JP7094482B2 - Air conditioner - Google Patents

Description

The present invention relates to an air conditioner.

As an air conditioner for constant temperature and humidity air conditioning, a heat pump that exchanges heat between heat source air and air conditioning air via a refrigerant, an electric heater that heats the air conditioning air exchanged by the heat pump, and humidifying the air conditioning air. Those equipped with a steam humidifier and a blower that supplies air-conditioned air adjusted to a target temperature and humidity to the air-conditioned space by these devices are known.

Japanese Unexamined Patent Publication No. 2016-23851

In such an air-cooled heat pump, defrosting operation is indispensable because frosting occurs in the heat exchanger for the heat source of the heat pump when the heat source air becomes low temperature. When the defrosting operation is performed, the air for air conditioning cannot be heated by the heat exchanger for air supply of the heat pump, so the heat pump heating and the electric heater heating are switched before and after the defrosting operation, but the rise and fall of both are different. Is likely to occur. Therefore, there is a problem that the supply air temperature varies and exceeds the allowable range of the target supply air temperature.

In order to solve the above problems, the present invention targets an air heat source compression type heat pump that exchanges heat of air conditioning air with a refrigerant, a heater that heats the air conditioning air, and a supply air temperature of the air conditioning air. The control device includes a defrosting monitoring unit that monitors the necessity of defrosting operation of the heat pump and outputs a defrosting start signal and a defrosting end signal, and the defrosting start signal. In response to this, the heating capacity of the heat pump is lowered to zero, and the heating capacity of the heater is increased so as to offset the decrease in the supply air temperature, and then the defrosting operation is started and the defrosting is completed. After receiving the signal and ending the defrosting operation, the heating capacity of the heat pump is increased from zero, and the heating capacity of the heater is lowered so as to offset the increase in the air supply temperature accompanying the increase to the air supply temperature. The most important feature is that it is provided with a defrosting temperature control unit that suppresses the difference from the target air supply temperature.

According to the first aspect of the present invention, the defrosting temperature suppressing unit can suppress the variation exceeding the allowable range of the target air supply temperature, and the heat pump can be used to perform constant temperature and humidity constant air conditioning at all times. It can be used not only for constant temperature and humidity air conditioning, but also for general indoor air conditioning where defrosting operation is indispensable. Since it is an air conditioner that uses an air heat source compression type heat pump, the equipment and construction can be simplified and the cost can be reduced compared to the cold / hot water type. While minimizing the use of heaters, which are less energy efficient than heat pumps, overshoot of the supply air temperature due to heating of the heat pump can be prevented, and energy-saving and highly accurate constant temperature and humidity air conditioning can be performed.

According to the invention of claim 2, since the change in the supply air temperature of the air conditioning air due to the change in the output of the heat pump is compensated by the heating of the heater having no minimum limit output and good controllability, the followability is good, and overshoot and hunting are performed. Highly accurate constant temperature and humidity air conditioning can be performed.
According to the third aspect of the present invention, since the heat exchanger for the heat source is shared by a plurality of refrigeration cycles, the number of parts can be reduced and the size can be reduced. When operating multiple refrigeration cycles in a mixture of forward cycle (supply air cooling) and reverse cycle (supply air heating), the high-temperature refrigerant and low-temperature refrigerant exchange heat inside the shared heat source heat exchanger to generate heat. Energy is offset, which saves energy.
According to the invention of claim 4, the dead water region of the heat transfer tube group of the air supply heat exchanger and the heat source heat exchanger is reduced, the ventilation resistance of the heat transfer tube group is small, and energy is saved, and the air for air conditioning and the heat source are used. The contact area with air (the amount of heat flowing through) increases and the heat exchange efficiency improves.

It is a simplified explanatory drawing which shows the structure of the air conditioner of this invention. It is a simplified explanatory drawing of a heat exchanger. It is explanatory drawing which shows the control example of the air conditioner at the time of defrosting operation. It is an air diagram which shows the operation pattern example of the air conditioner. It is an air diagram which shows the heating control example of an air conditioner.

FIG. 1 is an embodiment of the air conditioner of the present invention, in which the air conditioner includes an air heat source compression type heat pump 1, a heater 2, a humidifier 3, an air supply blower 4, and a heat source blower 5. A control device 6 and a casing 7. The heat pump 1, the heater 2, the humidifier 3, the air supply blower 4, and the heat source blower 5 are housed in the casing 7. If the control device 6 cannot be installed inside the casing 7, it may be externally attached. The thick dotted arrow in the figure indicates the flow direction of the air conditioning air and the heat source air. From the air conditioner, the air conditioning air is supplied to the air-conditioned space S, and the heat source air is exhausted to the outside or the like. ..

The heat pump 1 includes two refrigerating cycles 8 and exchanges heat with a refrigerant for air conditioning air to cool or heat the air. The refrigeration cycle 8 includes a compressor 9 that compresses and conveys the refrigerant, an air supply heat exchanger 10 that transfers the heat of the refrigerant to the air conditioning air, and a heat source heat exchanger 11 that transfers the heat of the heat source air to the refrigerant. In a refrigerant circulation circuit composed of an expansion valve 12, a four-way valve 13, and other equipment, the steps of compression, condensation, expansion, and evaporation of the refrigerant are repeated, and the refrigerant evaporation process is applied to the air that exchanges heat with the refrigerant. It absorbs heat (air cooling) and dissipates heat (air heating) in the refrigerant condensation process. The two refrigeration cycles 8 are configured so that each of them can independently switch between air cooling and air heating by the four-way valve 13.

As shown in FIGS. 1 and 2, the air supply heat exchanger 10 and the heat source heat exchanger 11 are formed by connecting the fin group 15 to the heat transfer tube group 14. Refrigerant flows inside the heat transfer tube group 14, and air conditioning air and heat source air pass through the outer surface of the heat transfer tube group 14 and the fin group 15. The heat transfer tube group 14 is preferably formed of an elliptical tube, but may be a circular tube. The supply air heat exchanger 10 exchanges heat between the outside air or the return air as air conditioning air with a refrigerant, or exchanges heat between the mixed air of the outside air and the return air with a refrigerant as air conditioning air. The heat source heat exchanger 11 exchanges heat with the outside air or a mixed air of the outside air and the return air as the heat source air. In the illustrated example, one heat source heat exchanger 11 is shared by two refrigeration cycles 8, but a separate heat source heat exchanger may be provided for each refrigeration cycle 8 without sharing.

The heater 2 is an electric heating type that heats the air for air conditioning by electric heating. The humidifier 3 is a steam type that humidifies the air for air conditioning with steam. The air supply heat exchanger 10 and the heater 2 of the heat pump 1 are installed so as to heat the air conditioning air with the heater 2 after heat exchange with the air supply heat exchanger 10. The air-conditioning blower 4 takes in air-conditioning air into the machine, passes it through the air-conditioning heat exchanger 10, the heater 2, and the humidifier 3 of the heat pump 1, and passes the air-conditioned space S through a duct or the like (not shown). To supply air to. The heat source blower 5 takes in the heat source air into the machine, passes the heat source air through the heat source heat exchanger 11 of the heat pump 1, and exhausts the heat source air to the outside of the machine.

The control device 6 includes a setting unit 16 that sets a target temperature and a target humidity of the air-conditioned space S, a detection unit 17 that detects the temperature and humidity of the air-conditioned space S, an air-conditioning control unit 18, and a defrost monitoring unit 19. A defrosting temperature control unit 20, a heater control unit 21, a heat compensation unit 22, and a cooling compensation unit 23 are provided, and these are used in a microprocessor, various sensors, switches, and other control devices. Configure.

The air conditioning control unit 18 has a heat pump 1, a heater 2, and a humidification so that the temperature and humidity of the air-conditioned space S detected by the detection unit 17 become the target temperature and humidity of the air-conditioned space S set by the setting unit 16. The capacity of the device 3 and the air volume of the air supply blower 4 and the heat source blower 5 are increased or decreased to adjust the air supply temperature of the air conditioning air to the target air supply temperature and the target air supply humidity. The temperature and humidity of the air-conditioned space S are detected by a temperature / temperature sensor (not shown) provided in the air-conditioned space S.

The defrosting monitoring unit 19 monitors the necessity of the defrosting operation of the heat pump 1 and outputs a defrosting start signal and a defrosting end signal. Whether or not the heat pump 1 needs to be defrosted depends on whether or not the temperature, refrigerant pressure, refrigerant temperature, etc. of the heat source air when frosting occurs in the heat source heat exchanger 11 is detected. To judge. These temperatures and pressures are detected by a temperature sensor, a refrigerant pressure sensor, a refrigerant temperature sensor, etc. (not shown) provided in the heat pump 1. The defrosting method is a hot gas bypass method in which a bypass valve 24 is provided in the refrigerating cycle 8 and a high-temperature refrigerant is circulated only in the heat exchanger 11 for the heat source and the compressor 9 to defrost, but other defrosting methods are used. It may be a frost method.

As shown in FIGS. 1 and 3, the defrosting temperature suppressing unit 20 receives the defrosting start signal of the defrosting monitoring unit 19 and gradually lowers the heating capacity (HP output) of the heat pump 1 until it becomes zero. After gradually increasing the heating capacity (HT output) of the heater 2 so as to offset the decrease in the supply air temperature of the air conditioning air, the defrosting operation is started and the defrosting end signal of the defrosting monitoring unit 19 is sent. After receiving and finishing the defrosting operation, the heating capacity (HT output) of the heater 2 is gradually increased from zero to offset the increase in the supply air temperature of the air conditioning air. ) Is gradually lowered to suppress the difference between the supply air temperature and the target supply air temperature.

FIG. 3A shows changes in the HP output of the heat pump 1 and the HT output of the heater 2 by the defrosting temperature suppressing unit 20, and FIG. 3B shows the air heating temperature (HP temperature) by the heat pump 1 and the heater 2. The change of the air heating temperature (HT temperature) is shown. The defrosting temperature control unit 20 includes a heater control unit 21, and the heater control unit 21 changes every time the absolute value K (K1, K2) of the difference between the air heating temperature by the heat pump 1 and the target air supply temperature fluctuates. The absolute value K (K1, K2) is reset to the target air heating temperature T (T1, T2) by the heater 2 to increase or decrease the heating capacity of the heater 2.

FIG. 4 is a psychrometric chart showing a typical operation pattern of the air conditioner of the present invention. The points A indicated by black circles indicate the target air temperature and humidity, and the points B, C and D indicated by white circles indicate the temperature and humidity of the air conditioning air when taken into the machine. In the case of point B, the heat pump 1 cools and dehumidifies to the target humidity of point A, and then heats (reheats) the heat pump 1 or the heater 2 to the target temperature of point A. In the case of point C, after heating to the target temperature of point A with the heat pump 1 or the heater 2, humidification is performed to the target humidity of point A. In the case of point D, the heat pump 1 cools to the target temperature of point A and then humidifies to the target humidity of point A. In this way, the air conditioning air is adjusted to the target air supply temperature and supplied to the air-conditioned space S.

As shown in FIGS. 1 and 5, since the compressor 9 of the heat pump 1 has a structurally operable minimum output (minimum limit output), the target of point A is when the heat pump 1 heats the air for air conditioning. The supply air temperature may be exceeded (overshoot to point E). Therefore, when the heat compensation unit 22 determines whether or not the predicted air supply temperature of the air conditioning air when heated at the minimum limit output of the heat pump 1 exceeds the target air supply temperature of the point A, the heat pump 1 The air-conditioning air is heated to the target air supply temperature at point A by the heater 2 without heating with.

Further, when cooling the air conditioning air with the minimum limit output of the heat pump 1 from the point D in FIG. 4, if the temperature falls below the target supply air temperature (undershoot), the cooling compensation unit 23 performs the minimum limit of the heat pump 1. If the predicted air-conditioning air temperature when cooled by the output is lower than the target air-conditioning temperature after judging whether it is lower than the target air-conditioning temperature, cool it with the minimum limit output of the heat pump 1 and then set the air-conditioning air to the target air supply. It is heated (reheated) by the heater 2 without being heated by the heat pump 1 to the temperature.

The present invention is not limited to the above-mentioned examples. Although not shown, the number of refrigerating cycles 8 of the heat pump 1 can be freely increased or decreased. In the refrigeration cycle 8 of the heat pump 1, a set of a compressor 9, a heat exchanger 11 for a heat source, and a blower 5 for a heat source is installed outdoors, and the outdoor set and the rest of the air supply heat exchanger 10 in the casing 7 and the like. It may be a separate type in which the indoor set, which is a component of the refrigeration cycle 8 of the above, is connected by a refrigerant pipe. Further, a vaporization type humidifier may be provided between the humidifier 3 and the air supply heat exchanger 10. If the humidification is insufficient only with the vaporization type humidifier, the shortage is humidified with the steam humidifier. It is free to configure.

1 Heat pump 2 Heater 6 Control device 8 Refrigeration cycle 10 Air supply heat exchanger 11 Heat source heat exchanger 14 Heat transfer tube group 19 Defrost monitoring unit 20 Defrosting temperature control unit 21 Heater control unit 22 Heat compensation unit S Air-conditioned space

Claims (4)

An air heat source compression type heat pump (1) that exchanges heat with air conditioning air with a refrigerant, a heater (2) that heats the air conditioning air, and control that adjusts the supply air temperature of the air conditioning air to the target supply air temperature. Equipped with the device (6)
The control device (6) monitors the necessity of the defrosting operation of the heat pump (1) and outputs a defrosting start signal and a defrosting end signal to the defrosting monitoring unit (19) and the defrosting start signal. In response to this, the defrosting operation is started after increasing the heating capacity of the heater (2) so as to offset the decrease in the supply air temperature accompanying the decrease in the heating capacity of the heat pump (1) to zero. At the same time, after receiving the defrosting end signal and ending the defrosting operation, the heater (2) increases the heating capacity of the heat pump (1) from zero and offsets the increase in the supply air temperature accompanying the increase. For defrosting temperature control unit (20) that lowers the heating capacity of the above to suppress the difference between the supply air temperature and the target supply air temperature, and for the air conditioning when heated at the minimum limit output of the heat pump (1). If the predicted air supply temperature of the air exceeds the target air supply temperature by judging whether or not it exceeds the target air supply temperature, the air conditioning air is heated by the heater (2) without heating by the heat pump (1). An air conditioner including a heat compensating unit (22) for heating up to . The defrosting temperature suppressing unit (20) sets the absolute value (K) to the heater (K) every time the absolute value (K) of the difference between the air heating temperature of the heat pump (1) and the target air supply temperature fluctuates. The air conditioner according to claim 1, further comprising a heater control unit (21) that resets the target air heating temperature (T) of 2) to increase or decrease the heating capacity of the heater (2). The heat pump (1) includes a plurality of refrigerating cycles (8), and the refrigerating cycle (8) includes an air supply heat exchanger (10) that transfers heat of the refrigerant to the air conditioning air, and a heat source to the refrigerant. The invention according to claim 1 or 2, further comprising a heat source heat exchanger (11) for exchanging heat from the air, and sharing the heat source heat exchanger (11) in a plurality of the refrigeration cycles (8). Air conditioner. The air conditioner according to any one of claims 1 to 3, wherein the air supply heat exchanger (10) and the heat source heat exchanger (11) include a heat transfer tube group (14) composed of an elliptical tube. ..

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