WO2019155614A1

WO2019155614A1 - Air-conditioning device, air-conditioning system, and heat exchange unit

Info

Publication number: WO2019155614A1
Application number: PCT/JP2018/004650
Authority: WO
Inventors: 麻里夫佐藤
Original assignee: 三菱電機株式会社
Priority date: 2018-02-09
Filing date: 2018-02-09
Publication date: 2019-08-15
Also published as: JPWO2019155614A1; JP6903173B2

Abstract

An air-conditioning device comprising: a heat medium circuit (12) in which a heat medium flows, and in which a pump (25), a cascade heat exchanger (24), and a usage-side heat exchanger (26) for exchanging heat between a heat medium and air flowing in an air-conditioned space are connected by means of heat medium piping; a heat medium bypass circuit (13) in which the heat medium flowing from the usage-side heat exchanger flows; and a heat medium bypass heat exchanger (31) that is provided in the heat medium bypass circuit, and that exchanges heat between the heat medium and outside air supplied to the air-conditioned space.

Description

Air conditioner, air conditioning system, and heat exchange unit

The present invention relates to an air conditioner, an air conditioning system, and a heat exchange unit that adjust air in an air-conditioned space.

Conventionally, an air conditioning system including an air conditioner that adjusts air in an air-conditioned space and a ventilator that ventilates the air-conditioned space is known. Patent Document 1 discloses an air conditioner provided with a refrigerant circuit through which refrigerant flows, a brine circuit through which brine flows, and a ventilation device. In Patent Document 1, heat is exchanged between the return air discharged from the air-conditioned space and exhausted to the non-air-conditioned space, and the refrigerant is recovered. Further, Patent Document 1 includes a heat exchanger that exchanges heat between the brine flowing in the brine circuit and the outside air supplied to the air-conditioned space and the return air. In the conventional air conditioning system, the air conditioner and the ventilator are separate devices and perform separate controls.

JP-A-9-243110

The air conditioner disclosed in Patent Document 1 includes a heat exchanger that exchanges heat between the brine flowing in the brine circuit and the outside air supplied to the air-conditioned space and the return air. Thus, in an air conditioner used for ventilation, it is desired to recover and utilize the exhaust heat of the heat medium flowing in the heat medium circuit.

The present invention has been made to solve the above-described problems, and provides an air conditioner, an air conditioning system, and a heat exchange unit that recover exhaust heat of a heat medium flowing in a heat medium circuit.

The air conditioner according to the present invention includes a pump, a cascade heat exchanger, and a heat medium circuit in which a heat exchanger pipe is connected to a use side heat exchanger that exchanges heat between the air flowing in the air-conditioned space and the heat medium. A heat medium bypass circuit through which a heat medium flowing out from the use side heat exchanger flows, and a heat medium bypass heat exchanger provided in the heat medium bypass circuit for exchanging heat between the outside air supplied to the air-conditioned space and the heat medium .

According to the present invention, in the heat medium bypass circuit provided on the downstream side of the use side heat exchanger, the heat medium after the heat medium bypass heat exchanger is heat-exchanged by the use side heat exchanger, and the conditioned space Heat exchange with the outside air supplied to the. Thus, the exhaust heat of the heat medium after heat exchange is performed by the use side heat exchanger can be recovered, and the recovered exhaust heat can be used for supplying air to the air-conditioned space.

It is a schematic diagram which shows the air conditioning system 1 which concerns on Embodiment 1 of this invention. It is a circuit diagram which shows the air conditioning system 1 which concerns on Embodiment 1 of this invention. It is a circuit diagram which shows the air conditioning system 1 which concerns on a modification. It is a block diagram which shows the control part 50 which concerns on Embodiment 1 of this invention. It is a table | surface which shows control of the heat medium flow control valve 32 and the refrigerant | coolant flow control valve 34 of the air conditioning system 1 which concerns on Embodiment 1 of this invention. It is a circuit diagram which shows the air conditioning system 1 which concerns on Embodiment 2 of this invention. It is a table | surface which shows control of the heat medium flow control valve 32 and the refrigerant | coolant flow control valve 34 of the air conditioning system 1 which concerns on Embodiment 2 of this invention. It is a table | surface which shows control of the air conditioning system 1 which concerns on Embodiment 3 of this invention. It is a table | surface which shows control of the heat medium flow control valve 32 of the air conditioning system 1 which concerns on Embodiment 3 of this invention. It is a circuit diagram which shows the air conditioning system 100 which concerns on Embodiment 4 of this invention. It is a table | surface which shows control of the heat medium flow control valve 32 and the refrigerant | coolant flow control valve 34 of the air conditioning system 100 which concerns on Embodiment 4 of this invention. It is a table | surface which shows control of the heat medium flow control valve 32 of the air conditioning system 100 which concerns on Embodiment 4 of this invention.

Embodiment 1 FIG.
Hereinafter, embodiments of an air conditioner, an air conditioning system, and a heat exchange unit according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an air conditioning system 1 according to Embodiment 1 of the present invention. As shown in FIG. 1, the air conditioning system 1 includes an air conditioner 2 that adjusts air in an air conditioned space 8, a ventilator 6 that ventilates the air conditioned space 8, and a control unit that controls the air conditioner 2 and the ventilator 6. 50. The air conditioner 2 includes, for example, a heat source unit 4 provided in a non-air-conditioned space 9 that is outdoor, a heat exchange unit 3 provided in a ceiling space 10, and a use-side unit 5 that cools or heats the air-conditioned space 8. And.

(Air conditioning device 2)
FIG. 2 is a circuit diagram showing the air conditioning system 1 according to Embodiment 1 of the present invention. As shown in FIG. 2, the heat source unit 4 includes a compressor 21, a flow path switching device 20, a heat source heat exchanger 22, a heat source blower 22 a, and an outside air temperature detection unit 55, and the heat exchange unit 3 Supply the refrigerant. The compressor 21 sucks the refrigerant in a low temperature and low pressure state, compresses the sucked refrigerant, and discharges it as a refrigerant in a high temperature and high pressure state. The flow path switching device 20 switches whether the refrigerant discharged from the compressor 21 flows into the heat source heat exchanger 22 (solid line in FIG. 2) or the cascade heat exchanger 24 (broken line in FIG. 2). Thereby, both the cooling operation and the heating operation are performed in the air conditioner 2. The heat source heat exchanger 22 exchanges heat, for example, between the outside air and the refrigerant. The heat source heat exchanger 22 acts as a condenser during the cooling operation, and acts as an evaporator during the heating operation. The heat source blower 22 a sends outdoor air to the heat source heat exchanger 22. The outside air temperature detection unit 55 detects the temperature of outside air.

The use side unit 5 includes a use side heat exchanger 26 and a use side blower 26a, and adjusts the air in the air-conditioned space 8 by the heat medium supplied from the heat exchange unit 3. The use side heat exchanger 26 exchanges heat between, for example, room air and a heat medium. The use side heat exchanger 26 acts as an evaporator during the cooling operation, and acts as a condenser during the heating operation. The use side blower 26 a sends room air to the use side heat exchanger 26.

The heat exchange unit 3 is connected to the heat source unit 4 at the refrigerant piping port 11a, and is connected to the use side unit 5 at the heat medium piping port 12a. The heat exchange unit 3 includes a pump 25, a cascade heat exchanger 24, an expansion unit 23, a heat medium bypass circuit 13, and a heat medium flow rate adjustment valve 32. Note that the expansion unit 23 may be provided in the heat source unit 4. Further, the pump 25 may be provided in a pump unit different from the heat exchange unit 3. The heat exchange unit 3 includes a refrigerant bypass circuit 14, a refrigerant flow rate adjustment valve 34, a heat medium temperature detection unit 51, and a refrigerant temperature detection unit 52.

The pump 25 conveys the heat medium. The cascade heat exchanger 24 exchanges heat between the refrigerant and the heat medium. The expansion part 23 is a pressure reducing valve or an expansion valve that expands by depressurizing the refrigerant, and is composed of, for example, an electronic expansion valve whose opening degree is adjusted. The heat medium bypass circuit 13 bypasses the heat medium pipe between the cascade heat exchanger 24 and the pump 25, and a part of the heat medium conveyed from the pump 25 flows. The heat medium flow control valve 32 is provided in the heat medium circuit 12 and adjusts the flow rate of the heat medium flowing into the cascade heat exchanger 24. The heat medium temperature detection unit 51 is provided in the heat medium circuit 12 and detects the temperature of the heat medium conveyed from the pump 25.

The refrigerant bypass circuit 14 bypasses the refrigerant pipe between the cascade heat exchanger 24 and the compressor 21, and a part of the refrigerant flowing out of the cascade heat exchanger 24 flows. The refrigerant flow rate adjustment valve 34 is provided in the refrigerant circuit 11 and adjusts the flow rate of the refrigerant flowing out of the cascade heat exchanger 24. The refrigerant temperature detector 52 is provided in the refrigerant circuit 11 and detects the temperature of the refrigerant flowing out of the cascade heat exchanger 24. In the first embodiment, the refrigerant temperature detection unit 52 includes a cooling sensor 52a and a heating sensor 52b. The cooling sensor 52a is provided between the heat source heat exchanger 22 and the refrigerant flow rate adjustment valve 34, and is used for control during cooling operation. The heating sensor 52b is provided between the expansion portion 23 and the refrigerant flow rate adjustment valve 34, and is used for control during heating operation. Thus, it is preferable that the refrigerant temperature detector 52 is provided upstream of the refrigerant bypass circuit 14 in each of the cooling operation and the heating operation. In addition, the refrigerant temperature detection part 52 is good also as one.

Here, the compressor 21, the heat source heat exchanger 22, the expansion unit 23, and the cascade heat exchanger 24 are connected by a refrigerant pipe to constitute the refrigerant circuit 11. In addition, the heat medium circuit 12 is configured by connecting the pump 25, the cascade heat exchanger 24, and the use side heat exchanger 26 through a heat medium pipe.

(Ventilation device 6)
The ventilation device 6 ventilates the air-conditioned space 8, and includes a casing 41, a total heat exchanger 42, an air supply fan 43, an exhaust fan 44, an air supply temperature detection unit 53, and an exhaust temperature detection unit. 54, a heat medium bypass heat exchanger 31, and a refrigerant bypass heat exchanger 33. The casing 41 includes an outside air port 45 for taking in outside air, an air supply port 46 for taking outside air taken in from the outside air port 45 into the air-conditioned space 8, a return air port 47 for discharging air from the air-conditioned space 8, and a return air port An exhaust port 48 for exhausting the air discharged from 47 to the air-conditioned space 8 is formed.

The total heat exchanger 42 is provided in the casing 41 and exchanges heat between the return air and the outside air. The air supply fan 43 takes in outside air from the outside air port 45 and sends outside air from the air supply port 46 to the air-conditioned space 8. The exhaust fan 44 takes in air in the air-conditioned space 8 from the return air port 47 and discharges air from the exhaust port 48 to the non-air-conditioned space 9. The supply air temperature detector 53 detects the supply air temperature to the air-conditioned space 8. The exhaust temperature detector 54 detects the exhaust temperature from the air-conditioned space 8. The heat medium bypass heat exchanger 31 is provided in the heat medium bypass circuit 13 and exchanges heat between the outside air supplied to the conditioned space 8 and the heat medium. The refrigerant bypass heat exchanger 33 is provided in the refrigerant bypass circuit 14 and exchanges heat between the return air discharged from the air-conditioned space 8 and exhausted into the non-air-conditioned space 9 and the refrigerant.

When the heat medium flow control valve 32 is opened, the heat medium conveyed from the pump 25 passes through the heat medium circuit 12 and flows into the cascade heat exchanger 24, and the heat medium passes through the heat medium bypass circuit 13. Branches to the heat medium flowing into the bypass heat exchanger 31. On the other hand, when the heat medium flow control valve 32 is closed, the heat medium conveyed from the pump 25 does not pass through the portion of the heat medium circuit 12 where the heat medium flow control valve 32 is provided, and passes through the heat medium bypass circuit 13. And flows into the heat medium bypass heat exchanger 31.

In the first embodiment, the heat medium is configured to flow into the heat medium bypass circuit 13 regardless of whether the heat medium flow control valve 32 is opened or closed. However, the present invention is not limited to this. For example, it is possible to select whether the heat medium flows only to the heat medium circuit 12 or only to the heat medium bypass circuit 13 by providing the heat medium flow control valve 32 in both the heat medium circuit 12 and the heat medium bypass circuit 13. May be. The heat medium may be water or brine.

When the refrigerant flow rate adjustment valve 34 is opened, the refrigerant that has flowed out of the expansion unit 23 passes through the refrigerant circuit 11 and flows into the heat source heat exchanger 22, and passes through the refrigerant bypass circuit 14 to the refrigerant bypass heat exchanger 33. Branches to incoming refrigerant. On the other hand, when the refrigerant flow rate adjustment valve 34 is closed, the refrigerant that has flowed out of the expansion portion 23 does not pass through the portion of the refrigerant circuit 11 where the refrigerant flow rate adjustment valve 34 is provided, but passes through the refrigerant bypass circuit 14 and passes through the refrigerant bypass heat. It flows into the exchanger 33.

In the first embodiment, the refrigerant is configured to flow into the refrigerant bypass circuit 14 regardless of whether the refrigerant flow rate adjustment valve 34 is opened or closed. However, the present invention is not limited to this. For example, the refrigerant flow rate adjustment valve 34 may be provided in either the refrigerant circuit 11 or the refrigerant bypass circuit 14, so that whether the refrigerant flows only in the refrigerant circuit 11 or only in the refrigerant bypass circuit 14 may be selected.

FIG. 3 is a circuit diagram showing an air conditioning system 1 according to a modification. In the modification, as shown in FIG. 3, the heat medium flow control valve 32 includes a three-way valve 32a and a three-way valve 32b. The three-way valve 32 a is provided at a connection location between the outlet side of the pump 25 and the heat medium bypass circuit 13 and switches whether the heat medium flows into the heat medium bypass circuit 13. The three-way valve 32 b is provided at a connection location between the heat medium bypass circuit 13 and the inlet side of the cascade heat exchanger 24. By switching the three-way valve 32a and the three-way valve 32b, it can be uniquely determined whether or not the heat medium flows into the heat medium bypass circuit 13.

The refrigerant flow rate adjustment valve 34 includes a three-way valve 34a and a three-way valve 34b. The three-way valve 34 a is provided at a connection location between the expansion portion 23 and the refrigerant bypass circuit 14 and switches whether the refrigerant flows to the refrigerant bypass circuit 14. The three-way valve 34b is provided at a connection point between the refrigerant bypass circuit 14 and the outlet side of the heat source heat exchanger 22 during cooling. By switching the three-way valve 34a and the three-way valve 34b, it can be uniquely determined whether or not the refrigerant flows into the refrigerant bypass circuit 14.

(Operation of the air conditioner 2)
Next, the operation of the air conditioner 2 will be described. In the first embodiment, the air conditioner 2 performs a cooling operation. First, the flow of the refrigerant in the refrigerant circuit 11 will be described. In the cooling operation, the refrigerant sucked into the compressor 21 is compressed by the compressor 21 and discharged in a high-temperature and high-pressure gas state. The high-temperature and high-pressure gaseous refrigerant discharged from the compressor 21 passes through the flow path switching device 20 and flows into the heat source heat exchanger 22 acting as a condenser, and in the heat source heat exchanger 22, the heat source blower 22a. Heat is exchanged with the outside air sent by the air to condense and liquefy. The condensed refrigerant in the liquid state flows into the expansion section 23 and is expanded and decompressed in the expansion section 23 to become a low-temperature and low-pressure gas-liquid two-phase refrigerant.

The gas-liquid two-phase refrigerant flows into the cascade heat exchanger 24 acting as an evaporator, and in the cascade heat exchanger 24, heat is exchanged with the heat medium to evaporate and gasify. At this time, the heat medium is cooled. The evaporated low-temperature and low-pressure gaseous refrigerant passes through the flow path switching device 20 and is sucked into the compressor 21. Here, a part of the refrigerant flowing out of the heat source heat exchanger 22 flows into the refrigerant bypass circuit 14 and reaches the refrigerant bypass heat exchanger 33. The refrigerant exchanges heat with the exhaust gas in the refrigerant bypass heat exchanger 33 and returns to the refrigerant circuit 11 again. As shown in FIG. 3, when the refrigerant flow rate adjustment valve 34 includes a three-way valve 34 a and a three-way valve 34 b, the refrigerant can be controlled so as not to flow into the refrigerant bypass circuit 14.

Next, the flow of the heat medium in the heat medium circuit 12 will be described. The heat medium transported to the pump 25 flows into the cascade heat exchanger 24, and is cooled by heat exchange with the refrigerant in the cascade heat exchanger 24. The heat medium flowing out from the cascade heat exchanger 24 flows into the use side heat exchanger 26, and heat is exchanged with the air in the air-conditioned space 8 sent by the use side blower 26a in the use side heat exchanger 26 and heated. . At this time, the air in the conditioned space 8 is cooled to perform cooling. The heat medium flowing out from the use side heat exchanger 26 is sucked into the pump 25. Here, a part of the heat medium conveyed to the pump 25 flows into the heat medium bypass circuit 13 and reaches the heat medium bypass heat exchanger 31. The heat medium is heat-exchanged with the supply air in the heat medium bypass heat exchanger 31 and returns to the heat medium circuit 12 again. As shown in FIG. 3, when the heat medium flow control valve 32 includes a three-way valve 32 a and a three-way valve 32 b, the heat medium can be controlled so as not to flow into the heat medium bypass circuit 13.

(Operation of ventilation device 6)
Next, the operation of the ventilation device 6 will be described. When the air supply fan 43 operates, outside air is taken in from the outside air port 45 and is supplied to the air-conditioned space 8 from the air supply port 46 via the total heat exchanger 42 and the heat medium bypass heat exchanger 31. When the exhaust fan 44 operates, the air in the air-conditioned space 8 is taken in from the return air port 47 and is exhausted from the exhaust port 48 to the non-air-conditioned space 9 through the total heat exchanger 42 and the refrigerant bypass heat exchanger 33. The outside air and the return air are heat-exchanged in the total heat exchanger 42, and are supplied and exhausted, respectively.

(Control unit 50)
FIG. 4 is a block diagram showing the control unit 50 according to Embodiment 1 of the present invention. The control part 50 controls operation | movement of the air conditioning system 1, and is comprised by the microcomputer etc., for example. The control unit 50 performs control for interlocking the air conditioner 2 and the ventilator 6. As shown in FIG. 2, the control unit 50 includes a determination unit 61 and a valve adjustment unit 62.

(Control of heat medium flow control valve 32)
FIG. 5 is a table showing control of the heat medium flow rate adjustment valve 32 and the refrigerant flow rate adjustment valve 34 of the air conditioning system 1 according to Embodiment 1 of the present invention. First, the interlock control between the heat medium circuit 12 of the air conditioner 2 and the supply side of the ventilation device 6 will be described. As shown in FIG. 5, the determination unit 61 determines whether the heat medium temperature detected by the heat medium temperature detection unit 51 is lower than the supply air temperature detected by the supply air temperature detection unit 53 during the cooling operation. . When the determination unit 61 determines that the heat medium temperature is lower than the supply air temperature, the valve adjustment unit 62 closes the heat medium flow rate adjustment valve 32. Thereby, all of the heat medium flowing through the heat medium circuit 12 flows through the heat medium bypass circuit 13. Accordingly, since the amount of heat that moves from the supply air to the heat medium increases, the temperature of the air supplied from the supply port 46 to the air-conditioned space 8 in the ventilation device 6 can be lowered.

Further, when the heat medium temperature detected by the heat medium temperature detection unit 51 is equal to or higher than the supply air temperature detected by the supply air temperature detection unit 53 during the cooling operation, the valve adjustment unit 62 is the heat medium flow rate adjustment valve 32. open. Thereby, a part of the heat medium flowing in the heat medium circuit 12 flows to the heat medium bypass circuit 13, and the remaining part does not flow to the heat medium bypass circuit 13. Accordingly, since the amount of heat transferred from the heat medium to the supply air is reduced, it is possible to prevent the temperature of the air supplied from the supply port 46 to the air-conditioned space 8 in the ventilation device 6 from increasing. When the three-way valve 32a and the three-way valve 32b are used instead of the heat medium flow control valve 32, the heat medium can be controlled so as not to flow into the heat medium bypass circuit 13, so that the heat medium moves from the supply air to the supply air. The amount of heat to be generated can be further reduced.

(Control of refrigerant flow rate adjustment valve 34)
Interlocking control between the refrigerant circuit 11 of the air conditioner 2 and the exhaust side of the ventilation device 6 will be described. As shown in FIG. 5, the determination unit 61 determines whether the refrigerant temperature detected by the cooling sensor 52 a is higher than the exhaust temperature detected by the exhaust temperature detection unit 54 during the cooling operation. When the determination unit 61 determines that the refrigerant temperature is higher than the exhaust gas temperature, the valve adjustment unit 62 closes the refrigerant flow rate adjustment valve 34. As a result, all of the refrigerant flowing through the refrigerant circuit 11 flows through the refrigerant bypass circuit 14. Accordingly, the amount of warm heat that moves from the refrigerant to the exhaust increases, so that it can be supercooled. Further, the valve adjusting means 62 opens the refrigerant flow rate adjusting valve 34 when the refrigerant temperature detected by the cooling sensor 52a is equal to or lower than the exhaust temperature detected by the exhaust temperature detecting unit 54 during the cooling operation. Thereby, a part of the refrigerant flowing in the refrigerant circuit 11 flows into the refrigerant bypass circuit 14, and the remaining part does not flow into the refrigerant bypass circuit 14. Accordingly, since the amount of heat transferred from the exhaust to the refrigerant is reduced, the degree of supercooling can be maintained. When the three-way valve 34a and the three-way valve 34b are used instead of the refrigerant flow rate adjustment valve 34, control can be performed so that the refrigerant does not flow to the refrigerant bypass circuit 14, and thus the amount of heat transferred from the exhaust to the refrigerant can be reduced. Further reduction can be achieved.

According to the first embodiment, after the heat medium bypass heat exchanger 31 is heat-exchanged by the use-side heat exchanger 26 in the heat medium bypass circuit 13 provided on the downstream side of the use-side heat exchanger 26. The heat medium is exchanged with the outside air supplied to the air-conditioned space 8. Thus, this Embodiment 1 collect | recovers the exhaust heat of the heat medium after heat-exchange with the utilization side heat exchanger 26, and utilizes the collect | recovered exhaust heat for the air supply to the air-conditioning space 8 Can do. In addition, the heat medium bypass heat exchanger 31 exchanges heat between the heat medium flowing into the cascade heat exchanger 24 and the outside air supplied to the air-conditioned space 8, so that cool air is supplied to the supply air during the cooling operation. The cooling operation of the refrigerant circuit 11 can be assisted. Thus, the comfort of the air-conditioned space 8 after the supply of air can be improved by exhaust heat recovery.

When the refrigerant circuit 11, the refrigerant bypass circuit 14, and the refrigerant bypass heat exchanger 33 are provided as in the first embodiment, the refrigerant bypass heat exchanger 33 is exhausted to the non-air-conditioned space 9. Heat exchange is performed between the return air and the refrigerant that has been heat-exchanged by the heat source heat exchanger 22. Thus, Embodiment 1 can recover the exhaust heat of the air exhausted into the non-air-conditioned space 9 and use the exhaust heat in the refrigeration cycle of the refrigerant circuit 11.

The valve adjusting means 62 closes the heat medium flow rate adjusting valve 32 when it is determined that the heat medium temperature is lower than the supply air temperature during the cooling operation. Thereby, all of the heat medium flowing through the heat medium circuit 12 flows through the heat medium bypass circuit 13. Accordingly, since the amount of heat that moves from the supply air to the heat medium increases, the temperature of the air supplied from the supply port 46 to the air-conditioned space 8 in the ventilation device 6 can be lowered. Further, the valve adjustment means 62 closes the refrigerant flow rate adjustment valve 34 when it is determined that the refrigerant temperature is higher than the exhaust temperature during the cooling operation. As a result, all of the refrigerant flowing through the refrigerant circuit 11 flows through the refrigerant bypass circuit 14. Accordingly, the amount of warm heat that moves from the refrigerant to the exhaust increases, so that it can be supercooled.

Conventionally, there is no ventilator having a total heat exchanger that recovers exhaust heat of exhaust gas after heat exchange in the total heat exchanger. On the other hand, in this Embodiment 1, the exhaust heat of the exhaust after heat-exchange in the total heat exchanger 42 is utilized for an air conditioning. In the first embodiment, the space that is conditioned by the air conditioner 2 and the space that is supplied and exhausted by the ventilation device 6 are the same space, but may be different spaces. In the case of another space, the same effect as in the first embodiment is obtained when each of the spaces is warmed or cooled.

Embodiment 2. FIG.
FIG. 6 is a circuit diagram showing an air conditioning system 1 according to Embodiment 2 of the present invention. The second embodiment exemplifies the case where the heating operation is performed, and the circuit diagram of the second embodiment is the same as the circuit diagram of the first embodiment.

(Operation of the air conditioner 2)
Next, the operation of the air conditioner 2 will be described. In the second embodiment, the air conditioner 2 performs a heating operation. First, the flow of the refrigerant in the refrigerant circuit 11 will be described. The refrigerant sucked into the compressor 21 is compressed by the compressor 21 and discharged in a high-temperature and high-pressure gas state. The high-temperature and high-pressure gas refrigerant discharged from the compressor 21 passes through the flow path switching device 20 and flows into the cascade heat exchanger 24 that acts as a condenser. Heat exchanges to condense and liquefy.

The condensed liquid refrigerant flows into the expansion section 23 and is expanded and decompressed in the expansion section 23 to become a low-temperature and low-pressure gas-liquid two-phase refrigerant. Then, the gas-liquid two-phase refrigerant flows into the heat source heat exchanger 22 acting as an evaporator, and in the heat source heat exchanger 22, heat is exchanged with the outside air sent by the heat source blower 22a to evaporate and gasify. . The evaporated low-temperature and low-pressure gaseous refrigerant passes through the flow path switching device 20 and is sucked into the compressor 21. Here, a part of the refrigerant discharged from the compressor 21 flows into the refrigerant bypass circuit 14 and reaches the refrigerant bypass heat exchanger 33. The refrigerant exchanges heat with the exhaust gas in the refrigerant bypass heat exchanger 33 and returns to the refrigerant circuit 11 again. As shown in FIG. 3, when the refrigerant flow rate adjustment valve 34 includes a three-way valve 34 a and a three-way valve 34 b, the refrigerant can be controlled so as not to flow into the refrigerant bypass circuit 14.

Next, the flow of the heat medium in the heat medium circuit 12 will be described. The heat medium conveyed to the pump 25 flows into the cascade heat exchanger 24, and heat is exchanged with the refrigerant in the cascade heat exchanger 24 to be heated. The heat medium that has flowed out of the cascade heat exchanger 24 flows into the use side heat exchanger 26, and in the use side heat exchanger 26, heat is exchanged with the air in the air-conditioned space 8 sent by the use side blower 26a to be cooled. . At this time, the air in the air-conditioned space 8 is heated to perform heating. The heat medium flowing out from the use side heat exchanger 26 is sucked into the pump 25. Here, a part of the heat medium conveyed to the pump 25 flows into the heat medium bypass circuit 13 and reaches the heat medium bypass heat exchanger 31. The heat medium is heat-exchanged with the supply air in the heat medium bypass heat exchanger 31 and returns to the heat medium circuit 12 again. As shown in FIG. 3, when the heat medium flow control valve 32 includes a three-way valve 32 a and a three-way valve 32 b, the heat medium can be controlled so as not to flow into the heat medium bypass circuit 13.

(Control of heat medium flow control valve 32)
FIG. 7 is a table showing control of the heat medium flow rate adjustment valve 32 and the refrigerant flow rate adjustment valve 34 of the air conditioning system 1 according to Embodiment 2 of the present invention. Next, control of the heat medium flow control valve 32 will be described. As shown in FIG. 7, the determination unit 61 determines whether the heat medium temperature detected by the heat medium temperature detection unit 51 is higher than the supply air temperature detected by the supply air temperature detection unit 53 during the heating operation. . When the determination unit 61 determines that the heat medium temperature is higher than the supply air temperature, the valve adjustment unit 62 closes the heat medium flow rate adjustment valve 32. Thereby, all of the heat medium flowing through the heat medium circuit 12 flows through the heat medium bypass circuit 13. Therefore, since the amount of heat that moves from the heat medium to the supply air increases, the temperature of the air supplied from the supply port 46 to the conditioned space 8 can be increased.

Further, when the heating medium temperature detected by the heating medium temperature detection unit 51 is equal to or lower than the supply air temperature detected by the supply air temperature detection unit 53 during the heating operation, the valve adjustment unit 62 heats the heat medium flow rate adjustment valve 32. open. Thereby, a part of the heat medium flowing in the heat medium circuit 12 flows to the heat medium bypass circuit 13, and the remaining part does not flow to the heat medium bypass circuit 13. Accordingly, since the amount of heat transferred from the supply air to the heat medium is reduced, the temperature of the air supplied from the supply port 46 to the air-conditioned space 8 in the ventilation device 6 can be suppressed.

(Control of refrigerant flow rate adjustment valve 34)
Next, control of the refrigerant flow rate adjustment valve 34 will be described. The determination unit 61 determines whether the refrigerant temperature detected by the heating sensor 52b is lower than the exhaust temperature detected by the exhaust temperature detection unit 54 during the heating operation. When the determination unit 61 determines that the refrigerant temperature is lower than the exhaust gas temperature, the valve adjustment unit 62 closes the refrigerant flow rate adjustment valve 34. As a result, all of the refrigerant flowing through the refrigerant circuit 11 flows through the refrigerant bypass circuit 14. Accordingly, since the amount of warm heat that moves from the exhaust to the refrigerant increases, evaporation can be assisted. Moreover, the rotation speed of the heat source blower 22a can also be reduced. Further, the valve adjusting means 62 opens the refrigerant flow rate adjusting valve 34 when the refrigerant temperature detected by the heating sensor 52b is equal to or higher than the exhaust temperature detected by the exhaust temperature detecting unit 54 during the heating operation. Thereby, a part of the refrigerant flowing in the refrigerant circuit 11 flows into the refrigerant bypass circuit 14, and the remaining part does not flow into the refrigerant bypass circuit 14. Therefore, the amount of warm heat moving from the refrigerant to the exhaust is reduced, so that the degree of superheat can be maintained.

The heat medium bypass heat exchanger 31 exchanges heat between the heat medium flowing into the cascade heat exchanger 24 and the outside air supplied to the air-conditioned space 8, so that hot air is supplied to the supply air during the heating operation. The heating operation of the circuit 11 can be assisted. Thus, the comfort of the air-conditioned space 8 after the supply of air can be improved by exhaust heat recovery.

When the heating medium temperature is determined to be higher than the supply air temperature during the heating operation, the valve adjustment unit 62 closes the heating medium flow rate adjustment valve 32. Thereby, all of the heat medium flowing through the heat medium circuit 12 flows through the heat medium bypass circuit 13. Therefore, since the amount of heat that moves from the heat medium to the supply air increases, the temperature of the air supplied from the supply port 46 to the conditioned space 8 can be increased. Further, the valve adjustment means 62 closes the refrigerant flow rate adjustment valve 34 when it is determined that the refrigerant temperature is lower than the exhaust temperature during the heating operation. As a result, all of the refrigerant flowing through the refrigerant circuit 11 flows through the refrigerant bypass circuit 14. Accordingly, since the amount of warm heat that moves from the exhaust to the refrigerant increases, evaporation can be assisted.

Embodiment 3 FIG.
FIG. 8 is a table showing control of the air conditioning system 1 according to Embodiment 3 of the present invention. The third embodiment is control in the case of performing cooling mainly under low outside air, such as cooling of a computer room in winter, and is different from the first embodiment in that control is performed based on the outside air temperature. In the third embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. The description will focus on differences from the first embodiment.

As shown in FIG. 8, the control unit 50 stops the heat source unit 4 including the compressor 21 when the temperature of the outside air detected by the outside air temperature detection unit 55 is lower than the outside air temperature threshold. At that time, the control unit 50 continues the operation of the pump 25. The heat medium conveyed by the pump 25 is cooled by the heat medium bypass heat exchanger 31 because it is heat-exchanged with the low-temperature outside air. Therefore, the air-conditioned space 8 can be cooled without operating the heat source unit 4. The control unit 50 continues the operation of the heat source unit 4 including the compressor 21 when the temperature of the outside air detected by the outside air temperature detection unit 55 is equal to or higher than the outside air temperature threshold.

FIG. 9 is a table showing control of the heat medium flow control valve 32 of the air conditioning system 1 according to Embodiment 3 of the present invention. Next, the control during the cooling operation in the low outside air as in the third embodiment will be described. As shown in FIG. 9, the determination unit 61 determines whether the heat medium temperature detected by the heat medium temperature detection unit 51 is higher than the supply air temperature detected by the supply air temperature detection unit 53 during the cooling operation. . When the determination unit 61 determines that the heat medium temperature is higher than the supply air temperature, the valve adjustment unit 62 closes the heat medium flow rate adjustment valve 32. Thereby, all of the heat medium flowing through the heat medium circuit 12 flows through the heat medium bypass circuit 13. Therefore, since the amount of warm heat that moves from the heat medium to the supply air increases, the heat medium can be cooled. Therefore, even if the compressor 21 is stopped and the cooling amount in the cascade heat exchanger 24 is reduced, the heat medium is cooled and the cooling operation can be performed. Thereby, an energy-saving driving | operation is realizable. Note that whether or not the cooling operation is possible with the compressor 21 stopped depends not only on the outside air temperature but also on the set temperature of the use side unit 5, the temperature of the return air, and the like.

Embodiment 4 FIG.
FIG. 10 is a circuit diagram showing an air conditioning system 100 according to Embodiment 4 of the present invention. The fourth embodiment is different from the first embodiment in that an air supply side drain pan 161, an exhaust side drain pan 162, a hose 163, and a vaporization filter 164 are provided. In the fourth embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. The description will focus on differences from the first embodiment.

As shown in FIG. 10, the supply-side drain pan 161 is installed below the heat medium bypass heat exchanger 31 and receives condensed water adhering to the heat medium bypass heat exchanger 31. The exhaust side drain pan 162 is installed below the refrigerant bypass heat exchanger 33 and receives condensed water adhering to the refrigerant bypass heat exchanger 33. The hose 163 connects the exhaust side drain pan 162 and the vaporization filter 164. The vaporization filter 164 is provided between the total heat exchanger 42 and the intake fan, and vaporizes moisture.

During the heating operation, the refrigerant is cooled by exchanging heat with the refrigerant in the refrigerant bypass heat exchanger 33, and moisture contained in the exhaust is condensed. The condensed water flows down from the refrigerant bypass heat exchanger 33 to the exhaust side drain pan 162. The condensed water received by the exhaust side drain pan 162 reaches the vaporization filter 164 through the hose 163. Water is vaporized by the vaporization filter 164 and taken into the supply air that has passed through the vaporization filter 164. Thereby, the air-conditioned space 8 can be humidified without requiring water supply during heating operation. For example, in a greenhouse where tropical plants and the like are cultivated, heating is performed even in summer. In such a heating application in summer, when the heat medium temperature is lower than the supply air temperature, the valve adjustment means 62 closes the heat medium flow rate adjustment valve 32 to stop the compressor 21 as in the third embodiment. However, the air-conditioned space 8 can be heated.

FIG. 11 is a table showing control of the heat medium flow rate adjustment valve 32 and the refrigerant flow rate adjustment valve 34 of the air conditioning system 100 according to Embodiment 4 of the present invention. Here, the control at the time of the humidification heating operation will be described. As shown in FIG. 11, the determination unit 61 determines whether the refrigerant temperature detected by the heating sensor 52 b is lower than the exhaust temperature detected by the exhaust temperature detection unit 54 during the heating operation. When the determination unit 61 determines that the refrigerant temperature is lower than the exhaust gas temperature, the valve adjustment unit 62 closes the refrigerant flow rate adjustment valve 34. As a result, the amount of warm heat moving from the exhaust to the refrigerant increases, so that evaporation can be assisted. Further, condensed water accumulates in the exhaust side drain pan 162, and the condensed water flows to the vaporization filter 164 through the hose 163. That is, moisture can be supplied to the vaporization filter 164.

Furthermore, the determination unit 61 determines whether the heat medium temperature detected by the heat medium temperature detection unit 51 is higher than the supply air temperature detected by the supply air temperature detection unit 53 during the heating operation. When the determination unit 61 determines that the heat medium temperature is higher than the supply air temperature, the valve adjustment unit 62 closes the heat medium flow rate adjustment valve 32. As a result, the amount of heat transferred from the heat medium to the supply air increases, so that the temperature of the air supplied from the supply port 46 to the conditioned space 8 can be increased. At that time, the air supplied to the air-conditioned space 8 from the air supply port 46 receives water from the vaporization filter 164 supplied with the moisture condensed in the refrigerant bypass heat exchanger 33. Thereby, humidified warm air can be supplied to the air-conditioned space 8.

In addition, when the exhaust temperature is considerably higher than the refrigerant temperature, the dew condensation accumulated in the exhaust side drain pan 162 increases, and the moisture content of the vaporization filter 164 increases, so that the humidification effect is further enhanced. In addition, when the heat medium temperature is considerably higher than the supply air temperature, the amount of water that the supply air receives from the vaporization filter 164 increases, so that the humidification effect is enhanced. In addition, when the moisture contained in the outside air is transferred to the return air by the total heat exchanger 42 and the relative humidity of the exhaust gas is increased, the humidification effect is further enhanced. Furthermore, when the outside air is warmed to return air by the total heat exchanger 42 and the relative humidity of the supply air is lowered, the humidification effect is further enhanced.

During the cooling operation, the supply air is cooled by heat exchange with the heat medium in the heat medium bypass heat exchanger 31, and moisture contained in the supply air is condensed. The condensed water flows down from the heat medium bypass heat exchanger 31 to the supply side drain pan 161. Thereby, it can suppress that the humidity of the air-conditioning space 8 by supply air rises at the time of air_conditionaing | cooling operation.

FIG. 12 is a table showing control of the heat medium flow control valve 32 of the air conditioning system 100 according to Embodiment 4 of the present invention. Here, the control at the time of the dehumidifying and cooling operation will be described. As illustrated in FIG. 12, the determination unit 61 determines whether the heat medium temperature detected by the heat medium temperature detection unit 51 is lower than the supply air temperature detected by the supply air temperature detection unit 53 during the cooling operation. . When the determination unit 61 determines that the heat medium temperature is lower than the supply air temperature, the valve adjustment unit 62 closes the heat medium flow rate adjustment valve 32. Thereby, all of the heat medium flowing through the heat medium circuit 12 flows through the heat medium bypass circuit 13. Accordingly, since the amount of heat that moves from the supply air to the heat medium increases, the temperature of the air supplied from the supply port 46 to the air-conditioned space 8 in the ventilation device 6 can be lowered. Here, since water condensed in the heat medium bypass heat exchanger 31 flows into the supply side drain pan 161, dehumidified cold air is sent to the air-conditioned space 8. In addition, when the outside air is cooled by the return air by the total heat exchanger 42 and the relative humidity of the supply air becomes high, the dehumidifying effect is enhanced. Further, when the supply air temperature is considerably higher than the heat medium temperature, the dehumidifying effect is enhanced.

1 air conditioning system, 2 air conditioner, 3 heat exchange unit, 4 heat source unit, 5 use side unit, 6 ventilator, 8 air conditioned space, 9 non-air conditioned space, 10 ceiling space, 11 refrigerant circuit, 11a refrigerant piping port, 12 Heat medium circuit, 12a Heat medium pipe port, 13 Heat medium bypass circuit, 14 Refrigerant bypass circuit, 20 Flow path switching device, 21 Compressor, 22 Heat source heat exchanger, 22a Heat source blower, 23 Expansion section, 24 Cascade heat exchange , 25 pump, 26 use side heat exchanger, 26a use side blower, 31 heat medium bypass heat exchanger, 32 heat medium flow control valve, 32a three way valve, 32b three way valve, 33 refrigerant bypass heat exchanger, 34 refrigerant flow rate Regulating valve, 34a three-way valve, 34b three-way valve, 41 casing, 42 total heat exchanger, 43 Air fan, 44 Exhaust fan, 45 Outside air port, 46 Air supply port, 47 Return air port, 48 Exhaust port, 50 Control unit, 51 Heat medium temperature detection unit, 52 Refrigerant temperature detection unit, 52a Cooling sensor, 52b For heating Sensor, 53 Supply air temperature detection unit, 54 Exhaust temperature detection unit, 55 Outside air temperature detection unit, 61 Determination unit, 62 Valve adjustment unit, 100 Air conditioning system, 161 Supply side drain pan, 162 Exhaust side drain pan, 163 hose, 164 Evaporation filter.

Claims

A heat medium circuit in which a heat exchanger pipe is connected to a pump, a cascade heat exchanger, and a heat exchanger that exchanges heat between the air flowing in the air-conditioned space and the heat medium;
A heat medium bypass circuit through which a heat medium flowing out from the use side heat exchanger flows;
A heat medium bypass heat exchanger provided in the heat medium bypass circuit for exchanging heat between the outside air supplied to the conditioned space and the heat medium;
An air conditioner comprising:
The air conditioning apparatus according to claim 1, further comprising a heat medium flow adjustment valve that is provided in the heat medium circuit and adjusts a flow rate of the heat medium flowing into the cascade heat exchanger.
A heat medium temperature detecting unit for detecting the temperature of the heat medium flowing into the cascade heat exchanger;
A supply air temperature detector for detecting a supply air temperature to the air-conditioned space;
The air conditioning apparatus according to claim 2, further comprising a control unit that controls the operation of the heat medium flow control valve.
The controller is
Determination means for determining whether the heat medium temperature detected by the heat medium temperature detection unit during cooling operation is lower than the supply air temperature detected by the supply air temperature detection unit;
The air conditioning apparatus according to claim 3, further comprising: a valve adjustment unit that closes the heat medium flow rate adjustment valve when the determination unit determines that the heat medium temperature is lower than the supply air temperature.
The controller is
A determination unit that determines whether the heat medium temperature detected by the heat medium temperature detection unit during heating operation is higher than the supply air temperature detected by the supply air temperature detection unit;
The air conditioner according to claim 3, further comprising: a valve adjustment unit that closes the heat medium flow rate adjustment valve when the determination unit determines that the heat medium temperature is higher than the supply air temperature.
The air conditioner according to any one of claims 1 to 5, further comprising a supply-side drain pan that receives condensed water adhering to the heat medium bypass heat exchanger.
A refrigerant circuit in which a compressor, a heat source heat exchanger, an expansion unit, and the cascade heat exchanger that exchanges heat between the refrigerant and the heat medium are connected by a refrigerant pipe, and the refrigerant flows;
A refrigerant bypass circuit that bypasses the refrigerant flowing between the expansion section and the heat source heat exchanger;
A refrigerant bypass heat exchanger provided in the refrigerant bypass circuit and configured to exchange heat between the return air exhausted from the air-conditioned space and exhausted into the non-air-conditioned space and the refrigerant. The air conditioning apparatus according to item.
The air conditioning apparatus according to claim 7, further comprising a refrigerant flow rate adjustment valve that is provided in the refrigerant circuit and adjusts a flow rate of the refrigerant flowing out of the cascade heat exchanger.
A refrigerant temperature detector for detecting a refrigerant temperature flowing out of the cascade heat exchanger;
An exhaust temperature detector for detecting an exhaust temperature from the air-conditioned space;
The air conditioning apparatus according to claim 8, further comprising a control unit that controls an operation of the refrigerant flow rate adjustment valve.
The controller is
Determination means for determining whether the refrigerant temperature detected by the refrigerant temperature detection unit is higher than the exhaust temperature detected by the exhaust temperature detection unit during cooling operation;
The air conditioning apparatus according to claim 9, further comprising: a valve adjustment unit that closes the refrigerant flow rate adjustment valve when the determination unit determines that the refrigerant temperature is higher than the exhaust temperature.
The controller is
Determination means for determining whether the refrigerant temperature detected by the refrigerant temperature detection unit is lower than the exhaust temperature detected by the exhaust temperature detection unit during heating operation;
The air conditioning apparatus according to claim 9 or 10, further comprising: a valve adjustment unit that closes the refrigerant flow rate adjustment valve when the determination unit determines that the refrigerant temperature is lower than the exhaust temperature.
An exhaust side drain pan that receives condensed water adhering to the refrigerant bypass heat exchanger;
The air conditioner according to any one of claims 7 to 11, further comprising a vaporization filter that vaporizes the condensed water accumulated in the exhaust side drain pan and humidifies the supply air.
An outside temperature detector for detecting the temperature of the outside air;
The air conditioner according to any one of claims 7 to 12, further comprising a control unit that stops the compressor when the temperature of the outside air detected by the outside air temperature detection unit is lower than an outside air temperature threshold value.
A heat medium temperature detecting unit for detecting the temperature of the heat medium flowing into the cascade heat exchanger;
An air supply temperature detection unit for detecting an air supply temperature to the air-conditioned space,
The controller is
Determination means for determining whether the heat medium temperature detected by the heat medium temperature detection unit is higher than the supply air temperature detected by the supply air temperature detection unit;
Claims dependent on claim 7 depending on claim 7, further comprising: a valve adjusting means for closing the heat medium flow rate adjusting valve when the determining means determines that the heat medium temperature is higher than the supply air temperature. 13. The air conditioning apparatus according to 13.
The air conditioner according to any one of claims 1 to 14,
An air outlet that takes in outside air, an air inlet that supplies the outside air taken in from the outside air to the air-conditioned space, a return air outlet that discharges air in the air-conditioned space, and air that is discharged from the air return An exhaust port for exhausting the air-conditioned space to the non-air-conditioned space, and a ventilation device formed to ventilate the air-conditioned space;
Air conditioning system equipped with.
The ventilator is
The air conditioning system according to claim 15, further comprising a total heat exchanger that exchanges heat between outside air taken in from the outside air port and return air discharged from the return air port.
An air conditioner having a use side heat exchanger and having a use side unit for adjusting air in an air-conditioned space,
A heat source unit having a compressor and a heat source heat exchanger;
A cascade heat exchanger that exchanges heat between the refrigerant supplied from the heat source unit and the heat medium supplied to the user side unit, an expansion unit, a pump that conveys the heat medium, and the user side heat A heat exchange unit having a heat medium bypass circuit provided with a heat medium bypass heat exchanger for exchanging heat between the heat medium that flows through the heat medium flowing out of the exchanger and is supplied to the air-conditioned space; and
An air conditioner comprising:
A heat exchange unit connected to a heat source unit having a compressor and a heat source heat exchanger, and a use side unit having a use side heat exchanger and adjusting air in an air-conditioned space,
A cascade heat exchanger that exchanges heat between the refrigerant supplied from the heat source unit and the heat medium supplied to the user side unit, an expansion unit, a pump that conveys the heat medium, and the user side heat A heat exchange unit comprising: a heat medium bypass circuit provided with a heat medium bypass heat exchanger for exchanging heat between the outside air supplied to the air-conditioned space and the heat medium through which the heat medium flowing out from the exchanger flows.