CN113939698B

CN113939698B - Refrigeration cycle device

Info

Publication number: CN113939698B
Application number: CN202080041490.3A
Authority: CN
Inventors: 稻垣孝治; 加藤吉毅; 河野纮明; 牧本直也
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2019-06-07
Filing date: 2020-05-27
Publication date: 2023-04-28
Anticipated expiration: 2040-05-27
Also published as: JP7275876B2; JP2020200978A; WO2020246338A1; CN113939698A

Abstract

A refrigeration cycle device (10) is provided with a compressor (11), a radiator (12) that heats supply air using a refrigerant discharged from the compressor as a heat source during indoor heating, and a decompression unit (13) that decompresses the refrigerant that has passed through the radiator. The refrigeration cycle device is provided with an evaporator (14) functioning as a cooler for cooling a heat generating device when the device is cooled and functioning as a heat absorber when the device is heated indoors, and an opening degree control unit (80 a) for controlling the throttle opening degree of the pressure reducing unit. The radiator has a condensing unit (121) for condensing the refrigerant, and a liquid storage unit (122) for separating the refrigerant passing through the condensing unit into gas and liquid and storing the liquid refrigerant remaining in the cycle. The opening control unit controls the throttle opening of the decompression unit during indoor heating so as to maintain the refrigerant state on the refrigerant outlet side of the evaporator in a saturated state or a wet state. The lower limit of the throttle opening of the adjustment region at the time of indoor heating is smaller than the adjustment region of the throttle opening of the decompression portion at the time of equipment cooling.

Description

Refrigeration cycle device

Cross-reference to related applications

The present application is based on Japanese patent application No. 2019-107327 filed on 6/7 of 2019, the contents of which are incorporated herein by reference.

Technical Field

The present invention relates to a refrigeration cycle apparatus capable of performing indoor heating for heating supply air blown to a space to be air-conditioned and device cooling for cooling heat generating devices.

Background

Conventionally, there is known a vapor compression refrigeration cycle apparatus that heats air by exchanging heat between a refrigerant discharged from a compressor and air blown into a vehicle interior (for example, refer to patent document 1). In general, such a refrigeration cycle apparatus mixes oil for lubricating a compressor into a refrigerant, and circulates the refrigerant containing the oil in a cycle.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2010-42698

However, the refrigeration cycle apparatus of patent document 1 is a cycle structure in which excess refrigerant in the cycle is stored in an accumulator disposed on the refrigerant suction side of the compressor (so-called accumulator cycle). Such a circulation structure can supply the gas refrigerant to the compressor while returning the oil to the compressor, but cannot grasp the state of the refrigerant at the refrigerant outlet side of the evaporator, and it is difficult to make the state of the refrigerant at the refrigerant outlet side of the evaporator into an overheated state. This results in a decrease in the cooling capacity of the evaporator, and is therefore not preferable.

In this regard, a circulation structure (so-called receiver circulation) is considered in which a liquid storage portion for storing the remaining refrigerant in the circulation is provided on the refrigerant outlet side of the radiator. In this circulation structure, the refrigerant state on the refrigerant outlet side of the evaporator can be brought into an overheated state. On the other hand, in the receiver cycle, in the case of heating the blowing air blown into the room with the refrigerant discharged from the compressor, the refrigerant evaporation pressure in the evaporator is lowered. As a result, the flow rate of the refrigerant passing through the evaporator decreases, and the viscosity of the oil flowing into the evaporator increases, so that the oil is likely to remain in the evaporator.

Disclosure of Invention

The present invention provides a refrigeration cycle device capable of returning oil to a refrigerant suction side of a compressor during indoor heating without disposing an accumulator on the refrigerant suction side of the compressor.

In accordance with one aspect of the present invention,

a refrigerating cycle apparatus is provided, which comprises a refrigerating unit,

an apparatus cooling apparatus capable of performing indoor heating for heating supply air blown to an air-conditioning target space and cooling heat generating apparatus, comprising:

a compressor that compresses and discharges a refrigerant containing oil;

A radiator that heats air blown to a space to be air-conditioned using the refrigerant discharged from the compressor as a heat source when heating indoors;

a decompression unit that decompresses the refrigerant passing through the radiator;

an evaporator that functions as a cooler for cooling the heat generating device by using the latent heat of vaporization of the refrigerant depressurized by the depressurization portion when the device is cooled, and functions as a heat absorber when the device is heated indoors; and

an opening degree control unit that controls a throttle opening degree of the pressure reducing unit,

the radiator has a condensing portion for condensing the refrigerant and a liquid storage portion for separating gas from liquid of the refrigerant passing through the condensing portion and storing the liquid refrigerant remaining in the cycle,

the opening control unit controls the throttle opening of the decompression unit during indoor heating to maintain the refrigerant state at the refrigerant outlet side of the evaporator in a saturated state or in a wet state,

the lower limit of the throttle opening adjustment area of the decompression section at the time of indoor heating is smaller than the throttle opening adjustment area of the decompression section at the time of equipment cooling.

In this way, the circulation structure in which the radiator is provided with the liquid storage portion for storing the surplus refrigerant in the circulation is provided, and therefore, the refrigerant state on the refrigerant outlet side of the evaporator can be brought into the superheated state.

In addition, during indoor heating, the throttle opening of the pressure reducing portion is controlled so as to maintain the refrigerant state on the refrigerant outlet side of the evaporator in a saturated state or a wet state. The lower limit of the throttle opening adjustment region of the pressure reducing portion at the time of indoor heating is smaller than the throttle opening adjustment region of the pressure reducing portion at the time of equipment cooling. Thus, during indoor heating, the refrigerant in a gas-liquid two-phase state is sucked into the compressor, and therefore, the oil in the cycle is easily returned to the compressor together with the refrigerant.

As described above, according to the refrigeration cycle apparatus of the present aspect, oil can be returned to the refrigerant suction side of the compressor during indoor heating, without disposing the accumulator on the refrigerant suction side of the compressor.

Here, "saturated state" refers to an equilibrium state in which the liquid refrigerant and the gas refrigerant are stably coordinated. In other words, the "saturated state" is a state in which the refrigerant state exists on the saturation vapor line on the mollier diagram. In addition, the "wet state" refers to a state in which the refrigerant turns into wet vapor. In other words, the "wet state" is a state in which the dryness of the refrigerant exceeds 0% and is 100% or less. Further, the "superheated state" refers to a state in which the refrigerant is dry vapor. In other words, the "overheated state" is a state in which the refrigerant has a degree of superheat.

In accordance with another aspect of the present invention,

an indoor cooling device capable of performing indoor heating for heating air blown to an air-conditioning target space, and device cooling for cooling heat generating devices, and indoor cooling for cooling air blown to an air-conditioning target space, comprising:

a compressor that compresses and discharges a refrigerant containing oil;

a first decompression unit that decompresses the refrigerant passing through the radiator;

a second decompression portion disposed in parallel with the first decompression portion on a downstream side of the radiator in the refrigerant flow;

a device cooler that functions as a cooler for cooling the heat generating device by using the latent heat of vaporization of the refrigerant depressurized by the first depressurizing unit when the device is cooled, and functions as a heat absorber when the device is heated indoors;

a cooler for air conditioner; the air conditioner cooler cools the air by utilizing the evaporation latent heat of the refrigerant decompressed by the second decompression part; and

an opening degree control unit that controls the throttle opening degrees of the first decompression unit and the second decompression unit,

the opening control unit controls the throttle opening of the first decompression unit during indoor heating to maintain the refrigerant state at the refrigerant outlet side of the equipment cooler in a saturated state or in a wet state,

the lower limit of the throttle opening adjustment area of the first pressure reducing portion at the time of indoor heating is smaller than the throttle opening adjustment area of the first pressure reducing portion at the time of equipment cooling.

In this way, since the radiator is provided with the circulation structure in which the liquid storage portion for storing the surplus refrigerant in the circulation, the refrigerant state on the refrigerant outlet side of the equipment cooler and the air conditioner cooler can be brought into an overheated state.

In addition, during indoor heating, the throttle opening of the first pressure reducing portion is controlled so as to maintain the refrigerant state at the refrigerant outlet side of the equipment cooler in a saturated state or a wet state. The lower limit of the throttle opening adjustment area of the first pressure reducing portion at the time of indoor heating is smaller than the throttle opening adjustment area of the first pressure reducing portion at the time of equipment cooling. Thus, during indoor heating, the refrigerant in a gas-liquid two-phase state is sucked into the compressor, and therefore, the oil in the cycle is easily returned to the compressor together with the refrigerant.

The bracketed reference symbols for the respective components and the like indicate examples of correspondence between the components and the like and specific components and the like described in the embodiments described below.

Drawings

Fig. 1 is a schematic configuration diagram of an air conditioner including a refrigeration cycle apparatus according to a first embodiment.

Fig. 2 is a schematic diagram showing a first expansion valve for the refrigeration cycle apparatus.

Fig. 3 is a schematic diagram showing a valve element of the first expansion valve.

Fig. 4 is a schematic diagram showing the valve element in the direction indicated by the arrow IV in fig. 2.

Fig. 5 is an explanatory diagram for explaining a relationship between the throttle opening degree and the opening area in the first expansion valve.

Fig. 6 is a schematic block diagram of a control device of the refrigeration cycle apparatus.

Fig. 7 is an explanatory diagram for explaining a control method of each pressure reducing portion for each operation mode in the refrigeration cycle apparatus according to the first embodiment.

Fig. 8 is a mollier diagram for explaining the state of the refrigerant when the apparatus is cooled and when the indoor is heated.

Fig. 9 is an explanatory diagram for explaining the high-low pressure difference of the refrigerant in the cycle at the time of cooling the apparatus and at the time of heating the room.

Fig. 10 is an explanatory diagram for explaining a control method of each pressure reducing portion for each operation mode in the refrigeration cycle apparatus according to the second embodiment.

Fig. 11 is a schematic configuration diagram of a facility cooling system including a refrigeration cycle apparatus according to a third embodiment.

Fig. 12 is an explanatory diagram for explaining a control method of each pressure reducing portion for each operation mode in the refrigeration cycle apparatus according to the third embodiment.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts to those described in the previous embodiments are denoted by the same reference numerals, and description thereof may be omitted. In the embodiment, when only a part of the components is described, the components described in the previous embodiment can be applied to other parts of the components. The following embodiments can be partially combined even if not specifically shown, as long as the embodiments do not cause any particular combination disorder.

(first embodiment)

The present embodiment will be described below with reference to fig. 1 to 9. The present embodiment describes an example in which the refrigeration cycle apparatus 10 of the present invention is applied to an air conditioner 1 that adjusts the temperature of the vehicle interior space to an appropriate temperature. In the present embodiment, the vehicle interior space is an air-conditioning target space.

Although not shown, the refrigeration cycle apparatus 10 shown in fig. 1 is mounted on a hybrid vehicle that obtains driving force for vehicle running from an engine and a motor for running. The hybrid vehicle is configured as a plug-in hybrid vehicle capable of charging a battery BT mounted on the vehicle with electric power supplied from an external power source when the vehicle is parked. The driving force output from the engine is used not only for running the vehicle but also for generating electric power by the motor generator. The electric power generated by the motor generator and the electric power supplied from the external power source are stored in the battery BT. The battery BT power stored in the battery BT is supplied not only to the motor for running but also to various in-vehicle devices including the constituent devices of the refrigeration cycle apparatus 10.

The refrigeration cycle device 10 can perform indoor heating for heating the air blown into the vehicle interior, indoor cooling for cooling the air blown into the vehicle interior, and device cooling for cooling the battery BT.

The refrigeration cycle apparatus 10 is constituted by a vapor compression refrigeration cycle. The refrigeration cycle apparatus 10 includes a refrigerant circuit 100 in which a refrigerant circulates. The refrigeration cycle device 10 is provided with a compressor 11, a radiator 12, a first pressure reducing unit 13, a facility cooler 14, a second pressure reducing unit 15, an air conditioning cooler 16, and an evaporation pressure adjusting valve 17 for the refrigerant circuit 100.

A freon-based refrigerant (for example, HFO134 a) is enclosed in the refrigerant circuit 100 as a refrigerant. The refrigerant circuit 100 is a subcritical cycle in which the pressure on the high pressure side of the cycle does not exceed the critical pressure of the refrigerant. As the refrigerant, a refrigerant other than HFO134a may be used.

The refrigerant is mixed with oil (i.e., refrigerating machine oil) for lubricating the compressor 11. The oil is, for example, a polyalkylene glycol oil (i.e., PAG oil) having compatibility with the liquid refrigerant. A portion of the oil circulates in a cycle with the refrigerant.

As a flow path through which the refrigerant flows, the refrigerant circuit 100 includes a first refrigerant flow path 100a, a second refrigerant flow path 100b, and a third refrigerant flow path 100c. In the refrigerant circuit 100, the second refrigerant flow path 100b and the third refrigerant flow path 100c are connected to the first refrigerant flow path 100a so that the refrigerants flow in parallel with each other.

In the first refrigerant flow path 100a, the compressor 11 and the radiator 12 are arranged in series. Specifically, in the first refrigerant flow path 100a, a radiator 12 is disposed downstream of the compressor 11.

In the second refrigerant flow path 100b, the first pressure reducing portion 13 and the equipment cooler 14 are arranged in series. Specifically, in the second refrigerant flow path 100b, the equipment cooler 14 is disposed downstream of the first pressure reducing portion 13.

In the third refrigerant flow path 100c, the second pressure reducing portion 15 and the air conditioning cooler 16 are arranged in series. Specifically, in the third refrigerant flow path 100c, the air-conditioning cooler 16 is disposed downstream of the second pressure reducing portion 15.

The compressor 11 is a device that compresses and discharges a refrigerant. The compressor 11 is constituted by an electric compressor that drives a compression mechanism portion for compressing a refrigerant to rotate by a motor. The compressor 11 controls the rotation speed of the motor based on a control signal output from a control device 80 described later.

A radiator 12 is connected to the refrigerant discharge side of the compressor 11. The radiator 12 radiates heat from the refrigerant discharged from the compressor 11. The radiator 12 is a heat exchanger that radiates high-temperature and high-pressure refrigerant (hereinafter also referred to as high-pressure refrigerant) discharged from the compressor 11 to a high-temperature heat medium circulating in the high-temperature heat medium circuit 30.

The radiator 12 includes a condensing unit 121, a liquid storage unit 122, and a supercooling unit 123. The condensing portion 121 condenses the high-pressure refrigerant by radiating heat to the high-temperature heat medium. The liquid storage unit 122 performs gas-liquid separation of the refrigerant passing through the condensation unit 121, and stores the separated liquid refrigerant as a surplus refrigerant in the cycle. The supercooling unit 123 supercools the liquid refrigerant stored in the liquid storage unit 122 by radiating heat to the high-temperature heat medium before flowing into the condensing unit 121.

The radiator 12 heats the air blown into the vehicle interior using the refrigerant discharged from the compressor 11 as a heat source. Specifically, the radiator 12 can radiate heat from the high-pressure refrigerant to the air blown into the vehicle interior via the high-temperature heat medium circuit 30, thereby heating the air.

Here, the high-temperature heat medium circuit 30 is a circuit for circulating the high-temperature heat medium. For example, a solution containing ethylene glycol, an antifreeze solution, or the like is used as the high-temperature heat medium. In the present embodiment, the high-temperature heat medium constitutes the first heat medium. The high-temperature heat medium circuit 30 is provided with a radiator 12, a high-temperature side pump 31, a heater core 32, a high-temperature side radiator 33, a high-temperature side flow rate adjustment valve 34, and the like.

The high Wen Cebeng is a pump for pumping the high-temperature heat medium to the radiator 12 in the high-temperature heat medium circuit 30. The high Wen Cebeng is constituted by an electric pump that controls the rotation speed according to a control signal output from the control device 80.

The heater core 32 is disposed in a casing 61 of the indoor air conditioning unit 60 described later. The heater core 32 is a heat exchanger for heating the air by exchanging heat between the high-temperature heat medium heated by the radiator 12 and the air passing through the air conditioning cooler 16 described later.

The high-temperature side radiator 33 is a heat exchanger that radiates the high-temperature heat medium heated by the radiator 12 to the outside air. The high-temperature-side radiator 33 is disposed on the front side of the vehicle that contacts the running wind when the vehicle is running. In the high-temperature heat medium circuit 30, the high-temperature side radiator 33 and the heater core 32 are connected in parallel with respect to the flow of the high-temperature heat medium.

The high-temperature side flow rate adjustment valve 34 is a flow rate adjustment valve that adjusts a flow rate ratio of a flow rate of the high-temperature heat medium flowing into the heater core 32 to a flow rate of the high-temperature heat medium flowing into the high-temperature side radiator 33, among the high-temperature heat medium heated by the radiator 12. The high-temperature side flow rate adjustment valve 34 is constituted by a three-way valve type flow rate adjustment valve. The high-temperature side flow regulating valve 34 is disposed at a connection portion between the inlet side of the heater core 32 and the inlet side of the high-temperature side radiator 33 in the high-temperature medium circuit 30.

In the high-temperature heat medium circuit 30 having such a configuration, the flow rate ratio is adjusted by the high-temperature side flow rate adjustment valve 34, whereby the usage pattern of the high-pressure refrigerant can be changed. The high-temperature heat medium circuit 30 can heat the vehicle interior by, for example, increasing the flow rate of the high-temperature heat medium flowing into the heater core 32 by the high-temperature side flow rate adjustment valve 34, thereby using the heat of the high-temperature heat medium for heating the supply air. On the other hand, the high-temperature heat medium circuit 30 can discharge the heat of the high-temperature heat medium to the outside air by increasing the flow rate of the high-temperature heat medium flowing into the high-temperature side radiator 33 by using the high-temperature side flow rate adjustment valve 34, for example.

The refrigerant outlet side of the radiator 12 branches toward the second refrigerant flow path 100b and the third refrigerant flow path 100 c. The first pressure reducing portion 13 and the equipment cooler 14 are disposed in the second refrigerant flow path 100 b. The second pressure reducing portion 15 and the air conditioning cooler 16 are disposed in the third refrigerant flow path 100 c.

The first pressure reducing portion 13 has a first opening/closing valve 131 and a first expansion valve 132 that are fully closed or fully opened. The first opening/closing valve 131 is a solenoid valve that opens and closes the second refrigerant flow path 100 b. The first opening/closing valve 131 controls opening/closing operations in response to a control signal from a control device 80 described later.

The first expansion valve 132 is an expansion valve that decompresses the refrigerant flowing through the second refrigerant flow path 100 b. The first expansion valve 132 is constituted by an electric expansion valve. The first expansion valve 132 controls the throttle opening according to a control signal from the control device 80 described later. The first expansion valve 132 is described in detail later.

The equipment cooler 14 is an evaporator (i.e., a chiller) that evaporates the refrigerant depressurized by the first depressurizing unit 13 by exchanging heat with the low-temperature heat medium circulating in the low-temperature heat medium circuit 40. In the equipment cooler 14, the refrigerant absorbs heat from the low-temperature heat medium and evaporates, thereby cooling the low-temperature heat medium. The equipment cooler 14 is constituted by a stacked heat exchanger in which a plurality of refrigerant flow path portions through which a refrigerant flows and a plurality of heat medium flow path portions through which a low-temperature heat medium flows are alternately stacked.

The equipment cooler 14 according to the present embodiment functions as a cooler that cools the battery BT by utilizing the latent heat of vaporization of the refrigerant depressurized by the first depressurizing unit 13 when the equipment is cooled, and functions as a heat absorber when the indoor heating is performed. Specifically, the equipment cooler 14 cools the battery BT via the low-temperature heat medium circuit 40 when the equipment is cooled, and absorbs heat from the outside air when the indoor heating is performed.

Here, the low-temperature heat medium circuit 40 is a circuit for circulating the low-temperature heat medium. For example, a solution containing ethylene glycol, an antifreeze solution, or the like is used as the low-temperature heat medium. In the present embodiment, the low-temperature heat medium constitutes the second heat medium. The low-temperature heat medium circuit 40 is provided with a device cooler 14, a low-temperature side pump 41, a battery cooling unit 42, a low-temperature side radiator 43, a first flow path switching valve 44, a second flow path switching valve 45, and the like.

The low-temperature side pump 41 is a pump for pumping the low-temperature medium to the equipment cooler 14 in the low-temperature medium circuit 40. The low-temperature side pump 41 is constituted by an electric pump that controls the rotation speed according to a control signal output from the control device 80.

The battery cooling unit 42 cools the battery BT using the low-temperature heat medium flowing through the low-temperature heat medium circuit 40. The battery BT is electrically connected to an inverter and a charger, not shown. The battery BT supplies electric power to the inverter and stores electric power supplied from the charger. The battery BT is constituted by a lithium ion battery, for example.

The low-temperature side radiator 43 is a heat exchanger that absorbs heat from the outside air by heat exchange between the low-temperature heat medium cooled by the equipment cooler 14 and the outside air. The low temperature side radiator 43 is disposed on the front side of the vehicle that contacts the traveling wind when the vehicle travels, together with the high temperature side radiator 33. The low-temperature side radiator 43 and the battery cooling section 42 are connected in parallel with respect to the flow of the low-temperature heat medium in the low-temperature heat medium circuit 40.

The first flow path switching valve 44 switches between a state in which the low-temperature heat medium flows into the battery cooling portion 42 and a state in which the low-temperature heat medium does not flow into the battery cooling portion 42. The first flow path switching valve 44 is constituted by an electromagnetic valve that controls opening and closing operations according to a control signal output from the control device 80.

The second flow path switching valve 45 switches between a state in which the low-temperature heat medium flows to the low-temperature side radiator 43 and a state in which the low-temperature heat medium does not flow to the low-temperature side radiator 43. The second flow path switching valve 45 is constituted by an electromagnetic valve that controls opening and closing operations according to a control signal output from the control device 80.

In the low-temperature heat medium circuit 40 configured as described above, the flow path of the low-pressure refrigerant is changed by the first flow path switching valve 44 and the second flow path switching valve 45, whereby the use mode of the low-pressure refrigerant can be changed. The low-temperature heat medium circuit 40 can cool the battery BT using the low-temperature heat medium cooled by the equipment cooler 14 by, for example, opening the first flow switching valve 44. On the other hand, the low-temperature heat medium circuit 40 can absorb heat from the outside air by, for example, opening the second flow path switching valve 45 to flow the low-temperature heat medium to the low-temperature side radiator 43.

The second decompression portion 15 is disposed in parallel with the first decompression portion 13 on the downstream side of the refrigerant flow of the radiator 12. The second pressure reducing portion 15 has a second opening/closing valve 151 and a second expansion valve 152 that are fully closed or fully opened. The second on-off valve 151 is a solenoid valve that opens and closes the third refrigerant flow path 100 c. The second opening/closing valve 151 controls opening/closing operations in response to a control signal from a control device 80 described later.

The second expansion valve 152 is an expansion valve that decompresses the refrigerant flowing through the third refrigerant flow path 100 c. The second expansion valve 152 is constituted by an electric expansion valve having a valve element and an electric actuator. The valve body is configured to be capable of changing a throttle opening, which is an opening of the refrigerant flow path. The electric actuator includes a stepping motor that displaces the valve element to change the throttle opening of the second expansion valve 152. The second expansion valve 152 controls the throttle opening according to a control signal from the control device 80 described later.

The air conditioner cooler 16 is disposed in a casing 61 of an indoor air conditioner unit 60 described later. The air conditioning cooler 16 is a heat exchanger that evaporates the refrigerant decompressed by the second decompression portion 15 by exchanging heat between the refrigerant and the air blown into the vehicle interior. The air-conditioning cooler 16 cools the air-sending air by using the latent heat of vaporization of the refrigerant decompressed by the second decompression unit 15. That is, the air-conditioning cooler 16 cools the air by evaporating the low-pressure refrigerant by absorbing heat from the air.

An evaporation pressure adjustment valve 17 is disposed on the refrigerant outlet side of the air conditioning cooler 16. The evaporation pressure adjustment valve 17 is a pressure adjustment valve for maintaining the pressure of the refrigerant on the refrigerant outlet side of the air-conditioning cooler 16 at a pressure higher than the pressure of the refrigerant on the refrigerant outlet side of the equipment cooler 14. Specifically, the evaporating pressure adjusting valve 17 is configured to maintain the temperature of the refrigerant on the refrigerant outlet side of the air-conditioning cooler 16 at a temperature (for example, 1 ℃) or higher at which frosting of the air-conditioning cooler 16 can be suppressed.

In the refrigeration cycle apparatus 10 configured as described above, the second refrigerant flow path 100b and the third refrigerant flow path 100c are connected to the first refrigerant flow path 100a on the downstream side of the evaporation pressure adjustment valve 17. The refrigeration cycle apparatus 10 has a circulation structure (i.e., no accumulator circulation) in which the equipment cooler 14 and the air-conditioning cooler 16 are connected to the refrigerant suction side of the compressor 11 without passing through an accumulator. Specifically, the refrigeration cycle apparatus 10 is configured to have a high-pressure side in the cycle provided with the liquid storage portion 122, and a low-pressure side in the cycle not provided with the liquid storage portion (i.e., a receiver cycle).

Next, the indoor air conditioning unit 60 will be described with reference to fig. 1. The indoor air conditioning unit 60 shown in fig. 1 is a member for adjusting the supply air blown into the vehicle interior to an appropriate temperature. The indoor air conditioning unit 60 is disposed inside the forefront instrument panel in the vehicle interior. The indoor air conditioning unit 60 houses the air conditioning cooler 16, the heater core 32, and the like inside a casing 61 that forms a housing.

The housing 61 is a passage forming portion that forms an air flow path for blowing supply air into the vehicle interior. An internal and external air box for adjusting the ratio of the internal air and the external air introduced into the casing 61 is disposed on the upstream side of the casing 61 in the air flow, not shown.

Inside the case 61, a blower 62 for blowing air introduced from the inside and outside air tanks into the vehicle interior is disposed. The blower 62 is constituted by an electric blower that rotates a centrifugal fan by a motor. The blower 62 controls the rotational speed based on a control signal output from a control device 80 described later.

Inside the casing 61, the air conditioning cooler 16 is disposed downstream of the air flow of the blower 62. Inside the casing 61, the downstream side of the air flow of the air conditioner cooler 16 is divided into a warm air flow path 63 and a cool air flow path 64. The heater core 32 is disposed in the warm air flow path 63. The cool air flow path 64 is a flow path for allowing air passing through the air conditioning cooler 16 to flow around the heater core 32.

An air mix door 65 is disposed between the air conditioner cooler 16 and the heater core 32 inside the case 61. The air mix door 65 is a member for adjusting the air volume ratio of the air passing through the warm air flow path 63 and the air passing through the cool air flow path 64. An air mixing space 66 for mixing the warm air passing through the warm air passage 63 with the cool air passing through the cool air passage 64 is formed on the downstream side of the warm air passage 63 and the cool air passage 64 inside the casing 61. Although not shown, a plurality of openings for blowing out the supply air adjusted to a desired temperature in the air mixing space 66 into the vehicle interior are formed in the most downstream portion of the air flow inside the case 61.

Next, the first expansion valve 132 of the present embodiment will be described. As shown in fig. 2, the first expansion valve 132 includes a main body 133, a shaft 134, a valve body 135, and a stepping motor 136.

The main body 13 is formed of a metal block having a substantially hollow shape. The body portion 133 is formed with a refrigerant inflow portion 133a, a decompression chamber 133b, and a refrigerant outflow portion 133c. The refrigerant inflow portion 133a is a portion into which the refrigerant flowing out of the radiator 12 flows. The decompression chamber 133b is a portion for decompressing the refrigerant flowing into the refrigerant inflow portion 133 a. The refrigerant outflow portion 133c is a portion that causes the refrigerant decompressed by the decompression chamber 133b to flow out to the outside.

A valve seat 133d that contacts and separates from the valve element 135 is formed in the pressure reducing chamber 133 b. The valve seat 133d is formed on the refrigerant outflow portion 133c side.

The stepper motor 136 is an actuator for displacing the shaft 134 in the axial direction DRa. The stepping motor 136 gradually rotates the output shaft at a constant angle in accordance with a control signal (i.e., a pulse signal) from the control device 80 described later. The axial direction DRa is a direction in which the axial center CL of the shaft 134 extends.

The shaft 134 is made of a metal rod-like member. One side of the shaft 134 in the axial direction DRa is coupled to a direct-motion conversion mechanism, not shown. The linear motion converting mechanism converts the rotational motion of the output shaft of the stepping motor 136 into linear motion. Thus, the shaft 134 is displaced in the axial direction DRa when the output shaft of the stepping motor 136 rotates.

The other side portion of the shaft 134 in the axial direction DRa is positioned in the decompression chamber 133b. The other side of the shaft 134 in the axial direction DRa is coupled to the valve element 135. The shaft 134 and the valve body 135 of the present embodiment are formed as an integrally molded product. The shaft 134 may be formed separately from the valve element 135.

The valve element 135 is formed in a disk shape. The valve element 135 is brought into contact with and separated from the valve seat 133d by displacing the shaft 134 in the axial direction DRa. The first expansion valve 132 has a smaller throttle opening degree when the valve element 135 approaches the valve seat 133d, and has a larger throttle opening degree when the valve element 135 is away from the valve seat 133 d. Further, the throttle opening is the distance (i.e., the lift amount) of the valve seat 133d from the valve element 135.

As shown in fig. 3 and 4, a bleed port 135a having a constant opening area is formed in the valve body 135. The relief port 135a is a communication hole that depressurizes the refrigerant flowing in from the refrigerant inflow portion 133a side and flows toward the refrigerant outflow portion 133c side even in a state where the valve body 135 is in contact with the valve seat 133 d.

Since the first expansion valve 132 thus configured is provided with the relief port 135a, as shown in fig. 5, when the throttle opening is lower than the predetermined opening, the opening area is defined by the relief port 135a. Further, the opening area shown in fig. 5 is the sectional area of the refrigerant flow path in the decompression chamber 133b.

Next, an outline of the electronic control unit of the air conditioner 1 will be described with reference to fig. 6. The control device 80 has a computer including a processor, a memory, and peripheral circuits thereof. The control device 80 performs various operations and processes based on a program stored in the memory, and controls various devices connected to the output side. The memory of the control device 80 is constituted by a non-transitory physical storage medium.

The output side of the control device 80 is connected to various devices including the constituent devices of the refrigeration cycle apparatus 10. Specifically, the compressor 11, the first pressure reducing portion 13, the second pressure reducing portion 15, the high-temperature side pump 31, the high-temperature side flow rate adjustment valve 34, the low-temperature side pump 41, the flow

path switching valves

44 and 45, the blower 62, the air mixing door 65, and the like are connected to the output side of the control device 80.

The input side of the control device 80 is connected to a sensor group 81 for controlling the air conditioner. The sensor group 81 includes an inside air temperature sensor, an outside air temperature sensor, a solar sensor, a PT sensor that detects the pressure and temperature of the refrigerant outlet side of each of the

coolers

14 and 16, and the like.

Accordingly, the detection signal of the sensor group 81 is input to the control device 80. Thus, the refrigeration cycle device 10 can adjust the temperature of the air blown into the vehicle interior or the like in accordance with the physical quantity detected by the sensor group 81, and can realize comfortable air conditioning.

The input side of the control device 80 is connected to an operation panel 82 for various input operations. The operation panel 82 is disposed near the instrument panel and has various operation switches. Operation signals from various operation switches provided on the operation panel 82 are input to the control device 80.

The various operation switches of the operation panel 82 include an automatic switch, an operation mode switching switch, an air volume setting switch, a temperature setting switch, a blowing mode switching switch, and the like. The refrigeration cycle apparatus 10 can appropriately switch the operation mode of the refrigeration cycle apparatus 10 by receiving an input to the operation panel 82.

Here, the control device 80 integrally constitutes a control unit that controls various devices connected to the output side. The control device 80 of the present embodiment includes an opening degree control unit 80a that controls the throttle opening degrees of the first decompression unit 13 and the second decompression unit 15. The opening degree control unit 80a may be configured separately from the control device 80.

Hereinafter, the operation of the air conditioner 1 will be described. The air conditioner 1 is configured to be capable of performing indoor cooling, equipment cooling, and indoor heating as operation modes. Therefore, in the present embodiment, the operation of the air conditioner 1 will be described with respect to indoor cooling, equipment cooling, and indoor heating, respectively.

< indoor refrigeration >)

The indoor cooling is an operation mode in which air cooled to a desired temperature by the indoor air conditioning unit 60 is blown into the vehicle interior. The control device 80 appropriately determines the operating states of various devices during indoor cooling by using the detection signals of the sensor group 81 and the operation signals of the operation panel 82.

For example, as shown in fig. 7, the control device 80 controls the

pressure reducing portions

13 and 15 so that the first opening/closing valve 131 is fully closed, the second opening/closing valve 151 is fully opened, and the second expansion valve 152 is in a variable throttle state. That is, the control device 80 controls the first decompression unit 13 to be in the fully closed state, and controls the second decompression unit 15 to perform the decompression function. Specifically, the control device 80 controls the throttle opening degree of the second expansion valve 152 so that the refrigerant state on the refrigerant outlet side of the air-conditioning cooler 16 becomes an overheated state having a degree of superheat at the time of indoor cooling.

In addition, the control device 80 controls the high-temperature side flow rate adjustment valve 34 so that the entire amount of the high-temperature heat medium passing through the radiator 12 flows to the high-temperature side radiator 33. Further, the control device 80 controls the air mix door 65 to a position where the warm air flow path 63 is fully closed and the cool air flow path 64 is fully opened. The control device 80 appropriately determines a control signal for another device using the detection signal of the sensor group 81 and the operation signal of the operation panel 82.

In the refrigeration cycle apparatus 10 during indoor refrigeration, the high-pressure refrigerant discharged from the compressor 11 flows into the condensation portion 121 of the radiator 12. The refrigerant flowing into the condensation unit 121 is condensed by radiating heat to the high-temperature heat medium flowing through the high-temperature heat medium circuit 30. Thereby, the high-temperature heat medium flowing through the high-temperature heat medium circuit 30 is heated to raise the temperature.

The high-temperature heat medium heated by the condensing unit 121 flows through the high-temperature side radiator 33, and radiates heat to the outside air. That is, during indoor cooling, the high-pressure refrigerant in the cycle radiates heat to the outside air via the high-temperature heat medium.

On the other hand, the refrigerant passing through the condensation unit 121 flows into the liquid storage unit 122, and is separated into gas and liquid. Then, the liquid refrigerant separated by the liquid storage portion 122 flows into the supercooling portion 123. The refrigerant flowing into the supercooling portion 123 is supercooled by radiating heat to the high-temperature heat medium flowing through the high-temperature heat medium circuit 30.

The refrigerant flowing out of the supercooling portion 123 flows into the second decompressing portion 15, and is decompressed by the second expansion valve 152 of the second decompressing portion 15. In addition, since the first opening/closing valve 131 is fully closed during indoor cooling, the refrigerant does not flow into the first expansion valve 132, and the entire amount of the refrigerant is reduced in pressure by the second pressure reducing portion 15.

The refrigerant decompressed by the second decompression portion 15 flows into the air-conditioning cooler 16. The refrigerant flowing into the air conditioning cooler 16 absorbs heat from the air blown from the blower 62 and evaporates. Thereby, the air blown from the blower 62 is cooled.

The refrigerant having passed through the air-conditioning cooler 16 is sucked into the compressor 11 through the evaporation pressure adjustment valve 17. The refrigerant sucked into the compressor 11 is compressed again by the compressor 11 until becoming a high-pressure refrigerant.

As described above, when cooling the interior of the vehicle, the air-conditioning cooler 16 blows out the air cooled by the air-conditioning air into the interior of the vehicle, thereby cooling the interior of the vehicle.

< device Cooling >)

The device cooling is an operation mode for cooling the battery BT as a heat generating device by using the latent heat of vaporization of the refrigerant. The control device 80 appropriately determines the operating states of various devices when the devices are cooled by using the detection signals of the sensor group 81 and the operation signals of the operation panel 82.

For example, as shown in fig. 7, the control device 80 controls the

pressure reducing portions

13 and 15 so that the second opening/closing valve 151 is fully closed, the first opening/closing valve 131 is fully opened, and the first expansion valve 132 is in a variable throttle state. That is, the control device 80 controls the second decompression unit 15 to be in the fully closed state, and controls the first decompression unit 13 to perform the decompression function.

The control device 80 controls the throttle opening of the first expansion valve 132 so that the refrigerant state on the refrigerant outlet side of the plant cooler 14 becomes a superheated state having a degree of superheat when the plant is cooled. Specifically, the control device 80 controls the throttle opening of the first expansion valve 132 in the adjustment region Xb shown in fig. 5 when the equipment is cooled. As shown in fig. 5, the adjustment region Xb of the throttle opening degree of the first expansion valve 132 at the time of equipment cooling is set to a region in which the opening area is not defined by the relief port 135 a. That is, the adjustment region Xb of the throttle opening of the first expansion valve 132 at the time of equipment cooling is set such that the lower limit Xbmin of the adjustment region Xb is larger than the range of the prescribed position Xs in which the opening area is prescribed by the relief port 135 a.

In addition, the control device 80 controls the high-temperature side flow rate adjustment valve 34 so that the entire amount of the high-temperature heat medium passing through the radiator 12 flows to the high-temperature side radiator 33. Further, the control device 80 controls the flow of the entire amount of the low-temperature heat medium passing through the equipment cooler 14 to the battery cooling unit 42 so that the first flow path switching valve 44 is fully opened and the second flow path switching valve 45 is fully closed. The control device 80 appropriately determines a control signal for another device using the detection signal of the sensor group 81 and the operation signal of the operation panel 82.

In the refrigeration cycle apparatus 10 at the time of cooling the equipment, the high-pressure refrigerant discharged from the compressor 11 flows into the condensation portion 121 of the radiator 12. As shown by the solid line in fig. 8, the refrigerant flowing into the condensation unit 121 is condensed by radiating heat to the high-temperature heat medium flowing through the high-temperature heat medium circuit 30 (i.e., point a1→point A2 in fig. 8). Thereby, the high-temperature heat medium flowing through the high-temperature heat medium circuit 30 is heated to raise the temperature.

The high-temperature heat medium heated by the condensing unit 121 flows to the high-temperature side radiator 33, and radiates heat to the outside air. That is, when the apparatus is cooled, the high-pressure refrigerant in the cycle radiates heat to the outside air via the high-temperature heat medium.

On the other hand, the refrigerant passing through the condensation unit 121 flows into the liquid storage unit 122, and is separated into gas and liquid. Then, the liquid refrigerant separated by the liquid storage portion 122 flows into the supercooling portion 123. The refrigerant flowing into the supercooling portion 123 radiates heat to the high-temperature heat medium flowing through the high-temperature heat medium circuit 30, and is supercooled (i.e., point a2→point A3 in fig. 8).

The refrigerant flowing out of the supercooling portion 123 flows into the first decompression portion 13, and is decompressed by the first expansion valve 132 of the first decompression portion 13 (i.e., point a3→point A4 in fig. 8). Further, since the second on-off valve 151 is fully closed during the cooling of the equipment, the refrigerant does not flow into the second expansion valve 152, and the entire amount of the refrigerant is depressurized by the first depressurizing portion 13.

The refrigerant decompressed by the first decompression portion 13 flows into the equipment cooler 14. The refrigerant flowing into the equipment cooler 14 absorbs heat from the low-temperature heat medium flowing through the low-temperature heat medium circuit 40 and evaporates (i.e., point a4→point A5 in fig. 8). Thereby, the low-temperature thermal medium is cooled.

At the time of cooling the equipment, the throttle opening of the first decompression portion 13 is set so that the refrigerant state on the refrigerant outlet side of the equipment cooler 14 becomes an overheated state. Therefore, the refrigerant having passed through the equipment cooler 14 becomes a gas refrigerant having a degree of superheat, and is sucked into the compressor 11. The refrigerant sucked into the compressor 11 is compressed again by the compressor 11 until becoming a high-pressure refrigerant.

Here, the low-temperature heat medium cooled by the equipment cooler 14 flows to the battery cooling unit 42, and absorbs heat from the battery BT. Thereby, battery BT is cooled. That is, when the device is cooled, the battery BT is cooled by the latent heat of vaporization of the refrigerant in the device cooler 14.

As described above, when the device is cooled, the low-temperature heat medium cooled by the device cooler 14 is supplied to the battery cooling unit 42, whereby the battery BT can be cooled.

Here, in the above-described equipment cooling, the high-temperature side flow rate adjustment valve 34 is controlled so that the entire amount of the high-temperature heat medium passing through the radiator 12 flows to the high-temperature side radiator 33, but the present invention is not limited thereto. For example, in the case where heating of the vehicle interior is required when the equipment is cooled, the control device 80 may control the high-temperature side flow rate adjustment valve 34 so that the high-temperature heat medium passing through the radiator 12 flows to the heater core 32. Thereby, the equipment cooling and the indoor heating can be simultaneously performed.

In the above-described equipment cooling, the respective

pressure reducing units

13 and 15 are controlled so that the second opening/closing valve 151 is fully closed and the first opening/closing valve 131 is fully opened, and the throttle opening of the first expansion valve 132 is a predetermined opening degree, but the present invention is not limited thereto. For example, when indoor cooling is required during cooling of the equipment, the control device 80 may control the second pressure reducing portion 15 so that the second on-off valve 151 is fully opened and the throttle opening of the second expansion valve 152 is a predetermined opening. Thereby, the equipment cooling and the indoor cooling can be simultaneously performed.

< indoor heating >)

The indoor heating is an operation mode in which air heated to a desired temperature by the indoor air conditioning unit 60 is blown into the vehicle interior. The control device 80 appropriately determines the operating states of various devices during indoor heating by using the detection signals of the sensor group 81 and the operation signals of the operation panel 82.

For example, as shown in fig. 7, the control device 80 controls the

pressure reducing portions

13 and 15 so that the second opening/closing valve 151 is fully closed and the first opening/closing valve 131 is fully opened, and the first expansion valve 132 is in a throttled state. That is, the control device 80 controls the second decompression unit 15 to be in the fully closed state, and controls the first decompression unit 13 to perform the decompression function.

The control device 80 controls the throttle opening of the first expansion valve 132 so that the refrigerant state on the refrigerant outlet side of the equipment cooler 14 becomes a saturated state or a wet state at the time of indoor heating. Specifically, the control device 80 controls the throttle opening of the first expansion valve 132 in the adjustment region Xh shown in fig. 5 when heating the room. As shown in fig. 5, the adjustment region Xb of the throttle opening of the first expansion valve 132 during indoor heating is set to a region including the opening area defined by the relief port 135 a. That is, the lower limit of the adjustment region Xh of the throttle opening degree of the first expansion valve 132 at the time of indoor heating is smaller than the lower limit of the adjustment region Xb at the time of equipment cooling. To be described in detail, in order not to overlap with the adjustment region Xb during the equipment cooling, the upper limit Xhmax of the adjustment region Xh of the throttle opening degree of the first expansion valve 132 during the indoor heating is smaller than the lower limit Xbmin of the adjustment region Xb during the equipment cooling.

Here, the control device 80 controls the throttle opening degree of the first expansion valve 132 so that the adjustment frequency of the throttle opening degree of the first expansion valve 132 at the time of indoor heating is smaller than the adjustment frequency of the throttle opening degree of the first expansion valve 132 at the time of equipment cooling. Specifically, the control device 80 controls the first expansion valve 132 to be in a fixed throttle state in which the throttle opening is fixed. The control device 80 of the present embodiment controls the first expansion valve 132 to a predetermined throttle opening degree (for example, a throttle opening degree around a predetermined position Xs) in the adjustment region Xh.

In addition, the control device 80 controls the high-temperature side flow rate adjustment valve 34 so that the entire amount of the high-temperature heat medium passing through the radiator 12 flows to the heater core 32. Further, the control device 80 controls the flow of the entire amount of the low-temperature heat medium passing through the equipment cooler 14 to the low-temperature side radiator 43 so that the first flow path switching valve 44 is fully closed and the second flow path switching valve 45 is fully opened.

The control device 80 controls the air mix door 65 to a position where the cool air flow path 64 is fully closed and the warm air flow path 63 is fully opened. The control device 80 appropriately determines a control signal for another device using the detection signal of the sensor group 81 and the operation signal of the operation panel 82.

In the refrigeration cycle apparatus 10 during indoor heating, the high-pressure refrigerant discharged from the compressor 11 flows into the condensation portion 121 of the radiator 12. As shown by the broken line in fig. 8, the refrigerant flowing into the condensation unit 121 is condensed by radiating heat to the high-temperature heat medium flowing through the high-temperature heat medium circuit 30 (i.e., b1→b2 in fig. 8). Thereby, the high-temperature heat medium flowing through the high-temperature heat medium circuit 30 is heated to raise the temperature.

The high-temperature heat medium heated by the condensation unit 121 flows to the heater core 32, and radiates heat to the air blown into the vehicle interior. That is, during indoor heating, the high-pressure refrigerant in the cycle radiates heat to the supply air blown into the vehicle interior via the high-temperature heat medium.

On the other hand, the refrigerant passing through the condensation unit 121 flows into the liquid storage unit 122, and is separated into gas and liquid. Then, the liquid refrigerant separated by the liquid storage portion 122 flows into the supercooling portion 123. The refrigerant flowing into the supercooling portion 123 radiates heat to the high-temperature heat medium flowing through the high-temperature heat medium circuit 30, and is supercooled (i.e., b2→b3 in fig. 8).

The refrigerant flowing out of the supercooling portion 123 flows into the first decompression portion 13, and is decompressed by the first expansion valve 132 of the first decompression portion 13 (i.e., b3→b4 of fig. 8). Further, at the time of indoor heating, the second opening/closing valve 151 is fully closed, so that the refrigerant does not flow into the second expansion valve 152, and the entire amount of the refrigerant is depressurized by the first depressurizing portion 13.

Here, the throttle opening of the first expansion valve 132 is smaller during indoor heating than during equipment cooling. Thus, as shown in fig. 9, during indoor heating, the pressure Pd of the high-pressure refrigerant becomes higher (i.e., pd1 > Pd 2) than during cooling of the equipment, and the pressure Ps of the low-pressure refrigerant becomes lower (i.e., ps1 < Ps 2) than during cooling of the equipment. In other words, the high-low pressure difference Δp1 of the refrigerant in the cycle at the time of indoor heating is larger than the high-low pressure difference Δp2 of the refrigerant in the cycle at the time of equipment cooling.

Therefore, at the time of indoor heating, the temperature of the refrigerant decompressed by the first decompression portion 13 may be extremely low. In this case, the density of the refrigerant flowing on the low pressure side in the cycle becomes small, and thereby the flow rate of the refrigerant passing through the low pressure side heat exchanger becomes small. In addition, on the low pressure side in the cycle, the viscosity of the oil increases due to the decrease in the temperature of the refrigerant.

The refrigerant decompressed by the first decompression portion 13 flows into the equipment cooler 14. The refrigerant flowing into the equipment cooler 14 absorbs heat from the low-temperature heat medium flowing through the low-temperature heat medium circuit 40 and evaporates (i.e., point b4→point B5 in fig. 8). Thereby, the low-temperature thermal medium is cooled. The low-temperature heat medium cooled by the equipment cooler 14 flows to the low-temperature side radiator 43, and absorbs heat from the outside air.

In the indoor heating, the throttle opening of the first expansion valve 132 is set so that the refrigerant state at the refrigerant outlet side of the equipment cooler 14 becomes a saturated state or a wet state. Therefore, the refrigerant having passed through the equipment cooler 14 is a gas-liquid two-phase refrigerant, and is sucked into the compressor 11. The refrigerant sucked into the compressor 11 is compressed again by the compressor 11 until becoming a high-pressure refrigerant.

As described above, when heating the interior of the vehicle, the air heated by the heater core 32 is blown into the vehicle interior, so that the interior of the vehicle can be heated. During indoor heating, the oil in the equipment cooler 14 is returned to the compressor 11 together with the liquid refrigerant.

Here, the first flow path switching valve 44 is controlled to be in the fully closed state so that the low-temperature heat medium does not pass through the battery cooling unit 42 during the indoor heating, but the present invention is not limited thereto. In the indoor heating, the control device 80 may control the first flow path switching valve 44 to the fully open state so that the low-temperature heat medium passes through the battery cooling unit 42.

This allows the refrigerant to absorb the heat released from the battery BT through the equipment cooler 14 via the low-temperature heat medium. Therefore, the exhaust heat of the battery BT can be used as a heat source for heating the air blown into the vehicle interior.

The refrigeration cycle apparatus 10 described above has a circulation structure in which the radiator 12 is provided with the reservoir 122 for storing the surplus refrigerant in the circulation. In this way, the refrigerant state on the refrigerant outlet side of the equipment cooler 14 and the air-conditioning cooler 16 can be brought into an overheated state during indoor cooling and equipment cooling.

In addition, at the time of indoor heating, the throttle opening degree of the first expansion valve 132 is controlled so as to maintain the refrigerant state on the refrigerant outlet side of the equipment cooler 14 in a saturated state or a wet state. The lower limit of the throttle opening adjustment region Xh of the first expansion valve 132 at the time of indoor heating is smaller than the throttle opening adjustment region Xb of the first expansion valve 132 at the time of equipment cooling. Thus, during indoor heating, the refrigerant in a gas-liquid two-phase state is sucked into the compressor 11, and therefore, the oil in the cycle is easily returned to the compressor 11 together with the refrigerant.

Therefore, according to the refrigeration cycle apparatus 10 of the present embodiment, oil can be returned to the refrigerant suction side of the compressor 11 during indoor heating, without disposing an accumulator on the refrigerant suction side of the compressor 11.

The second pressure reducing portion 15 of the refrigeration cycle apparatus 10 of the present embodiment includes the second opening/closing valve 151 and is configured to be fully closable. The control device 80 controls the second decompression unit 15 to be in the fully closed state during indoor heating, and controls the first decompression unit 13 to perform a decompression function. In this way, when heating the interior of the vehicle, the refrigerant having absorbed heat by the equipment cooler 14 is discharged to the radiator 12 via the compressor 11, whereby the refrigerant having passed through the radiator 12 can be used as a heat source to heat the supply air blown into the interior of the vehicle.

However, in the refrigeration cycle apparatus 10 of the present embodiment, the throttle opening degree of the first expansion valve 132 is reduced during indoor heating. At this time, if the dryness of the refrigerant on the refrigerant outlet side of the equipment cooler 14 becomes too small, the amount of liquid refrigerant sucked by the compressor 11 increases. In this case, since liquid compression is generated in the compressor 11, the compression efficiency of the compressor 11 is deteriorated.

In contrast, the first decompression portion 13 of the refrigeration cycle device 10 is provided with a discharge port 135a in the first expansion valve 132, and is configured such that the refrigerant is decompressed when the refrigerant passes through the discharge port 135 a. As described above, if the discharge port 135a is provided in the first expansion valve 132 of the first pressure reducing portion 13, the refrigerant flows through the discharge port 135a during indoor heating, and thus, the dryness of the refrigerant on the refrigerant outlet side of the equipment cooler 14 can be suppressed from becoming excessively small.

The control device 80 of the present embodiment controls the throttle opening of the first pressure reducing portion 13 so that the adjustment frequency of the throttle opening of the first pressure reducing portion 13 at the time of indoor heating is smaller than the adjustment frequency of the throttle opening of the first pressure reducing portion 13 at the time of equipment cooling. If the frequency of adjustment of the throttle opening of the first decompression portion 13 is reduced, the refrigerant state of the refrigerant outlet side of the equipment cooler 14 is easily stabilized. Therefore, by reducing the frequency of adjustment of the throttle opening of the first pressure reducing portion 13 during indoor heating, the refrigerant state on the refrigerant outlet side of the equipment cooler 14 during indoor heating can be maintained in a saturated state or a wet state.

The control device 80 controls the throttle opening of the first decompression portion 13 to maintain the refrigerant state on the refrigerant outlet side of the equipment cooler 14 in a saturated state or in a superheated state when the equipment is cooled. If the refrigerant outlet side of the equipment cooler 14 is maintained in a saturated state or an overheated state, the enthalpy of the refrigerant outlet side of the equipment cooler 14 can be increased as compared with the case where the refrigerant outlet side is maintained in a wet state. Therefore, by controlling the throttle opening of the first pressure reducing portion 13 to maintain the state of the refrigerant on the refrigerant outlet side of the equipment cooler 14 in the saturated state or the superheated state at the time of equipment cooling, the heat generating equipment can be sufficiently cooled by the refrigerant passing through the equipment cooler 14.

The radiator 12 of the refrigeration cycle device 10 has a supercooling portion 123 that radiates heat from the liquid refrigerant stored in the liquid storage portion 122. Thereby, the refrigerant state on the refrigerant outlet side of the radiator 12 becomes the supercooled state, and the enthalpy on the refrigerant outlet side of the radiator 12 decreases. Therefore, at the time of indoor heating, the supply air blown to the space to be air-conditioned can be sufficiently heated by the refrigerant passing through the radiator 12.

(modification of the first embodiment)

In the first embodiment described above, the first expansion valve 132 is exemplified by a structure in which the relief port 135a is provided in the valve body 135, but the present invention is not limited thereto. The first expansion valve 132 may have, for example, a relief port 135a formed in the main body 133. The drain port 135a is not limited to the communication hole, and may be formed of a communication groove.

The first expansion valve 132 is preferably provided with a bleed port 135a, but is not limited thereto. The first expansion valve 132 may be configured without the bleed port 135a.

In the first embodiment described above, as the adjustment region Xh of the throttle opening degree of the first expansion valve 132 at the time of indoor heating, the adjustment region in which the upper limit of the adjustment region Xh is smaller than the lower limit of the adjustment region Xb at the time of equipment cooling is exemplified, but the present invention is not limited thereto. The adjustment region Xh of the throttle opening degree of the first expansion valve 132 during indoor heating may be, for example, an upper limit Xhmax of which is larger than a lower limit Xbmin of the adjustment region Xb during equipment cooling so that the adjustment region Xb during equipment cooling and a part of the adjustment region Xh overlap.

In the first embodiment described above, the example in which the first expansion valve 132 is set to the fixed throttle state at the time of indoor heating has been described, but the present invention is not limited thereto. For example, the control device 80 may change the throttle opening of the first expansion valve 132 in the adjustment region Xh during indoor heating.

In the first embodiment described above, the example in which the first expansion valve 132 is set to the variable throttle state at the time of cooling the equipment has been described, but the present invention is not limited thereto. For example, the control device 80 may fix the throttle opening of the first expansion valve 132 in the adjustment region Xb when the apparatus is cooled. In this case, the adjustment frequency of the throttle opening of the first expansion valve 132 at the time of indoor heating can be made the same as the adjustment frequency of the throttle opening of the first expansion valve 132 at the time of equipment cooling. These modifications are also applicable to the following embodiments.

In the first embodiment described above, the radiator 12 is exemplified as a member having the supercooling portion 123, but is not limited thereto. Radiator 12 may be formed of a member having no supercooling portion 123, for example.

(second embodiment)

Next, a second embodiment will be described with reference to fig. 10. In this embodiment, a part different from the first embodiment will be mainly described, and a part similar to the first embodiment may be omitted.

The control method of the first expansion valve 132 at the time of indoor heating in the present embodiment is different from that in the first embodiment. As shown in fig. 10, the control device 80 controls the

pressure reducing portions

13 and 15 so that the second opening/closing valve 151 is fully closed, the first opening/closing valve 131 is fully opened, and the first expansion valve 132 is in a fixed throttle state. Specifically, the control device 80 controls the first expansion valve 132 to the minimum throttle opening (i.e., the minimum opening) in the adjustment region Xh at the time of indoor heating. Thus, the opening area of the first expansion valve 132 coincides with the opening area of the relief port 135 a. The opening area of the drain port 135a is set to an area where the refrigerant outlet side of the equipment cooler 14 is saturated or wet when indoor heating is performed under standard environmental conditions, for example.

The other structures are the same as those of the first embodiment. The refrigeration cycle apparatus 10 of the present embodiment has a structure common to the first embodiment. Therefore, the same operational effects as those of the first embodiment can be obtained by the structure common to the first embodiment.

The control device 80 of the refrigeration cycle apparatus 10 according to the present embodiment controls the first expansion valve 132 to the minimum opening degree at the time of indoor heating. Thus, during indoor heating, the refrigerant in the gas-liquid two-phase state is likely to return to the compressor 11, and therefore, the oil in the cycle can be returned to the compressor 11 together with the refrigerant.

(third embodiment)

Next, a third embodiment will be described with reference to fig. 11. In this embodiment, a part different from the first embodiment will be mainly described, and a part similar to the first embodiment may be omitted.

In this embodiment, an example will be described in which the refrigeration cycle apparatus 10A of the present invention is applied to a device cooling system for cooling a battery BT as a heat generating device. The refrigeration cycle apparatus 10A shown in fig. 11 can perform equipment cooling and indoor heating.

The refrigeration cycle apparatus 10A includes a compressor 11A, a radiator 12A, a pressure reducing portion 13A, a device cooler 14A, and a control device 80. The refrigerant circuit 100 of the refrigeration cycle apparatus 10A includes a compressor 11A, a radiator 12A, a pressure reducing portion 13A, and a device cooler 14A in this order. The compressor 11A is configured in the same manner as the compressor 11 described in the first embodiment.

The radiator 12A radiates heat from the refrigerant discharged from the compressor 11A. The radiator 12A is a heat exchanger that radiates high-pressure refrigerant discharged from the compressor 11 to a high-temperature heat medium flowing through the high-temperature heat medium circuit 30A. Specifically, the radiator 12A includes a condensing portion 121A that condenses the refrigerant, and a liquid storage portion 122A that performs gas-liquid separation of the refrigerant passing through the condensing portion 121A and stores the liquid refrigerant remaining in the cycle. The condensation unit 121A and the liquid storage unit 122A are configured in the same manner as those described in the first embodiment.

Here, the high-temperature heat medium circuit 30A includes a radiator 12A, a high Wen Cebeng a, a heater core 32A, a high-temperature side radiator 33A, a high-temperature side flow regulating valve 34A, and the like, as in the first embodiment. The high Wen Cebeng a, the heater core 32A, the high-temperature-side radiator 33A, and the high-temperature-side flow regulating valve 34A are configured in the same manner as those described in the first embodiment.

The outlet side of the radiator 12 is connected to the pressure reducing portion 13A. The decompression portion 13A is an expansion valve that decompresses the refrigerant passing through the radiator 12. The pressure reducing portion 13A is configured in the same manner as the first expansion valve 132 described in the first embodiment. That is, the pressure reducing portion 13A is constituted by an electrical expansion valve in which a relief port 135a is formed in the valve body 135.

The equipment cooler 14A is an evaporator that evaporates the refrigerant decompressed by the decompression unit 13A by exchanging heat between the refrigerant and the low-temperature heat medium circulating in the low-temperature heat medium circuit 40A. The equipment cooler 14A functions as a cooler that cools the battery BT by using the latent heat of vaporization of the refrigerant depressurized by the depressurization portion 13A when the equipment is cooled, and functions as a heat absorber when the indoor heating is performed.

Here, the low-temperature heat medium circuit 40A includes the equipment cooler 14A, the low-temperature side pump 41A, the battery cooling unit 42A, the low-temperature side radiator 43A, the first flow path switching valve 44A, the second flow path switching valve 45A, and the like, as in the first embodiment. The low-temperature side pump 41A, the battery cooling unit 42A, the low-temperature side radiator 43A, the first flow path switching valve 44A, and the second flow path switching valve 45A are configured to be the same as those described in the first embodiment.

The operation of the equipment cooling system will be described below. The equipment cooling system is configured to be capable of performing equipment cooling and indoor heating as operation modes.

< device Cooling >)

For example, as shown in fig. 12, the control device 80 controls the pressure reducing portion 13A to be in a variable throttle state. That is, the control device 80 controls the throttle opening of the decompression portion 13A so that the refrigerant state on the refrigerant outlet side of the equipment cooler 14A becomes an overheated state having a degree of superheat when the equipment is cooled. Specifically, the control device 80 controls the throttle opening of the pressure reducing portion 13A in the adjustment region Xb shown in fig. 5 when the equipment is cooled. That is, the control device 80 controls the throttle opening of the pressure reducing portion 13A in the same manner as the first expansion valve 132 of the first embodiment when the equipment is cooled.

In the refrigeration cycle apparatus 10A at the time of cooling the equipment, the high-pressure refrigerant discharged from the compressor 11A flows into the condensation portion 121A of the radiator 12A. The refrigerant flowing into the condensation unit 121A is condensed by radiating heat to the high-temperature heat medium flowing through the high-temperature heat medium circuit 30A.

The refrigerant having passed through the condensation unit 121A flows into the liquid storage unit 122A, and is separated into gas and liquid. Then, the liquid refrigerant separated by the liquid storage portion 122A flows into the decompression portion 13A, and is decompressed by the decompression portion 13A.

The refrigerant decompressed by the decompression portion 13A flows into the equipment cooler 14A. The refrigerant flowing into the equipment cooler 14A absorbs heat from the low-temperature heat medium flowing through the low-temperature heat medium circuit 40A and evaporates. Thereby, the low-temperature thermal medium is cooled.

At the time of cooling the equipment, the throttle opening of the decompression portion 13A is set so that the refrigerant state on the refrigerant outlet side of the equipment cooler 14A becomes an overheated state. Therefore, the refrigerant having passed through the equipment cooler 14A becomes a gas refrigerant having a degree of superheat, and is sucked into the compressor 11A. The refrigerant sucked into the compressor 11A is compressed again by the compressor 11A until becoming a high-pressure refrigerant.

Here, the low-temperature heat medium cooled by the equipment cooler 14A flows to the battery cooling unit 42A, and absorbs heat from the battery BT. Thereby, battery BT is cooled. That is, when the device is cooled, the battery BT is cooled by the latent heat of vaporization of the refrigerant in the device cooler 14A.

As described above, when the device is cooled, the low-temperature heat medium cooled by the device cooler 14A is supplied to the battery cooling unit 42A, whereby the battery BT can be cooled.

< indoor heating >)

The indoor heating is an operation mode in which air heated to a desired temperature by the indoor air conditioning unit 60A is blown into the vehicle interior. The control device 80 appropriately determines the operating states of various devices during indoor heating by using the detection signals of the sensor group 81 and the operation signals of the operation panel 82.

For example, as shown in fig. 12, the control device 80 controls the pressure reducing portion 13A to be in a fixed throttle state. That is, the control device 80 controls the throttle opening of the pressure reducing portion 13A so that the refrigerant state on the refrigerant outlet side of the equipment cooler 14A becomes a saturated state or a wet state when the equipment is cooled. Specifically, during indoor heating, the control device 80 controls the throttle opening of the pressure reducing portion 13A in the adjustment region Xh shown in fig. 5. That is, the control device 80 controls the throttle opening of the pressure reducing portion 13A in the same manner as the first expansion valve 132 of the first embodiment when heating the room.

Thus, during indoor heating, the high-pressure refrigerant discharged from the compressor 11A flows into the condensation portion 121A of the radiator 12A in the refrigeration cycle apparatus 10A. The refrigerant flowing into the condensation unit 121A dissipates heat from the high-temperature heat medium flowing through the high-temperature heat medium circuit 30A and condenses. Thereby, the high-temperature heat medium flowing through the high-temperature heat medium circuit 30A is heated and raised in temperature.

The high-temperature heat medium heated by the condensation unit 121A flows to the heater core 32A, and radiates heat to the supply air blown into the vehicle interior. That is, during indoor heating, the high-pressure refrigerant in the cycle radiates heat to the supply air blown into the vehicle interior via the high-temperature heat medium.

On the other hand, the refrigerant having passed through the condensation unit 121A flows into the liquid storage unit 122A, and is separated into gas and liquid. Then, the liquid refrigerant separated by the liquid storage portion 122A flows into the decompression portion 13A, and is decompressed by the decompression portion 13A.

The refrigerant decompressed by the decompression portion 13A flows into the equipment cooler 14A. The refrigerant flowing into the equipment cooler 14A absorbs heat from the low-temperature heat medium flowing through the low-temperature heat medium circuit 40A and evaporates. Thereby, the low-temperature thermal medium is cooled. The low-temperature heat medium cooled by the equipment cooler 14A flows to the low-temperature side radiator 43A, and absorbs heat from the outside air.

Here, at the time of indoor heating, the throttle opening of the decompression portion 13A is set so that the refrigerant state on the refrigerant outlet side of the equipment cooler 14A becomes a saturated state or a wet state. Therefore, the refrigerant having passed through the equipment cooler 14A is a gas-liquid two-phase refrigerant, and is sucked into the compressor 11A. The refrigerant sucked into the compressor 11A is compressed again by the compressor 11A until becoming a high-pressure refrigerant.

As described above, when heating the interior of the vehicle, the supply air heated by the heater core 32A is blown into the vehicle interior, so that the interior of the vehicle can be heated. During indoor heating, the oil in the equipment cooler 14A returns to the compressor 11 together with the liquid refrigerant.

The refrigeration cycle apparatus 10A of the present embodiment has a structure common to the first embodiment. Therefore, the same operational effects as those of the first embodiment can be obtained by the structure common to the first embodiment.

Specifically, since the refrigeration cycle apparatus 10A has a circulation structure in which the radiator 12A is provided with the reservoir 122A for storing the surplus refrigerant in the circulation, the refrigerant state on the refrigerant outlet side of the equipment cooler 14A can be brought into an overheated state when the equipment is cooled.

In addition, during indoor heating, the throttle opening of the pressure reducing portion 13A is controlled so as to maintain the refrigerant state on the refrigerant outlet side of the equipment cooler 14A in a saturated state or a wet state. The lower limit of the throttle opening adjustment region Xh of the pressure reducing portion 13A at the time of indoor heating is smaller than the throttle opening adjustment region Xb of the pressure reducing portion 13A at the time of equipment cooling. Thus, during indoor heating, the refrigerant in a gas-liquid two-phase state is sucked into the compressor 11A, and thus the oil in the cycle is easily returned to the compressor 11A together with the refrigerant.

The decompression section 13A has the following structure: a discharge port 135a is provided, the discharge port 135a having a constant opening area, and the refrigerant is depressurized as the refrigerant passes through the discharge port 135 a. Thus, even if the throttle opening of the pressure reducing portion 13A is reduced during indoor heating, the dryness of the refrigerant on the refrigerant outlet side of the equipment cooler 14A can be suppressed from becoming too small by flowing the refrigerant through the discharge port 135 a.

The control device 80 controls the throttle opening of the pressure reducing portion 13A so that the frequency of adjustment of the throttle opening of the pressure reducing portion 13A during indoor heating is smaller than the frequency of adjustment of the throttle opening of the pressure reducing portion 13A during equipment cooling. This can maintain the refrigerant state on the refrigerant outlet side of the equipment cooler 14A in a saturated state or in a wet state during indoor heating.

The control device 80 controls the throttle opening of the pressure reducing portion 13A so as to maintain the refrigerant state on the refrigerant outlet side of the equipment cooler 14A in a saturated state or in a superheated state when the equipment is cooled. As a result, the enthalpy of the refrigerant outlet side of the equipment cooler 14A can be increased as compared with the case where the throttle opening degree of the decompression portion 13A is controlled to maintain the refrigerant state in the wet state. Therefore, by controlling the throttle opening of the pressure reducing portion 13A to maintain the refrigerant outlet side of the equipment cooler 14A in the refrigerant state or the saturated state or the overheated state at the time of equipment cooling, the battery BT can be sufficiently cooled by the refrigerant passing through the equipment cooler 14A.

(other embodiments)

While the representative embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications, for example, can be made.

In the above-described embodiment, the refrigeration cycle apparatus 10 is exemplified as an apparatus capable of performing indoor cooling, equipment cooling, and indoor heating, but is not limited thereto. The refrigeration cycle apparatus 10 may be configured to be capable of performing dehumidification and heating of a vehicle interior, for example.

In the above-described embodiment, the refrigeration cycle apparatus 10 is exemplified as an apparatus capable of performing indoor cooling, equipment cooling, and indoor heating, but is not limited thereto. The refrigeration cycle apparatus 10 may be configured to be capable of performing only indoor cooling and indoor heating, for example. The refrigeration cycle apparatus 10 may be configured to be capable of performing dehumidification and heating of the vehicle interior.

The configurations of the refrigeration cycle apparatus 10 described in the above embodiments are not limited to those disclosed in the above embodiments. The compressor 11 may be driven by an internal combustion engine, for example. The radiator 12 may be configured to omit the liquid storage portion 122 and the supercooling portion 123 and to include only the condensing portion 121, for example. The second expansion valve 152 may be constituted by a mechanical expansion valve or a fixed throttle, for example. The first and second on-off

valves

131 and 151 may be disposed downstream of the first and

second expansion valves

132 and 152, for example. The first and second on-off

valves

131 and 151 may be disposed in parallel with the first and

second expansion valves

132 and 152, for example. The first decompression portion 13 and the second decompression portion 15 may be constituted by an electric expansion valve having a full-close function. The evaporation pressure adjustment valve 17 may be disposed in the second refrigerant flow path 100b instead of the third refrigerant flow path 100c, for example.

In the above-described embodiment, the example in which the liquid such as the antifreeze is used as the high-temperature heat medium and the low-temperature heat medium has been described, but the present invention is not limited thereto. The high-temperature heat medium and the low-temperature heat medium may be gas as long as they have excellent heat conductivity.

The respective configurations of the high-temperature heat medium circuit 30 described in the above embodiment are not limited to those disclosed in the above embodiment. The high-temperature heat medium circuit 30 may be configured to adjust the flow rate ratio of the refrigerant flowing to the heater core 32 and the high-temperature side radiator 33 by providing two flow rate adjustment valves corresponding to the heater core 32 and the high-temperature side radiator 33, respectively, for example.

The structure of the low-temperature heat medium circuit 40 described in the above embodiment is not limited to that disclosed in the above embodiment. The low-temperature heat medium circuit 40 may be configured to switch a flow path using a three-way valve type flow path switching valve.

The device cooled by the low-temperature heat medium flowing through the low-temperature heat medium circuit 40 may be a heat generating device that generates heat during operation, or may be a device other than the battery BT.

In the vehicle-mounted heat generating device, there are a motor that outputs driving force for running, an inverter that converts the frequency of electric power supplied to the motor, a charger for charging the battery BT, and the like, in addition to the battery BT.

Therefore, the low-temperature heat medium circuit 40 may be configured to cool not only the battery BT but also the motor, inverter, charger, and the like. Such a structure can be realized by connecting various heat generating devices in parallel or in series with respect to the flow of the low-temperature heat medium.

In the above-described embodiment, the relationship between the high-temperature side radiator 33 and the low-temperature side radiator 43 is not mentioned, but the high-temperature side radiator 33 and the low-temperature side radiator 43 are not limited to the independent structures. For example, the high-temperature side radiator 33 and the low-temperature side radiator 43 may be integrated by thermally moving heat of the high-temperature heat medium and heat of the low-temperature heat medium with each other. Specifically, the heat medium may be integrated so as to be thermally movable with each other by sharing the constituent parts (for example, heat exchange fins) of the high-temperature side radiator 33 and a part of the low-temperature side radiator 43.

In the above-described embodiment, the example in which the refrigeration cycle apparatus 10 is applied to the air conditioner 1 and the equipment cooling system of the hybrid vehicle has been described, but the present invention is not limited thereto. The refrigeration cycle apparatus 10 can be applied to, for example, the air conditioner 1 and the equipment cooling system of the electric vehicle. The refrigeration cycle apparatus 10 can be applied not only to a moving body such as a vehicle but also to a stationary apparatus and a stationary system.

In the above-described embodiments, constituent elements are not necessarily essential, except those specifically and clearly indicated as essential and those obviously regarded as essential in principle.

In the above-described embodiment, when reference is made to the number, value, number, range, and other numerical values of the constituent elements of the embodiment, the number is not limited to a specific number except the case where the number is explicitly indicated as being particularly necessary and the case where the number is obviously considered to be limited to the specific number in principle.

In the above-described embodiments, when referring to the shape, positional relationship, and the like of the structural elements and the like, the shape, positional relationship, and the like are not limited to those specifically and clearly indicated, and the case where the shape, positional relationship, and the like are limited in principle.

In the above-described embodiment, when acquiring the external environment information (for example, the humidity outside the vehicle) of the vehicle from the sensor is described, the sensor may be omitted and the external environment information may be received from a server or cloud outside the vehicle. Alternatively, the sensor may be eliminated, the related information related to the external environment information may be acquired from a server or cloud outside the vehicle, and the external environment information may be estimated from the acquired related information.

The control device and its method described in the present invention can be implemented by a special purpose computer provided by a processor and a memory that constitute a program programmed to perform one or more functions embodied by a computer program. Alternatively, the control device and the method thereof described in the present invention may be implemented by a special purpose computer provided by a processor configured by one or more special purpose hardware logic circuits. Alternatively, the control device and the method thereof described in the present invention may be implemented by one or more special purpose computers configured by combining a processor and a memory programmed to perform one or more functions with one or more processors configured by hardware logic circuits. In addition, the computer program may also be stored as instructions executed by a computer in a non-transitory, tangible storage medium readable by a computer.

(summary)

According to the first aspect of some or all of the embodiments described above, the refrigeration cycle apparatus includes a compressor, a radiator, a pressure reducing portion, an evaporator, and an opening degree control portion that controls a throttle opening degree of the pressure reducing portion. The radiator has a condensing portion that condenses the refrigerant, and a liquid storage portion that performs gas-liquid separation of the refrigerant passing through the condensing portion and stores the liquid refrigerant remaining in the cycle. The opening control unit controls the throttle opening of the decompression unit during indoor heating so as to maintain the refrigerant state on the refrigerant outlet side of the evaporator in a saturated state or a wet state. The lower limit of the throttle opening adjustment area of the decompression section at the time of indoor heating is smaller than the throttle opening adjustment area of the decompression section at the time of equipment cooling.

According to a second aspect, the pressure reducing portion has the following structure: a discharge port is provided, which has a constant opening area, and the refrigerant is depressurized as the refrigerant passes through the discharge port.

When the dryness of the refrigerant at the refrigerant outlet side of the evaporator becomes too small during indoor heating, the amount of liquid refrigerant sucked into the compressor increases. In this case, since liquid compression is generated in the compressor, the compression efficiency of the compressor is deteriorated.

In contrast, if the relief port is provided in the pressure reducing portion, even if the throttle opening of the pressure reducing portion is reduced during indoor heating, the dryness of the refrigerant on the refrigerant outlet side of the evaporator can be suppressed from becoming too small by flowing the refrigerant through the relief port.

According to the third aspect, the opening degree control unit controls the throttle opening degree of the pressure reducing unit so that the adjustment frequency of the throttle opening degree of the pressure reducing unit during indoor heating is smaller than the adjustment frequency of the throttle opening degree of the pressure reducing unit during cooling of the apparatus. If the frequency of adjustment of the throttle opening of the decompression portion is reduced, the refrigerant state on the refrigerant outlet side of the evaporator is easily stabilized. Therefore, by reducing the frequency of adjustment of the throttle opening of the pressure reducing portion during indoor heating, the refrigerant state on the refrigerant outlet side of the evaporator during indoor heating can be maintained in a saturated state or a wet state.

According to the fourth aspect, the opening degree control unit controls the throttle opening degree of the decompression unit to maintain the refrigerant state on the refrigerant outlet side of the evaporator in the saturated state or the overheated state when the apparatus is cooled.

If the throttle opening of the decompression portion is controlled to maintain the refrigerant state on the refrigerant outlet side of the evaporator in the saturated state or the superheated state, the enthalpy on the refrigerant outlet side of the evaporator can be increased as compared with the case where the throttle opening of the decompression portion is controlled to maintain the refrigerant state in the wet state. Therefore, by controlling the throttle opening of the decompression portion to maintain the refrigerant state on the refrigerant outlet side of the evaporator in the saturated state or the superheated state at the time of cooling the apparatus, the heat generating apparatus can be sufficiently cooled by the refrigerant passing through the evaporator.

According to a fifth aspect, a refrigeration cycle apparatus includes a compressor, a radiator, a first pressure reducing portion, a second pressure reducing portion, a device cooler, an air conditioning cooler, and an opening degree control portion that controls throttle opening degrees of the first pressure reducing portion and the second pressure reducing portion. The radiator has a condensing portion that condenses the refrigerant, and a liquid storage portion that performs gas-liquid separation of the refrigerant passing through the condensing portion and stores the liquid refrigerant remaining in the cycle. The opening control unit controls the throttle opening of the first decompression unit during indoor heating so as to maintain the refrigerant state on the refrigerant outlet side of the equipment cooler in a saturated state or in a wet state. The lower limit of the throttle opening adjustment area of the first pressure reducing portion at the time of indoor heating is smaller than the throttle opening adjustment area of the first pressure reducing portion at the time of equipment cooling.

According to the sixth aspect, the second pressure reducing portion is configured to be fully closable. The opening control unit controls the second decompression unit to be in a fully closed state during indoor heating, and controls the first decompression unit to perform a decompression function. By discharging the refrigerant having absorbed heat by the equipment cooler to the radiator via the compressor, the air-conditioning space can be heated by the refrigerant having passed through the radiator as a heat source.

According to a seventh aspect, the first pressure reducing portion has the following structure: a discharge port is provided, which has a constant opening area, and the refrigerant is depressurized as the refrigerant passes through the discharge port. In this way, if the first pressure reducing portion is provided with the discharge port, the dryness of the refrigerant on the refrigerant outlet side of the equipment cooler can be suppressed from becoming too small by flowing the refrigerant through the discharge port at the time of indoor heating.

According to the eighth aspect, the opening degree control unit controls the opening degree of the throttle of the first pressure reducing unit so that the frequency of adjustment of the opening degree of the throttle of the first pressure reducing unit during indoor heating is smaller than the frequency of adjustment of the opening degree of the throttle of the first pressure reducing unit during equipment cooling.

If the frequency of adjustment of the throttle opening of the first pressure reducing portion is reduced, the refrigerant state on the refrigerant outlet side of the equipment cooler is easily stabilized. Therefore, by reducing the frequency of adjustment of the throttle opening of the first pressure reducing portion during indoor heating, the refrigerant state on the refrigerant outlet side of the equipment cooler during indoor heating can be maintained in a saturated state or a wet state.

According to the ninth aspect, the opening degree control unit controls the throttle opening degree of the first decompression unit to maintain the state of the refrigerant on the refrigerant outlet side of the equipment cooler in the saturated state or the overheated state when the equipment is cooled.

If the refrigerant outlet side of the equipment cooler is maintained in a saturated state or an overheated state, the enthalpy of the refrigerant outlet side of the equipment cooler can be increased as compared with the case of maintaining the refrigerant in a wet state. Therefore, by controlling the throttle opening of the first pressure reducing portion so as to maintain the state of the refrigerant on the refrigerant outlet side of the equipment cooler in the saturated state or the overheated state at the time of cooling the equipment, the heat generating equipment can be sufficiently cooled by the refrigerant passing through the equipment cooler.

According to a tenth aspect, the radiator includes a supercooling portion that radiates heat from the liquid refrigerant stored in the liquid storage portion. Thereby, the refrigerant state at the refrigerant outlet side of the radiator becomes a supercooled state, and the enthalpy at the refrigerant outlet side of the radiator is reduced. Therefore, at the time of indoor heating, the air blown to the space to be air-conditioned can be sufficiently heated by the refrigerant passing through the radiator. The "supercooled state" refers to a state in which the refrigerant becomes supercooled liquid.

Claims

1. A refrigeration cycle apparatus capable of performing indoor heating for heating air blown to an air-conditioning target space and device cooling for cooling a heat generating device (BT), comprising:

a compressor (11A) that compresses and discharges a refrigerant containing oil;

a radiator (12A) that heats the supply air using the refrigerant discharged from the compressor as a heat source when heating the indoor space;

a decompression unit (13A) that decompresses the refrigerant that has passed through the radiator;

an evaporator (14A) that functions as a cooler for cooling the heat generating device by utilizing the latent heat of vaporization of the refrigerant depressurized by the depressurization portion when the device is cooled, and as a heat absorber when the indoor heating is performed; and

an opening degree control unit (80 a) that controls the throttle opening degree of the pressure reducing unit,

the radiator has a condensing unit (121A) for condensing the refrigerant and a liquid storage unit (122A) for separating the refrigerant passing through the condensing unit into gas and liquid and storing the liquid refrigerant remaining in the circulation,

the opening control unit controls the throttle opening of the decompression unit to maintain the refrigerant state at the refrigerant outlet side of the evaporator in a saturated state or in a wet state during indoor heating,

The lower limit of the throttle opening of the adjustment region at the time of indoor heating is smaller than the adjustment region of the throttle opening of the decompression portion at the time of equipment cooling, and the throttle opening of the decompression portion at the time of indoor heating is smaller than the throttle opening at the time of equipment cooling.

2. A refrigeration cycle device according to claim 1, wherein,

the pressure reducing part has the following structure: a bleed port (135 a) is provided, having a constant opening area, through which refrigerant is depressurized as it passes.

3. A refrigeration cycle device according to claim 1, wherein,

the opening degree control unit controls the throttle opening degree of the pressure reducing unit so that the adjustment frequency of the throttle opening degree of the pressure reducing unit during indoor heating is smaller than the adjustment frequency during cooling of the equipment.

4. A refrigeration cycle device according to any one of claim 1 to 3, wherein,

the opening degree control unit controls the throttle opening degree of the pressure reducing unit to maintain the refrigerant state on the refrigerant outlet side of the evaporator in a saturated state or in a superheated state when the equipment is cooled.

5. A refrigeration cycle device according to any one of claim 1 to 3, wherein,

the radiator has a supercooling part (123) which radiates heat from the refrigerant stored in the liquid storage part.

6. A refrigeration cycle apparatus capable of performing indoor heating for heating air blown to a space to be air-conditioned, equipment cooling for cooling a heat generating equipment (BT), and indoor cooling for cooling the air, the refrigeration cycle apparatus comprising:

a compressor (11) that compresses and discharges a refrigerant containing oil;

a radiator (12) that heats the air-conditioning space by using the refrigerant discharged from the compressor as a heat source when heating the indoor space;

a first decompression unit (13) that decompresses the refrigerant that has passed through the radiator;

a second pressure reducing portion (15) disposed in parallel with the first pressure reducing portion on a downstream side of the radiator in the refrigerant flow;

a device cooler (14) that functions as a cooler for cooling the heat generating device by utilizing the latent heat of vaporization of the refrigerant depressurized by the first depressurizing unit when the device is cooled, and as a heat absorber when the indoor heating is performed;

A cooler (16) for an air conditioner; the air conditioner cooler cools the air by utilizing the evaporation latent heat of the refrigerant decompressed by the second decompression portion; and

an opening degree control unit (80 a) that controls the throttle opening degrees of the first decompression unit and the second decompression unit,

the radiator has a condensing part (121) for condensing the refrigerant and a liquid storage part (122) for separating the gas from the liquid of the refrigerant passing through the condensing part and storing the liquid refrigerant remaining in the circulation,

the opening control unit controls the throttle opening of the first decompression unit to maintain the state of the refrigerant on the refrigerant outlet side of the equipment cooler in a saturated state or a wet state during indoor heating,

the lower limit of the throttle opening of the adjustment region at the time of indoor heating is smaller than the adjustment region of the throttle opening of the first decompression portion at the time of equipment cooling, and the throttle opening of the first decompression portion at the time of indoor heating is smaller than the throttle opening of the first decompression portion at the time of equipment cooling.

7. A refrigeration cycle device according to claim 6, wherein,

the second decompression portion is configured to be fully closable,

The opening control unit controls the second decompression unit to be in a fully closed state during indoor heating, and controls the first decompression unit to perform a decompression function.

8. A refrigeration cycle device according to claim 6, wherein,

the first decompression section has the following structure: a bleed port (135 a) is provided, having a constant opening area, through which refrigerant is depressurized as it passes.

9. A refrigeration cycle device according to any one of claims 6 to 8, wherein,

the opening degree control unit controls the throttle opening degree of the first pressure reducing unit so that the adjustment frequency of the throttle opening degree of the first pressure reducing unit during indoor heating is smaller than the adjustment frequency during cooling of the equipment.

10. A refrigeration cycle device according to any one of claims 6 to 8, wherein,

the opening degree control unit controls the throttle opening degree of the first decompression unit to maintain the state of the refrigerant on the refrigerant outlet side of the equipment cooler in a saturated state or in a superheated state when the equipment is cooled.

11. A refrigeration cycle device according to any one of claims 6 to 8, wherein,