JP3969381B2 - Multi-room air conditioner - Google Patents

Description

  The present invention relates to a multi-room air conditioner in which a plurality of indoor units are connected to a single outdoor unit, and the cooling operation and the heating operation are performed without mixing the cooling operation and the heating operation. The present invention relates to the provision of a comfortable and highly efficient dehumidifying operation with a simple structure and the expansion of operation mode combinations in the operation of multiple units.

  In a multi-room air conditioner in which a plurality of indoor units are connected to one outdoor unit and the cooling operation and the heating operation are performed without mixing the cooling operation and the heating operation, the dehumidifying operation is performed in the heating cycle. It is described in JP-A-11-304286. The technique described in the publication is branched from the middle of the pipe line of the outdoor heat exchanger, includes a bypass decompression unit, and includes a bypass circuit connected between the plurality of cooling and heating decompression units and the indoor heat exchanger. The indoor unit has a dehumidifying function, and each indoor unit can freely select a cooling function and a dehumidifying function, so that a cooling operation and a dehumidifying operation can be performed simultaneously, and a heating operation and a dehumidifying operation can be performed simultaneously. It is possible to provide a multi-room air conditioner excellent in the above, and an outline thereof will be described with reference to FIG. FIG. 3 is a refrigeration cycle diagram of a conventional multi-chamber air conditioner described in Japanese Patent Laid-Open No. 11-304286.

  In such a two-chamber air conditioner, when both of the two rooms are in cooling operation, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows through the circuit switching valve 2 to the outdoor heat exchanger 3 where The refrigerant is condensed by exchanging heat with the outside air, and becomes high-pressure liquid refrigerant. The liquid refrigerant divided by the refrigerant pipes 10a and 10b is depressurized through the electric expansion valves 4a and 4b for cooling and heating, and the first and second indoor sides. The air in the two chambers is cooled through the heat exchangers 5a and 5b and the indoor first and second side heat exchangers 6a and 6b, and the refrigerant evaporates to become a low-temperature and low-pressure gas refrigerant. Return to 1.

  At this time, the dehumidifying electric expansion valves 15a and 15b of the indoor unit are fully opened to reduce pressure loss, and the bypass electric expansion valves 14a and 14b of the bypass circuits 13a and 13b are fully closed.

  When only one room is to be cooled, one of the heating / cooling electric expansion valves 4a or 4b is closed and the cooling operation for only one room is performed.

  On the other hand, when the two rooms are in the dehumidifying operation, the heating and cooling electric expansion valves 4a and 4b are fully opened, and the refrigerant is depressurized through the dehumidifying electric expansion valves 15a and 15b. Since 5a and 5b serve as condensers and serve as reheaters, and the indoor second heat exchangers 6a and 6b serve as evaporators, the air is dehumidified and discharged from each indoor unit.

  During this dehumidifying operation, control is performed to reduce the rotational speed of the outdoor blower 12 in order to increase the capacity of the indoor first heat exchangers 5a and 5b as reheaters.

  Further, in order to increase the capacity of the indoor first heat exchangers 5a and 5b as a reheater, the electric expansion valves 4a and 4b for cooling and heating are greatly reduced and the electric expansion valves 14a and 14b for bypass are opened. The amount of reheat is increased by sending a gas-liquid two-phase refrigerant that has not radiated much heat in the outdoor heat exchanger 3 to the indoor first heat exchangers 5a and 5b.

In addition, when one room is cooled and the other room is dehumidified, for example, the indoor unit to be cooled is the indoor unit A, and the electric expansion valve 4a for cooling and heating of the circuit for flowing the refrigerant to the indoor unit side is operated as a decompressor to dehumidify. When the electric expansion valve 15a is fully opened and the bypass electric expansion valve 14a is fully closed, the first and second heat exchangers 5a and 5b on the indoor side act as evaporators to cool the room A.

  Then, the indoor unit to be dehumidified is the indoor unit B, the heating / cooling electric expansion valve 4b of the circuit for flowing the refrigerant to the indoor unit side is closed almost fully closed, the bypass electric expansion valve 14b is fully opened, and the dehumidifying electric expansion valve is opened. If 15b is operated as a pressure reducer, the indoor first heat exchanger 5b functions as a condenser and the indoor second heat exchanger 6b functions as an evaporator. Therefore, dehumidification is performed without cooling the air in the room B. It can be carried out.

  Next, when both of the two rooms are in the heating operation, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 passes through the four-way valve 2 and the second indoor side, the first heat exchangers 6a and 5a, the second indoor side, The refrigerant flows into the first heat exchangers 6b and 5b and is condensed by exchanging heat with the indoor air, and becomes high-pressure liquid refrigerant. The liquid refrigerant is depressurized through the electric expansion valves 4a and 4b for heating and cooling, and is outdoors. The heat exchanger 3 exchanges heat with the outside air to absorb heat, and the refrigerant evaporates to become a low-temperature and low-pressure gas refrigerant, and returns to the compressor 1 through the circuit switching valve 2.

  At this time, the dehumidifying electric expansion valves 15a and 15b of the indoor unit are fully opened to reduce pressure loss, and the bypass electric expansion valves 14a and 14b of the bypass circuits 13a and 13b are fully closed.

  When heating only one room, if the indoor unit that stops heating is, for example, the indoor unit A, the blower 9a for the indoor side first and second heat exchangers 5a and 6a of the indoor unit is stopped and air conditioning is performed. Only the room where the blower 9b for the indoor side first and second heat exchangers 5b and 6b of the indoor unit B is operated is heated by closing the electric expansion valve 4a so that the refrigerant does not flow. Can do.

When one room is heated and the other rooms are dehumidified, for example, the indoor unit to be heated is the indoor unit B, and the electric expansion valve 4b for cooling and heating in the circuit for flowing the refrigerant to the indoor unit side is used as a decompressor, and the electric expansion for dehumidification It is only necessary to fully open the valve 15b and fully close the bypass electric expansion valve 14b. If the electric expansion valve 4a for cooling and heating on the indoor unit A side to be dehumidified is fully opened and the electric expansion valve 15a for dehumidification works as a pressure reducer. The indoor second heat exchanger 6a functions as a reheater, and the indoor first heat exchanger 5a functions as an evaporator, so that dehumidification can be performed without cooling indoor air (for example, , See Patent Document 1).
JP-A-11-304286

  However, in the above-described conventional configuration, when the reheat dehumidifying operation is performed, it branches off from the middle of the pipe line of the outdoor heat exchanger, and includes a bypass decompression means, and includes a plurality of air conditioning and decompression means and the indoor heat exchanger. There is a problem that the cost increases because it is necessary to provide a bypass circuit connected between them.

  Further, when the number of indoor units connected increases, it is necessary to provide bypass circuits for the number of connected units, and there is a problem that it is difficult to secure a space unless the outdoor units are enlarged.

  In addition, when the bypass circuit is not provided, when the outside air temperature is very low as in winter, or when the rotation speed of the outdoor fan cannot be lowered to secure the cooling capacity because the other room is performing the cooling operation. There is a problem that the amount of exhaust heat in the outdoor heat exchanger is large and the room temperature in the room where the dehumidifying operation is performed cannot be prevented.

  The present invention solves such a conventional problem, and there is no need to provide a bypass circuit connected between a plurality of decompression means for cooling and heating and the indoor heat exchanger, and the number of indoor units connected increases. Another object of the present invention is to provide a multi-room air conditioner that can perform a comfortable reheating and dehumidifying operation at low cost and without lowering the room temperature without increasing the size of the outdoor unit due to the space of the bypass circuit.

  In order to solve the above problems, a multi-room air conditioner of the present invention includes a compressor, a four-way valve, an outdoor heat exchanger, an outdoor fan that ventilates the outdoor heat exchanger, and a plurality of outdoor throttle devices. And an indoor heat exchanger in which a first heat exchanger and a second heat exchanger are connected via a decompression means, and a plurality of indoor units that can be reheated and dehumidified are connected. In the multi-chamber air conditioner, the second heat exchanger is disposed on the upstream side of the refrigerant flow of the first heat exchanger during a heating cycle, and the heat exchange capacity of the second heat exchanger is The first heat exchanger is configured to be larger than the heat exchange capacity.

  As a result, the reheat dehumidification operation can be performed to obtain a high dehumidification capability without having to provide a bypass circuit in the middle of the outdoor heat exchanger.

  The multi-room air conditioner of the present invention does not provide a bypass circuit connected between a plurality of air-conditioning decompression means and the indoor heat exchanger, and even if the number of indoor units connected increases, Therefore, there is an effect that it is possible to perform a comfortable reheat dehumidifying operation at a low cost without causing a decrease in room temperature without increasing the size of the outdoor unit.

  A first invention includes a compressor, a four-way valve, an outdoor heat exchanger, an outdoor fan that ventilates the outdoor heat exchanger, and an outdoor unit that includes a plurality of outdoor throttle devices, a first heat exchanger, 2 is a multi-room air conditioner having an indoor heat exchanger in which two heat exchangers are connected via a pressure reducing means, and configured by connecting a plurality of indoor units capable of reheat dehumidification operation, The two heat exchangers are disposed upstream of the refrigerant flow of the first heat exchanger during the heating cycle, and the heat exchange capacity of the second heat exchanger is greater than the heat exchange capacity of the first heat exchanger. With this configuration, it is possible to provide a depressurizing means for bypass, and without providing a bypass circuit connected between the plurality of depressurizing means for cooling and heating and the indoor heat exchanger, Even if the number of connected units increases, the outdoor unit is enlarged due to the space of the bypass circuit. An effect that can at room temperature decrease at a low cost without comfortable reheat dehumidifying operation without.

  According to the second invention, in particular, in the first invention, the pressure reducing means is variable in flow rate, and this configuration has an effect that a comfortable reheat dehumidification operation can be performed at low cost.

  The third invention detects the outside air temperature particularly in the first invention, and if the outside air temperature detected when the reheat dehumidifying operation is selected at the start of the operation is not less than a predetermined temperature, the operation is performed in the cooling cycle. If it is smaller, it is operated in the heating cycle. By making this configuration, when the outside air temperature is lower than the predetermined temperature, the reheating dehumidifying operation is performed in the heating cycle so that the dehumidifying operation can be performed without lowering the room temperature. When the cooling capacity is required at a temperature or higher, the dehumidifying operation can be performed in the cooling cycle to greatly reduce the humidity, and a comfortable dehumidifying operation can be performed at low cost.

  In the fourth invention, in particular, when the reheat dehumidifying operation is selected at the start of operation in the first invention, the reheat dehumidifying operation is performed in the heating cycle. There is an effect that the range of the comfortable reheat dehumidification operation can be expanded.

  In the fifth aspect of the invention, in particular, in the first aspect of the invention, the cooling cycle is used when the cooling and dehumidifying operation are used together, and the heating cycle is used when heating and the dehumidifying operation are used together. Therefore, it is possible to provide a multi-room air conditioner that can perform a dehumidification operation and is excellent in comfort at low cost.

  Embodiments of the present invention will be described below with reference to the drawings. The multi-room air conditioner described in this embodiment is one in which a plurality of indoor units are connected in parallel to one outdoor unit. Here, a case in which two indoor units A and B are connected will be described. To do. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a refrigeration cycle diagram showing a first embodiment of the present invention. During operation in the cooling cycle, the refrigerant flows in the direction of the solid arrow in FIG. 1, and the refrigerant discharged from the compressor 1 is condensed in the outdoor heat exchanger 3 and depressurized in the electric expansion valves 4a and 4b for cooling and heating, It evaporates in the indoor heat exchangers 5a, 6a, 5b, 6b and returns to the compressor 1.

  When the refrigerant evaporates in the indoor heat exchangers 5a, 6a, 5b, 6b, the air to be conditioned is conditioned by the heat absorbed. Further, the flow of the refrigerant during the heating operation is reversed in the direction of the dotted arrow in FIG. 1, and the air conditioning of the air-conditioned room is conditioned by the heat released when condensing in the indoor heat exchangers 5a, 6a, 5b, 6b. I am doing.

  There are two types of discharge refrigerant amounts: a type that is adjusted by operating and stopping the compressor 1, and a type that is adjusted by varying the rotational speed of the compressor 1. The electric expansion valves 4a and 4b for cooling and heating are provided in the refrigerant circuit corresponding to the heat exchangers of the plurality of indoor units, and the amount of decompression and the refrigerant flow rate to the indoor heat exchangers 5a and 5b are determined depending on the opening degree of the valves. Is adjusted.

  When the reheat dehumidifying operation is performed in the cooling cycle, if the outside air temperature is very low as in winter, the amount of heat exhausted by the outdoor heat exchanger 3 is large, and even if the rotational speed of the outdoor fan 12 is lowered, The capacity as a reheater of the 1 heat exchanger 5a, 5b is insufficient and the room temperature is lowered.

  Further, when the indoor unit A is performing cooling operation and the indoor unit B is performing dehumidifying operation, if the rotational speed of the outdoor blower 12 is decreased, the amount of exhaust heat of the outdoor heat exchanger 3 is reduced, and the cooling capacity of the indoor unit A cannot be ensured. Further, as in the conventional example, bypass decompression means 14a and 14b are provided, and bypass circuits 13a and 13b connected between the plurality of cooling and heating decompression means 4a and 4b and the indoor first heat exchangers 5a and 5b are provided. If it is provided, the cost increases, or the number of indoor units connected increases, the outdoor unit must be enlarged in order to secure space for the bypass circuits 13a and 13b.

  Therefore, in this embodiment, each indoor unit has first heat exchangers 5a and 5b and second heat exchangers 6a and 6b, and these first heat exchangers 5a and 5b and second heat exchanger 6a. , 6b are connected to dehumidifying throttle devices (capillary tubes 7a, 7b and on-off valves 8a, 8b as bypass means thereof), and in the indoor heat exchanger, the second heat exchangers 6a, 6b are connected during the heating cycle. The heat exchange capacity of the second heat exchangers 6a and 6b is the heat exchange capacity of the first heat exchangers 5a and 5b. It is comprised so that it may become larger.

  The dehumidifying operation can be performed by a cooling cycle and a heating cycle by switching the circuit switching valve 2.

When the reheat dehumidifying operation is performed in the cooling cycle, the refrigerant flows in the direction of the solid line arrow in FIG. 1 and the refrigerant discharged from the compressor 1 is supplied from the outdoor heat exchanger 12 to the refrigerant pipes 10a and 10b and the electric expansion for air conditioning. Valves 4a and 4b, first heat exchangers 5a and 5b, dehumidifying throttle devices (capillary tubes 7a and 7b and on-off valves 8a and 8b serving as bypass means thereof), indoor second heat exchangers 6a and 6b, and refrigerant piping 11a , 11b and the compressor 1 are circulated in this order. At this time, the electric expansion valve for cooling and heating is fully opened, the on-off valves 8a and 8b of the dehumidifying and throttling device are closed, the refrigerant is caused to flow through the capillary tubes 7a and 7b, and the indoor first heat exchangers 5a and 5b are opened. A dehumidifying operation is performed by using the condenser and the indoor first heat exchange 6a, 6b as an evaporator. At this time, the heat exchange capacity of the second heat exchangers 6a and 6b that function as an evaporator is configured to be greater than the heat exchange capacity of the first heat exchangers 5a and 5b that function as a condenser. The dehumidifying operation can be performed while lowering the value greatly.

  When one room is cooled and the other rooms are dehumidified, for example, if the indoor unit to be cooled is an indoor unit B, the open / close valve 7b of the circuit for flowing the refrigerant to the indoor unit B side is opened, and the electric expansion valve 4b for cooling and heating is installed. The first and second heat exchangers 5a of the indoor unit A are closed by closing the on-off valve 7a on the indoor unit A side to be appropriately throttled and dehumidified, reducing the pressure by the capillary tube 7a, and fully opening the electric expansion valve 4a for cooling and heating. 5b denotes an evaporator, the indoor first heat exchanger 5b of the indoor unit B functions as a condenser, and the indoor second heat exchanger 6b functions as an evaporator. Cooling is performed on the indoor unit A side, Then, dehumidifying operation can be performed while greatly reducing the humidity.

  When the reheat dehumidifying operation is performed in the heating cycle, the refrigerant flows in the direction of the dotted arrow in FIG. 1 and the refrigerant discharged from the compressor 1 is discharged from the refrigerant pipes 11a and 11b to the second heat exchangers 6a and 6b and the dehumidifying throttle. Apparatus (capillary tubes 7a and 7b and on-off valves 8a and 8b as bypass means thereof), first indoor heat exchangers 5a and 5b, electric expansion valves 4a and 4b for cooling and heating, refrigerant pipes 10a and 10b, outdoor heat exchangers 12 Cycles in the order of the compressor 1.

  At this time, the on-off valves 8a and 8b of the dehumidifying and throttling device are closed, the refrigerant is caused to flow by flowing the refrigerant through the capillary tubes 7a and 7b, and the electric expansion valve for cooling and heating is appropriately throttled to appropriately restrict the indoor second heat exchanger 6a, The reheat dehumidifying operation is performed by using 6b as a condenser and the indoor first heat exchangers 5a and 5b as evaporators.

  At this time, the heat exchange capacity of the second heat exchangers 6a and 6b functioning as condensers is configured to be larger than the heat exchange capacity of the first heat exchangers 5a and 5b functioning as evaporators. A sufficient amount of heat radiation can be secured even at outside temperatures, and a drop in room temperature can be prevented.

  When heating one room and dehumidifying the other room, for example, if the indoor unit to be heated is the indoor unit B, the on-off valve 7b of the circuit for flowing the refrigerant to the indoor unit B side is opened, and the electric expansion valve 4b for cooling and heating is installed. The first and second heat exchangers 5a of the indoor unit A are closed by closing the on-off valve 7a on the indoor unit A side to be appropriately throttled and dehumidified, reducing the pressure by the capillary tube 7a, and fully opening the electric expansion valve 4a for cooling and heating. 5b is a condenser, the indoor second heat exchanger 6b of the indoor unit B is a condenser, and the indoor first heat exchanger 5b is an evaporator. Heating is performed on the indoor unit A side, and the indoor unit B side is heated. Then, reheat dehumidification operation can be performed without cooling indoor air.

  In this way, even if the number of indoor units is increased without providing a bypass circuit connecting between the plurality of decompression units for cooling and heating and the indoor heat exchanger, the bypass circuit space can be reduced. Therefore, a comfortable reheat dehumidification operation can be performed at low cost without increasing the size of the outdoor unit.

  Although the case where two indoor units are connected has been described here, the present invention can be similarly implemented when three or more indoor units are connected.

(Embodiment 2)
FIG. 2 is a refrigeration cycle diagram showing a second embodiment of the present invention, except for the dehumidifying electric expansion valves 15a and 15b between the first heat exchangers 5a and 5b and the second heat exchangers 6a and 6b. Same as 1.

  Table 1 shows the operation of the heating / cooling electric expansion valves 4a, 4b and the dehumidifying electric expansion valves 15a, 15b according to combinations of the respective operation modes. The dehumidifying throttle device is an electric expansion valve 15a, 15b for dehumidification that can adjust the flow rate. According to this configuration, the throttle flow rate of the dehumidifying throttle device can be adjusted, and the capacities of the condenser and the evaporator are adjusted. Thus, there is an effect that a comfortable reheat dehumidification operation can be performed at low cost.

(Embodiment 3)
The refrigeration cycle diagram showing the third embodiment of the present invention is the same as FIG. 1 as in the first embodiment. As shown in FIG. 1, an outdoor air temperature sensor 16 for detecting the outside air temperature is provided in the outdoor unit.

  When the operation is started from the state where the multi-chamber air conditioner is stopped, the outside air temperature sensor 16 detects the outside air temperature when the reheat dehumidifying operation is selected, and the detected outside air temperature is equal to or higher than a predetermined temperature. If so, the operation is performed in the cooling cycle, and if the temperature is lower than the predetermined temperature, the dehumidifying operation is performed in the heating cycle. The predetermined temperature is set to 30 ° C., for example, so as to expand the range of the dehumidifying operation in the heating cycle.

  According to this configuration, when the outside air temperature is less than or equal to a predetermined temperature, the reheat dehumidifying operation is performed in the heating cycle. When required, a dehumidifying operation can be performed in a cooling cycle to greatly reduce the humidity, and a comfortable dehumidifying operation can be performed at low cost.

(Embodiment 4)
The refrigeration cycle diagram showing the fourth embodiment of the present invention is the same as FIG. When the operation is started from the state where the multi-chamber air conditioner is stopped, the reheat dehumidification operation is performed in the heating cycle when the reheat dehumidification operation is selected. Since the reheat dehumidifying operation is performed in the cycle, the dehumidifying operation can be performed without lowering the room temperature, and the range of the comfortable reheat dehumidifying operation without lowering the room temperature can be expanded.

(Embodiment 5)
The refrigeration cycle diagram showing the fifth embodiment of the present invention is the same as FIG. When the dehumidifying operation is selected for a certain indoor unit, if the other room is in the cooling operation, the dehumidifying operation is performed as it is, and if the other room is in the heating operation, the dehumidifying operation is performed as it is. Thus, according to this configuration, it is possible to provide a multi-room air conditioner that can perform a dehumidifying operation regardless of the operation mode of the other room and is excellent in comfort at low cost.

Refrigeration cycle diagram showing the first embodiment of the present invention Refrigeration cycle diagram showing a second embodiment of the present invention Refrigeration cycle diagram of a conventional multi-room air conditioner

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Outdoor heat exchanger 4a, 4b Air-conditioning electronic expansion valve 5a, 5b Indoor first heat exchanger 6a, 6b Indoor second heat exchanger 7a, 7b On-off valve 8a, 8b Capillary tube ( Dehumidifying squeezing device)
9a, 9b Indoor blower 10a, 10b Refrigerant piping 11a, 11b Refrigerant piping 12 Outdoor blower 13a, 13b Bypass piping 14a, 14b Bypass electric expansion valve 15a, 15b Dehumidification electric expansion valve 16 External temperature sensor

Claims (5)

Decompressing a compressor, a four-way valve, an outdoor heat exchanger, an outdoor fan that ventilates the outdoor heat exchanger, and a plurality of outdoor expansion devices, a first heat exchanger, and a second heat exchanger A multi-room air conditioner having a plurality of indoor units connected to each other and capable of reheating and dehumidifying operation, wherein the second heat exchanger is a heating unit. It is arranged upstream of the refrigerant flow of the first heat exchanger during the cycle, and the heat exchange capacity of the second heat exchanger is configured to be larger than the heat exchange capacity of the first heat exchanger. A multi-room air conditioner characterized by 2. The multi-chamber air conditioner according to claim 1, wherein the pressure reducing means has a variable flow rate. The outside air temperature is detected, and when the reheat dehumidifying operation is selected at the start of operation, if the outside air temperature detected is equal to or higher than a predetermined temperature, it is operated in a cooling cycle, and if it is lower than the predetermined temperature, it is operated in a heating cycle. The multi-room air conditioner according to claim 1. The multi-room air conditioner according to claim 1, wherein when the reheat dehumidifying operation is selected at the start of operation, the reheat dehumidifying operation is performed in a heating cycle. The multi-room air conditioner according to claim 1, wherein the air conditioner is operated in a cooling cycle when the cooling and dehumidifying operation are used together, and is operated in the heating cycle when the heating and dehumidifying operation are used together.

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