JPWO2011099063A1 - Air conditioner - Google Patents

Abstract

Provided is an air conditioner that can reduce the load on the environment while ensuring safety. The air conditioner 101 is provided at a concentration detector 39 that detects the concentration of the refrigerant leaked from the refrigerant circuit, and a refrigerant inlet / outlet of the heat medium relay unit 3, and circulates the refrigerant based on information from the concentration detector 39. And a blocking device (first blocking device 37, second blocking device 38) for blocking.

Description

  The present invention relates to an air conditioner applied to, for example, a building multi-air conditioner.

  Conventionally, in an air conditioner such as a multi air conditioning system for buildings, for example, a refrigerant is circulated between an outdoor unit that is a heat source unit arranged outside a building and an indoor unit arranged inside a building. And the refrigerant | coolant thermally radiated and absorbed heat, and air-conditioning object space was cooled or heated with the air heated and cooled. In such a building multi-air conditioner, a plurality of indoor units are connected, and there are many cases where a stopped indoor unit and an operating indoor unit are mixed. In addition, the pipe connecting the outdoor unit and the indoor unit may be up to 100 m. The longer the pipe, the more refrigerant will be filled into the system.

  Such indoor units of multi-air conditioners for buildings are usually arranged and used in indoor spaces where people are present (for example, office spaces, living rooms, stores, etc.). When the refrigerant leaks from the indoor unit arranged in the indoor space for some reason, depending on the type of the refrigerant, it has flammability and toxicity, which is a big problem from the viewpoint of human influence and safety. Moreover, even if it is a refrigerant | coolant which is not harmful to a human body, the oxygen concentration in indoor space will fall by refrigerant | coolant leakage, and it is assumed that it has a bad influence on a human body. Thus, a technique is disclosed in which the system is stopped when refrigerant leaks from the refrigeration cycle (see, for example, Patent Document 1).

JP 2000-320936 A (for example, page 5)

  By the way, in recent years, from the viewpoint of global warming, there has been a movement to limit the use of HFC refrigerants having a high global warming potential (for example, R410A, R404A, R407C, R134a, etc.), and refrigerants having a low global warming potential ( For example, an air conditioner using carbon dioxide or the like has been proposed. Even when carbon dioxide is used as a refrigerant in a building multi-air conditioner, since a large amount of refrigerant is required, measures must be taken when the refrigerant leaks into the indoor space.

Table 1 shows the limit concentrations when the conventional refrigerant (R410A) and the carbon dioxide refrigerant leak. Below the limit concentration [kg / m ³ ] in Table 1, it is shown that the human body is not adversely affected, and the value of ISO 5149 is used as this value. As can be seen from Table 1, it can be seen that the limit concentration of the carbon dioxide refrigerant is significantly smaller than the limit concentration of the conventional refrigerant. That is, the carbon dioxide refrigerant means that a slight refrigerant leakage causes a bad influence on the human body with respect to the refrigerant leakage as compared with the conventional refrigerant.

  The technique described in Patent Document 1 uses carbon dioxide as a refrigerant and stops the system when a carbon dioxide refrigerant leak occurs like a conventional refrigerant leak. No measures are taken against leaks. In other words, when carbon dioxide is used as a refrigerant, it is necessary to take some measures to reduce refrigerant leakage on the premise that the human body is not adversely affected.

  The present invention has been made in order to solve the above-described problems, and provides an air conditioner that can reduce the load applied to the environment while ensuring safety.

  The air conditioner according to the present invention includes at least an expansion device and a use side heat exchanger in an indoor unit, and the compressor, the heat source side heat exchanger, the expansion device, and the use side heat exchanger include An air conditioner in which a refrigerant circuit in which a heat source side refrigerant that transitions to a supercritical state is circulated is formed is provided inside the indoor unit or in an installation space of the indoor unit, and leaks from the refrigerant circuit A concentration detector that detects the concentration of the refrigerant, and a shut-off device that is provided on the inlet / outlet side inside the indoor unit and blocks the circulation of the heat source side refrigerant based on information from the concentration detector. It is what.

  An air conditioner according to the present invention includes at least a compressor and a heat source side heat exchanger in an outdoor unit, and includes at least a heat exchanger related to heat medium, a throttling device, and a pump in a heat medium converter, and at least The use side heat exchanger is provided in the indoor unit, and the compressor, the heat source side heat exchanger, the expansion device, and the refrigerant side flow path of the heat exchanger related to heat medium are connected in series with each other in a supercritical state. The refrigerant circulation circuit in which the heat source side refrigerant that transitions to circulates, the heat medium side flow path of the heat exchanger related to heat medium, the pump, and the use side heat exchanger are connected in piping, and the heat medium A heat medium circulation circuit that circulates, wherein the air conditioner is provided in the heat medium converter or in an installation space of the heat medium converter, and the concentration of the refrigerant leaked from the refrigerant circuit is determined. A concentration detecting device for detecting the heat medium converter; Provided doorway side of the section, a blocking device for blocking the circulation of the heat-source side refrigerant on the basis of information from the said concentration detecting device is intended to have.

  According to the air conditioner of the present invention, it is possible to detect refrigerant leakage from the refrigerant circuit, and not only greatly improve safety but also reduce environmental load.

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 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 diagram which shows typically an example of the internal structure of an indoor unit. It is a schematic diagram which shows typically another example of the internal structure of an indoor unit. It is the schematic which shows the example of installation of the air conditioning apparatus which concerns on Embodiment 2 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 cooling only operation mode 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 heating only operation mode 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 cooling main operation mode of the air conditioning apparatus which concerns on Embodiment 2 of this invention. It is a refrigerant circuit diagram which shows the flow of the refrigerant | coolant at the time of the heating main operation mode of the air conditioning apparatus which concerns on Embodiment 2 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 an air-conditioning apparatus 100 according to Embodiment 1 of the present invention. Based on FIG. 1, the detailed circuit structure of the air conditioning apparatus 100 is demonstrated. FIG. 1 shows an example in which four indoor units 300 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.

As shown in FIG. 1, the air conditioner 100 is configured by connecting an outdoor unit (heat source unit) 200 and an indoor unit 300 (indoor units 300a to 300d) via a pipe 400 (pipe 400a, pipe 400b). Has been. That is, in the air conditioner 100, a plurality of indoor units 300 are connected to the outdoor unit 200 in parallel. The pipe 400 is a refrigerant pipe that conducts the refrigerant (heat source side refrigerant). Further, it is assumed that carbon dioxide (CO ₂ ) is sealed in the air conditioner 100 as a refrigerant. However, the refrigerant is not limited to carbon dioxide, and another single refrigerant or a mixed refrigerant (for example, a mixed refrigerant of carbon dioxide and diethyl ether) that transitions to a supercritical state may be used as the refrigerant.

[Outdoor unit 200]
In the outdoor unit 200, a compressor 201, an oil separator 202, a flow path switching device 203 such as a four-way valve, a heat source side heat exchanger 204, and an accumulator 205 are connected in series by a pipe 400. It is installed. The oil separator 202 and the suction side of the compressor 201 are connected by an oil return capillary 206.

  The compressor 201 sucks the refrigerant, compresses the refrigerant to be brought into a high-temperature and high-pressure state, and conveys the refrigerant to the refrigerant circuit. For example, the compressor 201 may be composed of an inverter compressor that can control the capacity. The oil separator 202 is provided on the discharge side of the compressor 201 and separates the refrigerant and the refrigeration oil. The flow path switching device 203 is provided on the downstream side of the oil separator 202, and switches between 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) 204 functions as an evaporator during heating operation, functions as a radiator (gas cooler) during cooling operation, and is supplied with air supplied from a blower such as a fan (not shown). Heat exchange is performed with the refrigerant. The accumulator 205 is provided on the suction side of the compressor 10, and surplus refrigerant due to a difference between the heating operation mode and the cooling operation mode, a transitional operation change (for example, a change in the number of indoor units 300 operated). The excess refrigerant is stored. The oil return capillary 206 returns the refrigeration oil captured by the oil separator 202 to the low pressure side of the compressor 201.

[Indoor unit 300]
In the indoor unit 300, a first shut-off device 303, an expansion device 302, a use-side heat exchanger (indoor-side heat exchanger) 301, and a second shut-off device 304 are connected and mounted in series. . The 1st cutoff device 303 is comprised by the two-way valve etc., and opens and closes the piping 400a. The first shut-off device 303 is provided on the pipe 400 a side of the use side heat exchanger 301. The use-side heat exchanger 301 functions as a radiator during heating operation, functions as an evaporator during cooling operation, and performs heat exchange between air supplied from a blower such as a fan (not shown) and the refrigerant, and air conditioning. Heating air or cooling air to be supplied to the target space is generated.

  The expansion device 302 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. The 2nd cutoff device 304 is comprised by the two-way valve etc., and opens and closes the piping 400b. The second shut-off device 304 is provided in the pipe 400a between the expansion device 302a and the heat source side heat exchanger 204.

  In the first embodiment, an example is shown in which four indoor units 300 are connected, and are illustrated as an indoor unit 300a, an indoor unit 300b, an indoor unit 300c, and an indoor unit 300d from the lower side of the drawing. Further, according to the indoor unit 300a to the indoor unit 300d, the use side heat exchanger 301 also uses the use side heat exchanger 301a, the use side heat exchanger 301b, the use side heat exchanger 301c, and the use side heat exchange from the lower side of the drawing. It is shown as a container 301d. Similarly, the diaphragm device 302 is also illustrated as a diaphragm device 302a, a diaphragm device 302b, a diaphragm device 302c, and a diaphragm device 302d from the bottom of the drawing.

  Similarly, the first blocking device 303 is also illustrated as a first blocking device 303a, a first blocking device 303b, a first blocking device 303c, and a first blocking device 303d from the lower side of the drawing. Similarly, the second blocking device 304 is also illustrated as a first blocking device 304a, a first blocking device 304b, a first blocking device 304c, and a first blocking device 304d from the lower side of the drawing. The number of connected indoor units 300 is not limited to four.

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 the indoor units 300 are driven will be described as an example. In FIG. 2, the flow direction of the refrigerant is indicated by arrows.

  The low-temperature / low-pressure refrigerant is compressed by the compressor 201 and discharged as a high-temperature / high-pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant discharged from the compressor 201 flows into the oil separator 202. In the oil separator 202, the refrigerant and the refrigerating machine oil mixed in the refrigerant are separated. The separated refrigeration oil is returned to the low pressure side of the compressor 201 through the oil return capillary 206 and finally returned to the compressor 201. The high-temperature and high-pressure refrigerant separated in the oil separator 202 passes through the flow path switching device 203 and flows into the heat source side heat exchanger 204.

  The high-temperature and high-pressure gas refrigerant that has flowed into the heat-source-side heat exchanger 204 radiates heat to the air by exchanging heat with air supplied from a blower (not shown). Since carbon dioxide is used as the refrigerant, the high-temperature and high-pressure gas refrigerant that has flowed into the heat source-side heat exchanger 204 flows out of the heat source-side heat exchanger 204 in a supercritical state in a lowered temperature state. To do. The low-temperature / high-pressure supercritical refrigerant flows out of the outdoor unit 200 through the pipe 400a. And it flows into each of indoor unit 300a-indoor unit 300d.

  The refrigerant flowing into the indoor unit 300a to the indoor unit 300d passes through the first blocking device 303a to the first blocking device 303d, and is expanded (depressurized) by each of the expansion device 302a to the expansion device 302d. It becomes a liquid two-phase state. This gas-liquid two-phase refrigerant flows into each of the use side heat exchanger 301a to the use side heat exchanger 301d. The gas-liquid two-phase refrigerant that has flowed into the use side heat exchanger 301a to the use side heat exchanger 301d 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 301a to the use side heat exchanger 301d.

  Usually, temperature sensors (a temperature sensor 306 and a temperature sensor 307 shown in FIG. 4) are provided at the refrigerant inlet / outlet of the use side heat exchanger 301. The refrigerant supply amount to the use side heat exchanger 301 is adjusted using temperature information from a temperature sensor provided at the refrigerant inlet / outlet of the use side heat exchanger 301. Specifically, the degree of superheat (refrigerant temperature at the outlet side−refrigerant temperature at the inlet) is calculated from information from these temperature sensors, and the expansion device 302 is opened so that the degree of superheat is about 2 to 5 ° C. The refrigerant supply amount to the use side heat exchanger 301 is adjusted.

  The low-pressure gas refrigerant that has flowed out of the use-side heat exchanger 301a to the use-side heat exchanger 301d flows out of the indoor unit 300a to the indoor unit 300d through the second shut-off device 304a to the second shut-off device 304d, and passes through the pipe 400b. It passes through and flows into the outdoor unit 200. The refrigerant that has flowed into the outdoor unit 200 flows into the accumulator 205 through the flow path switching device 203. The refrigerant flowing into the accumulator 205 is separated from the liquid refrigerant and the gas refrigerant, and the gas refrigerant is sucked into the compressor 201 again.

  In such a cooling operation mode, since the superheat degree control is performed in each indoor unit 300, the liquid refrigerant does not flow into the accumulator 205. However, when there is a transitional state or the indoor unit 300 is stopped, a small amount of refrigerant (dryness of about 0.95) may flow into the accumulator 205. The liquid refrigerant flowing into the accumulator 205 is evaporated and sucked into the compressor 201, or sucked into the compressor 201 through an oil return hole (not shown) provided in the outlet pipe of the accumulator 205. .

[Heating operation mode]
FIG. 3 is a refrigerant circuit diagram illustrating a refrigerant flow when the air-conditioning apparatus 100 is in the heating operation mode. In FIG. 3, the case where all the indoor units 300 are driven will be described as an example. In FIG. 3, the flow direction of the refrigerant is indicated by arrows.

  The low-temperature / low-pressure refrigerant is compressed by the compressor 201 and discharged as a high-temperature / high-pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant discharged from the compressor 201 flows into the oil separator 202. In the oil separator 202, the refrigerant and the refrigerating machine oil mixed in the refrigerant are separated. The separated refrigeration oil is returned to the low pressure side of the compressor 201 through the oil return capillary 206 and finally returned to the compressor 201. The high-temperature and high-pressure refrigerant separated in the oil separator 202 flows out from the outdoor unit 200 through the pipe 400b via the flow path switching device 203. The refrigerant that has flowed out of the outdoor unit 200 flows into each of the indoor units 300a to 300d.

The high-temperature and high-pressure gas refrigerant flowing into the indoor units 300a to 300d is
By exchanging heat with air (indoor air) supplied from a blower (not shown) through the second shut-off device 304a to the second shut-off device 304d and using the use-side heat exchanger 301a to the use-side heat exchanger 301d, the air In the supercritical state, the temperature is lowered and flows out from the use side heat exchanger 301a to the use side heat exchanger 301d. The low-temperature / high-pressure supercritical refrigerant is expanded (depressurized) in each of the expansion devices 302a to 302d to be in a low-temperature / low-pressure gas-liquid two-phase state, and the first cutoff device 303a to the first cutoff. It flows out from the indoor unit 300a to the indoor unit 300d through the device 303d.

  As described above, a temperature sensor and a pressure sensor (pressure sensor 308 shown in FIG. 4) are usually provided at the refrigerant outlet of the use side heat exchanger 301. The refrigerant supply amount to the use side heat exchanger 301 is adjusted using information from a temperature sensor and a pressure sensor provided at the refrigerant outlet of the use side heat exchanger 301. Specifically, the degree of supercooling (saturation temperature converted from the detected pressure of the 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 302 is determined, and the refrigerant supply amount to the use side heat exchanger 301 is adjusted.

  The low-temperature, low-pressure gas-liquid two-phase refrigerant that has flowed out of the indoor units 300a to 300d flows into the outdoor unit 200 through the pipe 400a. This refrigerant flows into the heat source side heat exchanger 204. The low-temperature / constant-pressure gas-liquid two-phase refrigerant flowing into the heat source side heat exchanger 204 absorbs heat from the air by exchanging heat with air supplied from a blower (not shown), and the degree of dryness gradually increases. Become. And it becomes a gas-liquid two-phase refrigerant | coolant with a large dryness in the exit of the heat source side heat exchanger 204, and flows out from the heat source side heat exchanger 204. FIG. The refrigerant that has flowed out of the heat source side heat exchanger 204 flows into the accumulator 205 through the flow path switching device 203. The refrigerant flowing into the accumulator 205 is separated from the liquid refrigerant and the gas refrigerant, and the gas refrigerant is sucked into the compressor 201 again.

  In such a heating operation mode, surplus refrigerant is always present in the accumulator 205. The liquid refrigerant flowing into the accumulator 205 is evaporated and sucked into the compressor 201, or sucked into the compressor 201 through an oil return hole (not shown) provided in the outlet pipe of the accumulator 205. .

  FIG. 4 is a schematic diagram schematically illustrating an example of the internal configuration of the indoor unit 300. FIG. 5 is a schematic diagram illustrating another example of the internal configuration of the indoor unit 300. Based on FIG.4 and FIG.5, the characteristic matter of the air conditioning apparatus 100 which concerns on Embodiment 1 is demonstrated. As described above, the indoor unit 300 includes the first shut-off device 303, the expansion device 302, the use-side heat exchanger 301, and the second shut-off device 304. As shown in FIGS. 4 and 5, the indoor unit 300 is provided with a temperature sensor 306, a temperature sensor 307, a pressure sensor 308, and a concentration detection device 305.

  The temperature sensor 306 is provided between the first shut-off device 303 and the use side heat exchanger 301 and detects the temperature of the refrigerant flowing through this portion. The temperature sensor 307 is provided between the expansion device 302 and the use side heat exchanger 301, and detects the temperature of the refrigerant flowing through this portion. The pressure sensor 308 is provided at the same position as the temperature sensor 307 and detects the pressure of the refrigerant flowing through this portion. The concentration detection device 305 detects the concentration of the refrigerant (carbon dioxide in the first embodiment), and particularly detects the concentration of the refrigerant in a space where a person exists.

  4 and 5 show an example in which the concentration detection device 305 is provided in the vicinity of the use-side heat exchanger 301 inside the indoor unit 300, but the installation position is limited to this position. It is not a thing. For example, the concentration detection device 305 may be provided in a space where the indoor unit 300 is installed without being installed in the indoor unit 300. That is, since the installation purpose of the concentration detection device 305 is to detect the refrigerant concentration in a space where a person exists, the concentration detection device 305 may be installed in any place in the space where the indoor unit 300 is installed. Further, for example, the concentration detection device 305 may be incorporated in a remote controller (not shown).

  In FIG. 4, the first shut-off device 303 is provided on the pipe 400 a side of the use side heat exchanger 301, and the second shut-off device 304 is provided on the pipe 400 b side of the use side heat exchanger 301. The case where the expansion device 302 and the use side heat exchanger 301 are provided between 303 and the second shut-off device 304 is shown as an example. On the other hand, as shown in FIG. 5, a first shut-off device 303 may be provided between the use side heat exchanger 301 and the expansion device 302. Moreover, the 1st cutoff device 303 and the 2nd cutoff device 304 are an open state at the time of electricity supply, and a non-energized state is a closed state.

The concentration detection device 305 has a built-in switch structure in which the switch is turned on when the concentration is lower than the predetermined concentration, and the switch is turned off when the concentration is higher than the predetermined concentration. Needless to say, the concentration detection device 305 may not have a built-in switch structure, and the switch (contact point) may be a separate component. This predetermined concentration is the leakage limit concentration of the refrigerant used. When carbon dioxide is used as a refrigerant, the leakage limit concentration is 0.07 [kg / m ³ ] (see Table 1). Therefore, this concentration is set to a predetermined concentration, and the switch built in the concentration detection device 305 is turned ON / OFF. It is normal to do.

However, in the air conditioner 100, taking into account variations in the concentration detection device 305, the concentration distribution in the indoor space, and the like, a concentration that is 1/10 of the leakage limit concentration is determined as the predetermined concentration. That is, in the air conditioner 100, the switch is turned ON / OFF with 0.007 [kg / m ³ ] as a threshold value (predetermined concentration). Specifically, the switch ON is less than 0.007 [kg / m ^3], a state of the switch OFF is 0.007 [kg / m ^3] or more.

  Moreover, the electric part of the 1st cutoff device 303 and the 2nd cutoff device 304 is made into the direct current drive instead of alternating current drive. This is because the first shut-off device 303 and the second shut-off device 304 are in an open state during the normal operation of the air conditioner 100, but the first shut-off device 303 and the second shut-off device 304 are in response to a request for extending the life of the electrical unit. This is because an electric part of direct current drive instead of alternating current drive is adopted for the interrupting device 304. Specifically, the valves of the first shut-off device 303 and the second shut-off device 304 are opened and closed by a stepping motor. That is, the 1st cutoff device 303 and the 2nd cutoff device 304 have a stepping motor as an electric part.

  Moreover, since the 1st cutoff device 303 is installed in the high voltage | pressure side (at the time of air_conditionaing | cooling operation), CV value may be small and is about CV = 2 (1 or more) in about 5HP (horsepower). On the other hand, since the 2nd cutoff device 304 is installed in the low voltage | pressure side (at the time of air_conditionaing | cooling operation), it is necessary to make a CV value large, and about 5HP, it is about CV = 5 (5 or more). As shown in FIG. 5, when the first shut-off device 303 is provided between the expansion device 302 and the use side heat exchanger 301, the CV value is large because it is in a low pressure state during the cooling operation. Must be selected. In this case, it is preferable to select one having V = 5. However, the installation as shown in FIG. 4 is advantageous in terms of cost because the CV value of the first shut-off device 303 can be reduced.

  In addition, due to the nature required to shut off in an emergency, the minimum operating pressure difference between the first shut-off device 303 and the second shut-off device 304 must be a sufficiently small value of about 0 [kPa]. The air conditioner 100 is a heat pump type air conditioner that can switch between cooling and heating. Therefore, since the flow is reversed between the refrigerant and the heating, the first shutoff device 303 is capable of bidirectional flow. And used in the second shut-off device 304. Further, the concentration detection device 305 is assumed to be safe when power is lost or when power is not supplied to the concentration detection device 305 from a commercial power source.

In Embodiment 1, since carbon dioxide is used as the refrigerant, it is necessary to reduce the amount of leakage from the first shut-off device 303 and the second shut-off device 304, and 3.0 × 10 ⁻⁹ [m ³ / sec It is necessary to make it about. This is an amount that assumes a case where carbon dioxide continues to leak into the smallest room where the indoor unit 300 is supposed to be installed for several years.

Next, operations of the first blocking device 303 and the second blocking device 304 will be described. When the concentration detection device 305 detects carbon dioxide having a predetermined concentration of 0.007 [kg / m ³ ], the control device (not shown) determines that refrigerant leakage has occurred from the refrigerant circuit, and switches the concentration detection device 305. Is turned off to stop energization of the first shut-off device 303 and the second shut-off device 304. As a result, the first shut-off device 303 and the second shut-off device 304 are closed, and the refrigerant flowing from the outdoor unit 200 through the pipe 400a and the pipe 400b can be shut off, and the refrigerant leaks into the room. Can be prevented.

  The air conditioner 100 that employs the configuration as described above can detect refrigerant leakage from the refrigerant circuit, and greatly improves safety. Moreover, since the air conditioning apparatus 100 uses what changed to a supercritical state for a refrigerant | coolant, it can reduce environmental impact.

Embodiment 2. FIG.
FIG. 6 is a schematic diagram illustrating an installation example of the air-conditioning apparatus according to Embodiment 2 of the present invention. Based on FIG. 6, the installation example of an air conditioning apparatus is demonstrated. This air conditioner uses a refrigeration cycle (refrigerant circulation circuit A, heat medium circulation circuit B) that circulates refrigerant (heat source side refrigerant, heat medium) so that each indoor unit can be in the cooling mode or the heating mode as an operation mode. It can be freely selected. In the second embodiment, differences from the first embodiment will be mainly described, and the same parts as those in the first embodiment will be denoted by the same reference numerals and description thereof will be omitted.

  In the air conditioning apparatus 100 according to the first embodiment, a system that uses the refrigerant as it is (direct expansion system) is adopted. However, in the air conditioning apparatus according to the second embodiment, the refrigerant (heat source side refrigerant) is indirectly used. The method used for the system (indirect method) is adopted. That is, the air-conditioning apparatus according to Embodiment 2 transmits cold heat or heat stored in the heat source side refrigerant to a refrigerant (hereinafter referred to as a heat medium) different from the heat source side refrigerant, and The space to be air-conditioned is cooled or heated with heat.

  In FIG. 6, the air-conditioning apparatus according to the present embodiment includes one outdoor unit 1 that is a heat source unit, a plurality of indoor units 2, and heat that is interposed between the outdoor unit 1 and the indoor unit 2. And a medium converter 3. The heat medium relay unit 3 performs heat exchange between the heat source side refrigerant and the heat medium. The outdoor unit 1 and the heat medium relay unit 3 are connected by a refrigerant pipe 4 that conducts the heat source side refrigerant. The heat medium relay unit 3 and the indoor unit 2 are connected by a pipe (heat medium pipe) 5 that conducts the heat medium. The cold or warm heat generated by the outdoor unit 1 is delivered to the indoor unit 2 via the heat medium converter 3.

  The outdoor unit 1 is usually disposed in an outdoor space 6 that is a space (for example, a rooftop) outside a building 9 such as a building, and supplies cold or hot energy to the indoor unit 2 via the heat medium converter 3. It is. The indoor unit 2 is arranged at a position where cooling air or heating air can be supplied to the indoor space 7 that is a space (for example, a living room) inside the building 9, and the cooling air is supplied to the indoor space 7 that is the air-conditioning target space. Alternatively, heating air is supplied. The heat medium relay unit 3 is configured as a separate housing from the outdoor unit 1 and the indoor unit 2 and is configured to be installed at a position different from the outdoor space 6 and the indoor space 7. Is connected to the refrigerant pipe 4 and the pipe 5, respectively, and transmits cold heat or hot heat supplied from the outdoor unit 1 to the indoor unit 2.

  As shown in FIG. 6, in the air conditioner according to Embodiment 2, the outdoor unit 1 and the heat medium converter 3 use two refrigerant pipes 4, and the heat medium converter 3 and each indoor unit 2. Are connected using two pipes 5 respectively. Thus, in the air conditioning apparatus according to Embodiment 2, each unit (outdoor unit 1, indoor unit 2, and heat medium converter 3) is connected using two pipes (refrigerant pipe 4, pipe 5). Therefore, construction is easy.

  In FIG. 6, the heat medium converter 3 is inside the building 9 but is a space different from the indoor space 7 such as a ceiling (for example, a space such as a ceiling behind the building 9, hereinafter, An example of a state where it is installed in the space 8) is shown. The heat medium relay 3 can also be installed in a common space where there is an elevator or the like. Moreover, in FIG. 6, although the case where the indoor unit 2 is a ceiling cassette type is shown as an example, the present invention is not limited to this, and the indoor unit 2 is directly or directly in the indoor space 7 such as a ceiling embedded type or a ceiling suspended type. Any type of air can be used as long as heating air or cooling air can be blown out by a duct or the like.

  In FIG. 6, although the case where the outdoor unit 1 is installed in the outdoor space 6 is shown as an example, the present invention is not limited to this. For example, the outdoor unit 1 may be installed in an enclosed space such as a machine room with a ventilation opening. If the exhaust heat can be exhausted outside the building 9 by an exhaust duct, the outdoor unit 1 may be installed inside the building 9. It may be installed, or may be installed inside the building 9 when the water-cooled outdoor unit 1 is used. Even if the outdoor unit 1 is installed in such a place, no particular problem occurs.

  Further, the heat medium relay unit 3 can be installed in the vicinity of the outdoor unit 1. However, it should be noted that if the distance from the heat medium relay unit 3 to the indoor unit 2 is too long, the power for transporting the heat medium becomes considerably large, and the energy saving effect is diminished. Furthermore, the number of connected outdoor units 1, indoor units 2, and heat medium converters 3 is not limited to the number shown in FIG. 6, but in building 9 where the air conditioner according to Embodiment 2 is installed. The number of units may be determined accordingly.

  FIG. 7 is a schematic circuit configuration diagram showing an example of a circuit configuration of an air-conditioning apparatus (hereinafter referred to as air-conditioning apparatus 101) according to Embodiment 2. Based on FIG. 7, the detailed structure of the air conditioning apparatus 101 is demonstrated. As shown in FIG. 7, the outdoor unit 1 and the heat medium relay unit 3 are connected to the refrigerant pipe 4 via the heat exchanger related to heat medium 15 a and the heat exchanger related to heat medium 15 b provided in the heat medium converter 3. Connected with. Moreover, the heat medium relay unit 3 and the indoor unit 2 are also connected by the pipe 5 via the heat exchanger related to heat medium 15a and the heat exchanger related to heat medium 15b. The refrigerant pipe 4 will be described in detail later.

[Outdoor unit 1]
In the outdoor unit 1, a compressor 10, a first refrigerant flow switching device 11 such as a four-way valve, a heat source side heat exchanger 12, and an accumulator 19 are connected and connected in series through a refrigerant pipe 4. Yes.

  The compressor 10 sucks the heat source side refrigerant and compresses the heat source side refrigerant to a high temperature and high pressure state. For example, the compressor 10 may be composed of an inverter compressor capable of capacity control. The first refrigerant flow switching device 11 has a flow of the heat source side refrigerant in the heating operation mode (in the heating only operation mode and the heating main operation mode) and in the cooling operation mode (in the all cooling operation mode and the cooling main operation mode). ) To switch the flow of the heat source side refrigerant.

  The heat source side heat exchanger 12 functions as an evaporator during heating operation, functions as a radiator (gas cooler) during cooling operation, and between the air supplied from a blower such as a fan (not shown) and the heat source side refrigerant. Heat exchange is performed. The accumulator 19 is provided on the suction side of the compressor 10, and surplus refrigerant due to a difference between the heating operation mode and the cooling operation mode, a change in the transient operation (for example, a change in the number of indoor units 2 operated). The excess refrigerant is stored.

[Indoor unit 2]
Each indoor unit 2 is equipped with a use side heat exchanger 26. The use side heat exchanger 26 is connected to the heat medium flow control device 25 and the second heat medium flow switching device 23 of the heat medium converter 3 by the pipe 5. The use-side heat exchanger 26 performs heat exchange between air supplied from a blower such as a fan (not shown) and a heat medium, and generates heating air or cooling air to be supplied to the indoor space 7. To do.

  FIG. 7 shows an example in which four indoor units 2 are connected to the heat medium relay unit 3. The indoor unit 2a, the indoor unit 2b, the indoor unit 2c, and the indoor unit 2d from the lower side of the drawing. It is shown. Further, in accordance with the indoor unit 2a to the indoor unit 2d, the use side heat exchanger 26 also uses the use side heat exchanger 26a, the use side heat exchanger 26b, the use side heat exchanger 26c, and the use side heat exchange from the lower side of the drawing. It is shown as a container 26d. Similar to FIG. 6, the number of connected indoor units 2 is not limited to the four shown in FIG.

[Heat medium converter 3]
The heat medium relay unit 3 includes two heat medium heat exchangers 15, two expansion devices 16, one switching device 17, four second refrigerant flow switching devices 18, and two pumps 21. Four first heat medium flow switching devices 22, four second heat medium flow switching devices 23, four heat medium flow control devices 25, a first blocking device 37, and a second blocking device 38 , And a concentration detection device 39 are mounted. The first shut-off device 37 and the second shut-off device 38 are respectively installed on the inlet side and the outlet side of the heat medium relay unit 3.

  The two heat exchangers between heat mediums 15 (heat medium heat exchanger 15a and heat medium heat exchanger 15b) 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 1 and stored in the heat source side refrigerant is transmitted to the heat medium. The heat exchanger related to heat medium 15a is provided between the expansion device 16a, the second refrigerant flow switching device 18a (1), and the second refrigerant flow switching device 18a (2) in the refrigerant circuit A, It serves for cooling of the heat medium in the cooling / heating mixed operation mode. The heat exchanger related to heat medium 15b is provided between the expansion device 16b in the refrigerant circuit A, the second refrigerant flow switching device 18b (1), and the second refrigerant flow switching device 18b (2). It is used for heating of the heat medium in the cooling / heating mixed operation mode.

  The two expansion devices 16 (the expansion device 16a and the expansion device 16b) have a function as a pressure reducing valve or an expansion valve, and expand the heat source side refrigerant by reducing the pressure. The expansion device 16a is provided on the upstream side of the heat exchanger related to heat medium 15a in the flow of the heat source side refrigerant in the cooling only operation mode. The expansion device 16b is provided on the upstream side of the heat exchanger related to heat medium 15b in the flow of the heat source side refrigerant in the cooling only operation mode. The two expansion devices 16 may be configured by a device whose opening degree can be variably controlled, for example, an electronic expansion valve.

  The opening / closing device 17 (third refrigerant flow switching device) is composed of a two-way valve or the like, and opens and closes the refrigerant pipe 4. The opening / closing device 17 is provided in the refrigerant pipe 4 between the first shut-off device 37 and the heat exchanger related to heat medium 15a.

  Four second refrigerant flow switching devices 18 (second refrigerant flow switching device 18a (1), second refrigerant flow switching device 18a (2), second refrigerant flow switching device 18b (1), second refrigerant The flow path switching device 18b (2)) is configured by a two-way valve or the like, and switches the flow of the heat source side refrigerant according to the operation mode. The second refrigerant flow switching device 18a (the second refrigerant flow switching device 18a (1) and the second refrigerant flow switching device 18a (2)) is configured such that the heat source side refrigerant flows during the cooling only operation mode. It is provided on the downstream side of the heat exchanger 15a. The second refrigerant flow switching device 18b (the second refrigerant flow switching device 18b (1) and the second refrigerant flow switching device 18b (2)) is configured so that the heat source side refrigerant flows during the cooling only operation mode. It is provided on the downstream side of the heat exchanger 15b.

  The two pumps 21 (pump 21 a and pump 21 b) circulate a heat medium that conducts through the pipe 5. The pump 21 a is provided in the pipe 5 between the heat exchanger related to heat medium 15 a and the second heat medium flow switching device 23. The pump 21 b is provided in the pipe 5 between the heat exchanger related to heat medium 15 b and the second heat medium flow switching device 23. The two pumps 21 may be constituted by, for example, pumps capable of capacity control. The pump 21a may be provided in the pipe 5 between the heat exchanger related to heat medium 15a and the first heat medium flow switching device 22. Further, the pump 21b may be provided in the pipe 5 between the heat exchanger related to heat medium 15b and the first heat medium flow switching device 22.

  The four first heat medium flow switching devices 22 (first heat medium flow switching device 22a to first heat medium flow switching device 22d) are configured by three-way valves or the like, and switch the flow path of the heat medium. Is. The first heat medium flow switching device 22 is provided in a number (here, four) according to the number of indoor units 2 installed. In the first heat medium flow switching device 22, one of the three sides is in the heat exchanger 15a, one of the three is in the heat exchanger 15b, and one of the three is in the heat medium flow rate. Each is connected to the adjusting device 25 and provided on the outlet side of the heat medium flow path of the use side heat exchanger 26. In correspondence with the indoor unit 2, the first heat medium flow switching device 22a, the first heat medium flow switching device 22b, the first heat medium flow switching device 22c, and the first heat medium flow from the lower side of the drawing. This is illustrated as a switching device 22d.

  The four second heat medium flow switching devices 23 (second heat medium flow switching device 23a to second heat medium flow switching device 23d) 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 23 is set according to the number of installed indoor units 2 (here, four). In the second heat medium flow switching device 23, one of the three heat transfer medium heat exchangers 15a, one of the three heat transfer medium heat exchangers 15b, and one of the three heat transfer side heats. The heat exchanger is connected to the exchanger 26 and provided on the inlet side of the heat medium flow path of the use side heat exchanger 26. In correspondence with the indoor unit 2, the second heat medium flow switching device 23a, the second heat medium flow switching device 23b, the second heat medium flow switching device 23c, and the second heat medium flow from the lower side of the drawing. This is illustrated as a switching device 23d.

  The four heat medium flow control devices 25 (the heat medium flow control device 25a to the heat medium flow control device 25d) are composed of two-way valves or the like that can control the opening area, and adjust the flow rate of the heat medium flowing through the pipe 5. To do. The number of the heat medium flow control devices 25 is set according to the number of indoor units 2 installed (four in this case). One of the heat medium flow control devices 25 is connected to the use-side heat exchanger 26, and the other is connected to the first heat medium flow switching device 22, and is connected to the outlet side of the heat medium flow channel of the use-side heat exchanger 26. Is provided. In correspondence with the indoor unit 2, the heat medium flow adjustment device 25 a, the heat medium flow adjustment device 25 b, the heat medium flow adjustment device 25 c, and the heat medium flow adjustment device 25 d are illustrated from the lower side of the drawing. Further, the heat medium flow control device 25 may be provided on the inlet side of the heat medium flow path of the use side heat exchanger 26.

    Further, the heat medium converter 3 includes various detection means (two first temperature sensors 31, four second temperature sensors 34, four third temperature sensors 35, a pressure sensor 36, and a concentration detection device 39). Is provided. Information (for example, temperature information, pressure information, and heat source side refrigerant concentration information) detected by these detection means is sent to a control device (not shown) that performs overall control of the operation of the air conditioner 101, and the compressor 10 Drive frequency, heat source side heat exchanger 12 and utilization side heat exchanger 26 provided near the rotation speed of the blower (not shown), switching of the first refrigerant flow switching device 11, pump 21 drive frequency, second refrigerant flow It is used for control of switching of the path switching device 18, opening and closing of the first blocking device 37, opening and closing of the second blocking device 38, switching of the flow path of the heat medium, and the like.

  The two first temperature sensors 31 (first temperature sensor 31 a and first temperature sensor 31 b) are the heat medium flowing out from the heat exchanger related to heat medium 15, that is, the temperature of the heat medium at the outlet of the heat exchanger related to heat medium 15. For example, a thermistor may be used. The first temperature sensor 31a is provided in the pipe 5 on the inlet side of the pump 21a. The first temperature sensor 31b is provided in the pipe 5 on the inlet side of the pump 21b.

  The four second temperature sensors 34 (second temperature sensor 34a to second temperature sensor 34d) are provided between the first heat medium flow switching device 22 and the heat medium flow control device 25, and use side heat exchangers. The temperature of the heat medium that has flowed out of the heater 26 is detected. The number of the second temperature sensors 34 (four here) according to the number of indoor units 2 installed is provided. In correspondence with the indoor unit 2, the second temperature sensor 34a, the second temperature sensor 34b, the second temperature sensor 34c, and the second temperature sensor 34d are illustrated from the lower side of the drawing.

  The four third temperature sensors 35 (third temperature sensor 35 a to third temperature sensor 35 d) are provided on the inlet side or the outlet side of the heat source side refrigerant of the heat exchanger related to heat medium 15, and the heat exchanger related to heat medium 15. 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 15 is detected, and may be composed of a thermistor or the like. The third temperature sensor 35a is provided between the heat exchanger related to heat medium 15a and the second refrigerant flow switching device 18a. The third temperature sensor 35b is provided between the heat exchanger related to heat medium 15a and the expansion device 16a. The third temperature sensor 35c is provided between the heat exchanger related to heat medium 15b and the second refrigerant flow switching device 18b. The third temperature sensor 35d is provided between the heat exchanger related to heat medium 15b and the expansion device 16b.

Similar to the installation position of the third temperature sensor 35d, the pressure sensor 36 is provided between the heat exchanger related to heat medium 15b and the expansion device 16b, and between the heat exchanger related to heat medium 15b and the expansion device 16b. The pressure of the flowing heat source side refrigerant is detected.
The concentration detection device 39 detects the concentration of the refrigerant inside the heat medium relay unit 3.

  The control device (not shown) is constituted by a microcomputer or the like, and based on detection information from various detection means and instructions from the remote controller, the driving frequency of the compressor 10 and the rotational speed of the blower (including ON / OFF) , Switching of the first refrigerant flow switching device 11, driving of the pump 21, opening of the expansion device 16, opening and closing of the first blocking device 37, opening and closing of the second blocking device 38, opening and closing of the switching device 17, and second refrigerant flow The switching of the path switching device 18, the switching of the first heat medium flow switching device 22, the switching of the second heat medium flow switching device 23, the opening degree of the heat medium flow control device 25, and the like are controlled. The operation mode is executed. Note that the control device may be provided for each unit, or may be provided in the outdoor unit 1 or the heat medium relay unit 3.

  The pipe 5 that conducts the heat medium is composed of one that is connected to the heat exchanger related to heat medium 15a and one that is connected to the heat exchanger related to heat medium 15b. The pipe 5 is branched (here, four branches each) according to the number of indoor units 2 connected to the heat medium relay unit 3. The pipe 5 is connected by a first heat medium flow switching device 22 and a second heat medium flow switching device 23. By controlling the first heat medium flow switching device 22 and the second heat medium flow switching device 23, the heat medium from the heat exchanger related to heat medium 15a flows into the use-side heat exchanger 26, or the heat medium Whether the heat medium from the intermediate heat exchanger 15b flows into the use side heat exchanger 26 is determined.

  In the air conditioner 101, the compressor 10, the first refrigerant flow switching device 11, the heat source side heat exchanger 12, the first shut-off device 37, the opening / closing device 17, the second refrigerant flow switching device 18, and the heat medium. A refrigerant circuit A is configured by connecting the refrigerant flow path of the heat exchanger 15 a, the expansion device 16, the second shut-off device 38, and the accumulator 19 through the refrigerant pipe 4. Further, the heat medium flow path of the heat exchanger related to heat medium 15a, the pump 21, the first heat medium flow switching device 22, the heat medium flow control device 25, the use side heat exchanger 26, and the second heat medium flow path. The switching device 23 is connected by a pipe 5 to constitute a heat medium circulation circuit B. That is, a plurality of usage-side heat exchangers 26 are connected in parallel to each of the heat exchangers between heat media 15, and the heat medium circulation circuit B has a plurality of systems.

  Therefore, in the air conditioning apparatus 101, the outdoor unit 1 and the heat medium relay unit 3 are connected via the heat exchanger related to heat medium 15a and the heat exchanger related to heat medium 15b provided in the heat medium converter 3. The heat medium relay unit 3 and the indoor unit 2 are also connected via the heat exchanger related to heat medium 15a and the heat exchanger related to heat medium 15b. That is, in the air conditioner 101, 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 15a and the intermediate heat exchanger 15b. It is like that.

  Each operation mode executed by the air conditioner 101 will be described. The air conditioner 101 can perform a cooling operation or a heating operation in the indoor unit 2 based on an instruction from each indoor unit 2. That is, the air conditioning apparatus 101 can perform the same operation for all the indoor units 2 and can perform different operations for each of the indoor units 2.

  The operation mode executed by the air conditioner 101 includes a cooling only operation mode in which all the driven indoor units 2 execute a cooling operation, and a heating only operation in which all the driven indoor units 2 execute a heating operation. There are a cooling main operation mode as a cooling / heating mixed operation mode with a larger mode and a cooling load, and a heating main operation mode as a cooling / heating mixed operation mode with a larger heating load. Below, each operation mode is demonstrated with the flow of a heat-source side refrigerant | coolant and a heat medium.

[Cooling operation mode]
FIG. 8 is a refrigerant circuit diagram illustrating a refrigerant flow when the air-conditioning apparatus 101 is in the cooling only operation mode. In FIG. 8, the cooling only operation mode will be described by taking as an example a case where a cooling load is generated only in the use side heat exchanger 26a and the use side heat exchanger 26b. In FIG. 8, the pipes represented by the thick lines indicate the pipes through which the refrigerant (heat source side refrigerant and heat medium) flows. In FIG. 8, the flow direction of the heat source side refrigerant is indicated by solid line arrows, and the flow direction of the heat medium is indicated by broken line arrows.

  In the cooling only operation mode shown in FIG. 8, in the outdoor unit 1, the first refrigerant flow switching device 11 is switched so that the heat source side refrigerant discharged from the compressor 10 flows into the heat source side heat exchanger 12. In the heat medium converter 3, the pump 21a and the pump 21b are driven, the heat medium flow control device 25a and the heat medium flow control device 25b are opened, and the heat medium flow control device 25c and the heat medium flow control device 25d are fully closed. The heat medium circulates between the heat exchanger related to heat medium 15a and the heat exchanger related to heat medium 15b and the use side heat exchanger 26a and the use side heat exchanger 26b.

First, the flow of the heat source side refrigerant in the refrigerant circuit A will be described.
The low-temperature and low-pressure refrigerant is compressed by the compressor 10 and discharged as a high-temperature and high-pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant discharged from the compressor 10 flows into the heat source side heat exchanger 12 via the first refrigerant flow switching device 11. And it becomes a high voltage | pressure refrigerant | coolant by which the temperature fell in the supercritical state, radiating heat to outdoor air with the heat source side heat exchanger 12. The high-pressure refrigerant that has flowed out of the heat source side heat exchanger 12 flows out of the outdoor unit 1 and flows into the heat medium relay unit 3 through the refrigerant pipe 4. The high-pressure refrigerant flowing into the heat medium relay unit 3 is branched after passing through the first shut-off device 37 and the opening / closing device 17 and is expanded by the expansion device 16a and the expansion device 16b to become a low-temperature / low-pressure two-phase refrigerant. . The opening / closing device 17 is open.

  This two-phase refrigerant flows into each of the heat exchanger related to heat medium 15a and the heat exchanger related to heat medium 15b acting as an evaporator, and absorbs heat from the heat medium circulating in the heat medium circulation circuit B. It becomes a low-temperature, low-pressure gas refrigerant while cooling. The gas refrigerant that has flowed out of the heat exchanger related to heat medium 15a and the heat exchanger related to heat medium 15b passes through the second refrigerant flow switching device 18a (1) and the second refrigerant flow switching device 18b (1). It flows out of the heat medium relay unit 3 through the shut-off device 38, and flows into the outdoor unit 1 again through the refrigerant pipe 4. The refrigerant that has flowed into the outdoor unit 1 is again sucked into the compressor 10 via the first refrigerant flow switching device 11 and the accumulator 19.

  At this time, the second refrigerant flow switching device 18a (1) and the second refrigerant flow switching device 18b (1) are opened, and the second refrigerant flow switching device 18a (2) and the second refrigerant flow switching device 18b ( 2) is closed. Since both the second refrigerant flow switching device 18a (2) and the second refrigerant flow switching device 18b (2) are closed, the bypass pipe 4d (between the first blocking device 37 and the opening / closing device 17) The second refrigerant flow switching device 18a (2) and the second refrigerant flow switching device 18b (2) are connected, and the refrigerant passing through the refrigerant pipe 4) that enables bypassing the heat exchanger related to heat medium 15 is connected. There is no flow. However, one end of the bypass pipe 4d is in a high pressure state, and the bypass pipe 4d is filled with a high-pressure heat source side refrigerant.

  Further, the opening degree of the expansion device 16a is controlled so that the superheat (superheat degree) obtained as a difference between the temperature detected by the third temperature sensor 35a and the temperature detected by the third temperature sensor 35b becomes constant. Is done. Similarly, the opening degree of the expansion device 16b is controlled so that the superheat obtained as the difference between the temperature detected by the third temperature sensor 35c and the temperature detected by the third temperature sensor 35d is constant.

Next, the flow of the heat medium in the heat medium circuit B will be described.
In the cooling only operation mode, the cold heat of the heat source side refrigerant is transmitted to the heat medium in both the heat exchanger related to heat medium 15a and the heat exchanger related to heat medium 15b, and the cooled heat medium is piped 5 by the pump 21a and the pump 21b. The inside will be allowed to flow. The heat medium pressurized and discharged by the pump 21a and the pump 21b passes through the second heat medium flow switching device 23a and the second heat medium flow switching device 23b, and the use side heat exchanger 26a and the use side heat exchange. Flows into the vessel 26b. The heat medium absorbs heat from the indoor air in the use side heat exchanger 26a and the use side heat exchanger 26b, thereby cooling the indoor space 7.

  Then, the heat medium flows out of the use side heat exchanger 26a and the use side heat exchanger 26b and flows into the heat medium flow control device 25a and the heat medium flow control device 25b. At this time, the heat medium flow control device 25a and the heat medium flow control device 25b control the flow rate of the heat medium to a flow rate necessary to cover the air conditioning load required in the room, so that the use-side heat exchanger 26a. And it flows into the use side heat exchanger 26b. The heat medium flowing out from the heat medium flow control device 25a and the heat medium flow control device 25b passes through the first heat medium flow switching device 22a and the first heat medium flow switching device 22b, and the heat exchanger related to heat medium 15a. And flows into the heat exchanger related to heat medium 15b, and is sucked into the pump 21a and the pump 21b again.

  In the pipe 5 of the use side heat exchanger 26, the heat medium is directed from the second heat medium flow switching device 23 to the first heat medium flow switching device 22 via the heat medium flow control device 25. Flowing. The air conditioning load required in the indoor space 7 includes the temperature detected by the first temperature sensor 31a, the temperature detected by the first temperature sensor 31b, and the temperature detected by the second temperature sensor 34. By controlling so as to keep the difference between the two as a target value, it can be covered. As the outlet temperature of the heat exchanger related to heat medium 15, either the temperature of the first temperature sensor 31a or the first temperature sensor 31b may be used, or the average temperature thereof may be used. At this time, the first heat medium flow switching device 22 and the second heat medium flow switching device 23 ensure a flow path that flows to both the heat exchanger related to heat medium 15a and the heat exchanger related to heat medium 15b. In addition, the intermediate opening is set.

  When the cooling only operation mode is executed, it is not necessary to flow the heat medium to the use side heat exchanger 26 (including the thermo-off) without the heat load. The heat medium is prevented from flowing to the heat exchanger 26. In FIG. 8, a heat medium is flowing because there is a heat load in the use side heat exchanger 26a and the use side heat exchanger 26b, but in the use side heat exchanger 26c and the use side heat exchanger 26d, the heat load is passed. The corresponding heat medium flow control device 25c and heat medium flow control device 25d are fully closed. When a heat load is generated from the use side heat exchanger 26c or the use side heat exchanger 26d, the heat medium flow control device 25c or the heat medium flow control device 25d is opened to circulate the heat medium. That's fine.

[Heating operation mode]
FIG. 9 is a refrigerant circuit diagram illustrating a refrigerant flow when the air-conditioning apparatus 101 is in the heating only operation mode. In FIG. 9, the heating only operation mode will be described by taking as an example a case where a thermal load is generated only in the use side heat exchanger 26a and the use side heat exchanger 26b. In FIG. 9, pipes represented by thick lines indicate pipes through which the refrigerant (heat source side refrigerant and heat medium) flows. In FIG. 9, the flow direction of the heat source side refrigerant is indicated by solid line arrows, and the flow direction of the heat medium is indicated by broken line arrows.

  In the heating only operation mode shown in FIG. 9, in the outdoor unit 1, the first refrigerant flow switching device 11 uses the heat source side refrigerant discharged from the compressor 10 as a heat medium without passing through the heat source side heat exchanger 12. It switches so that it may flow into converter 3. In the heat medium converter 3, the pump 21a and the pump 21b are driven, the heat medium flow control device 25a and the heat medium flow control device 25b are opened, and the heat medium flow control device 25c and the heat medium flow control device 25d are fully closed. The heat medium circulates between the heat exchanger related to heat medium 15a and the heat exchanger related to heat medium 15b and the use side heat exchanger 26a and the use side heat exchanger 26b.

First, the flow of the heat source side refrigerant in the refrigerant circuit A will be described.
The low-temperature and low-pressure refrigerant is compressed by the compressor 10 and discharged as a high-temperature and high-pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant discharged from the compressor 10 passes through the first refrigerant flow switching device 11 and flows out of the outdoor unit 1. The high-temperature and high-pressure gas refrigerant that has flowed out of the outdoor unit 1 flows into the heat medium relay unit 3 through the refrigerant pipe 4. The high-temperature and high-pressure gas refrigerant that has flowed into the heat medium relay unit 3 passes through the second shut-off device 38 and then is branched to be branched into the second refrigerant flow switching device 18a (1) and the second refrigerant flow switching device 18b ( It flows into each of the heat exchanger related to heat medium 15a and the heat exchanger related to heat medium 15b via 1).

  The high-temperature and high-pressure gas refrigerant that has flowed into the heat exchanger related to heat medium 15a and the heat exchanger related to heat medium 15b is a high-pressure gas whose temperature has dropped in a supercritical state while dissipating heat to the heat medium circulating in the heat medium circuit B. Becomes a refrigerant. The liquid refrigerant flowing out of the heat exchanger related to heat medium 15a and the heat exchanger related to heat medium 15b is expanded by the expansion device 16a and the expansion device 16b to become a low-temperature, low-pressure two-phase refrigerant. This two-phase refrigerant flows out of the heat medium relay unit 3 through the opening / closing device 17 and the first shut-off device 37, and flows into the outdoor unit 1 again through the refrigerant pipe 4. The opening / closing device 17 is open.

  The refrigerant that has flowed into the outdoor unit 1 flows into the heat source side heat exchanger 12 that functions as an evaporator. And the refrigerant | coolant which flowed into the heat source side heat exchanger 12 absorbs heat from outdoor air in the heat source side heat exchanger 12, and becomes a low-temperature and low-pressure gas refrigerant. The low-temperature and low-pressure gas refrigerant flowing out from the heat source side heat exchanger 12 is again sucked into the compressor 10 via the first refrigerant flow switching device 11 and the accumulator 19.

  At this time, the second refrigerant flow switching device 18a (1) and the second refrigerant flow switching device 18b (1) are opened, and the second refrigerant flow switching device 18a (2) and the second refrigerant flow switching device 18b ( 2) is closed. Since both the second refrigerant flow switching device 18a (2) and the second refrigerant flow switching device 18b (2) are closed, there is no refrigerant flow through the bypass pipe 4d. However, one end of the bypass pipe 4d is a low-pressure two-phase pipe, and the bypass pipe 4d is filled with a low-pressure refrigerant.

  Further, the expansion device 16a has a constant subcool (degree of subcooling) obtained as a difference between a value obtained by converting the pressure detected by the pressure sensor 36 into a saturation temperature and a temperature detected by the third temperature sensor 35b. The opening degree is controlled. Similarly, the expansion device 16b has an opening degree so that a subcool obtained as a difference between a value obtained by converting the pressure detected by the pressure sensor 36 into a saturation temperature and a temperature detected by the third temperature sensor 35d is constant. Be controlled. When the saturation temperature at the intermediate position of the heat exchanger related to heat medium 15 can be measured, the temperature at the intermediate position may be used instead of the pressure sensor 36, and the system can be configured at low cost.

Next, the flow of the heat medium in the heat medium circuit B will be described.
In the heating only operation mode, the heat of the heat source side refrigerant is transmitted to the heat medium in both the heat exchanger 15a and the heat exchanger 15b, and the heated heat medium is piped 5 by the pump 21a and the pump 21b. The inside will be allowed to flow. The heat medium pressurized and discharged by the pump 21a and the pump 21b passes through the second heat medium flow switching device 23a and the second heat medium flow switching device 23b, and the use side heat exchanger 26a and the use side heat exchange. Flows into the vessel 26b. The heat medium radiates heat to the indoor air in the use side heat exchanger 26a and the use side heat exchanger 26b, thereby heating the indoor space 7.

  Then, the heat medium flows out of the use side heat exchanger 26a and the use side heat exchanger 26b and flows into the heat medium flow control device 25a and the heat medium flow control device 25b. At this time, the heat medium flow control device 25a and the heat medium flow control device 25b control the flow rate of the heat medium to a flow rate necessary to cover the air conditioning load required in the room, so that the use-side heat exchanger 26a. And it flows into the use side heat exchanger 26b. The heat medium flowing out from the heat medium flow control device 25a and the heat medium flow control device 25b passes through the first heat medium flow switching device 22a and the first heat medium flow switching device 22b, and the heat exchanger related to heat medium 15a. And flows into the heat exchanger related to heat medium 15b, and is sucked into the pump 21a and the pump 21b again.

  In the pipe 5 of the use side heat exchanger 26, the heat medium is directed from the second heat medium flow switching device 23 to the first heat medium flow switching device 22 via the heat medium flow control device 25. Flowing. The air conditioning load required in the indoor space 7 includes the temperature detected by the first temperature sensor 31a, the temperature detected by the first temperature sensor 31b, and the temperature detected by the second temperature sensor 34. By controlling so as to keep the difference between the two as a target value, it can be covered. As the outlet temperature of the heat exchanger related to heat medium 15, either the temperature of the first temperature sensor 31a or the first temperature sensor 31b may be used, or the average temperature thereof may be used.

  At this time, the first heat medium flow switching device 22 and the second heat medium flow switching device 23 ensure a flow path that flows to both the heat exchanger related to heat medium 15a and the heat exchanger related to heat medium 15b. In addition, the intermediate opening is set. In addition, the usage-side heat exchanger 26a should be controlled by the temperature difference between the inlet and the outlet, but the temperature of the heat medium on the inlet side of the usage-side heat exchanger 26 is detected by the first temperature sensor 31b. By using the first temperature sensor 31b, the number of temperature sensors can be reduced and the system can be configured at low cost.

  When the heating only operation mode is executed, it is not necessary to flow the heat medium to the use side heat exchanger 26 (including the thermo-off) without the heat load. The heat medium is prevented from flowing to the heat exchanger 26. In FIG. 9, since there is a heat load in the use side heat exchanger 26a and the use side heat exchanger 26b, a heat medium is passed, but in the use side heat exchanger 26c and the use side heat exchanger 26d, the heat load The corresponding heat medium flow control device 25c and heat medium flow control device 25d are fully closed. When a heat load is generated from the use side heat exchanger 26c or the use side heat exchanger 26d, the heat medium flow control device 25c or the heat medium flow control device 25d is opened to circulate the heat medium. That's fine.

[Cooling operation mode]
FIG. 10 is a refrigerant circuit diagram illustrating a refrigerant flow when the air-conditioning apparatus 101 is in the cooling main operation mode. In FIG. 10, the cooling main operation mode will be described by taking as an example a case where a cooling load is generated in the use side heat exchanger 26a and a heating load is generated in the use side heat exchanger 26b. In addition, in FIG. 10, the pipe | tube represented by the thick line has shown the piping through which a refrigerant | coolant (a heat source side refrigerant | coolant and a heat medium) circulates. Further, in FIG. 10, the flow direction of the heat source side refrigerant is indicated by a solid line arrow, and the flow direction of the heat medium is indicated by a broken line arrow.

  In the cooling main operation mode shown in FIG. 10, in the outdoor unit 1, the first refrigerant flow switching device 11 is switched so that the heat source side refrigerant discharged from the compressor 10 flows into the heat source side heat exchanger 12. In the heat medium converter 3, the pump 21a and the pump 21b are driven, the heat medium flow control device 25a and the heat medium flow control device 25b are opened, and the heat medium flow control device 25c and the heat medium flow control device 25d are fully closed. The heat medium is circulated between the heat exchanger related to heat medium 15a and the use side heat exchanger 26a, and between the heat exchanger related to heat medium 15b and the use side heat exchanger 26b.

First, the flow of the heat source side refrigerant in the refrigerant circuit A will be described.
The low-temperature and low-pressure refrigerant is compressed by the compressor 10 and discharged as a high-temperature and high-pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant discharged from the compressor 10 flows into the heat source side heat exchanger 12 via the first refrigerant flow switching device 11. And it becomes the refrigerant | coolant which temperature fell in the supercritical state, radiating heat | fever to outdoor air with the heat source side heat exchanger 12. FIG. The refrigerant that has flowed out of the heat source side heat exchanger 12 flows out of the outdoor unit 1 and flows into the heat medium relay unit 3 through the refrigerant pipe 4. The refrigerant flowing into the heat medium relay 3 passes through the first shut-off device 37, passes through the bypass pipe 4d and the second refrigerant flow switching device 18b (2), and heats between the heat media acting as a condenser (gas cooler). It flows into the exchanger 15b.

  The refrigerant that has flowed into the heat exchanger related to heat medium 15b becomes a refrigerant whose temperature is further lowered while dissipating heat to the heat medium circulating in the heat medium circuit B. The refrigerant flowing out of the heat exchanger related to heat medium 15b is expanded by the expansion device 16b and becomes a low-pressure two-phase refrigerant. This low-pressure two-phase refrigerant flows into the heat exchanger related to heat medium 15a acting as an evaporator via the expansion device 16a. The low-pressure two-phase refrigerant that has flowed into the heat exchanger related to heat medium 15a absorbs heat from the heat medium circulating in the heat medium circuit B, and becomes a low-pressure gas refrigerant while cooling the heat medium. This gas refrigerant flows out of the heat exchanger related to heat medium 15 a, flows out of the heat medium converter 3 through the second refrigerant flow switching device 18 a (1) and the second blocking device 38, and passes through the refrigerant pipe 4. Then flows into the outdoor unit 1 again. The refrigerant that has flowed into the outdoor unit 1 is again sucked into the compressor 10 via the first refrigerant flow switching device 11 and the accumulator 19.

  At this time, the second refrigerant flow switching device 18a (1) is opened, the second refrigerant flow switching device 18a (2) is closed, the second refrigerant flow switching device 18b (1) is closed, and the second refrigerant flow switching. The switching device 18b (2) is open. Since the second refrigerant flow switching device 18a (2) is closed and the second refrigerant flow switching device 18b (2) is opened, the high-pressure refrigerant flows inside the bypass pipe 4d, and the bypass pipe 4d. Is filled with high-pressure heat-source-side refrigerant.

  Further, the opening degree of the expansion device 16b is controlled so that the superheat obtained as the difference between the temperature detected by the third temperature sensor 35a and the temperature detected by the third temperature sensor 35b becomes constant. Further, the expansion device 16a is fully opened, and the opening / closing device 17 is closed. The expansion device 16b controls the opening degree so that a subcool obtained as a difference between a value obtained by converting the pressure detected by the pressure sensor 36 into a saturation temperature and a temperature detected by the third temperature sensor 35d is constant. May be. Alternatively, the expansion device 16b may be fully opened, and the superheat or subcool may be controlled by the expansion device 16a.

Next, the flow of the heat medium in the heat medium circuit B will be described.
In the cooling main operation mode, the heat of the heat source side refrigerant is transmitted to the heat medium in the heat exchanger related to heat medium 15b, and the heated heat medium is caused to flow in the pipe 5 by the pump 21b. In the cooling main operation mode, the cold heat of the heat source side refrigerant is transmitted to the heat medium by the heat exchanger related to heat medium 15a, and the cooled heat medium is caused to flow in the pipe 5 by the pump 21a. The heat medium pressurized and discharged by the pump 21a and the pump 21b passes through the second heat medium flow switching device 23a and the second heat medium flow switching device 23b, and the use side heat exchanger 26a and the use side heat exchange. Flows into the vessel 26b.

  In the use side heat exchanger 26b, the heat medium radiates heat to the indoor air, thereby heating the indoor space 7. In the use-side heat exchanger 26a, the indoor space 7 is cooled by the heat medium absorbing heat from the indoor air. At this time, the heat medium flow control device 25a and the heat medium flow control device 25b control the flow rate of the heat medium to a flow rate necessary to cover the air conditioning load required in the room, so that the use-side heat exchanger 26a. And it flows into the use side heat exchanger 26b. The heat medium whose temperature has slightly decreased after passing through the use side heat exchanger 26b flows into the heat exchanger related to heat medium 15b through the heat medium flow control device 25b and the first heat medium flow switching device 22b, and again. It is sucked into the pump 21b. The heat medium whose temperature has slightly increased after passing through the use side heat exchanger 26a flows into the heat exchanger related to heat medium 15a through the heat medium flow control device 25a and the first heat medium flow switching device 22a, and again. It is sucked into the pump 21a.

  During this time, the warm heat medium and the cold heat medium are not mixed by the action of the first heat medium flow switching device 22 and the second heat medium flow switching device 23, and the use side has a heat load and a heat load, respectively. It is introduced into the heat exchanger 26. In the pipe 5 of the use side heat exchanger 26, the first heat medium flow switching device 22 from the second heat medium flow switching device 23 via the heat medium flow control device 25 on both the heating side and the cooling side. The heat medium is flowing in the direction to The air conditioning load required in the indoor space 7 is the difference between the temperature detected by the first temperature sensor 31b on the heating side and the temperature detected by the second temperature sensor 34 on the heating side, This can be covered by controlling the difference between the temperature detected by the two temperature sensor 34 and the temperature detected by the first temperature sensor 31a as a target value.

  When executing the cooling main operation mode, it is not necessary to flow the heat medium to the use side heat exchanger 26 (including the thermo-off) without the heat load, so the flow path is closed by the heat medium flow control device 25 and the use side The heat medium is prevented from flowing to the heat exchanger 26. In FIG. 10, a heat medium is flowing because there is a heat load in the use side heat exchanger 26a and the use side heat exchanger 26b, but in the use side heat exchanger 26c and the use side heat exchanger 26d, the heat load is passed. The corresponding heat medium flow control device 25c and heat medium flow control device 25d are fully closed. When a heat load is generated from the use side heat exchanger 26c or the use side heat exchanger 26d, the heat medium flow control device 25c or the heat medium flow control device 25d is opened to circulate the heat medium. That's fine.

[Heating main operation mode]
FIG. 11 is a refrigerant circuit diagram illustrating a refrigerant flow when the air-conditioning apparatus 101 is in the heating main operation mode. In FIG. 11, the heating main operation mode will be described by taking as an example a case where a thermal load is generated in the use side heat exchanger 26a and a cold load is generated in the use side heat exchanger 26b. In addition, in FIG. 11, the pipe | tube represented by the thick line has shown the piping through which a refrigerant | coolant (a heat source side refrigerant | coolant and a heat medium) circulates. Moreover, in FIG. 11, the flow direction of the heat source side refrigerant is indicated by a solid line arrow, and the flow direction of the heat medium is indicated by a broken line arrow.

  In the heating-main operation mode shown in FIG. 11, in the outdoor unit 1, the first refrigerant flow switching device 11 uses the heat source side refrigerant discharged from the compressor 10 without passing through the heat source side heat exchanger 12. It switches so that it may flow into converter 3. In the heat medium converter 3, the pump 21a and the pump 21b are driven, the heat medium flow control device 25a and the heat medium flow control device 25b are opened, and the heat medium flow control device 25c and the heat medium flow control device 25d are fully closed. The heat medium circulates between the heat exchanger related to heat medium 15a and the use-side heat exchanger 26b, and between the heat exchanger related to heat medium 15b and the use-side heat exchanger 26a.

First, the flow of the heat source side refrigerant in the refrigerant circuit A will be described.
The low-temperature and low-pressure refrigerant is compressed by the compressor 10 and discharged as a high-temperature and high-pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant discharged from the compressor 10 passes through the first refrigerant flow switching device 11 and flows out of the outdoor unit 1. The high-temperature and high-pressure gas refrigerant that has flowed out of the outdoor unit 1 flows into the heat medium relay unit 3 through the refrigerant pipe 4. The high-temperature and high-pressure gas refrigerant that has flowed into the heat medium relay unit 3 passes through the second shut-off device 38 and the second refrigerant flow switching device 18b (1), and heat exchange between heat media acts as a condenser (gas cooler). Flow into the vessel 15b.

  The gas refrigerant that has flowed into the heat exchanger related to heat medium 15b becomes a refrigerant whose temperature has dropped in a supercritical state while radiating heat to the heat medium circulating in the heat medium circuit B. The refrigerant flowing out of the heat exchanger related to heat medium 15b is expanded by the expansion device 16b and becomes a low-pressure two-phase refrigerant. This low-pressure two-phase refrigerant flows into the heat exchanger related to heat medium 15a acting as an evaporator via the expansion device 16a. The low-pressure two-phase refrigerant that has flowed into the heat exchanger related to heat medium 15a evaporates by absorbing heat from the heat medium circulating in the heat medium circuit B, thereby cooling the heat medium. The low-pressure two-phase refrigerant flows out of the heat exchanger related to heat medium 15a, passes through the first blocking device 37 via the second refrigerant flow switching device 18a (2) and the bypass pipe 4d, and passes through the heat medium converter 3. And flows into the outdoor unit 1 again through the refrigerant pipe 4.

  The refrigerant that has flowed into the outdoor unit 1 flows into the heat source side heat exchanger 12 that functions as an evaporator. And the refrigerant | coolant which flowed into the heat source side heat exchanger 12 absorbs heat from outdoor air in the heat source side heat exchanger 12, and becomes a low-temperature and low-pressure gas refrigerant. The low-temperature and low-pressure gas refrigerant flowing out from the heat source side heat exchanger 12 is again sucked into the compressor 10 via the first refrigerant flow switching device 11 and the accumulator 19.

  At this time, the second refrigerant flow switching device 18a (1) is closed, the second refrigerant flow switching device 18a (2) is opened, the second refrigerant flow switching device 18b (1) is opened, and the second refrigerant flow switching The switching device 18b (2) is closed. Since the second refrigerant flow switching device 18a (2) is open and the second refrigerant flow switching device 18b (2) is closed, the low-pressure two-phase refrigerant flows in the bypass pipe 4d, and the bypass The pipe 4d is filled with a low-pressure heat source side refrigerant.

  Further, the opening of the expansion device 16b is controlled so that a subcool obtained as a difference between a value obtained by converting the pressure detected by the pressure sensor 36 into a saturation temperature and a temperature detected by the third temperature sensor 35b is constant. Is done. Further, the expansion device 16a is fully opened, and the opening / closing device 17 is closed. Note that the expansion device 16b may be fully opened, and the subcooling may be controlled by the expansion device 16a.

Next, the flow of the heat medium in the heat medium circuit B will be described.
In the heating main operation mode, the heat of the heat source side refrigerant is transmitted to the heat medium in the heat exchanger related to heat medium 15b, and the heated heat medium is caused to flow in the pipe 5 by the pump 21b. In the heating main operation mode, the cold heat of the heat source side refrigerant is transmitted to the heat medium by the heat exchanger related to heat medium 15a, and the cooled heat medium is caused to flow in the pipe 5 by the pump 21a. The heat medium pressurized and discharged by the pump 21a and the pump 21b passes through the second heat medium flow switching device 23a and the second heat medium flow switching device 23b, and the use side heat exchanger 26a and the use side heat exchange. Flows into the vessel 26b.

  In the use side heat exchanger 26b, the heat medium absorbs heat from the indoor air, thereby cooling the indoor space 7. Moreover, in the use side heat exchanger 26a, the heat medium radiates heat to the indoor air, thereby heating the indoor space 7. At this time, the heat medium flow control device 25a and the heat medium flow control device 25b control the flow rate of the heat medium to a flow rate necessary to cover the air conditioning load required in the room, so that the use-side heat exchanger 26a. And it flows into the use side heat exchanger 26b. The heat medium whose temperature has slightly increased after passing through the use side heat exchanger 26b flows into the heat exchanger related to heat medium 15a through the heat medium flow control device 25b and the first heat medium flow switching device 22b, and again. It is sucked into the pump 21a. The heat medium whose temperature has slightly decreased after passing through the use side heat exchanger 26a flows into the heat exchanger related to heat medium 15b through the heat medium flow control device 25a and the first heat medium flow switching device 22a, and again. It is sucked into the pump 21b.

  During this time, the warm heat medium and the cold heat medium are not mixed by the action of the first heat medium flow switching device 22 and the second heat medium flow switching device 23, and the use side has a heat load and a heat load, respectively. It is introduced into the heat exchanger 26. In the pipe 5 of the use side heat exchanger 26, the first heat medium flow switching device 22 from the second heat medium flow switching device 23 via the heat medium flow control device 25 on both the heating side and the cooling side. The heat medium is flowing in the direction to The air conditioning load required in the indoor space 7 is the difference between the temperature detected by the first temperature sensor 31b on the heating side and the temperature detected by the second temperature sensor 34 on the heating side, This can be covered by controlling the difference between the temperature detected by the two temperature sensor 34 and the temperature detected by the first temperature sensor 31a as a target value.

  When the heating main operation mode is executed, it is not necessary to flow the heat medium to the use side heat exchanger 26 (including the thermo-off) without the heat load, so the flow path is closed by the heat medium flow control device 25 and the use side The heat medium is prevented from flowing to the heat exchanger 26. In FIG. 7, a heat medium flows because there is a heat load in the use side heat exchanger 26a and the use side heat exchanger 26b. However, in the use side heat exchanger 26c and the use side heat exchanger 26d, the heat load is passed. The corresponding heat medium flow control device 25c and heat medium flow control device 25d are fully closed. When a heat load is generated from the use side heat exchanger 26c or the use side heat exchanger 26d, the heat medium flow control device 25c or the heat medium flow control device 25d is opened to circulate the heat medium. That's fine.

  The configurations and operations of the first blocking device 37, the second blocking device 38, and the concentration detecting device 39 are the same as the first blocking device 303, the second blocking device 304, and the concentration of the air conditioner 100 according to Embodiment 1. This is the same as the detection device 305. The basic specifications of the air conditioning apparatus 101 according to the second embodiment, such as the electric drive system, the minimum operating pressure difference, and the leakage amount, are the same as those of the air conditioning apparatus 100 according to the first embodiment. Note that the concentration detection device 39 is further improved in safety by using a battery that can be operated by a battery, assuming that power is not supplied from the commercial power source to the concentration detection device 39 during a power failure.

When the concentration detector 39 installed in the heat medium relay ³ detects carbon dioxide with a predetermined concentration of 0.007 [kg / m ³ ], it is determined that refrigerant leakage has occurred from the heat medium relay 3, and the concentration The switch of the detection device 39 is turned off, and the energization to the first cutoff device 37 and the second cutoff device 38 is stopped. As a result, the first shut-off device 37 and the second shut-off device 38 are closed, and the refrigerant flowing from the outdoor unit 1 through the refrigerant pipe 4 can be shut off, thereby preventing the refrigerant from leaking into the room. be able to.

  In the second embodiment, the case where the concentration detection device 39 is provided inside the heat medium relay unit 3 is shown as an example, but the installation position is not limited to this position. For example, the concentration detector 39 may be provided in a space where the heat medium relay unit 3 is installed without being installed in the heat medium relay unit 3. That is, since the installation purpose of the concentration detection device 39 is to detect the refrigerant concentration in the space where a person exists, it may be installed in any place in the space where the heat medium relay unit 3 is installed. is there. Further, for example, the concentration detection device 39 may be incorporated in a remote controller (not shown).

[Refrigerant piping 4]
As described above, the air-conditioning apparatus 101 according to Embodiment 2 has several operation modes. In these operation modes, the heat source side refrigerant flows through the refrigerant pipe 4 that connects the outdoor unit 1 and the heat medium relay unit 3.

[Piping 5]
In some operation modes executed by the air-conditioning apparatus 101 according to Embodiment 2, a heat medium such as water or antifreeze flows through the pipe 5 connecting the heat medium converter 3 and the indoor unit 2.

[Heat source side refrigerant]
The case where carbon dioxide (CO ₂ ), which has a relatively low global warming potential, is used as the heat source-side refrigerant, but has been described as an example. May be used as the heat source side refrigerant. For example, a mixture of carbon dioxide and diethyl ether can be used as the heat source side refrigerant.

[Heat medium]
As the heat medium, for example, brine (antifreeze), water, a mixed solution of brine and water, a mixed solution of water and an additive having a high anticorrosive effect, or the like can be used. Therefore, in the air conditioning apparatus 101, even if the heat medium leaks into the indoor space 7 through the indoor unit 2, it contributes to the improvement of safety because a highly safe heat medium is used. Become.

  The air-conditioning apparatus 101 that employs the configuration described above can detect refrigerant leakage from the refrigerant circuit (refrigerant circulation circuit A), and greatly improves safety. Moreover, since the air conditioning apparatus 101 uses what changes to a supercritical state for a refrigerant | coolant, it can reduce environmental impact.

  In the air conditioning apparatus 101 according to Embodiment 2, the pressure in the bypass pipe 4d varies depending on the switching state of the first refrigerant flow switching device 11, and is filled with either the high-pressure refrigerant or the low-pressure refrigerant. It is.

  Further, in the cooling main operation mode and the heating main operation mode, when the state (heating or cooling) of the heat exchanger related to heat medium 15b and the heat exchanger related to heat medium 15a is changed, the water that has been used up to now is cooled down. As a result, cold water is heated to become hot water, resulting in wasted energy. Therefore, the air conditioner 101 is configured so that the heat exchanger related to heat medium 15b is always on the heating side and the heat exchanger related to heat medium 15a is on the cooling side in both the cooling main operation mode and the heating main operation mode. doing.

  Further, when the heating load and the cooling load are mixed in the use side heat exchanger 26, the first heat medium flow switching device corresponding to the use side heat exchanger 26 performing the heating operation. 22 and the second heat medium flow switching device 23 are switched to flow paths connected to the heat exchanger related to heat medium 15b for heating, and the first heat medium corresponding to the use side heat exchanger 26 performing the cooling operation By switching the flow path switching device 22 and the second heat medium flow path switching device 23 to a flow path connected to the heat exchanger related to heat medium 15a for cooling, in each indoor unit 2, heating operation and cooling operation are performed. It can be done freely.

  The first heat medium flow switching device 22 and the second heat medium flow switching device 23 described in the second embodiment can switch a three-way flow such as a three-way valve, or a two-way flow such as an on-off valve. What is necessary is just to switch a flow path, such as combining two things which perform opening and closing of. In addition, the first heat medium can be obtained by combining two things such as a stepping motor drive type mixing valve that can change the flow rate of the three-way flow path and two things that can change the flow rate of the two-way flow path such as an electronic expansion valve. The flow path switching device 22 and the second heat medium flow path switching device 23 may be used. In this case, it is possible to prevent water hammer due to sudden opening and closing of the flow path. Further, in the second embodiment, the case where the heat medium flow control device 25 is a two-way valve has been described as an example, but with a bypass pipe that bypasses the use-side heat exchanger 26 as a control valve having a three-way flow path. You may make it install.

  Further, the heat medium flow control device 25 may be a stepping motor drive type that can control the flow rate flowing through the flow path, and may be a two-way valve or a device in which one end of the three-way valve is closed. Further, as the heat medium flow control device 25, a device that opens and closes a two-way flow path such as an open / close valve may be used, and the average flow rate may be controlled by repeating ON / OFF.

  In addition, the second refrigerant flow switching device 18 is shown as if it is a two-way flow switching valve. However, the present invention is not limited to this, and a plurality of three-way flow switching valves are used and the refrigerant flows in the same manner. You may comprise as follows. Further, the second refrigerant flow switching device 18 may be configured using a four-way valve.

  Although the air-conditioning apparatus 101 according to Embodiment 2 has been described as being capable of cooling and heating mixed operation, the present invention is not limited to this. For example, there is one heat exchanger 15 between the heat medium and one expansion device 16, and a plurality of use side heat exchangers 26 and heat medium flow control devices 25 are connected in parallel to either the cooling operation or the heating operation. Even in a configuration that can only be performed, the same effect can be obtained.

  Moreover, it goes without saying that the same holds true even when only one use-side heat exchanger 26 and one heat medium flow control device 25 are connected. As the heat exchanger 15 between heat mediums 15 and the expansion device 16, Of course, there is no problem even if there are multiple things that move in the same way. Further, the case where the heat medium flow control device 25 is built in the heat medium converter 3 has been described as an example. However, the heat medium flow control device 25 is not limited thereto, and may be built in the indoor unit 2. 3 and the indoor unit 2 may be configured separately.

  In general, the heat source side heat exchanger 12 and the use side heat exchanger 26 are provided with a blower, and in many cases, condensation or evaporation is promoted by blowing air, but this is not restrictive. For example, the use side heat exchanger 26 may be a panel heater using radiation, and the heat source side heat exchanger 12 is of a water-cooled type that moves heat by water or antifreeze. Can also be used. That is, the heat source side heat exchanger 12 and the use side heat exchanger 26 can be used regardless of the type as long as they have a structure capable of radiating heat or absorbing heat.

  In the second embodiment, the case where there are four usage-side heat exchangers 26 has been described as an example, but the number is not particularly limited. Moreover, although the case where the number of heat exchangers between heat mediums 15a and the heat exchangers between heat mediums 15b is two has been described as an example, naturally the present invention is not limited to this, and the heat medium can be cooled or / and heated. If it comprises, you may install how many. Furthermore, the number of pumps 21a and 21b is not limited to one, and a plurality of small-capacity pumps may be connected in parallel.

  In the second embodiment, the first heat medium flow switching device 22, the second heat medium flow switching device 23, and the heat medium flow control device 25 are connected to each use side heat exchanger 26 one by one. However, the present invention is not limited to this, and a plurality of each of the use side heat exchangers 26 may be connected. In this case, the first heat medium flow switching device, the second heat medium flow switching device, and the heat medium flow control device connected to the same use side heat exchanger 26 may be operated in the same manner. .

  As described above, the air-conditioning apparatus according to Embodiments 1 and 2 can detect refrigerant leakage from the refrigerant circuit and greatly improve safety. It should be noted that the contents described in the first embodiment can be appropriately applied to the contents of the second embodiment, and the contents described in the second embodiment can be appropriately applied to the contents of the first embodiment.

  DESCRIPTION OF SYMBOLS 1 Outdoor unit, 2 Indoor unit, 2a Indoor unit, 2b Indoor unit, 2c Indoor unit, 2d Indoor unit, 3 Heat medium converter, 4 Refrigerant piping, 4d Bypass piping, 5 Piping, 6 Outdoor space, 7 Indoor space, 8 Space, 9 building, 10 compressor, 11 first refrigerant flow switching device, 12 heat source side heat exchanger, 15 heat medium heat exchanger, 15a heat medium heat exchanger, 15b heat medium heat exchanger, 16 Throttle device, 16a Throttle device, 16b Throttle device, 17 Opening / closing device, 18 Second refrigerant flow switching device, 18a Second refrigerant flow switching device, 18a (1) Second refrigerant flow switching device, 18a (2) First 2 refrigerant flow switching device, 18b second refrigerant flow switching device, 18b (1) second refrigerant flow switching device, 18b (2) refrigerant flow switching device, 19 accumulator, 21 pump, 21a pump, 21b 22a first heat medium flow switching device, 22a first heat medium flow switching device, 22b first heat medium flow switching device, 22c first heat medium flow switching device, 22d first heat medium flow switching. Device, 23 second heat medium flow switching device, 23a second heat medium flow switching device, 23b second heat medium flow switching device, 23c second heat medium flow switching device, 23d second heat medium flow switching Apparatus, 25 heat medium flow control device, 25a heat medium flow control device, 25b heat medium flow control device, 25c heat medium flow control device, 25d heat medium flow control device, 26 use side heat exchanger, 26a use side heat exchanger , 26b utilization side heat exchanger, 26c utilization side heat exchanger, 26d utilization side heat exchanger, 31 first temperature sensor, 31a first temperature sensor, 31b first temperature sensor, 34 second temperature sensor, 34 Second temperature sensor, 34b Second temperature sensor, 34c Second temperature sensor, 34d Second temperature sensor, 35 Third temperature sensor, 35a Third temperature sensor, 35b Third temperature sensor, 35c Third temperature sensor, 35d Third Temperature sensor, 36 Pressure sensor, 37 First shut-off device, 38 Second shut-off device, 39 Concentration detection device, 100 Air conditioner, 101 Air conditioner, 200 Outdoor unit, 201 Compressor, 202 Oil separator, 203 Flow path Switching device, 204 Heat source side heat exchanger, 205 Accumulator, 206 Oil return capillary, 300 Indoor unit, 300a Indoor unit, 300b Indoor unit, 300c Indoor unit, 300d Indoor unit, 301 Usage side heat exchanger, 301a Usage side heat Exchanger, 301b user side heat exchanger, 301c user side heat exchanger , 301d Use side heat exchanger, 302 expansion device, 302a expansion device, 302b expansion device, 302c expansion device, 302d expansion device, 303 first interruption device, 303a first interruption device, 303b first interruption device, 303c first interruption Device 303d first blocking device 304 second blocking device 304a second blocking device 304b second blocking device 304c second blocking device 304d second blocking device 305 concentration detection device 306 temperature sensor 307 temperature sensor , 308 Pressure sensor, 400 piping, 400a piping, 400b piping, A refrigerant circulation circuit, B heat medium circulation circuit.

An air conditioner according to the present invention includes at least a compressor and a heat source side heat exchanger in an outdoor unit, and includes at least an expansion device and a use side heat exchanger in the indoor unit, the compressor, the heat source side An air conditioner in which a heat exchanger, the expansion device, and the use side heat exchanger are connected by piping and a refrigerant circuit in which a heat source side refrigerant that transitions to a supercritical state circulates is formed, Based on the information from the concentration detection device provided in the installation space of the indoor unit, the concentration detection device for detecting the concentration of the refrigerant leaked from the refrigerant circuit, and provided on the refrigerant inlet / outlet side of the indoor unit And a shut-off device that shuts off the circulation of the heat-source-side refrigerant. The shut-off device uses a DC power supply as its electrical part, and is open when energized and closed when not energized.

An air conditioner according to the present invention includes at least a compressor and a heat source side heat exchanger in an outdoor unit, and includes at least a heat exchanger related to heat medium, a throttling device, and a pump in a heat medium converter, and uses at least A side heat exchanger is provided in the indoor unit, and the compressor, the heat source side heat exchanger, the expansion device, and the refrigerant side flow path of the heat exchanger related to heat medium are piped in series to be in a supercritical state. The refrigerant circulation circuit in which the transitioning heat source side refrigerant circulates, the heat medium side flow path of the heat exchanger related to heat medium, the pump, and the use side heat exchanger are connected in series to circulate the heat medium. An air conditioner in which a heat medium circulation circuit is formed, and is provided in the heat medium converter or in an installation space of the heat medium converter, and detects a concentration of refrigerant leaked from the refrigerant circuit. a concentration detection device, refrigerant in the heat medium relay unit Provided on the inlet side, has a blocking device for blocking the circulation of the heat-source side refrigerant on the basis of information from the said concentration detecting device, the blocking device, the electrical unit is a DC power source drive, at the time of energization opening Closed when the power is off.

Claims (12)

The outdoor unit includes at least a compressor and a heat source side heat exchanger,
At least the expansion device and the use side heat exchanger are provided in the indoor unit,
An air conditioner in which the compressor, the heat source side heat exchanger, the expansion device, and the use side heat exchanger are connected by piping, and a refrigerant circuit in which a heat source side refrigerant that transitions to a supercritical state circulates is formed. There,
A concentration detecting device that is provided in the indoor unit or in the installation space of the indoor unit and detects the concentration of refrigerant leaked from the refrigerant circuit;
An air conditioner, comprising: a shut-off device that is provided on an entrance / exit side inside the indoor unit and blocks the circulation of the heat source-side refrigerant based on information from the concentration detection device. The outdoor unit includes at least a compressor and a heat source side heat exchanger,
At least a heat exchanger between heat media, a throttling device, and a pump are provided in the heat medium converter,
At least use side heat exchanger in the indoor unit,
Refrigerant circulation in which a refrigerant side flow path of the compressor, the heat source side heat exchanger, the expansion device, and the heat exchanger related to heat medium is connected in series, and the heat source side refrigerant that transitions to a supercritical state circulates. Circuit,
An air conditioner in which a heat medium side flow path, the pump, and the use side heat exchanger of the inter-heat medium heat exchanger are connected in series to form a heat medium circulation circuit in which the heat medium circulates. Because
A concentration detector provided in the heat medium converter or in an installation space of the heat medium converter to detect the concentration of the refrigerant leaked from the refrigerant circuit;
An air conditioner, comprising: a shut-off device that is provided on an inlet / outlet side in the heat medium converter and shuts off circulation of a heat source side refrigerant based on information from the concentration detection device. . The blocking device is
The air conditioner according to claim 1 or 2, wherein the air conditioner is in an open state when energized and in a closed state when not energized. The blocking device is
4. The air conditioner according to claim 3, wherein energization is turned off when the concentration of the heat-source-side refrigerant detected by the concentration detection device exceeds a predetermined concentration. The air conditioner according to claim 4, wherein the predetermined concentration is set to be less than a leakage limit concentration of the heat source side refrigerant. The blocking device is
The air conditioner according to any one of claims 1 to 5, wherein the electric part is driven by a DC power source. The blocking device is
The air conditioner according to claim 6, further comprising a stepping motor as the electrical unit. The air conditioner according to any one of claims 1 to 7, wherein a leakage amount of the heat source side refrigerant from the shut-off device is set to 3.0 x 10 ^-9 [m ³ / sec] or less. . The CV value of the shut-off device installed on the high-pressure side during cooling operation among the shut-off devices is 1 or more, and the CV value of the shut-off device installed on the low-pressure side is 5 or more. The air conditioning apparatus as described in any one of. The minimum operating pressure difference of the shut-off device is
It is set as 0 [kgf / cm < ² >] vicinity. The air conditioning apparatus as described in any one of Claims 1-9 characterized by the above-mentioned. The blocking device is
The air conditioner according to any one of claims 1 to 10, wherein a bidirectional flow of the heat source side refrigerant is possible. The concentration detector is
The air conditioner according to any one of claims 1 to 11, wherein power is supplied from a commercial power source or a battery.

Images