JP6721060B2 - Air conditioner - Google Patents

Description

The present invention relates to an air conditioner, and particularly to control of a drain pump used in the air conditioner.

In the air conditioner, drain water (condensed water) is generated from the indoor heat exchanger during cooling operation, and is discharged to the outside by natural drainage or a drain pump. An air conditioner indoor unit equipped with a drain pump device has an advantage that drain water can be discharged even if the installation location is selected near the center of the air-conditioned space or away from the wall surface. On the other hand, since the drain pump is driven, there is a demerit that power consumption increases and energy saving performance deteriorates.

As a conventional technique to improve it, the drain pump is operated at a high output when the rotation speed of the indoor blower exceeds a predetermined rotation speed, and the drain pump is operated at a low output when the rotation speed of the indoor blower is lower than the predetermined rotation speed. By doing so, a technique of reducing power consumption while maintaining the required drain pump discharge capacity is disclosed (for example, refer to Patent Document 1).

JP, 2004-093003, A

However, in the air conditioner described in Patent Document 1, the cooling capacity is estimated by the blower rotation speed of the indoor unit, and when the capacity is low, the drain pump is made to have a low output, or the pump is stopped when the cooling thermostat is turned off. However, estimating the amount of drain water generated only by the number of revolutions of the indoor blower and varying the output of the pump or simply stopping the pump while the thermostat is off leads to insufficient drain water discharge, and in the worst case There was a problem that the water exceeded the storage allowable amount and overflowed, and dropped into the room.
In addition, when the output of the drain pump is lowered or stopped, the drain water flows backward from the discharge side, which causes a problem such as abnormal noise.

The present invention has been made to solve the above problems, and provides an air conditioner capable of reducing power consumption of a drain pump without causing insufficient drain water discharge or overflow during cooling operation. The purpose is to

The air conditioner according to the present invention is an indoor heat exchanger arranged in a refrigerant circuit in which a refrigerant is circulated by a compressor, and a drain pan for collecting drain water generated in the indoor heat exchanger during a cooling operation. A drain pump for draining drain water from the drain pan, a water level detection means provided in the drain pan for detecting a stored water level of the drain water, and a control means for controlling the operation of the drain pump, and the control means The first mode in which the drain pump is stopped by the information of the thermo-off or the information of the operation stop when the thermo-off during the cooling operation or the operation of the compressor is stopped, and the high water level is detected even once from the time when the main power to the air conditioner is turned on. When there is a history of the above , there is a second mode in which the drain pump is continuously operated with priority over the first mode.

The air conditioner of the present invention has an effect of reducing power consumption while maintaining high reliability without causing drain water to overflow.

It is a refrigerant circuit block diagram of the air conditioner which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the indoor unit of the air conditioner which concerns on Embodiment 1 of this invention. It is a flowchart which shows the control flow of the air conditioner which concerns on Embodiment 1 of this invention. It is a characteristic view which shows the control characteristic of the air conditioner which concerns on Embodiment 1 of this invention.

Embodiment 1.
1 to 4 are explanatory views of an air conditioner according to Embodiment 1 of the present invention. FIG. 1 is a refrigerant circuit configuration diagram schematically showing a configuration of a refrigerant circuit, and FIG. 2 is an indoor unit thereof. FIG. 3 is a flowchart showing a control flow for explaining the air conditioner, and FIG. 4 is a characteristic diagram showing control operation characteristics according to this control flow.

In FIG. 1, the air conditioner 100 is composed of an outdoor unit 101 and an indoor unit 102, which are connected to each other by a refrigerant pipe.
In the outdoor unit 101, heat is exchanged between the compressor 1 capable of changing the operating frequency for compressing the refrigerant (compressor operating frequency), the four-way valve 2 for changing the flow direction of the refrigerant, and the outdoor air. The outdoor heat exchanger 3, an outdoor blower 4 that supplies outdoor air toward the outdoor heat exchanger 3, and an expansion valve that expands the refrigerant are provided. On the other hand, the indoor unit 102 is provided with an indoor heat exchanger 6 that exchanges heat with indoor air, and an indoor blower 7 that supplies indoor air toward the indoor heat exchanger 6. The refrigerant is, for example, a single HFO refrigerant such as HFO-1234yf or a mixed refrigerant of HFO refrigerant and HFC refrigerant such as R32.

In the operation of the air conditioner 100, when cooling the room, the refrigerant discharged from the compressor 1 flows in the order of the four-way valve 2, the outdoor heat exchanger 3, the expansion valve 5, and the indoor heat exchanger 6 and then again. A refrigerant circuit that returns to the compressor 1 via the four-way valve 2 is formed, and the refrigeration cycle is executed. When heating the room, the refrigerant discharged from the compressor 1 flows through the four-way valve 2, the indoor heat exchanger 6, the expansion valve 5, and the outdoor heat exchanger 3 in this order, and then passes through the four-way valve 2 again. A refrigerant circuit that returns to the compressor 1 is formed, and the refrigeration cycle is executed.

FIG. 2 shows an indoor unit of a ceiling-embedded air conditioner as an air conditioner. This air conditioner indoor unit includes an indoor unit body having a box-shaped casing having a substantially rectangular parallelepiped shape and a decorative panel 14, and a suction grill 15 to which an air filter 16 is attached is opened in the center of the decorative panel 14. There is an air outlet around the suction grill 15 of the decorative panel 14. Then, four bolts from the building are set vertically downward toward the air conditioner body, and these four bolts are respectively fastened to the hanging fittings of the air conditioner body.

The air conditioner according to the present invention is an indoor heat exchanger arranged in a refrigerant circuit in which a refrigerant is circulated by a compressor, and a drain pan for collecting drain water generated in the indoor heat exchanger during a cooling operation. A drain pump for draining drain water from the drain pan, a water level detection means provided in the drain pan for detecting a stored water level of the drain water, and a control means for controlling the operation of the drain pump, and the control means A first mode in which the drain pump is stopped by the information of the thermo-off or the information of the operation stop when the thermo- off during the cooling operation or the operation of the compressor is stopped, and the drain pump is operated with priority over the first mode. It has a second mode.

The drain pan 11 is provided with a drain pump 12 and a water level detection sensor 13 for detecting the drain amount (water level) of the drain water collected in the drain pan. The water level detection sensor 13 operates the float switch (ON state) when the water level becomes higher than a predetermined amount indicating the drain water level abnormality, and transmits a signal indicating that it is in the ON state to the indoor control device. Then, the microcomputer of the indoor control device that receives the signal determines that the water level is abnormal.

This air conditioner controls the compressor drive during cooling operation and heating operation based on the information of the intake air temperature detected by the intake air temperature sensor installed at the intake port of the indoor unit and the air conditioning set temperature set by the remote controller by the user. To execute. At that time, in the case of the cooling operation, the indoor control device controls the drain pump with the output of the drain pump preset according to the operating conditions such as the operating frequency of the compressor and the rotation speed of the indoor blower.

During the cooling operation of the air conditioner, if the intake air temperature falls below the air conditioning set temperature and the thermostat is turned off, and the compressor stops and refrigerant circulation stops, the drain generated from the surface of the indoor heat exchanger Since the amount of water generated is greatly reduced, it is not necessary to continuously operate the drain pump for discharging the generated drain water, and it can be stopped. As a result, the power consumption for driving the drain pump can be reduced. That is, in the normal cooling operation, the indoor control device performs the operation control in the first mode in which the operation of the drain pump is stopped when the thermostat is turned off or the operation of the compressor is stopped.

However, depending on the drain water discharge status up to that time, depending on the drain water discharge status, in order to avoid overflow of the drain pump, if the water level detection level of the drain water is high, the indoor control device The operation control in the second mode in which the driving operation is continued without stopping the drain pump is performed with priority over the operation control in the first mode. If there is a history that a high water level was detected by the water level detection sensor even once the main power to the air conditioner was turned on, there is a concern that the drain pan may be contaminated or the drain pump itself may not operate properly. When the thermostat is turned off in the cooling operation or the compressor is stopped, the control device gives priority to the operation control in the first mode described above and executes the operation control in the second mode for continuing the operation drive without stopping the drain pump. To do. This has the effect of reducing power consumption without causing drain water to overflow.

FIG. 3 is a control flow chart for explaining a control operation relating to the drain pump operation when the thermostat is turned off or the compressor is stopped in the cooling operation of the air conditioner. The drive control operation of the drain pump will be described below with reference to FIG.

First, when the air conditioner starts the cooling operation in step S1, the drain pump operates at a predetermined rotation speed set in advance. After that, in step S2, it is determined whether the intake air temperature is lower than the air conditioning set temperature to be in the thermo-off state, or the operation of the compressor is stopped in response to the operation stop command by the remote control operation by the user. If the compressor is not stopped, the process proceeds to step S6, and the drain pump is continuously operated. On the other hand, if it is determined that the thermostat is off/compressor is stopped (YES), the process proceeds to the next step S3, and it is determined whether the drain water level is below a specified value or the water level has not exceeded a specified value in the past. I do. Then, if YES, the process proceeds to step S4 to perform the operation control in the first mode for stopping the operation of the drain pump, and if NO, the process proceeds to step S5 to continue the driving operation without stopping the drain pump. Two-mode operation control is performed.

In this way, when the indoor control device determines that the thermostat is off/compressor stopped, the drain water level is below the specified value, or the water level has not exceeded the specified value in the past. By selecting the operation control according to the first mode in which the operation of the drain pump is stopped or the operation control in the second mode in which the driving operation is continued without stopping the drain pump, and performing the control in accordance therewith, The drain water can be appropriately discharged to the outside without overflowing the drain water, and further, the power consumption required for driving the pump can be reduced.

In addition, the indoor control device uses a heat exchanger temperature sensor provided in the refrigerant pipe of the heat exchanger to detect the temperature of the refrigerant flowing through the indoor heat exchanger, and the circulating refrigerant after operation and after the compressor is stopped. Detect the temperature condition of. Then, the heat exchanger temperature detected by this heat exchanger temperature sensor is compared with the suction air temperature detected by the suction air temperature sensor, and if the heat exchanger temperature is lower than a predetermined temperature than the suction air temperature, the compressor Even if is stopped, the drain pump will continue to operate. With this, even after the compressor is stopped and the refrigerant circulation is stopped, while the indoor heat exchanger itself maintains a low temperature, the air in the air-conditioned room contacts the indoor heat exchanger to generate condensed water, The drain water generated there can be properly discharged to the outside of the indoor unit main body by operating the drain pump.

Further, the air conditioner further includes an indoor suction humidity sensor that detects the humidity of the conditioned air sucked from the indoor space at the suction port of the indoor unit together with the indoor suction temperature sensor. If the indoor suction humidity detected by this indoor suction humidity sensor is in a high humidity condition higher than a predetermined threshold value, the indoor control device continues to operate the drain pump even if the compressor operation is stopped by satisfying the thermo-off condition. The operation control is performed in the second mode. As a result, even if a larger amount of drain water than the drain water generated during the air conditioning operation under normal air conditions is collected in the drain pan, it can be discharged to the outside of the indoor unit main body without overflowing.

Next, control when the drain pump is stopped after drain water is discharged from the indoor unit body will be described.
Generally, when the drive operation of the drain pump is stopped, the drain water that is connected to the drain pump discharge port and rises upward and is drained by the pump discharge force It will flow back toward the drain pan. The noise that the drain water generated at that time collides with the rotating blades of the pump and the noise that collides with the inner wall surface of the drain pan, etc. is emitted from the indoor unit as an abnormal noise to the indoor air-conditioned space, and it is heard as an unpleasant sound to the user. Become.

In addition, when the intake air temperature drops below the set temperature during the cooling operation and the compressor is stopped due to the thermo-off state, the noise from the indoor unit is reduced to the thermo-on state due to the decrease in the rotation speed of the indoor blower. Often smaller than air conditioning operation. Therefore, if the drain pump is stopped when the thermostat is turned off or the compressor is stopped during the cooling operation, an abnormal noise due to the reverse flow of the drain water will be heard more conspicuously.

Therefore, in the stop control when the drain pump operation is stopped, the drain pump rotational speed is stepwise reduced to stop, or the continuous but gentle reduction of the rotational speed is controlled to stop the drain pump. It is possible to suppress the backflow force of the drain water that has been lifted to the discharge start-up pipe by the pump and reduce the occurrence of abnormal noise.

FIG. 4 is a control characteristic diagram of the drain pump drive when the thermostat is turned off during cooling operation or when the compressor is stopped. The vertical axis represents the drain pump rotation speed [rpm] and the horizontal axis represents time [t]. .. (A) shows the case where the drain pump drive operation is continued even after the time indicated by the dotted line indicating "thermo off/compressor stop" has passed, and (b) shows the drain pump operation at the time "thermo off/compressor stop". It shows the case of stopping. On the other hand, in (c), the operation control is shown in which the rotation speed of the drain pump is gradually reduced from the time of "thermo off/compressor stop" and it takes time to stop. While the compressor is running in the thermo-on state, the drain water is discharged from the indoor unit by operating at the drain pump speed N4, and when the thermo-off/compressor is stopped, the drain pump is in one stage up to the speed N2. The operation control is performed by lowering and operating in that state for a predetermined time, and then further lowering the rotation speed of the drain pump until it stops to zero. It should be noted that the number of stages for reducing the rotation speed of the drain pump may be two or more stages, and can be set according to the amount of drain water generated from the indoor heat exchanger and the drain pump discharge capacity.

Furthermore, (d) shows an operation of continuously and gently decreasing the rotation speed of the drain pump from the time of "thermo off/compressor stop" and performing operation control in which it takes time to stop. This is an operation control in which the drain pump is operated at the rotation speed N4 during operation of the compressor in the thermo-on state, and when the thermo-off/compressor is stopped, the rotation speed is continuously reduced from N4 to zero, which is the stop. The braking time from the thermo-off/compressor stop to the stop of the drain pump speed zero can be set according to the amount of drain water generated from the indoor heat exchanger and the drain pump discharge capacity.

As described above, the drain pump is not stopped immediately when the thermostat is turned off, but the drain pump reverse speed is gradually or continuously reduced by gradually controlling the operation of the drain pump speed. Therefore, it is possible to suppress the generation of abnormal sound from the indoor unit side.

1 Compressor 2 Four-way valve 3 Outdoor heat exchanger 4 Outdoor blower 5 Expansion valve 6 Indoor heat exchanger 7 Indoor blower 8 Blower motor 9 Bell mouth 11 Drain pan 12 Drain pump 13 Water level detection sensor 14 Makeup panel 15 Suction grill 16 Air filter 100 Air conditioner 101 Outdoor unit 102 Indoor unit

Claims (4)

An indoor heat exchanger arranged in a refrigerant circuit in which a refrigerant is circulated by a compressor, a drain pan that collects drain water generated in the indoor heat exchanger during a cooling operation, and drain water is drained from the drain pan. A drain pump, a water level detection means provided in the drain pan for detecting the stored water level of the drain water, and a control means for controlling the operation of the drain pump are provided, and the control means is used when the thermostat is turned off during cooling operation or the compression is performed. The first mode in which the drain pump is stopped by the information of thermo-off or the information of the operation stop when the operation of the machine is stopped, and the first mode in which there is a history of detecting the high water level even once from the time when the main power of the air conditioner is turned on, An air conditioner having a second mode in which the drain pump is continuously operated with priority over the first mode. When performing the operation of the drain pump according to the second mode, the air conditioner according to claim 1, wherein the stopping the drain pump from stopping of the thermo-off or the compressor during the cooling operation after a predetermined time has elapsed. The air conditioner according to claim 2, wherein when the drain pump is stopped, the drain pump is stopped while the rotation speed of the drain pump is gradually reduced. The air conditioner according to claim 2, wherein when the drain pump is stopped, the drain pump is stopped while continuously lowering the rotation speed of the drain pump.

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