JPH0743194B2 - Heat pump type air conditioner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to improvement of a heat pump type air conditioner, and more particularly to measures for shortening defrosting time for defrosting frost grown on a heat source side heat exchanger during heating. .

(Prior Art) Conventionally, as a heat pump type air conditioner of this type, as disclosed in, for example, Japanese Patent Laid-Open No. 54-164053, an inverter for controlling the rotation speed (capacity control) of a compressor and a heat source side It is equipped with a frost detector that detects frost formation on the heat exchanger. When frost is formed during heating, the refrigerant circulation system uses a four-way switching valve to reverse the heating cycle (defrost cycle).
It is known that the defrosting capacity of the heat source side heat exchanger is shortened by increasing the defrosting capacity by driving the compressor to the maximum rotation speed with the inverter.

(Problems to be Solved by the Invention) By the way, in the case where a plurality of compressors are provided in parallel for one refrigerant circulation system in order to improve the operation capacity, if the capacity of all the compressors is to be controlled by the inverter, the capacity of the inverter, In particular, since it is necessary to increase the current allowable value of the power transistor, which leads to high cost and upsizing of the equipment, only a part of the compressor is capacity controlled by the inverter and the rest is driven by the commercial power source with fixed capacity. Therefore, it is desirable to secure low cost and compactness of the device.

However, in that case, while the compressor is operating at the time of defrosting at a high capacity that is partly higher than the capacity corresponding to the commercial frequency by the inverter, the rest is performed at medium capacity equivalent to the commercial frequency. Therefore, the defrosting is performed without fully exerting the capacity of the remaining compressor, and the shortening of the defrosting time is not so effective.

In view of such a point, the present inventors have made detailed measurements of various amounts during the defrosting cycle during defrosting, and as shown in FIG. 3, the high pressure of the refrigerant is significantly lower than that during heating, And because the low pressure and a slight decrease, the specific volume of the refrigerant increases and the pressure difference between the high and low refrigerant becomes smaller,
As a result, it was found that the current supplied to the motor that drives the compressor (output current of the inverter) is greatly reduced as indicated by the broken line in the figure, which makes it possible to control all compressors with high efficiency by the inverter during defrosting. Even so, I was aware that the defrosting time could be shortened more effectively without causing damage to the inverter.

Therefore, an object of the present invention is to control the capacity of a part of a plurality of compressors connected in parallel as described above with an inverter sufficient to drive only the compressor during heating, and fix the capacity of other parts with a commercial power source. In the case of defrosting, while using an inverter that can drive only some of the above compressors during defrosting, by operating all the compressors with a high capacity that is higher than the drive capacity of the commercial power source, The objective is to reduce the defrosting time more effectively while ensuring low cost and compactness.

(Means for Solving the Problem) In order to achieve the above object, the solution means of the present invention is a compressor, a four-way switching valve, an air conditioning load side heat exchanger, an expansion mechanism, and a heat source side heat exchanger. In a heat pump type air conditioner that forms a closed circuit refrigerant circulation system with a compressor, the compressor is connected in parallel with a first compressor whose capacity is controlled by an inverter during heating and the first compressor (1a). It is composed of a second compressor that is connected and is driven by a commercial power source at the time of heating and has a fixed capacity, and the inverter (10) is the first compressor of the first and second compressors (1a) and (1b). Frost detection means for detecting only the first compressor (1a) having an output current value sufficient for driving during heating, and frost detection means for detecting frost formation on the heat source side heat exchanger; and the frost detection means. Received the output of
A configuration provided with defrosting operation control means for switching the refrigerant circulation system to a cycle opposite to the heating cycle and controlling both the first and second compressors with the inverter to have a capacity higher than the capacity corresponding to the commercial frequency. It is what

(Operation) With the above configuration, according to the present invention, only a part of the plurality of compressors corresponding to the output current value of the inverter is heated during heating when the output current value from the inverter to the one compressor is large. Is controlled by the above-mentioned inverter, and the rest is driven by a commercial power source with fixed capacity. On the other hand, at the time of defrosting in which the output current value from the inverter for one compressor becomes small, the capacity of all the compressors is controlled by the inverter, so that the defrosting time can be shortened more effectively.

Here, the inverter is sufficient to drive only a part of the plurality of compressors during heating, but even if the capacity of all the compressors is controlled by the inverter during the defrosting,
Since the current value supplied to the compressors of the stand is extremely small compared with the time of heating, the maximum output current value of the inverter is not exceeded and the inverter is not burned. Therefore, it is possible to enhance the defrosting ability while limiting the capacity of the inverter to a small value.

(Example) Hereinafter, the Example of this invention is described in detail based on drawing.

In FIG. 1, (1a) and (1b) are first and second compressors connected in parallel with each other, (2) is a four-way switching valve, and (3) is an indoor ventilation fan ( An air conditioning load side heat exchanger having 3a), (4) an expansion mechanism, (5) an outdoor side heat exchanger having a blower fan (5a),
(6) is an accumulator, and each of the devices (1) to
(6) is connected by a refrigerant pipe (7) so that refrigerant can circulate to form a closed-circuit refrigerant circulation system (A). During heating, the four-way switching valve (2) is switched as shown by the solid line to circulate the refrigerant. The system (A) is set to a heating cycle and the refrigerant is circulated as indicated by the solid line arrow, so that the heat amount absorbed from the outside air in the heat source side heat exchanger (5) acting as an evaporator acts as a condenser and the air conditioning load side heat exchange is performed. The indoor unit (3) repeatedly radiates heat to the indoor air to heat the room, and at the time of cooling and defrosting, the four-way switching valve (2) is switched as shown by the broken line to set the refrigerant circulation system (A) as a heating cycle. Is a reverse cycle (that is, a cooling cycle or a defrosting cycle), and the refrigerant is circulated as indicated by a dashed arrow to transfer heat in the opposite direction to cool the room or to the heat source side heat exchanger (5). Defrost grown frost It has been made to so that.

Further, (10) is an inverter for controlling the capacity of the first compressor (1a) alone or simultaneously for the two compressors (1a), (1b), and (11) is the inverter (10). The inverter (10) is a commercial power source that is a drive source of the second compressor (1b) and a drive source of the second compressor (1b), and the inverter (10) outputs a frequency signal according to the deviation between the room temperature and the room temperature set value during cooling and heating. And a high frequency signal higher than the commercial frequency during defrosting during heating.

The inverter (10) has an output current value sufficient to drive only the first compressor (1a) of the first compressor (1a) and the second compressor (1b) during heating. The capacity is selected.

Further, (12) is a frost formation detecting means composed of a dicer for detecting frost formation in the heat source side heat exchanger (5), and the frost formation detection signal of the frost formation detection means (12) is the above-mentioned two units. Compressor (1
It is input to the control circuit (13) that controls the operation of a) and (1b).

The internal structure of the control circuit (13) is shown in FIG.
In the figure, (MC1) is a first compressor motor driven based on the frequency signal from the inverter (10),
(MC2) is a second compressor motor driven by power supply from a commercial power supply (11).

Further, (3X) is an air blow / temperature control relay that is turned on when the changeover switch (14) is in the air blow position and temperature control position, and (52F1) is turned on when the air blow / temperature control relay (3X) is turned on. Indoor fan relay, (15) 2-pole cold / warm selector switch, (16) switches to the COLD terminal side when the room temperature is below the room temperature set value, and switches to the HOT terminal side when the room temperature is above the set value. It is a temperature switch to replace.

In addition, (52Fo) is during cooling and heating
When the temperature switch (16) is on the COLD terminal side when the warm switch (15) is switched to the heating side, and when the cold / warm switch (15) is switched to the cooling side, the temperature switch (16) is set to HOT.
The outdoor blower fan relay that can be turned on when it is on the terminal side, (52C1) is the first compressor motor relay that can be turned on during the above cooling and heating, and (10X) is the first compression motor relay. Of the compressor motor relay (52C1) that is turned on when the normally open contact (52C1-2) of the relay is closed (52C2) is the delay timer of the delay timer (10X). A second compressor motor relay that can be turned on when its normally open contact (10X-1) is closed after a timer time, wherein the first compressor motor relay (52C1) is the first compressor motor (52C1). MC1) power supply circuit with its normally open contact (52C1-
1) is installed, and the second compressor motor relay (52C2) has its normally open contact (52C2-1) in the power supply circuit from the commercial power supply (11) of the second compressor motor (MC2). Is installed. Therefore, at the time of heating, the first compressor motor (MC
The inverter (10) controls the rotation speed of the first compressor (1a) to control the capacity of the first compressor (1a), and the second compressor motor relay (52C2) is turned on to turn on the second compressor motor (MC).
2) is driven by a commercial power source (11) to operate the second compressor (1b) at a fixed capacity.

In addition, (20S) is a four-way switching solenoid valve that is turned on when the cooling / warming switch (15) is switched to the cooling side to switch the four-way switching valve (2) as shown by the broken line, and (23DX) is a cold / warm switching. A frost detection relay that is turned on when a frost detection signal from the frost detection means (12) is received when the switch (15) is switched to the heating side, and is connected to the power supply circuit of the four-way switching solenoid valve (20S). Is a normally open contact (23DX) that turns on the four-way switching solenoid valve (20S) when frost is detected to switch the refrigerant circulation system (A) to the defrost cycle.
-1) is installed and the outdoor fan relay (52
The fo) power supply circuit is provided with a normally closed contact (23DX-2) for turning off the outdoor fan relay (52Fo) when frost is detected. Similarly, the power supply circuit of the second compressor motor relay (52C2) is also provided. The second compressor motor relay (52C
2) is turned off to turn on the commercial power (1) of the second compressor (MC2).
A normally-closed contact (23DX-3) for stopping the drive by 1) is provided. Also, (23DY) is the frost detection relay (23
By closing the normally open contact (23DX-4) when the DX) turns on
The frost detection reaction relay that is turned on, (52C3) is the second when the normally open contact (23DY-1) of the frost detection reaction relay (23DY) is closed and the second
A second compressor / motor switching relay that is turned on based on closing of a normally closed contact (52C2-2) of the compressor / motor relay (52C2), and the inverter (10) to the second compressor. A normally open contact (52C3-1) of the second compressor motor switching relay (52C3) is provided in the middle of a power supply circuit (20) formed to supply a frequency signal to the motor (MC2). There is. Therefore, when frost is detected on the heat source side heat exchanger (5) during heating, the four-way switching solenoid valve (20S) is turned on based on the ON operation of the frost detection relay (23DX) to turn on the four-way switching valve (2 ) Is switched as indicated by the broken line, the refrigerant circulation system (A) is set to the cycle (defrost cycle) opposite to the heating cycle, and the outdoor fan relay (52Fo) is turned off to blow the fan of the heat source side heat exchanger (5). While stopping (5a), the second
After turning off the compressor motor relay (52C2) of No.2 and stopping the drive of the second compressor motor (MC2) by the commercial power supply (11), turn on the second compressor motor switching relay (52C3).
By operating and driving the second compressor motor (MC2) by the inverter (10) outputting high frequency signals, the first and second compressor motors (MC1), (MC2), that is, the two The defrosting operation control means (30) is configured so that the two compressors (1a) and (1b) connected in parallel are both controlled by the inverter (10) to have a capacity higher than the capacity corresponding to the commercial frequency. ing.

A normally closed contact (23DY-2) of the frost detection reaction relay (23DY) is provided in the power supply circuit of the indoor fan relay (52F1), and when defrosting, the air conditioning load side heat exchanger (3) It is designed to stop the blower fan (3a). In addition, in FIG. 3, (3X-1) is a normally open contact for self-holding of the blower / temperature control relay (3X).

Therefore, in the above embodiment, during heating, the first compressor motor (MC1) is controlled in rotation speed by the inverter (10) based on the ON operation of the first compressor motor relay (52C1), and Only the compressor (1a) is capacity controlled,
In the remaining second compressor (1b) connected in parallel to the first compressor (1a), the second compressor motor (MC2) is commercialized by turning on the second compressor motor relay (52C2). Power (11)
The ability is fixed by being driven by. Inverter (1
Since the capacity of 0) is selected to have an output current value sufficient to drive only the first compressor (1a) during heating, the inverter (10) has a low cost and a small size. Can be adopted.

Moreover, when the heat source side heat exchanger (5) is defrosted during the heating, the inverter (10) outputs the highest frequency signal to drive the first compressor (1a) to the maximum capacity. The output current value for the first compressor (1a) of (10) decreases, and a capacity (output current value) has a margin, and the second compressor motor switching relay (52C3)
Based on the ON operation, the second compressor motor (MC2) is driven by the inverter (10) to the maximum rotation speed within the range of the margin capacity (margin output current), and its capacity corresponds to the commercial frequency. Since the output current value of the inverter (10) does not exceed the maximum value and the defrosting capacity increases without incurring its burning, the defrosting at the heat source side heat exchanger (5) It will be effectively done with a short defrosting time.

Therefore, it is possible to enhance the defrosting capacity while adopting the inverter (10) having a small capacity with a small output current value.

In addition, although the present invention is applied to the cooling and heating device in the above-described embodiment, the present invention is not limited to this, and can be applied to a device having at least a heating function.

(Effects of the Invention) As described above, according to the heat pump type air conditioner of the present invention, during defrosting, the capacity is driven to be fixed by the first compressor and the commercial power supply whose capacity is controlled by the inverter during heating. Since the second compressor and the second compressor are both controlled to have a capacity higher than that corresponding to the commercial frequency by a small capacity inverter having an output current value sufficient to drive only the first compressor during heating, While adopting a low-cost and small-sized inverter as the above-mentioned inverter, the defrosting of the heat source side heat exchanger can be effectively performed with a shorter defrosting time, and thus the cost and size of the device can be reduced. It is possible to remarkably improve the defrosting ability.

[Brief description of drawings]

The drawings show an embodiment of the present invention, FIG. 1 is a refrigerant piping system diagram, FIG. 2 is an electric circuit diagram showing an internal configuration of a control circuit, and FIG. 3 is a high pressure and low pressure of the refrigerant during defrosting and an inverter. It is a figure which shows the characteristic of an output current. (1a) ... first compressor, (1b) ... second compressor,
(2) ... four-way switching valve, (3) ... air conditioning load side heat exchanger, (4) ... expansion mechanism, (5) ... heat source side heat exchanger,
(A) …… Refrigerant circulation system, (10) …… Inverter, (1
1) …… Commercial power supply, (12) …… Frost detection means, (30)…
... Defrosting operation control means.

Claims (1)

[Claims] 1. A compressor (1), a four-way switching valve (2), an air conditioning load side heat exchanger (3), an expansion mechanism (4) and a heat source side heat exchanger (5). In a heat pump type air conditioner that forms a refrigerant circulation system (A) of a circuit, the compressor (1) includes a first compressor (1a) whose capacity is controlled by an inverter (10) during heating, and the first compressor (1a). Second compressor (1b) connected in parallel to the compressor (1a) and having a fixed capacity to be driven by the commercial power supply (11) during heating, and the inverter (10) is connected to the first and second inverters (10). Of the second compressors (1a) and (1b), only the first compressor (1a) is configured to have an output current value sufficient for driving during heating, and the heat source side heat exchanger (5 ) Frost detection means (12) for detecting frost formation, and an output of the frost detection means (12),
The refrigerant circulation system (A) is switched to a cycle opposite to the heating cycle, and the first and second compressors (1a),
A defrosting operation control means (30) for controlling both (1b) by the inverter (10) to a capacity higher than that corresponding to a commercial frequency, a heat pump type air conditioner.