JP4647399B2 - Ventilation air conditioner - Google Patents

Description

  The present invention relates to a ventilation air conditioner in which the supply temperature of air supplied to a room is set to be relatively high, and the outside air alone or the outside air (intake air) including the room air can be dehumidified.

Conventionally, many proposals have been made on air conditioners that perform cooling and dehumidifying operation at high temperature and high humidity and heating operation at cold time. For example, in Patent Document 1, a compressor, a four-way valve, an outdoor heat exchanger, a cooling / heating throttle valve, two indoor heat exchangers, a four-way valve, and a compressor are sequentially connected, and dehumidification is performed between the two indoor heat exchangers. A refrigerant circuit in which a throttle valve and a solenoid valve are connected in parallel, a branch circuit in which two check valves are connected in opposite directions and bypass the throttle valve for cooling and heating, and two reverse valves via a solenoid valve from the discharge side of the compressor A heat pump type air conditioner comprising a dehumidifying and defrosting bypass circuit connected between stop valves is disclosed. This air conditioner opens the solenoid valve connected in parallel to perform normal cooling and heating operation, and also opens the solenoid valve of the bypass circuit so that the downstream indoor heat exchanger is dehumidified and air-cooled during cooling. The upstream indoor heat exchanger is operated as a reheater, and the outdoor heat exchanger is defrosted during heating.
A number of air conditioners having a ventilation function have been proposed. For example, Patent Document 2 discloses an all fresh air conditioner. This air conditioner includes a high temperature side refrigeration cycle having a constant speed compressor and a low temperature side refrigeration cycle having a variable speed compressor, and each of the evaporators of the indoor units in the high temperature side and low temperature side refrigeration cycles, respectively. It arrange | positions in an upstream and downstream, and is trying to cope with the fluctuation | variation of external air over a wide temperature range. That is, both refrigeration cycles are operated at a high temperature, and only the low temperature side refrigeration cycle is operated at a low temperature, and the temperature of the outside air exchanged by the evaporator is controlled to be constant.

Furthermore, an air conditioner having a plurality of compressors in one refrigerant circuit is also known. For example, in Patent Document 3, an outdoor unit provided with a heat source side heat exchanger and a first compressor and an indoor unit provided with a use side heat exchanger and a blower are connected by piping to be used with the first compressor. A multistage compression type air conditioner is disclosed in which a second compressor is provided in a refrigerant pipe connecting the side heat exchanger. Even if the refrigerant pipe connecting the outdoor unit and the indoor unit becomes long or the difference in height between the outdoor unit and the indoor unit becomes large, this air conditioner prevents the refrigerant circulation rate from decreasing and improves the air conditioning capacity. It is to secure.
However, all of the air conditioners disclosed in Patent Documents 1 to 3 are not satisfactory from the viewpoint of energy saving of the air conditioner because the air to be treated is excessively cooled.
JP-A-6-159839 JP 2001-27453 A JP-A-7-83520

On the other hand, as a conventional ventilation air conditioner with a dehumidifying function and a relatively high supply air temperature such as a replacement ventilation air conditioning system, (1) a method of processing outside air and indoor air with one air conditioner, 2) There is a method using an external air conditioner.
In the method (1), the indoor air mixed with the outside air is cooled to a dew point temperature or lower, and the reheated air is supplied into the room, and the total heat load is treated with low-temperature cold water or a refrigerant. In this method, relatively high temperature cold water cannot be used or the evaporation temperature of the refrigerant cannot be relatively high, and the high COP operation of the air conditioner is disabled. For example, it is impossible to take advantage of the original advantages of a high-temperature air supply type air conditioning system such as replacement ventilation air conditioning. Furthermore, when the sensible heat load is low at high humidity such as during the rainy season, reheating is required and heat loss occurs.
In the method (2), an outside air processing machine is separately installed, the outside air is cooled to a dew point temperature or lower with low-temperature cold water, and the outside air processing air is supplied to an air conditioner in which room air circulates. In this method, since the ratio of the heat load of the external air conditioner increases, not only does the individuality of the air conditioning system decrease, but an external air processing device needs to be installed, resulting in high costs. Further, similarly to the method (1), the heat load of the low-temperature cold water or the refrigerant is increased, and the high COP operation of the heat source device is disabled.

As described above, in the conventional ventilation air conditioner having the dehumidifying function, the total heat load is treated with the low-temperature cold water or the refrigerant in the method (1) in which the outside air and the room air are mixed in advance. It was necessary to reheat the dehumidified air during the rainy season, such as the inability to use cold water. Further, in the above method (2) of supplying the outside air treated air to the air conditioner, it is not only necessary to install an outside air treating machine, but also there is a problem that the thermal load of the low-temperature cold water or the refrigerant is large.
Accordingly, an object of the present invention is to eliminate the above-mentioned problems of the prior art, and provide an energy-saving and low-cost ventilation air conditioner that eliminates the need for a low-temperature heat source, reheat treatment of dehumidified air, and an outside air treatment machine. It is in.

In order to achieve the above-mentioned object, the ventilation air conditioner of the present invention has a main compressor, a four-way valve, a first heat exchanger, a main pressure reducing device, a second heat exchanger, and further a four-way valve and a main compressor connected in order. A refrigerant circuit, and a sub refrigerant circuit in which a sub pressure reducing device, an evaporator, and a sub compressor are sequentially connected. The upstream side of the sub refrigerant circuit is connected to the main pressure reducing device and the second heat exchange of the refrigerant circuit via an on-off valve. The discharge side of the sub-compressor, which is connected between the compressors and downstream of the sub-refrigerant circuit, is connected to the suction side of the main compressor of the refrigerant circuit, and the indoor air is heat-exchanged and evaporated by the second heat exchanger The intake air is heat-exchanged in a vessel.

In the ventilation air conditioner of the present invention, the sub-reducing device, the evaporator, and the sub-compressor are connected to the refrigerant pipe that bypasses the second heat exchanger in the refrigerant circuit, so the use or non-use of the evaporator is selected. it can. When not in use, the auxiliary refrigeration cycle such as the auxiliary compressor can be stopped to contribute to energy saving. On the other hand, since the evaporation temperature of the evaporator is lower than that of the second heat exchanger at the time of use, the intake air for ventilation exchanged in the evaporator is lower than the indoor conditioned air, and the dew point temperature is lowered. It is possible to supply indoor air that is heat-exchanged in the second heat exchanger at a relatively high temperature (for example, 25 ± 1 ° C.). As described in claim 2, the second heat exchanger and the evaporator can be used as a sensible heat exchanger and a latent heat exchanger, respectively.
Therefore, it is not necessary to use the first heat exchanger as a low-temperature heat source for dehumidification, and the capacity can be reduced. In addition, it is not necessary to reheat the dehumidified air or to install an outside air treatment machine, so the initial cost of the air conditioner is reduced. It will be cheap. In addition, when cooling and dehumidifying with one compressor, a capacity for operating the dehumidifying cooler is necessary, and that capacity is wasted when the dehumidifying cooler is not in operation, but the second heat exchanger Is used exclusively for sensible heat of room air, so the main compressor can be downsized. At the same time, the increase in energy required for ventilation and dehumidification is almost only the energy consumed by the sub-compressor, and the running cost is low. Not only this, but the supply air temperature of the indoor air can be made relatively high (lower capacity of the main compressor), so that a high COP operation is possible and an energy saving type ventilation air conditioner is provided. be able to.
The invention according to claim 3 is a system in which the supply path of indoor air heat-exchanged by the second heat exchanger and the supply path of intake air heat-exchanged by the evaporator are separated. For example, the ventilation air conditioner of the present invention can be used as a replacement ventilation air conditioner that can enjoy comfortable air conditioning.

Hereinafter, the present invention will be described in detail.
A basic refrigerant circuit of the ventilation air conditioner of the present invention is shown in FIG. In FIG. 1, a ventilation air conditioner A includes a refrigerant pipe 1, a main compressor 2, a four-way valve 3, a first heat exchanger 4, a main expansion valve (main decompression device) 5, a second heat exchanger 6, and further four-way. The valve 3 and the main compressor 2 have a refrigerant circuit that is sequentially connected in series. A refrigerant pipe 7 is connected to the refrigerant pipe 1 between the main expansion valve 5 and the second heat exchanger 6 and the suction side of the main compressor 2. In the refrigerant pipe 7, an electromagnetic open / close valve 8, an auxiliary pressure reducing device (hereinafter, exclusively represented by an auxiliary expansion valve) 9 using an expansion valve and a capillary tube, an evaporator 10 and an auxiliary compressor 11 are sequentially arranged in the refrigerant flow direction. It is installed. In other words, the refrigerant pipe 1 extending from the main expansion valve 5 is branched, one is connected to the second heat exchanger 6 and the refrigerant circuit downstream thereof, and the other is the sub expansion valve 9, the evaporator 10 and the sub compressor. 11 is connected to the sub refrigerant circuit including 11.

The main compressor 2 may be either a constant speed constant speed type compressor or a variable speed capacity control type compressor. The first heat exchanger 4 may be an air heat exchanger or a water heat exchanger. In the case of an air heat exchanger, the first heat exchanger 4 exchanges heat with indoor air or outdoor air exhausted to the outside. In the case of an anti-water heat exchanger, for example, water circulates between the cooling tower during cooling and between the hot water boiler during heating.
A circulation fan 12 is attached to the second heat exchanger 6, and the indoor air circulates between the second heat exchanger 6 and the room through the air supply path (return air path). In addition, a dehumidifying fan 13 is attached to the evaporator 10, and intake air heat-exchanged by the evaporator 10, for example, outdoor air, is taken into the room. Then, substantially the same amount of indoor air as fresh outdoor air introduced into the room is exhausted outside the room, and ventilation air conditioning is performed. In addition, if the air supply path | route in which the 2nd heat exchanger 6 is arrange | positioned, and the air supply path | route in which the evaporator 10 is arrange | positioned are made into another system, the pressure loss of room air can be reduced when not dehumidifying. In addition, the air to be treated that is heat-exchanged by the second heat exchanger 6 is not always 100% return air, and is, for example, return air mixed with outside air during heating in the intermediate period such as spring and autumn or in winter. May be.

Here, when the electromagnetic opening / closing valve 8 interposed in the refrigerant pipe 7 is opened, the refrigerant flows through both the second heat exchanger 6 in the refrigerant pipe 1 and the evaporator 10 in the refrigerant pipe 7. At this time, if the diameter of the refrigerant pipe 7 on the inlet side of the evaporator 10 is made smaller than the diameter of the refrigerant pipe 1 (capillary tube) or the opening of the sub-expansion valve 9 is reduced with the same diameter, it flows into the evaporator 10. Since the gas-liquid two-phase flow is further depressurized when passing through the sub-expansion valve 9, the evaporation temperature in the evaporator 10 becomes lower than the evaporation temperature in the second heat exchanger 6. Therefore, the intake air that has undergone heat exchange in the evaporator 10 has a lower temperature than the indoor air that has undergone heat exchange in the second heat exchanger 6. Therefore, since the dew point temperature of the heat-exchanged intake air is lower than the indoor conditioned air, the sensible heat heat exchange that can maintain the second heat exchanger 6 at a temperature level necessary for the sensible heat treatment of the return air. The evaporator 10 can function as a heat exchanger for dehumidification (latent heat).
The room temperature is controlled by a constant speed compressor based on the supply air path where the return air and the intake air merge, the suction path of the circulation fan 12 or the temperature detected by the temperature sensor disposed in the air conditioning target chamber. Is performed by frequency control of the capacity control type compressor.

Next, the operation of the ventilation air conditioner A will be described.
When the ventilation air conditioner A is in a cooling operation, the four-way valve 3 is connected to the refrigerant pipe 1 as shown by a solid line, and the high-temperature refrigerant gas compressed by the main compressor 2 passes through the four-way valve 3 to the first. The heat exchanger 4 cools with air or water and condenses. The condensed liquid refrigerant is depressurized by the main expansion valve 5 to be in a gas-liquid two-phase state, and is evaporated by exchanging heat with indoor air circulating by driving the circulation fan 12 in the second heat exchanger 6. The refrigerant returns to the main compressor 2 through the valve 3, and the refrigerant circulates through the refrigerant pipe 1 as described above. As described above, the room temperature during cooling is, for example, the supply air temperature after mixing the return air exchanged by the second heat exchanger 6 and the intake air of another system exchanged by the evaporator 10. Is detected by a temperature sensor, and compared to a set temperature (for example, 25 ° C.) set to a relatively high temperature, the main compressor 2 is maintained constant by starting / stopping or capacity-controlling.
Thus, since the supply temperature of indoor air is relatively high during cooling, the main compressor 2 having a relatively low capacity can be used, energy-saving ventilation air conditioning can be performed, and high COP operation is possible. is there.

In the case of cooling / dehumidifying operation of the ventilation air conditioner A, for example, a temperature / humidity sensor for detecting the relative humidity of the outside air is provided to obtain the dew point temperature of the outside air, and this dew point temperature is determined from the evaporation temperature (for example, 15 ° C.) of the evaporator 10. When low, the electromagnetic on-off valve 8 is opened. However, it is practically preferable to obtain the dew point temperature at a humidity that is, for example, 10% higher than the absolute humidity of the outside air, and to open the electromagnetic on-off valve 8 when the dew point temperature is lower than the evaporation temperature of the evaporator 10. When the electromagnetic on-off valve 8 is opened, a part of the gas-liquid two-phase flow depressurized by the main expansion valve 5 further bypasses the second heat exchanger 6 and further passes through the auxiliary expansion valve 9 of the refrigerant pipe 7. After the pressure is reduced and heat is exchanged with the intake air blown by the dehumidifying fan 13 in the evaporator 10 to evaporate and the refrigerant gas is compressed by the sub-compressor 11, the refrigerant pipe 1 on the suction side of the main compressor 2 It merges with the refrigerant gas inside. During the cooling / dehumidifying operation, the outside air dehumidified when the heat is exchanged in the evaporator 10 or a mixed air of the outside air and a part of the return air is taken into the room and used for ventilation.
In the present embodiment, since the second heat exchanger 6 is a heat exchanger dedicated to sensible heat of room air, the main compressor 2 is compared with an air conditioner that performs cooling and dehumidification with a single compressor. The capacity of can be reduced. At the same time, 10 to 30% of the capacity of the main compressor 2 can be used as the sub compressor 11. Even when such a low-capacity sub-compressor 11 is used, there is no particular hindrance to the dehumidification treatment of the outside air, so that energy-saving ventilation and cooling / dehumidification operations are possible, and the running cost is low. Incidentally, the process air volume ratio of the 2nd heat exchanger 6 and the evaporator 10 exists in the range of 7-8: 3-2. Further, it is not necessary to use the first heat exchanger 4 as a low-temperature heat source for dehumidification. In other words, the capacity of the main compressor 2 can be reduced because the second heat exchanger 6 need not have a dehumidifying function. In addition, as described above, since the small sub-compressor 11 only needs to be operated with respect to a relatively small amount of outside air, there is no need to reheat the dehumidified air during the rainy season or intermediate period, and the outside air processing machine Since installation is unnecessary, the equipment cost of the ventilation air conditioner is low.

FIG. 2 is a Mollier diagram of the refrigeration cycle during the cooling / dehumidifying operation.
The refrigerant circulating through the refrigerant pipe 1 is compressed into a high-temperature and high-pressure gas by the main compressor 2 (point a), is condensed by the first heat exchanger 4 through the four-way valve 3, and becomes a liquid refrigerant (point b). The pressure is reduced by the main expansion valve 5 (point c). The decompressed gas-liquid two-phase flow refrigerant evaporates by exchanging heat with the sensible heat of the indoor air in the second heat exchanger 6 (point d), and merges with the high-temperature refrigerant gas flowing in the refrigerant pipe 7 described below. Then, it returns to the main compressor 2 through the four-way valve 3 (point e) and is compressed to the point a again.
On the other hand, the gas-liquid two-phase flow refrigerant that is divided into the refrigerant pipe 7 from the refrigerant pipe 1 between the main expansion valve 5 and the second heat exchanger 6 is further decompressed by the sub-expansion valve 9 through the electromagnetic on-off valve 8. (Point f), heat is exchanged with the latent heat of the intake air in the evaporator 10, evaporates at a temperature lower than the evaporation temperature in the second heat exchanger 6 (point g), and is compressed by the sub compressor 11. The temperature is raised (point h). The refrigerant gas flowing out from the sub-compressor 11 is cooled when it joins the low-temperature refrigerant gas flowing in the refrigerant pipe 1 on the suction side of the main compressor 2, and is sucked into the main compressor 2 (point e).
As apparent from the Mollier diagram shown in FIG. 2, since the second heat exchanger 6 is a heat exchanger for sensible heat of room air, a main compressor 2 having a low capacity can be used. . Therefore, high COP operation is possible, and energy saving of the ventilation air conditioner A can be achieved.

When heating and operating the ventilation air conditioner A, the four-way valve 3 is electrically connected to the refrigerant pipe 1 in a state of being switched from the solid line shown in FIG. 1 to the position shown by the broken line as shown in FIG.
The high-temperature and high-pressure refrigerant gas compressed by the main compressor 2 passes through the four-way valve 3 and is condensed by exchanging heat with the indoor air blown by the circulation fan 12 in the second heat exchanger 6. At this time, the room air is heated. The condensed liquid refrigerant is decompressed by the main expansion valve 5, heated by air or water by the first heat exchanger 4 and evaporated, and then returns to the main compressor 2 through the four-way valve 3. As described above, the refrigerant circulates through the refrigerant pipe 1, and no refrigerant flows into the refrigerant pipe 7.
The indoor temperature during heating is, for example, detected by a temperature sensor after the heat exchange of indoor air or mixed air with outside air introduced for ventilation by the second heat exchanger 6, and a set temperature ( Compared to, for example, 25 ° C.), the main compressor 2 is maintained constant by starting / stopping or capacity control.

FIG. 4 is an explanatory diagram when the ventilation air conditioner A is applied to replacement ventilation air conditioning.
In FIG. 4, reference numeral 20 denotes an air conditioning target room, an air supply plenum chamber 21 is formed below the air conditioning target room 20 such as an underfloor space, and an exhaust plenum chamber 22 is positioned above the air conditioning target room 20 such as a ceiling space. Is formed. A porous plate 23 having high air resistance and high strength is stretched over the upper surface of the air supply plenum chamber 21, and a porous plate 24 is stretched over the lower surface of the exhaust plenum chamber 22. An exhaust duct 25 is connected to one side of the exhaust plenum chamber 22, and an exhaust port 26 for discharging room air to the outside is formed at the other end. An air supply duct 27 is connected to one side of the air supply plenum chamber 21. The air supply duct 27 is connected to an outside air introduction duct 29 having an outside air introduction port 28 for introducing outside air into the room at one end, and a damper 30 is interposed between the exhaust duct 25 and the air supply duct 27. The return air duct 31 is connected.
Inside the outside air introduction duct 29 and the return air duct 31, there are disposed an evaporator 10 provided with a dehumidifying fan 13 and a second heat exchanger 6 provided with a circulation fan 12 constituting the ventilation air conditioner A, respectively. Yes. A drain pan 32 that receives drain condensed during dehumidification is disposed below the evaporator 10. The drain is discharged to the outside of the outside air introduction duct 29 through a drain pipe (not shown). In addition, the 1st heat exchanger 4 of a present Example is an anti-water heat exchanger, and a cooling water circulates between an anti-water heat exchanger and the cooling tower 34 at the time of air_conditioning | cooling by the action | operation of the pump 33. If necessary, a hot water boiler may be connected in parallel with the cooling tower 34 to heat the circulating water during heating.

In the replacement ventilation air conditioning shown in FIG. 4, the wind speed of the air uniformly blown upward from the supply plenum chamber 21 into the room is set to 0.2 m / sec or less. Therefore, since the air in the air-conditioning target room 20 is not normally disturbed, a low-temperature air layer is formed in the lower layer and a high-temperature air layer is distributed in the upper layer during the cooling / dehumidifying operation. The air temperature in the air-conditioning target room 20 is controlled so as to coincide with the indoor set temperature based on the temperature detected by a temperature sensor installed at a predetermined height position. A part of the upper layer air is exhausted from the exhaust port 26 through the exhaust duct 25 to the outside, and the remaining air is cooled by the second heat exchanger 6 when passing through the return air duct 31, and is supplied to the air supply duct. 27 and the air supply plenum chamber 21 are supplied to the air-conditioned room 20. The ratio of the amount of air discharged to the outside and the amount of air returned to the room is controlled by adjusting the opening of the damper 30, and the amount of outdoor air corresponding to the amount of air discharged to the outside is the outside air introduction duct 29. Is introduced into the air-conditioning target room 20.
The dew point temperature of the outside air determined based on the relative humidity of the outside air detected by the temperature / humidity sensor or a set temperature somewhat lower than the dew point temperature is compared with the evaporation temperature of the evaporator 10, and when the former temperature is lower than the latter, The outside air taken into the outside air introduction duct 29 from the outside air introduction port 28 is dehumidified by the evaporator 10 and then sent to the air supply duct 27 and merges with the return air cooled by the second heat exchanger 6 described above. Air is supplied to the air-conditioned room 20.

When the dehumidification is not performed, the electromagnetic on-off valve 8 is closed. In order to reduce the air resistance, it is preferable to provide a bypass duct in the outside air introduction duct 29 that bypasses the evaporator 10. Further, this bypass duct may be connected to the return air duct 31 to guide the outside air to the second heat exchanger 6. Further, a damper may be interposed in one or both of the outside air introduction duct 29 and the bypass duct upstream of the evaporator 10.
When cooling or dehumidifying the replacement ventilation air conditioning system, the main compressor 2 having a relatively low capacity can be used because the temperature difference between the treated air mainly composed of return air and the supply air after treatment is small. Ventilation air conditioning is energy saving and high COP operation is possible.
When heating operation is performed, the air temperature distribution in the air-conditioning target room 20 is slightly different from that during cooling, but the supply air temperature is almost the same as that during cooling operation. It can be carried out.

FIG. 5 shows a refrigerant circuit when the ventilation air-conditioning apparatus of the present invention is a refrigerant multi-type.
This refrigerant multi-type ventilation air conditioner B includes a main expansion valve 5 and a second heat exchanger 6 and an electromagnetic on-off valve 8, a sub-expansion valve 9, an evaporator 10 and an evaporator 10 in the refrigerant pipe 1 in the refrigerant circuit shown in FIG. The refrigerant pipe 7 connected to the sub compressor 11 is unitized, and a plurality of units, for example, indoor units are connected in parallel.
That is, this embodiment is the main compressor 2, the four-way valve 3, the first heat exchanger 4, and accessories (for example, a fan or a circulation pump attached to the first heat exchanger 4, a suction of the main compressor 2) The first indoor unit is composed of a plurality of sets including a main expansion valve 5, a second heat exchanger 6 and a circulation fan 12 (not shown). Similarly, a second room having a function of treating outside air with a plurality of sets of an electromagnetic on-off valve 8, a sub-expansion valve 9, an evaporator 10, a sub-compressor 11, a dehumidifying fan 13 (not shown), etc. Configure the machine.

When this refrigerant circuit is explained in full detail, the main expansion valve 5a and the second heat exchanger 6a are connected to the refrigerant pipe 1 returning from the main compressor 2 through the four-way valve 3 to the main compressor 2 through the first heat exchanger 4. The main expansion valve 5b and the second heat exchanger 6b,..., The main expansion valve 5n and the second heat exchanger 6n are connected in parallel. Furthermore, between the main expansion valves 5a, 5b, ..., 5n and the second heat exchangers 6a, 6b, ..., 6n and the main compressor 2 so as to bypass the second heat exchangers 6a, 6b, ..., 6n. , 8n, sub-expansion valves 9a, 9b, ..., 9n, evaporators 10a, 10b, ..., 10n and sub-compressors 11a, 11b, ... , 11n are connected in series to refrigerant pipes 7a, 7b,.
In other words, the refrigerant pipe 1 extending from each of the main expansion valves 5a, 5b,..., 5n is branched, and one is connected to the second heat exchangers 6a, 6b,. , 8n, sub expansion valves 9a, 9b,..., 9n, evaporators 10a, 10b,..., 10n and sub compressors 11a, 11b,. It continues to the sub refrigerant circuit of the pipes 7a, 7b,.
According to the above-described refrigerant multi-type ventilation air conditioner, the second heat exchanger 6a and the evaporator 10a, the second heat exchanger 6b and the evaporator 10b, ..., the second heat exchanger 6n and the evaporator 10n, The above-described cooling / dehumidifying operation and cooling / heating operation can be performed individually.

In the above ventilation air conditioner B, the main expansion valves 5a to 5n may be arranged on the outdoor unit side, and the circulation fan 12 constituting the first indoor unit and the dehumidifying fan 13 constituting the second indoor unit are These may be arranged outside the casing of the indoor unit. The sub-compressors 11a to 11n are not necessarily provided individually, and can be a single variable capacity compressor. In that case, the capacity of the compressor is controlled according to the number of operating evaporators 10a to 10n and the heat load thereof. Depending on the case, it is not necessary to provide the evaporators 10a to 10n corresponding to the second heat exchangers 6a to 6n, and a part thereof may be omitted. For example, when only one evaporator 10a is provided, in addition to the evaporator 10a, a refrigerant pipe 7a that includes an electromagnetic on-off valve 8a, a sub-expansion valve 9a, and a sub-compressor 11a and branches from the downstream of the main expansion valve 5a is provided. Connect to the suction side of the main compressor 2.
On the other hand, the evaporators 10a to 10n may be a single indoor unit. In that case, the second heat exchangers 6a to 6n are also one indoor unit, and the refrigerant pipes 1 extending from the main expansion valves 5a to 5n are connected to the refrigerant pipes 7a to 7n. Moreover, the supply path of the return air heat-exchanged by each 2nd heat exchanger 6a-6n, and the supply path of the intake air heat-exchanged by each evaporator 10a-10n are made into one indoor unit. Can be placed in series or in parallel.

The basic refrigerant circuit of the ventilation air conditioner of this invention is shown. FIG. 2 is a Mollier diagram of the refrigeration cycle shown in FIG. 1. It is a refrigerant circuit shown in FIG. 1 at the time of heating operation. It is explanatory drawing of substitution ventilation air conditioning which shows one Example of the ventilation air conditioning apparatus of this invention. The refrigerant circuit at the time of setting the ventilation air-conditioning apparatus of this invention to a refrigerant | coolant multi-system is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Refrigerant piping, 2 ... Main compressor, 3 ... Four-way valve, 4 ... 1st heat exchanger, 5 ... Main expansion valve (main decompression device), 6 ... 2nd Two heat exchangers, 7 ... Refrigerant tube, 8 ... Electromagnetic on-off valve, 9 ... Sub expansion valve (sub decompression device), 10 ... Evaporator, 11 ... Sub compressor, 20 .. Air-conditioning target room, 25 ... Exhaust duct, 27 ... Air supply duct, 29 ... Outdoor air introduction duct (air supply path for outdoor air), 31 ... Return air duct (air supply for indoor air) Route), A, B ... Ventilation air conditioner.

Claims (3)

Main compressor, four-way valve, first heat exchanger, main decompression device, second heat exchanger, refrigerant circuit with sequential connection of four-way valve and main compressor , sub decompression device, evaporator, and sub compressor A sub-refrigerant circuit, and an upstream side of the sub-refrigerant circuit is connected between the main decompression device of the refrigerant circuit and the second heat exchanger via an on-off valve, and is connected to the sub-refrigerant circuit downstream side. Ventilation characterized in that the discharge side of the compressor is connected to the suction side of the main compressor of the refrigerant circuit , the indoor air is heat-exchanged by the second heat exchanger, and the intake air is heat-exchanged by the evaporator Air conditioner.   The ventilation air conditioner according to claim 1, wherein the second heat exchanger is a sensible heat exchanger, and the evaporator is a latent heat exchanger.   The ventilation air conditioner according to claim 1 or 2, wherein a heat supply-exchanged indoor air supply path and a heat-exchanged intake air supply path are separate systems.

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