WO2012101672A1

WO2012101672A1 - Air conditioner device

Info

Publication number: WO2012101672A1
Application number: PCT/JP2011/000406
Authority: WO
Inventors: 裕之森本; 山下　浩司
Original assignee: 三菱電機株式会社
Priority date: 2011-01-26
Filing date: 2011-01-26
Publication date: 2012-08-02
Also published as: CN103229004A; EP2669598A4; EP2669598B1; CN103229004B; AU2011357097A1; AU2011357097B2; US20130213078A1; JPWO2012101672A1; EP2669598A1

Abstract

The present invention obtains an air conditioner device that is able to have more minute low-pressure gas piping even when a refrigerant having a low refrigerant density at low pressures is used. The present invention is provided with: a refrigerant cycling circuit (10) that comprises a compressor (1), a heat-source-side heat exchanger (3), a throttle device (20), and a use-side heat exchanger (21) connected by piping, and that cycles a refrigerant having a saturated refrigerant gas density at 0°C that is 35-65% of that of R410A refrigerant; and a supercooling means (supercooling heat exchanger (4), throttle device (5), and bypass circuit (7)) that, during a cooling operation, causes the solution temperature of high-pressure liquid refrigerant sent from the heat-source-side heat exchanger (3) to the throttle device (20) to be no greater than 5°C.

Description

Air conditioner

The present invention relates to an air conditioner.

2. Description of the Related Art Conventionally, there is an air conditioner that includes a supercooling unit and that cools a refrigerant sent from a condenser to a throttling device with a bypass-side refrigerant (see, for example, Patent Document 1). In the air conditioner provided with such a supercooling means, the amount of refrigerant circulating to the expansion device is reduced, so that the pressure loss of the evaporator and the extension pipe at the rear stage of the expansion device can be reduced.

JP-A-6-265232 (FIG. 1, page 6)

By the way, in recent years, from the viewpoint of global warming, there has been a movement to limit the use of HFC refrigerants with high global warming potential (for example, R410A, R404A, R407C, R134a, etc.), and refrigerants with low global warming potential ( For example, an air conditioner using HFO1234yf, carbon dioxide, etc.) has been proposed. HFO1234yf has a significantly lower refrigerant density at low pressure than R410A, and its pressure characteristics at the same temperature are much lower than R410A. When cooling operation is performed using such a refrigerant having a low refrigerant density at low pressure in the air conditioner, the influence of pressure loss in the low-pressure gas piping is extremely large. Therefore, there has been a problem that the pipe diameter has to be increased in order to reduce the pressure loss.

In particular, in a large system such as a building multi-air conditioner (10HP), when R410A is used, the diameter of the low-pressure gas pipe is about 22.2 mm, but when a refrigerant with low refrigerant density at low pressure is used, About twice as much as φ44.5mm. Therefore, it is very difficult to bend the pipe, and the processing cost is greatly increased. In addition, the refrigerant pipe having such a large pipe diameter is usually hardly used in the market, so that the cost is greatly increased. Thus, reducing the pipe diameter of the low-pressure gas pipe is considered as one of the major problems when using a refrigerant having a low refrigerant density at low pressure.

The air conditioner of Patent Document 1 is effective in reducing pressure loss as described above. However, it is not assumed that a refrigerant having a low refrigerant density at low pressure is used as the working refrigerant, and the effect of reducing pressure loss is not sufficient. Therefore, simply applying a refrigerant having a low refrigerant density at a low pressure to the air conditioner cannot solve the problem of a large increase in the diameter of the low-pressure gas pipe as described above.

The present invention has been made to solve the above-described problem, and an object of the present invention is to obtain an air conditioner that can make a low-pressure gas pipe thin even when a refrigerant having a low refrigerant density at low pressure is used. To do.

In the air conditioner according to the present invention, the compressor, the heat source side heat exchanger, the expansion device, and the use side heat exchanger are connected by piping, and the saturated refrigerant gas density at 0 ° C. is 35 to 65% of the R410A refrigerant. And a supercooling means for setting the liquid temperature of the high-pressure liquid refrigerant sent to the expansion device from the heat source side heat exchanger to 5 ° C. or less during the cooling operation.

According to the present invention, since the liquid temperature of the high-pressure liquid refrigerant sent from the heat source side heat exchanger to the expansion device is 5 ° C. or lower during the cooling operation, the refrigeration effect can be increased and the refrigerant flow rate can be reduced. Can do. Therefore, the low pressure pipe can be made thin.

It is a schematic circuit block diagram which shows an example of the circuit structure of the air conditioning apparatus which concerns on Embodiment 1 of this invention. It is a refrigerant circuit diagram which shows the flow of the refrigerant | coolant at the time of the air_conditioning | cooling operation mode of the air conditioning apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the structural example of a double tube | pipe type supercooling heat exchanger. It is a graph which shows the relationship between a liquid temperature and a flow rate ratio. It is a graph which shows the relationship between a liquid temperature and a pressure loss ratio. It is a graph which shows the relationship between liquid temperature and piping diameter ratio. It is a refrigerant circuit diagram which shows the flow of the refrigerant | coolant at the time of the heating operation mode of the air conditioning apparatus which concerns on Embodiment 1 of this invention. It is a schematic circuit block diagram which shows an example of the circuit structure of the air conditioning apparatus which concerns on Embodiment 2 of this invention. It is a refrigerant circuit figure which shows the flow of the refrigerant | coolant at the time of the air_conditioning | cooling operation mode of the air conditioning apparatus which concerns on Embodiment 2 of this invention. It is a circuit block diagram of the air conditioning apparatus which concerns on Embodiment 3 (cooling / heating simultaneous type) of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a schematic circuit configuration diagram showing an example of a circuit configuration of the air-conditioning apparatus according to Embodiment 1 of the present invention. A detailed circuit configuration of the air conditioner will be described with reference to FIG. FIG. 1 shows an example in which four indoor units 20 are connected. In addition, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one. In FIG. 1 and the drawings to be described later, the same reference numerals denote the same or corresponding parts, which are common throughout the entire specification. Furthermore, the form of the constituent elements appearing in the whole specification is merely an example, and is not limited to these descriptions.

As shown in FIG. 1, an air conditioner 100 includes an outdoor unit (heat source unit) 10, an indoor unit 20a to an indoor unit 20d (hereinafter, may be collectively referred to as an indoor unit 20), an extension pipe 400a and an extension 400b. (Hereinafter, it may be collectively referred to as an extension pipe 400). That is, in the air conditioner 100, a plurality of indoor units 20 are connected to the outdoor unit 10 in parallel. The extension pipe 400 is a refrigerant pipe that conducts the refrigerant (heat source side refrigerant). Further, it is assumed that HFO1234yf or HFO1234ze is enclosed in the air conditioner 100 as a refrigerant.

[Outdoor unit 10]
The outdoor unit 10 includes a compressor 1, a flow switching device 2 such as a four-way valve, a heat source side heat exchanger 3, a supercooling heat exchanger 4, and an accumulator 6. A refrigerant circulation circuit in which refrigerant is circulated is connected to the user side heat exchanger 21 and the expansion device 22 by piping. The outdoor unit 10 further includes a supercooling heat exchanger 4 between the heat source side heat exchanger 3 and the expansion device 22. The outdoor unit 10 branches from between the supercooling heat exchanger 4 and the expansion device 22, and is connected to the inlet side of the accumulator 6 through the expansion device 5 and the low pressure side of the supercooling heat exchanger 4. A bypass circuit 7 is provided. The supercooling heat exchanger 4 exchanges heat between the high-pressure side refrigerant between the heat source side heat exchanger 3 and the expansion device 22 and the low-pressure side refrigerant obtained by decompressing a part of the high-pressure side refrigerant with the expansion device 5 to increase the pressure. Cool the side refrigerant.

The compressor 1 sucks the refrigerant, compresses the refrigerant to be brought into a high-temperature and high-pressure state, and conveys the refrigerant to a refrigerant circulation circuit. For example, the compressor 1 may be composed of an inverter compressor capable of controlling capacity. The flow path switching device 2 switches the refrigerant flow in the heating operation mode and the refrigerant flow in the cooling operation mode.

The heat source side heat exchanger (outdoor heat exchanger) 3 functions as an evaporator during heating operation, functions as a radiator during cooling operation, and is provided between air and refrigerant supplied from a blower such as a fan (not shown). Heat exchange. The accumulator 6 is provided on the suction side of the compressor 1, and surplus refrigerant due to a difference between the heating operation mode and the cooling operation mode, a change in transient operation (for example, a change in the number of operating indoor units 20). The excess refrigerant is stored.

Further, a pressure sensor 8 and a temperature sensor 9 are provided at the outlet (liquid side) of the supercooling heat exchanger 4. The outdoor unit 10 is further provided with various sensors such as a sensor (not shown) for detecting the suction temperature and the discharge temperature of the compressor 1.

In addition, the outdoor unit 10 is provided with a control device 10A. The control device 10A is connected so as to receive detection signals of various sensors in the outdoor unit 10 and various sensors described later in the indoor unit 20. The control device 10A performs control such as adjusting the opening degree of the expansion device 5 and the expansion device 22 based on detection signals from various sensors. Further, the control device 10 </ b> A performs the cooling operation mode and the heating operation mode by switching the flow path switching device 2. Although FIG. 1 shows a configuration in which the control device 10A is provided only in the outdoor unit 10, a sub-control device having a part of the function of the control device 10A is provided in each indoor unit 20, and the control device 10A and sub-control are provided. You may make it the structure which performs a cooperation process by performing data communication between apparatuses.

[Indoor unit 20]
In the indoor unit 20, a use side heat exchanger (indoor side heat exchanger) 21 (21a to 21d) and an expansion device 22 (22a to 22d) are connected in series to constitute a part of a refrigerant circulation circuit. The use-side heat exchanger 21 functions as a radiator during heating operation, functions as an evaporator during cooling operation, performs heat exchange between air supplied from a blower such as a fan (not shown) and the refrigerant, and is air-conditioned. Heating air or cooling air to be supplied to the target space is generated. The throttling device 22 has a function as a pressure reducing valve or an expansion valve, expands the refrigerant by depressurizing it, and may be constituted by a device whose opening degree can be variably controlled, for example, an electronic expansion valve.

Embodiment 1 shows an example in which four indoor units 20 are connected, and are illustrated as an indoor unit 20a, an indoor unit 20b, an indoor unit 20c, and an indoor unit 20d from the left side of the page. Further, according to the indoor unit 20a to the indoor unit 20d, the use side heat exchanger 21 also uses the use side heat exchanger 21a, the use side heat exchanger 21b, the use side heat exchanger 21c, and the use side heat exchanger from the left side of the page. It is illustrated as 21d. Similarly, the diaphragm device 22 is also illustrated as a diaphragm device 22a, a diaphragm device 22b, a diaphragm device 22c, and a diaphragm device 22d from the left side of the drawing. Note that the number of connected indoor units 20 is not limited to four.

In the indoor unit 20, temperature sensors 23 a to 23 d and 24 a to 24 d are provided at the refrigerant inlet / outlet of the use side heat exchanger 21. Detection signals from the temperature sensors 23a to 23d and 24a to 24d are output to the control device 10A. In this embodiment, the indoor unit is controlled by the control unit 10A for the outdoor unit. However, a control unit is provided for each indoor unit, and the indoor units 20a to 20d are controlled by the control unit. good.

In the air conditioner 100, as described above, the low-pressure refrigerant HFO1234yf or HFO1234ze is used as the refrigerant. The saturated gas density at 0 ° C. of these refrigerants is as shown in Table 1. Table 1 shows that HFO1234yf is 58% and HFO1234ze is 38% with respect to the gas density of R410A. That is, this refrigerant has a low-pressure gas density of about 35 to 65% compared to the R410A refrigerant currently used in many air conditioners. The values are obtained from REFPROP Version 8.0 released by NIST (National Institute of Standards and Technology).

Thus, when a refrigerant with a low gas density is used, when the same refrigerant flow rate (kg / hr) is simply flowed through the pipe, the flow rate of HFO1234yf is about twice that of R410A. Since the pressure loss is roughly proportional to the square of the flow velocity, the pressure loss of HFO1234yf is about four times that of R410A. As a result, when the same pipe diameter as that of the R410A refrigerant is used, the pressure loss is quadrupled, resulting in a large deterioration in performance. In order to suppress the HFO1234yf refrigerant to decrease in performance due to a pressure loss equivalent to that of the conventional refrigerant (R410A), it is necessary to double the pipe diameter of the conventional refrigerant. Since HFO1234yf and HFO1234ze have substantially the same density, the pressure loss of HFO1234yf and HFO1234ze shows substantially the same value.

In a small capacity system such as a room air conditioner, even if the pipe diameter is doubled, the original pipe diameter is small, so there is no particular problem in processing. However, in a system with a large capacity such as a multi air conditioner for buildings (10HP), as described in the prior art, the pipe diameter becomes as large as φ44.5 mm, which has a great adverse effect on workability and processing cost.

Therefore, in the first embodiment, the temperature of the high-pressure liquid refrigerant sent to the expansion device 22 from the heat source side heat exchanger 3 serving as a radiator in the cooling operation mode is lowered to 5 ° C. or lower. This is the point of the first embodiment. In this example, the condensation temperature is 49 ° C., and the degree of supercooling when the target temperature of the liquid temperature of the high-pressure liquid refrigerant is 5 ° C. or less is 44 ° C. or more. In this way, by setting the liquid temperature of the high-pressure liquid refrigerant to 5 ° C. or lower, the refrigeration effect can be increased as compared with, for example, a case where the liquid temperature is set to 44 ° C. (supercooling degree 5 ° C.). As a result, the refrigerant flow rate can be reduced, and the pipe size can be reduced.

Hereinafter, each operation mode which the air conditioning apparatus 100 performs is demonstrated.
[Cooling operation mode]
FIG. 2 is a refrigerant circuit diagram illustrating a refrigerant flow when the air-conditioning apparatus 100 is in the cooling operation mode. In FIG. 2, the case where all of the indoor units 20 are driven will be described as an example. In FIG. 2, the flow direction of the refrigerant is indicated by arrows.

A low temperature / low pressure refrigerant is compressed by the compressor 1 and discharged as a high temperature / high pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant discharged from the compressor 1 passes through the flow path switching device 2 and flows into the heat source side heat exchanger 3.

The high-temperature and high-pressure gas refrigerant that has flowed into the heat source side heat exchanger 3 becomes liquid by exchanging heat with air supplied from a blower (not shown) and flows out of the heat source side heat exchanger 3. The liquid refrigerant flowing out of the heat source side heat exchanger 3 flows into the high pressure side of the supercooling heat exchanger 4. On the low pressure side of the supercooling heat exchanger 4, a part of the refrigerant that has passed through the supercooling heat exchanger 4 is decompressed by the expansion device 5 of the bypass circuit 7 and flows into a low-pressure gas-liquid two-phase refrigerant. ing. Therefore, the liquid refrigerant on the high pressure side of the supercooling heat exchanger 4 is cooled by exchanging heat with the refrigerant on the low pressure side, and the liquid temperature decreases (increases the degree of supercooling) and flows out of the supercooling heat exchanger 4. To do. The low pressure two-phase refrigerant on the low pressure side of the supercooling heat exchanger 4 exchanges heat with the refrigerant on the high pressure side to become a low pressure gas refrigerant, exits the supercooling heat exchanger 4, and travels toward the accumulator 6.

Here, as described above, in this example, the opening degree of the expansion device 5 is adjusted so that the liquid temperature of the high-pressure liquid refrigerant at the outlet of the supercooling heat exchanger 4 is lowered to about 5 ° C. As a result, the refrigeration effect is increased, so that the opening degree of the expansion device 5 becomes smaller than when the degree of supercooling is set to 5 ° C. Therefore, the refrigerant supply amount to the use side heat exchanger 21 is reduced. As a result, the piping size can be reduced. The opening degree of the expansion device 5 is adjusted by the control device 10A based on detection signals from the pressure sensor 8 and the temperature sensor 9.

By the way, as shown in FIG. 3, the supercooling heat exchanger 4 of this Embodiment 1 employs a double-pipe system, a high-pressure liquid refrigerant that is a high-pressure side refrigerant in the annular part, and a low-pressure in the inner pipe. A gas-liquid two-phase refrigerant that is a side refrigerant is flowing. This is because when the gas-liquid two-phase refrigerant is caused to flow through the annular part, the liquid refrigerant is biased toward the bottom part of the annular part and the heat exchange performance is deteriorated.

In addition, the supercooling heat exchanger 4 is not limited to a double tube system, and a plate heat exchanger may be used. When this plate heat exchanger is used, the heat exchanger performance is effectively demonstrated by allowing the low-pressure gas-liquid two-phase refrigerant to flow from bottom to top and the high-pressure liquid refrigerant from top to bottom (to AC). can do.

The liquid refrigerant that has flowed out of the supercooling heat exchanger 4 passes through the extension pipe 400a toward the indoor unit 20 and flows into each of the indoor units 20a to 20d. The refrigerant flowing into the indoor unit 20a to the indoor unit 20d is expanded (depressurized) by each of the expansion devices 22a to 22d to be in a low-temperature / low-pressure gas-liquid two-phase state. The gas-liquid two-phase refrigerant flows into the use side heat exchanger 21a to the use side heat exchanger 21d. The gas-liquid two-phase refrigerant flowing into the use side heat exchanger 21a to the use side heat exchanger 21d absorbs heat from the air by exchanging heat with air (indoor air) supplied from a blower (not shown). The refrigerant flows out of the use side heat exchanger 21a to the use side heat exchanger 21d.

Here, the refrigerant supply amount to the use side heat exchanger 21 is adjusted using temperature information from the temperature sensors 23 a to 23 d and 24 a to 24 d provided at the refrigerant inlet / outlet of the use side heat exchanger 21. Yes. Specifically, the control device 10A acquires information from the temperature sensors 23a to 23d and 24a to 24d, and calculates the degree of superheat (refrigerant temperature on the outlet side−refrigerant temperature on the inlet side) based on the acquired information. . Then, the opening degree of the expansion device 22 is determined so that the degree of superheat is about 2 to 5 ° C., and the refrigerant supply amount to the use side heat exchanger 21 is adjusted.

The low-pressure gas refrigerant that has flowed out of the use side heat exchanger 21a to the use side heat exchanger 21d flows out of the indoor unit 20a to the indoor unit 20d, and flows into the outdoor unit 10 through the extension pipe 400b. The refrigerant flowing into the outdoor unit 10 passes through the flow path switching device 2 and flows into the accumulator 6. The refrigerant flowing into the accumulator 6 is separated from the liquid refrigerant and the gas refrigerant, and the gas refrigerant is sucked into the compressor 1 again.

In such a cooling operation mode, the superheat degree control is performed in each indoor unit 20 so that the superheat degree is in the positive range, so that the liquid refrigerant does not flow into the accumulator 6. However, when there is a transitional state or when the indoor unit 20 is stopped, a small amount of refrigerant (dryness of about 0.95) may flow into the accumulator 6. The liquid refrigerant that has flowed into the accumulator 6 is evaporated and sucked into the compressor 1 or is sucked into the compressor 1 through an oil return hole (not shown) provided in the outlet pipe of the accumulator 6. .

Next, the effect of reducing the high-pressure liquid refrigerant temperature at the outlet of the supercooling heat exchanger 4 to about 5 ° C. will be described. FIG. 4 shows the relationship between the liquid temperature at the outlet of the supercooling heat exchanger and the reduction rate of the refrigerant flow rate. The refrigerant flow rate ratio is 1 when the liquid temperature is 44 ° C. (supercooling degree 5 ° C.). Further, other calculation conditions are an evaporation temperature of 0 ° C. and a condensation temperature of 49 ° C.
As can be seen from FIG. 4, by setting the outlet liquid temperature of the supercooling heat exchanger 4 to about 5 ° C., the flow rate is about 66% when the liquid temperature is 44 ° C. (supercooling degree 5 ° C.), and the extension pipe 400a. It can be seen that the refrigerant flow rate flowing through 400b is reduced by 34%.

FIG. 5 is a graph showing the relationship between the liquid temperature at the outlet of the supercooling heat exchanger and the reduction ratio of the pressure loss of the piping. The pressure loss ratio when the liquid temperature is 44 ° C. (supercooling degree 5 ° C.) is 1. As can be seen from FIG. 5, by setting the outlet liquid temperature of the supercooling heat exchanger 4 to about 5 ° C., the pressure loss becomes about 44% when the liquid temperature is 44 ° C. (supercooling degree 5 ° C.). It can be seen that the pressure loss at 400a and 400b is reduced by 56%.

FIG. 6 is a graph showing the relationship between the liquid temperature at the outlet of the supercooling heat exchanger and the pipe diameter reduction ratio. The pipe diameter ratio when the liquid temperature is 44 ° C. (supercooling degree 5 ° C.) is 1. As can be seen from FIG. 6, by setting the outlet liquid temperature of the supercooling heat exchanger 4 to about 5 ° C., the pipe diameter becomes about 80% when the liquid temperature is 44 ° C. (supercooling degree 5 ° C.). It can be seen that the pipe diameters at 400a and 400b are reduced by 20%. That is, the pipe diameter can be reduced from one rank to two ranks, and the extension pipes 400a and 400b can be made thin. The extension pipe 400b, which is a low-pressure pipe through which the gas refrigerant passes, is greatly affected by pressure loss, and is thicker than the extension pipe 400a. Therefore, reducing the pipe diameter of the extension pipe 400b by one or two ranks is very effective since the effects of reducing the pipe cost, improving the workability, and the work cost can be obtained.

[Heating operation mode]
FIG. 7 is a refrigerant circuit diagram illustrating a refrigerant flow when the air-conditioning apparatus 100 is in the heating operation mode. In FIG. 7, the case where all the indoor units 20 are driven will be described as an example. In FIG. 7, the flow direction of the refrigerant is indicated by arrows. In the heating operation mode, the expansion device 5 is closed.

A low temperature / low pressure refrigerant is compressed by the compressor 1 and discharged as a high temperature / high pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows out of the outdoor unit 10 through the flow path switching device 2, and flows into each of the indoor units 20a to 20d through the extension pipe 400b.

The high-temperature and high-pressure gas refrigerant flowing into the indoor unit 20a to the indoor unit 20d exchanges heat with air (indoor air) supplied from a blower (not shown) in the use side heat exchanger 21a to the use side heat exchanger 21d. As a result, heat is radiated to the air, and the liquid is converted into a liquid state and flows out from the use side heat exchanger 21a to the use side heat exchanger 21d. The high-pressure liquid refrigerant is expanded (depressurized) by each of the expansion devices 22a to 22d to be in a low-temperature and low-pressure gas-liquid two-phase state, and flows out from the indoor units 20a to 20d.

The refrigerant supply amount to the use side heat exchanger 21 is adjusted using information from temperature sensors 23a to 23d and pressure sensors (not shown) provided at the refrigerant outlet of the use side heat exchanger 21. Yes. Specifically, the degree of supercooling (saturation temperature converted from the detected pressure of refrigerant on the outlet side-refrigerant temperature on the outlet side) is calculated from information from these sensors, and the degree of supercooling is about 2 to 5 ° C. Thus, the opening degree of the expansion device 22 is determined, and the refrigerant supply amount to the heat source side heat exchanger 3 is adjusted.

The low-temperature, low-pressure gas-liquid two-phase refrigerant that has flowed out of the indoor unit 20a to the indoor unit 20d flows into the outdoor unit 10 through the extension pipe 400a. This refrigerant passes through the supercooling heat exchanger 4 as it is and flows into the heat source side heat exchanger 3. The low-temperature / constant-pressure gas-liquid two-phase refrigerant flowing into the heat source side heat exchanger 3 absorbs heat from the air by exchanging heat with air supplied from a blower (not shown), and gradually increases in dryness. Become. Then, at the outlet of the heat source side heat exchanger 3, it becomes a gas-liquid two-phase refrigerant with a high degree of dryness and flows out of the heat source side heat exchanger 3. The refrigerant flowing out of the heat source side heat exchanger 3 flows into the accumulator 6 through the flow path switching device 2. The refrigerant flowing into the accumulator 6 is separated from the liquid refrigerant and the gas refrigerant, and the gas refrigerant is sucked into the compressor 1 again.

In the circuit of the first embodiment, in the heating operation mode, the flow rate of the refrigerant flowing into the extension pipe 400b cannot be reduced. However, since a high-pressure gas refrigerant flows through the extension pipe 400b (a refrigerant having a high density), the pressure loss The refrigerant does not flow through the supercooling heat exchanger 4. In addition, when a refrigerant | coolant is flowed to the supercooling heat exchanger 4, the low-pressure piping (outlet of the supercooling heat exchanger 4-> evaporator-> piping to the inlet of the accumulator 6) of the outdoor unit 10 can also be made thin. . Also in the heating operation mode, the liquid temperature of the high-pressure liquid refrigerant sent from the use side heat exchanger 21 to the expansion device 22 may be 5 ° C. or lower, or the degree of supercooling may be 44 ° C. or higher.

As described above, according to the first embodiment, the high-pressure liquid temperature is lowered to about 5 ° C. by the supercooling means (the supercooling heat exchanger 4, the expansion device 5, and the bypass circuit 7) in the cooling operation mode. Thus, the pipe diameter of the extension pipe (low pressure gas pipe) 400b can be reduced by one or two ranks. As a result, it is possible to reduce piping costs and construction costs, further reduce energy loss due to disposal, and contribute to environmental conservation. Moreover, since pressure loss can be reduced, an energy efficient operation can be performed, and an energy saving effect can also be obtained.

Embodiment 2. FIG.
In the first embodiment, the supercooling means is configured by the supercooling heat exchanger 4, the expansion device 5, and the bypass circuit 7, but in the second embodiment, the supercooling means is configured by the supercooling refrigerant circulation circuit. It is a thing.

FIG. 8 is a schematic diagram of an air-conditioning apparatus according to Embodiment 2 of the present invention. The air conditioner 101 includes a refrigerant circulation circuit 101A and a supercooling circuit 101B. In the second embodiment, differences from the first embodiment will be mainly described, and the same parts as those in the first embodiment are denoted by the same reference numerals. In addition, specific examples and modifications applied to the same components as those in the first embodiment are similarly applied to the present embodiment. This also applies to embodiments described later.

[Refrigerant circulation circuit 101A]
The refrigerant circulation circuit 101A includes a compressor 1, a flow switching device 2 such as a four-way valve, a heat source side heat exchanger 3, and an accumulator 6, and includes a use side heat exchanger 21 and a throttle device of the indoor unit 20. The refrigeration cycle in which refrigerant is circulated is connected with the pipe 22 together.

[Supercooling circuit 101B]
The supercooling circuit 101B includes a compressor 31, a condenser 32, a throttling device 33, and a supercooling heat exchanger 34, which are connected by piping so that the refrigerant circulates and functions as supercooling means. It constitutes the refrigeration cycle. The supercooling heat exchanger 34 performs heat exchange between the low-pressure side refrigerant circulating in the supercooling circuit 101B and the high-pressure side refrigerant between the heat source side heat exchanger 3 and the expansion device 22 of the refrigerant circulation circuit 101A.

In the refrigerant circulation circuit 101A, each device excluding the use side heat exchanger 21 and the expansion device 22 and the supercooling circuit 101B are installed in the same casing, and constitute an outdoor unit 30. Further, the compressor 31 of the subcooling circuit 101B is equipped with a compressor having a smaller capacity than the compressor 1.

Further, the outdoor unit 30 is provided with a control device 30A. The control device 30 </ b> A is connected so as to receive detection signals of various sensors in the outdoor unit 30 and various sensors described later in the indoor unit 20. The control device 30A performs control such as adjusting the opening degree of the expansion device 33 and the expansion device 22 based on detection signals from various sensors. The control device 30 </ b> A performs the cooling operation mode and the heating operation mode by switching the flow path switching device 2. Although FIG. 8 shows a configuration in which the control device 30A is provided only in the outdoor unit 30, a sub-control device having a part of the function of the control device 30A is provided in each indoor unit 20, and the control device 30A and sub-control are provided. You may make it the structure which performs a cooperation process by performing data communication between apparatuses.

Hereinafter, each operation mode which the air conditioning apparatus 101 performs is demonstrated.
[Cooling operation mode]
FIG. 9 is a refrigerant circuit diagram illustrating a refrigerant flow when the air-conditioning apparatus according to Embodiment 2 of the present invention is in the cooling operation mode. In FIG. 9, the case where all the indoor units 20 are driven will be described as an example. In FIG. 9, the flow direction of the refrigerant is indicated by arrows.

First, the operation of the refrigerant circulation circuit 101A will be described. The low-temperature and low-pressure refrigerant is compressed by the compressor 1 and discharged as a high-temperature and high-pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant discharged from the compressor 1 passes through the flow path switching device 2 and flows into the heat source side heat exchanger 3.

The high-temperature and high-pressure gas refrigerant that has flowed into the heat source side heat exchanger 3 becomes a liquid state by exchanging heat with air supplied from a blower (not shown) and flows out of the heat source side heat exchanger 3, and the supercooling heat It flows into the exchanger 34. The liquid refrigerant that has flowed into the supercooling heat exchanger 34 is cooled by the gas-liquid two-phase refrigerant generated in the supercooling circuit 101B, and the liquid temperature decreases (increases the degree of supercooling) so that the supercooling heat exchanger. 34 flows out.

Here, also in the second embodiment, as in the first embodiment, the temperature of the high-pressure liquid refrigerant at the outlet of the supercooling heat exchanger 34 is lowered to about 5 ° C. The temperature of the high-pressure liquid refrigerant depends on the heat exchange amount in the supercooling heat exchanger 34. Therefore, the temperature of the high-pressure liquid refrigerant at the outlet of the supercooling heat exchanger 34 is lowered to about 5 ° C. by adjusting the opening degree of the expansion device 33 of the subcooling circuit 101B and the rotation speed of the compressor 31. Yes. As a result, the same effect as in the first embodiment can be obtained.

The liquid refrigerant that has flowed out of the supercooling heat exchanger 34 goes to the indoor unit 20 through the extension pipe 400a and flows into each of the indoor units 20a to 20d. The refrigerant flowing into the indoor unit 20a to the indoor unit 20d is expanded (depressurized) by each of the expansion devices 22a to 22d to be in a low-temperature / low-pressure gas-liquid two-phase state. The gas-liquid two-phase refrigerant flows into the use side heat exchanger 21a to the use side heat exchanger 21d. The gas-liquid two-phase refrigerant flowing into the use side heat exchanger 21a to the use side heat exchanger 21d absorbs heat from the air by exchanging heat with air (indoor air) supplied from a blower (not shown). Then, it becomes a low-pressure gas refrigerant and flows out from the use side heat exchanger 21a to the use side heat exchanger 21d.

Here, the refrigerant supply amount to the use side heat exchanger 21 is adjusted using temperature information from the temperature sensors 23 a to 23 d and 24 a to 24 d provided at the refrigerant inlet / outlet of the use side heat exchanger 21. Yes. Specifically, the control device 30A calculates the degree of superheat (refrigerant temperature on the outlet side−refrigerant temperature on the inlet side) based on information from the temperature sensors 23a to 23d and 24a to 24d. As in the first embodiment, the opening degree of the expansion device 22 is determined so that the degree of superheat is about 2 to 5 ° C., and the refrigerant supply amount to the use side heat exchanger 21 is adjusted. .

In such a cooling operation mode, since the superheat degree control is performed in each indoor unit 20, the liquid refrigerant does not flow into the accumulator 6. However, when there is a transitional state or when the indoor unit 20 is stopped, a small amount of refrigerant (dryness of about 0.95) may flow into the accumulator 6. The liquid refrigerant that has flowed into the accumulator 6 is evaporated and sucked into the compressor 1 or is sucked into the compressor 1 through an oil return hole (not shown) provided in the outlet pipe of the accumulator 6. .

Next, the operation of the supercooling circuit 101B will be described. The refrigerant is compressed by the compressor 31 and discharged as a high-temperature and high-pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant discharged from the compressor 31 flows into the condenser 32. The high-temperature and high-pressure gas refrigerant that has flowed into the condenser 32 becomes a liquid state by exchanging heat with air supplied from a blower (not shown), flows out of the condenser 32, and flows into the expansion device 33. The opening degree of the expansion device 33 is adjusted so that the temperature of the high-pressure liquid refrigerant at the outlet of the supercooling heat exchanger 34 is lowered to about 5 ° C. as described above. The refrigerant flowing into the expansion device 33 is depressurized into a low-pressure gas-liquid two-phase flow and flows into the supercooling heat exchanger 34. The liquid refrigerant that has flowed into the supercooling heat exchanger 34 exchanges heat with the high-pressure liquid refrigerant generated in the refrigerant circuit 101A. The heat-exchanged gas-liquid two-phase refrigerant becomes a low-pressure gas refrigerant, flows out of the supercooling heat exchanger 34, and is sucked into the compressor 31 again.

Also in the second embodiment, the temperature of the high-pressure liquid refrigerant flowing out of the supercooling heat exchanger 34 is reduced to about 5 ° C. by the supercooling heat exchanger 34 as in the first embodiment. As a result, as in the first embodiment, the pipe diameter of the extension pipe (low pressure gas pipe) 400b can be reduced by about 1 to 2 ranks, and the pipe cost and the construction cost can be reduced.

In the circuit of the second embodiment, as in the first embodiment, in the heating operation mode, the flow rate of the refrigerant flowing into the extension pipe 400b cannot be reduced, but a high-pressure gas refrigerant flows (a refrigerant having a high density). The effect of pressure loss is small, and no refrigerant flows through the supercooling heat exchanger 34. That is, the supercooling circuit 101B is not operated.

In the second embodiment, the same refrigerant HFO1234yf or HFO1234ze is used for the refrigerant circulation circuit 101A and the supercooling circuit 101B, but the supercooling circuit 101B is replaced with another refrigerant having a low global warming potential, for example, dioxide dioxide. Carbon, HC refrigerant or the like may be used.

Embodiment 3 FIG.
The air conditioner of the third embodiment is the same as the outdoor unit 10 of the first embodiment shown in FIG. 1 or the implementation shown in FIG. 8. The outdoor unit 30 of the form 2 is applied.

FIG. 10 is a schematic configuration diagram of an air-conditioning apparatus according to Embodiment 3 of the present invention. In FIG. 10, the case where the outdoor unit 10 is provided among the outdoor unit 10 or the outdoor unit 30 is shown.
The air conditioner 102 is roughly composed of a heat source unit (outdoor unit) 40, a heat medium converter 60, and an indoor unit 50. The outdoor unit 40 and the heat medium converter 60 are connected by a refrigerant pipe 401 via a heat medium heat exchanger 61 a and a heat medium heat exchanger 61 b provided in the heat medium converter 60. The heat medium converter 60 and the indoor unit 50 are also connected by a pipe 500 via the heat exchanger related to heat medium 61a and the heat exchanger related to heat medium 61b.

[Outdoor unit 40]
As described above, the outdoor unit 40 includes each device and various sensors that constitute the outdoor unit 10 of the first embodiment shown in FIG. 1, and, like the first and second embodiments, the high-pressure liquid refrigerant is provided. The liquid temperature is lowered to about 5 ° C. The outdoor unit 40 is further provided with four check valves 41a to 41d in order to make the refrigerant flow in one direction. In the case of such a circuit, the temperature of the high-pressure liquid refrigerant can be lowered only in the cooling operation.

The check valve 41d is provided in the refrigerant pipe 401 between the heat medium converter 60 and the flow path switching device 2, and is a heat source side refrigerant only in a predetermined direction (direction from the heat medium converter 60 to the outdoor unit 40). Is allowed. The check valve 41a is provided in the refrigerant pipe 401 between the heat source side heat exchanger 12 and the heat medium converter 60, and only in a predetermined direction (direction from the outdoor unit 40 to the heat medium converter 60). The refrigerant flow is allowed. The check valve 41b is provided in the first connection pipe 42a, and causes the heat source side refrigerant discharged from the compressor 1 during the heating operation to flow to the heat medium converter 60. The check valve 41 c is provided in the second connection pipe 42 b and causes the heat source side refrigerant returned from the heat medium converter 60 during the heating operation to flow to the suction side of the compressor 1.

In the outdoor unit 40, the first connection pipe 42a includes a refrigerant pipe 401 between the flow path switching device 2 and the check valve 41d, and a refrigerant pipe 401 between the check valve 41a and the heat medium relay unit 60. , Are to be connected. In the outdoor unit 40, the second connection pipe 42b includes a refrigerant pipe 401 between the check valve 41d and the heat medium relay 60, and a refrigerant pipe 401 between the heat source side heat exchanger 12 and the check valve 41a. Are connected to each other. FIG. 10 shows an example in which the first connection pipe 42a, the second connection pipe 42b, the check valve 41a, the check valve 41b, the check valve 41c, and the check valve 41d are provided. However, these are not necessarily provided.

In addition, the outdoor unit 40 is provided with a control device 40A. The control device 40A is connected so as to receive detection signals from various sensors in the outdoor unit 40, the indoor unit 50, and the heat medium relay unit 60. The control device 40A performs control such as adjusting the opening degree of the expansion device 5 and the expansion device 22 based on detection signals from various sensors. Further, the control device 10 </ b> A performs the cooling operation mode and the heating operation mode by switching the flow path switching device 2. Although FIG. 10 shows a configuration in which the control device 40A is provided only in the outdoor unit 40, each indoor unit 50 and heat medium converter 60 is provided with a sub-control device having a part of the function of the control device 40A. A configuration may be adopted in which cooperative processing is performed by performing data communication between the control device 30A and the sub-control device. Further, the control device 30A may be provided for each unit, or may be provided in the heat medium converter 60.

[Indoor unit 50]
Each of the indoor units 50 is equipped with a load side heat exchanger 51 (51a to 51d). The load-side heat exchanger 51 is connected to the heat medium flow control devices 74 (74a to 74d) and the second heat medium flow switching devices 73 (73a to 73d) of the heat medium converter 60 through the pipe 500. ing. The load-side heat exchanger 51 performs heat exchange between air and air in the air-conditioning target space supplied from a fan such as a fan (not shown) and supplies the air to the indoor space. It produces working air.

FIG. 10 shows an example in which four indoor units 50 are connected to the heat medium converter 60, and are illustrated as an indoor unit 50a, an indoor unit 50b, an indoor unit 50c, and an indoor unit 50d from the bottom of the page. Show. Further, depending on the indoor unit 50a to the indoor unit 50d, the load-side heat exchanger 51 also loads the load-side heat exchanger 51a, the load-side heat exchanger 51b, the load-side heat exchanger 51c, and the load-side heat exchanger from the lower side of the page. It is shown as a container 51d. 1 and 2, the number of indoor units 50 connected is not limited to four as shown in FIG.

[Heat medium converter 60]
The heat medium relay 60 includes two heat medium heat exchangers 61 (61a, 61b), two expansion devices 62 (62a, 62b), two opening / closing devices 63 (63a, 63b), and two Channel switching device 64 (64a, 64b), two pumps 71 (71a, 71b), four first heat medium channel switching devices 72 (72a-72d), and four second heat medium channel switching A device 73 (73a to 73d) and four heat medium flow control devices 74 (74a to 74d) are mounted. The heat exchanger related to heat medium 61 corresponds to the use side heat exchanger constituting the refrigerant circulation circuit of the first and second embodiments.

The two heat exchangers between heat media 61 (heat medium heat exchanger 61a, heat medium heat exchanger 61b) function as a condenser (heat radiator) or an evaporator, and heat is generated by the heat source side refrigerant and the heat medium. Exchange is performed, and the cold or warm heat generated in the outdoor unit 40 and stored in the heat source side refrigerant is transmitted to the heat medium. The heat exchanger related to heat medium 61a is provided between the expansion device 62a and the flow path switching device 64a in the refrigerant circulation circuit A, and serves to heat the heat medium in the cooling / heating mixed operation mode. Further, the heat exchanger related to heat medium 61b is provided between the expansion device 62b and the flow path switching device 64b in the refrigerant circuit A and serves to cool the heat medium in the cooling / heating mixed operation mode. . Here, two heat exchangers for heat medium 61 are installed, but one may be installed, or three or more may be installed.

The two expansion devices 62 (the expansion device 62a and the expansion device 62b) have functions as pressure reducing valves and expansion valves, and expand the heat source side refrigerant by reducing the pressure. The expansion device 62a is provided on the upstream side of the heat exchanger related to heat medium 61a in the flow of the heat source side refrigerant during the cooling operation. The expansion device 62b is provided on the upstream side of the heat exchanger related to heat medium 61b in the flow of the heat source side refrigerant during the cooling operation. The two throttling devices 62 may be configured by a device whose opening degree can be variably controlled, for example, an electronic expansion valve.

The two opening / closing devices 63 (the opening / closing device 63a and the opening / closing device 63b) are constituted by two-way valves or the like, and open / close the refrigerant pipe 401. The opening / closing device 63a is provided in the refrigerant pipe 401 on the inlet side of the heat source side refrigerant. The opening / closing device 63b is provided in a pipe connecting the refrigerant pipe 401 on the inlet side and outlet side of the heat source side refrigerant. The two flow path switching devices 64 (the flow path switching device 64a and the flow path switching device 64b) are configured by a four-way valve or the like, and switch the flow of the heat source side refrigerant according to the operation mode. The flow path switching device 64a is provided on the downstream side of the heat exchanger related to heat medium 61a in the flow of the heat source side refrigerant during the cooling operation. The flow path switching device 64b is provided on the downstream side of the heat exchanger related to heat medium 61b in the flow of the heat source side refrigerant during the cooling only operation.

The two pumps 71 (pump 71a and pump 71b), which are heat medium delivery devices, circulate the heat medium conducted through the pipe 500. The pump 71 a is provided in the pipe 500 between the heat exchanger related to heat medium 61 a and the second heat medium flow switching device 73. The pump 71 b is provided in the pipe 500 between the heat exchanger related to heat medium 61 b and the second heat medium flow switching device 73. The two pumps 71 may be constituted by, for example, pumps capable of capacity control.

The four first heat medium flow switching devices 72 (the first heat medium flow switching device 72a to the first heat medium flow switching device 72d) are configured by three-way valves or the like, and switch the heat medium flow channels. Is. The number of first heat medium flow switching devices 72 (four here) according to the number of indoor units 50 installed is provided. In the first heat medium flow switching device 72, one of the three sides is in the heat exchanger 61a, one of the three is in the heat exchanger 61b, and one of the three is in the heat medium flow rate. Each is connected to the adjusting device 74 and provided on the outlet side of the heat medium flow path of the load side heat exchanger 51. In correspondence with the indoor unit 50, the first heat medium flow switching device 72 a, the first heat medium flow switching device 72 b, the first heat medium flow switching device 72 c, and the first heat medium flow channel from the lower side of the drawing. This is illustrated as a switching device 72d.

The four second heat medium flow switching devices 73 (second heat medium flow switching device 73a to second heat medium flow switching device 73d) are configured by three-way valves or the like, and switch the flow path of the heat medium. Is. The number of the second heat medium flow switching devices 73 is set according to the number of indoor units 50 installed (four in this case). In the second heat medium flow switching device 73, one of the three sides is in the heat exchanger related to heat medium 61a, one of the three is in the heat exchanger related to heat medium 61b, and one of the three is in the load side heat. Each is connected to the exchanger 51 and provided on the inlet side of the heat medium flow path of the load side heat exchanger 51. In correspondence with the indoor unit 50, the second heat medium flow switching device 73a, the second heat medium flow switching device 73b, the second heat medium flow switching device 73c, and the second heat medium flow from the lower side of the drawing. This is illustrated as a switching device 73d.

The four heat medium flow control devices 74 (the heat medium flow control device 74a to the heat medium flow control device 74d) are configured by two-way valves or the like that can control the opening area, and control the flow rate flowing through the pipe 500. is there. The number of the heat medium flow control devices 74 (four here) according to the number of installed indoor units 50 is provided. One of the heat medium flow control devices 74 is connected to the load side heat exchanger 51, and the other is connected to the first heat medium flow switching device 72, and is connected to the outlet side of the heat medium flow path of the load side heat exchanger 51. Is provided. In correspondence with the indoor unit 50, the heat medium flow rate adjustment device 74a, the heat medium flow rate adjustment device 74b, the heat medium flow rate adjustment device 74c, and the heat medium flow rate adjustment device 74d are illustrated from the lower side of the drawing. Further, the heat medium flow control device 74 may be provided on the inlet side of the heat medium flow path of the load side heat exchanger 51.

Further, the heat medium converter 60 is provided with various detection devices (two first temperature sensors 81, four second temperature sensors 82, four third temperature sensors 83, and a pressure sensor 84). Signals related to the detection of these detection devices are sent to, for example, the control device 40A, the driving frequency of the compressor 1, the rotational speed of the blower (not shown), the switching of the flow path switching device 2, the driving frequency of the pump 71, This is used for control such as switching of the flow path switching device 64 and switching of the flow path of the heat medium.

The two first temperature sensors 81 (first temperature sensor 81a and first temperature sensor 81b) are the heat medium flowing out from the heat exchanger related to heat medium 61, that is, the temperature of the heat medium at the outlet of the heat exchanger related to heat medium 61. For example, a thermistor may be used. The first temperature sensor 81a is provided in the pipe 500 on the inlet side of the pump 71a. The first temperature sensor 81b is provided in the pipe 500 on the inlet side of the pump 71b.

The four second temperature sensors 82 (second temperature sensor 82a to second temperature sensor 82d) are provided between the first heat medium flow switching device 72 and the heat medium flow control device 74, and are used for the load-side heat exchanger. The temperature of the heat medium flowing out from 51 is detected, and a thermistor or the like may be used. The number of the second temperature sensors 82 is set according to the number of installed indoor units 50 (here, four). In correspondence with the indoor unit 50, the second temperature sensor 82a, the second temperature sensor 82b, the second temperature sensor 82c, and the second temperature sensor 82d are illustrated from the lower side of the drawing.

The four third temperature sensors 83 (third temperature sensor 83a to third temperature sensor 83d) are provided on the inlet side or the outlet side of the heat source side refrigerant of the heat exchanger related to heat medium 61, and the heat exchanger related to heat medium 61. The temperature of the heat source side refrigerant flowing into the heat source or the temperature of the heat source side refrigerant flowing out of the heat exchanger related to heat medium 61 is detected, and may be composed of a thermistor or the like. The third temperature sensor 83a is provided between the heat exchanger related to heat medium 61a and the flow path switching device 64a. The third temperature sensor 83b is provided between the heat exchanger related to heat medium 61a and the expansion device 62a. The third temperature sensor 83c is provided between the heat exchanger related to heat medium 61b and the flow path switching device 64b. The third temperature sensor 83d is provided between the heat exchanger related to heat medium 61b and the expansion device 62b.

Similarly to the installation position of the third temperature sensor 83d, the pressure sensor 84 is provided between the heat exchanger related to heat medium 61b and the expansion device 62b, and between the heat exchanger related to heat medium 61b and the expansion device 62b. The pressure of the flowing heat source side refrigerant is detected.

The pipe 500 that conducts the heat medium is composed of one that is connected to the heat exchanger related to heat medium 61a and one that is connected to the heat exchanger related to heat medium 61b. The pipe 500 is branched (here, four branches) in accordance with the number of indoor units 50 connected to the heat medium relay unit 60. The pipe 500 is connected by the first heat medium flow switching device 72 and the second heat medium flow switching device 73. By controlling the first heat medium flow switching device 72 and the second heat medium flow switching device 73, the heat medium from the heat exchanger related to heat medium 61a flows into the load-side heat exchanger 51, or the heat medium Whether the heat medium from the intermediate heat exchanger 61b flows into the load-side heat exchanger 51 is determined.

In the air conditioner 102, the compressor 1, the flow path switching device 2, the heat source side heat exchanger 3, the switching device 63, the flow path switching device 64, the refrigerant flow path of the heat exchanger related to heat medium 61, and the expansion device 62. And the accumulator 6 is connected by the refrigerant | coolant piping 401, and the refrigerant | coolant circulation circuit A is comprised. Further, the heat medium flow path of the intermediate heat exchanger 61, the pump 71, the first heat medium flow switching device 72, the heat medium flow control device 74, the load side heat exchanger 51, and the second heat medium flow switching device. 73 are connected by a pipe 500 to constitute a heat medium circulation circuit B. That is, a plurality of load-side heat exchangers 51 are connected in parallel to each of the heat exchangers between heat media 61, and the heat medium circulation circuit B has a plurality of systems.

Therefore, in the air conditioner 102, the outdoor unit 40 and the heat medium converter 60 are connected via the heat exchanger related to heat medium 61a and the heat exchanger related to heat medium 61b provided in the heat medium converter 60. The heat medium converter 60 and the indoor unit 50 are also connected via the heat exchanger related to heat medium 61a and the heat exchanger related to heat medium 61b. That is, in the air conditioner 102, the heat source side refrigerant circulating in the refrigerant circuit A and the heat medium circulating in the heat medium circuit B exchange heat in the intermediate heat exchanger 61a and the intermediate heat exchanger 61b. It is supposed to be.

The air conditioner 102 can perform a cooling operation or a heating operation in the indoor unit 50 based on an instruction from each indoor unit 50. That is, the air conditioner 102 can perform the same operation for all the indoor units 50 and can perform different operations for each of the indoor units 50.

The air conditioner 102 has a cooling operation mode in which all of the driven indoor units 50 perform a cooling operation, a heating operation mode in which all of the driven indoor units 50 perform a heating operation, and a cooling load. A cooling main operation mode with a larger heating capacity and a heating main operation mode with a larger heating load can be performed.

As described above, according to the third embodiment, also in the air conditioner of the type capable of simultaneously performing cooling and heating, the pipe diameter of the low-pressure gas pipe is reduced as in the first and second embodiments. 1 to 2 ranks can be made thinner. As a result, it is possible to reduce piping costs and construction costs, further reduce energy loss due to disposal, and contribute to environmental conservation. Moreover, since pressure loss can be reduced, an energy efficient operation can be performed, and an energy saving effect can also be obtained.

The heat medium converter 60 may be divided into a parent heat medium converter having a gas-liquid separator and a throttle device and a child heat medium converter.

1 compressor, 2 flow switching device, 3 heat source side heat exchanger, 4 supercooling heat exchanger, 5 expansion device, 6 accumulator, 7 bypass circuit, 7 indoor space, 8 pressure sensor, 9 temperature sensor, 10 outdoor Machine, 10A control device, 20 (20a-20d) indoor unit, 21 (21a-21d) use side heat exchanger, 22 (22a-22d) expansion device, 23a-23d temperature sensor, 24a-24d temperature sensor, 30 outdoor Machine, 30A control device, 31 compressor, 32 condenser, 33 throttling device, 34 supercooling heat exchanger, 40 outdoor unit, 40A control device, 41a-41d check valve, 42a first connection piping, 42b second connection Piping, 50 (50a-50d) indoor unit, 51 (51a-51d) load side heat exchanger, 60 heat medium converter, 6 (61a, 61b) Heat exchanger between heat medium, 62 (62a, 62b) throttle device, 63 (63a, 63b) switchgear, 64 (64a, 64b) flow path switching device, 71 (71a, 71b) pump, 72 (72a to 72d) First heat medium flow switching device, 73 (73a to 73d) Second heat medium flow switching device, 74 (74a to 74d) Heat medium flow control device, 81 (81a, 81b) First temperature Sensor, 82 (82a to 84d) Second temperature sensor, 83 (83a to 83d) Third temperature sensor, 84 Pressure sensor, 100 Air conditioner, 101 Air conditioner, 101A Refrigerant circuit, 101B Subcooling circuit, 102 Air Harmonic device, 400 (400a, 400b) extension piping, 401 refrigerant piping, 500 piping, A refrigerant circulation circuit, B The heat medium circulation circuit.

Claims

A refrigerant circulation circuit in which a compressor, a heat source side heat exchanger, an expansion device, and a use side heat exchanger are connected by piping, and a refrigerant having a saturated refrigerant gas density at 0 ° C. of 35 to 65% of the R410A refrigerant circulates. When,
An air conditioner comprising: a supercooling unit configured to set a liquid temperature of the high-pressure liquid refrigerant sent from the heat source side heat exchanger to the expansion device during cooling operation to 5 ° C. or less.
The air conditioning apparatus according to claim 1, wherein the supercooling means sets the degree of supercooling of the high-pressure liquid refrigerant to 44 ° C or higher.
The temperature of the high-pressure liquid refrigerant sent from the use side heat exchanger to the expansion device during the heating operation is set to 5 ° C or lower, or the degree of supercooling is set to 44 ° C or higher. The air conditioning apparatus described.
The supercooling means cools the high-pressure side refrigerant by exchanging heat between the high-pressure side refrigerant between the heat source side heat exchanger and the expansion device and the low-pressure side refrigerant obtained by reducing a part of the high-pressure side refrigerant. The air-conditioning apparatus according to any one of claims 1 to 3, further comprising a supercooling heat exchanger.
The supercooling means includes a supercooling circuit in which a compressor, a condenser, a throttling device, and a supercooling heat exchanger are connected by piping, and the refrigerant circulates. The supercooling heat exchanger includes the supercooling circuit. 4. The heat exchange is performed between the circulating low-pressure side refrigerant and the high-pressure side refrigerant between the heat source side heat exchanger of the refrigerant circulation circuit and the expansion device. 5. Item 1. An air conditioner according to item 1.
6. The air conditioner according to claim 4 or 5, wherein the supercooling heat exchanger is a double-pipe heat exchanger, and the high-pressure side refrigerant is circulated through the annular portion and the low-pressure side refrigerant is circulated through the inner pipe. .
The said subcooling heat exchanger is the said plate heat exchanger, The said high voltage | pressure side refrigerant | coolant is distribute | circulated from the top to the bottom, and the said low voltage | pressure side refrigerant | coolant is distribute | circulated from the bottom to the top. Air conditioner.
The air conditioner according to any one of claims 1 to 7, wherein HFO1234yf or HFO1234ze is used as the refrigerant.
The refrigerant circulation circuit has a plurality of heat exchangers between heat mediums as the use side heat exchangers that exchange heat between the refrigerant and a heat medium different from the refrigerant and can exchange heat with heat mediums having different temperatures. ,
A plurality of pumps for circulating the heat medium related to heat exchange of the heat exchangers between the plurality of heat mediums, a load side heat exchanger for exchanging heat between the heat medium and the air related to the air-conditioning target space; A heat medium circulation circuit configured to connect a heat medium flow switching device for switching the passage to the load-side heat exchanger with respect to the heat medium related to the passage of the plurality of heat exchangers between heat mediums; The air conditioner according to any one of claims 1 to 8, wherein