorbs heat from the second refrigerant, and is sucked into the compressor 1. The first refrigerant that has passed through the condenser 2 flows through the bypass circuit 8 according to the opening degree of the bypass throttling means 9, and merges with the first refrigerant that has absorbed heat from the second refrigerant in the evaporator 4.
The opening degree of the throttle means 3 is adjusted based on the temperature detected by the compressor discharge temperature detecting means 6.

  And the 2nd refrigerant | coolant absorbed into the 1st refrigerant | coolant in the evaporator 4 passes through the throttle means 18 for evaporators substantially without being restrict | squeezed. Moreover, the 2nd refrigerant | coolant which flowed out from the indoor heat exchanger 12a passes through the expansion means 14a for indoor heat exchangers almost without being restrict | squeezed. The second refrigerant that has passed through the evaporator throttle means 18 and the indoor heat exchanger throttle means 14a is throttled by the indoor heat exchanger throttle means 14b and the outdoor heat exchanger throttle means 17, and the indoor heat exchanger 12b, The air flows into the outdoor heat exchanger 15 and is sucked into the second compressor 11 through the indoor heat exchanger opening / closing means 13c and the outdoor heat exchanger opening / closing means 16a which are opened by absorbing heat from the indoor air and the outdoor air. . In this case, the indoor heat exchanger opening / closing means 13a and 13d and the outdoor heat exchanger opening / closing means 16b are closed so that the second refrigerant does not flow.

  When the indoor heat exchanger 12a is used as an evaporator and the indoor heat exchanger 12b is used as a condenser and the second refrigeration circuit is operated simultaneously with cooling and heating, and the first refrigeration circuit 5 is also operated, as shown in FIG. The indoor heat exchanger switching means 13a and 13d are opened, the indoor heat exchanger switching means are closed, and the outdoor heat exchanger switching means is operated without change.

In the operation state as described above, the second refrigeration circuit 19 is in a heating operation and requires a large amount of heat radiation to the room air (for example, the indoor temperature is 5 ° C. and the set temperature is 30 ° C.) When the temperature of the outdoor air is high (for example, 40 ° C.) and the temperature of the second refrigerant flowing into the outdoor heat exchanger 15 must be equal to or higher than the temperature of the outdoor air, the high-pressure side pressure of the second refrigeration circuit 19 becomes high. .
Accordingly, the pressure of the second refrigerant flowing into the evaporator 4 is also increased, so that the condensation temperature is increased (for example, 50 ° C.), so that the evaporation temperature of the first refrigeration circuit 5 is also increased. At this time, when ensuring the same enthalpy difference as when the evaporation temperature is low, the degree of superheat of the first refrigerant flowing out of the evaporator 4 increases.

In the present embodiment, as shown in FIG. 6, the control unit 20 determines whether or not the temperature Ts of the first refrigerant detected by the compressor suction temperature detection means 7 is equal to or higher than a predetermined value α (for example, 25 ° C.). (S1).
When the temperature Ts is equal to or higher than the predetermined value α, the opening degree of the bypass throttling means 9 is increased so that the flow rate of the first refrigerant flowing through the bypass circuit 8 is increased (S2).

As a result, the first refrigerant from the evaporator 4 having a high degree of superheat and the first refrigerant from the outlet of the condenser 2 having a low degree of dryness are mixed at the outlet of the evaporator 4 and sucked into the compressor 1. As a result, the temperature Ts of the first refrigerant decreases and the degree of superheat decreases.
Accordingly, the suction density of the first refrigerant is improved and the flow rate of the first refrigerant is increased to reduce the evaporation capacity of the first refrigeration circuit 5 as compared with the case where the superheat degree of the first refrigerant sucked into the compressor 1 is large. Will be suppressed.

Moreover, by suppressing the evaporation capability fall of the 1st freezing circuit 5, the condensation capacity fall of the 2nd freezing circuit 19 which performs heat exchange with the evaporator 4 is suppressed, and the fall of the flow volume of a 2nd refrigerant | coolant is suppressed.
Therefore, the refrigeration oil is prevented from staying in the evaporator 4 due to the insufficient flow rate of the second refrigerant in the second refrigeration circuit 19, and the heat transfer inhibition by the refrigeration oil is prevented.

As described above, in the present embodiment, when the temperature of the first refrigerant detected by the compressor suction temperature detecting means 7 is equal to or higher than a predetermined value, the bypass is performed so that the flow rate of the first refrigerant flowing through the bypass circuit 8 is increased. By adjusting the throttling means 9, the first refrigerant from the evaporator 4 having a high degree of superheat and the first refrigerant from the outlet of the condenser 2 having a low degree of dryness are mixed at the outlet of the evaporator 4, The superheat degree of the 1st refrigerant | coolant suck | inhaled by the compressor 1 falls.
Accordingly, the suction density of the first refrigerant is improved and the flow rate of the first refrigerant is increased to reduce the evaporation capacity of the first refrigeration circuit 5 as compared with the case where the superheat degree of the first refrigerant sucked into the compressor 1 is large. Will be suppressed.

Moreover, by suppressing the evaporation capability fall of the 1st freezing circuit 5, the condensation capacity fall of the 2nd freezing circuit 19 which performs heat exchange with the evaporator 4 is suppressed, and the fall of the flow volume of a 2nd refrigerant | coolant is suppressed.
Therefore, the refrigeration oil is prevented from staying in the evaporator 4 due to the insufficient flow rate of the second refrigerant in the second refrigeration circuit 19, and the heat transfer inhibition by the refrigeration oil is prevented.

  Thereby, even when the second refrigeration circuit has a high load and the condensation temperature becomes high, and the degree of superheat of the first refrigerant increases at the evaporator outlet of the first refrigeration circuit, the decrease in the evaporation capacity of the first refrigeration circuit 5 is suppressed, The heat pump device can be operated until the temperature of the heat medium flowing into the condenser 2 becomes high, the heat storage amount of the heat medium can be increased, and a decrease in heat exchange efficiency due to stagnation of refrigeration oil in the evaporator 4 is suppressed, Energy saving can be improved.

Further, in the present embodiment, the opening degree of the bypass throttle means 9 is adjusted based on the temperature detected by the compressor intake temperature detection means 7, but as shown in FIG. 7, the compressor intake temperature detection means 7 It is also possible to adjust the opening degree of the bypass throttling means 9 based on the degree of superheat determined from the difference between the temperature detected in step S3 and the saturation temperature calculated based on the pressure detected by the compressor suction pressure detection means 21. it can.
Further, the opening degree of the bypass throttle means 9 is adjusted based on the degree of superheat determined from the difference between the temperature detected by the compressor suction temperature detection means 7 and the temperature detected by the bypass throttle means outlet temperature detection means 24. You can also
Further, the opening degree of the bypass throttling means 9 is based on the degree of superheat determined from the difference between the temperature detected by the compressor suction temperature detecting means 7 and the temperature detected by the first refrigeration circuit evaporator inlet temperature detecting means 23. Can also be adjusted.

  Further, in the present embodiment, the opening degree of the throttle means 3 is adjusted based on the temperature detected by the compressor discharge temperature detecting means 6, but the opening degree of the throttle means 3 is as shown in FIG. The temperature can be adjusted based on the difference between the temperature detected by the condenser heat medium inflow temperature detecting means 30 and the temperature detected by the condenser outlet temperature detecting means 31.

(Embodiment 2)
In FIG. 7, the refrigerant circuit figure of the heat pump apparatus 200 in the 2nd Embodiment of this invention is shown. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the second embodiment, the first refrigeration circuit 5 includes a supercooling heat exchanger 10 between the condenser 2 and the throttle means 3. The bypass circuit liquid pipe connection port 51 is provided between the condenser 2 and the supercooling heat exchanger 10. The bypass circuit 8 branches from between the condenser 2 and the supercooling heat exchanger 10, passes through the bypass throttle means 9 and the supercooling heat exchanger 10 in order, and joins between the evaporator 4 and the compressor 1. It is arranged as follows. In the supercooling heat exchanger 10, the first refrigerant that has flowed out of the condenser 2 and the first refrigerant that has passed through the bypass throttle means 9 exchange heat.

Also in the present embodiment, as shown in FIG. 6, the control unit 20 determines whether or not the temperature Ts of the first refrigerant detected by the compressor suction temperature detection means 7 is equal to or higher than a predetermined value α (for example, 25 ° C.) ( S1).
When the temperature Ts is equal to or higher than the predetermined value α, the opening degree of the bypass throttling means 9 is increased so that the flow rate of the first refrigerant flowing through the bypass circuit 8 is increased (S2).

As a result, the temperature of the first refrigerant at the outlet of the supercooling heat exchanger 10 of the first refrigeration circuit 5 is decreased, and at the outlet of the evaporator 4, the first refrigerant from the evaporator 4 having a high degree of superheat and the dryness. Is mixed with the first refrigerant from the bypass circuit 8 having a small value, and the degree of superheat of the first refrigerant sucked into the compressor 1 is reduced.
Accordingly, since the temperature of the first refrigerant flowing into the inlet of the evaporator 4 is lowered, the enthalpy difference of the first refrigeration circuit 5 in the evaporator 4 is increased and the refrigerant density on the high pressure side of the first refrigeration circuit 5 is lowered. To do.

Moreover, compared with the case where the superheat degree of the 1st refrigerant | coolant suck | inhaled by the compressor 1 is large, the suction density of a 1st refrigerant | coolant improves and the flow volume of a 1st refrigerant | coolant increases.
Therefore, even when the degree of superheat increases at the outlet of the evaporator 4 and the high pressure of the first refrigeration circuit 5 increases, the rotation speed decreases due to the high pressure restriction of the compressor 1 and the first refrigeration circuit in the evaporator 4 5 is suppressed, and the flow rate of the first refrigerant is increased to suppress a decrease in the evaporation capacity of the first refrigeration circuit 5.

Moreover, by lowering the temperature of the first refrigerant at the outlet of the supercooling heat exchanger 10 of the first refrigeration circuit 5,
The temperature of the 1st refrigerant | coolant of the evaporator 4 entrance of the 1st freezing circuit 5 falls, and the temperature of the low temperature side of the 2nd refrigerant of the 2nd freezing circuit 19 which performs heat exchange in the evaporator 4 also falls.
Accordingly, the enthalpy difference of the second refrigeration circuit 19 in the evaporator 4 is increased.

  As described above, in the present embodiment, when the temperature of the first refrigerant detected by the compressor suction temperature detecting means 7 is equal to or higher than a predetermined value, the bypass throttle is set so that the flow rate of the first refrigerant flowing through the bypass circuit 8 is increased. By adjusting the means 9, the temperature of the first refrigerant at the outlet of the supercooling heat exchanger 10 of the first refrigeration circuit 5 is decreased, and at the outlet of the evaporator 4, the first refrigerant from the evaporator 4 having a large degree of superheat. A refrigerant | coolant and the 1st refrigerant | coolant from the bypass circuit 8 with a small dryness will be mixed, and the superheat degree of the 1st refrigerant | coolant suck | inhaled by the compressor 1 will fall.

  Accordingly, since the temperature of the first refrigerant flowing into the inlet of the evaporator 4 is lowered, the enthalpy difference of the first refrigeration circuit 5 in the evaporator 4 is increased and the refrigerant density on the high pressure side of the first refrigeration circuit 5 is lowered. Then lower the high pressure.

Moreover, compared with the case where the superheat degree of the 1st refrigerant | coolant suck | inhaled by the compressor 1 is large, the suction density of a 1st refrigerant | coolant improves and the flow volume of a 1st refrigerant | coolant increases.
Therefore, even when the degree of superheat increases in the evaporator 4 and the high pressure of the first refrigeration circuit 5 increases, the rotation speed decreases due to the high pressure restriction of the compressor 1 and the first refrigeration circuit 5 in the evaporator 4. In addition to suppressing a decrease in the enthalpy difference, the flow rate of the first refrigerant is increased to suppress a decrease in the evaporation capacity of the first refrigeration circuit 5.

Moreover, by lowering the temperature of the first refrigerant at the outlet of the supercooling heat exchanger 10 of the first refrigeration circuit 5,
The temperature of the 1st refrigerant | coolant of the evaporator 4 entrance of the 1st freezing circuit 5 falls, and the temperature of the low temperature side of the 2nd refrigerant of the 2nd freezing circuit 19 which performs heat exchange in the evaporator 4 also falls.
Accordingly, the enthalpy difference of the second refrigeration circuit 19 in the evaporator 4 is increased.
As a result, the second refrigeration circuit has a high load and the condensation temperature increases, the degree of superheat of the first refrigerant increases at the outlet of the evaporator 4 of the first refrigeration circuit 5, and the heat medium flowing out of the condenser 2 has a high temperature. Even when the high pressure of the first refrigeration circuit 5 is high, that is, when high temperature water is discharged, a decrease in the evaporation capacity of the first refrigeration circuit 5 is suppressed, and the heat pump device until the temperature of the heat medium flowing into the condenser 2 becomes high. The heat storage amount of the heat medium can be increased, the condensing capacity can be increased without increasing the flow rate of the second refrigerant in the second refrigeration circuit 19, and the energy saving performance can be improved.

Further, in the present embodiment, the opening degree of the bypass throttle means 9 is adjusted based on the temperature detected by the compressor intake temperature detection means 7, but as shown in FIG. 7, the compressor intake temperature detection means 7 It is also possible to adjust the opening degree of the bypass throttling means 9 based on the degree of superheat determined from the difference between the temperature detected in step S3 and the saturation temperature calculated based on the pressure detected by the compressor suction pressure detection means 21. it can.
Further, the opening degree of the bypass throttle means 9 is adjusted based on the degree of superheat determined from the difference between the temperature detected by the compressor suction temperature detection means 7 and the temperature detected by the bypass throttle means outlet temperature detection means 24. You can also
Further, the opening degree of the bypass throttling means 9 is based on the degree of superheat determined from the difference between the temperature detected by the compressor suction temperature detecting means 7 and the temperature detected by the first refrigeration circuit evaporator inlet temperature detecting means 23. Can also be adjusted.

(Embodiment 3)
In the second embodiment, the bypass circuit 8 is branched from between the condenser 2 and the supercooling heat exchanger 10, but as shown in FIG. You may branch from between. That is, the bypass circuit liquid pipe connection port 51 may be provided between the supercooling heat exchanger 10 and the expansion means 3.
In the present embodiment, the same components as those in the second embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  Further, in this embodiment, the opening degree of the throttle means 3 is adjusted based on the temperature detected by the compressor discharge temperature detecting means 6, but as shown in FIGS. It can also be adjusted based on the difference between the temperature detected by the detection means 30 and the temperature detected by the condenser outlet temperature detection means 31.

  As described above, the heat pump device 100 according to the present invention suppresses an increase in the compressor intake temperature of the high-stage refrigeration circuit in the dual refrigeration cycle, and is an air conditioner, chiller, dryer, hot water supply air-conditioning composite device It can be applied to applications such as hot water heaters.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Condenser 3 Throttling means 4 Evaporator 5 1st freezing circuit 8 Bypass circuit 9 Bypass throttling means 19 2nd freezing circuit 20 Control part 51 Bypass circuit liquid pipe connection port 61 Bypass circuit gas pipe connection port 100 Heat pump apparatus

Claims (7)

A first refrigeration circuit for circulating a first refrigerant by connecting a compressor, a condenser, a throttle means, and an evaporator in a ring shape;
A bypass circuit in which one end is connected between the condenser and the throttling means, and the other end is connected between the evaporator and the compressor;
Bypass throttling means disposed in the bypass circuit;
A second refrigeration circuit for circulating a second refrigerant and exchanging heat with the first refrigeration circuit in the evaporator;
A control unit,
The controller is
When the temperature of the first refrigerant sucked into the compressor is equal to or higher than a predetermined value, the opening degree of the bypass throttling means is adjusted so that the flow rate of the first refrigerant flowing through the bypass circuit is increased. Heat pump device. A supercooling heat exchanger is provided between the condenser and the throttle means,
The said subcooling heat exchanger makes it heat-exchange the said 1st refrigerant | coolant which flowed out from the said condenser, and the said 1st refrigerant | coolant which distribute | circulated the said bypass circuit and flowed out from the said bypass throttle means. The heat pump apparatus according to 1.   The bypass circuit has one end connected between the condenser and the supercooling heat exchanger, and the other end connected between the evaporator and the compressor. The heat pump device described in 1.   The bypass circuit has one end connected between the supercooling heat exchanger and the throttle means, and the other end connected between the evaporator and the compressor. The heat pump device described in 1.   The heat pump apparatus according to any one of claims 1 to 4, further comprising a compressor suction temperature detection unit that detects a temperature of the first refrigerant sucked into the compressor. A compressor suction pressure detecting means for detecting the pressure of the first refrigerant sucked into the compressor;
The controller is
The bypass throttling means based on the degree of superheat determined from the difference between the temperature detected by the compressor suction temperature detection means and the saturation temperature calculated based on the pressure detected by the compressor suction pressure detection means The heat pump device according to claim 5, wherein an opening degree of the heat pump device is adjusted. A first refrigeration circuit evaporator inlet temperature detection means for detecting the inlet temperature of the evaporator;
The controller is
The opening degree of the bypass throttling means is adjusted based on the degree of superheat determined from the difference between the temperature detected by the compressor intake temperature detecting means and the temperature detected by the first refrigeration circuit evaporator inlet temperature detecting means. The heat pump device according to claim 5, wherein

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