JPS6066072A - Defroster for air conditioner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a defrosting device for a refrigeration cycle used in an air conditioning tank. As a defrosting method in a refrigeration cycle configured by sequentially connecting an indoor heat exchanger, a pressure reducer, and an outdoor heat exchanger with refrigerant piping, the four-way valve 2 switches from the heating cycle to the cooling cycle, as shown in Figure 1. ,
Generally, defrosting is carried out by converting the outdoor heat exchanger 6, which acts as an evaporator during heating and forms frost at low pressure, into a condenser. In addition, 1 is a compressor, 3 is an indoor heat exchanger,
4 is a pressure reducer, 6 is an accumulator, 9 is a pressure reducer, 10
1 is a solenoid valve, 18 is a refrigerant pipe, 19 is a bypass circuit, 7.
8 is a blower 11 is a frost detector, and 20 is a temperature sensor. However, in such a conventional defrosting system, the indoor heat exchanger 3 becomes an evaporator during defrosting operation, so an auxiliary heater 20 & is provided to prevent cold draft, and the refrigerant flowing to the indoor heat exchanger 3 is In order to suppress this as much as possible, control has been performed to open the solenoid valve 10 of the bypass circuit. In addition, in this type of system, after the defrosting is completed, when the indoor heat exchanger 3 returns to the heating cycle and changes into a condenser, the rise in pressure and temperature becomes slower and reaches a steady state because it was acting as an evaporator during defrosting. It takes time, lacks comfort and has drawbacks. Note that solid line arrows indicate the refrigerant flow during heating, and broken line arrows indicate the refrigerant flow during defrosting.

Purpose of the Invention The present invention has been made in view of the drawbacks of the conventional example, and
The purpose of this is to quickly increase heating capacity when the heating cycle resumes after defrosting, thereby improving comfort.

Composition of the invention In order to achieve the above object, the present invention provides a compressor.

A refrigeration cycle is constructed by sequentially connecting a four-way valve, an indoor heat exchanger, a flow rate control valve, and an outdoor heat exchanger with refrigerant piping, and a refrigeration cycle is constructed by connecting a four-way valve, an indoor heat exchanger, a flow rate control valve, and an outdoor heat exchanger in sequence, and a refrigeration cycle is formed between the flow rate control valve and the outdoor heat exchanger, and a refrigeration cycle is formed between the flow control valve and the outdoor heat exchanger. A first on-off valve is provided in the pipe line connected to the suction side, and a second on-off valve is provided on the pipe line connecting the four-way valve and the indoor heat exchanger. A control circuit is provided that closes the control valve and the second on-off valve, opens the first on-off valve, and switches the four-way valve.

With this configuration, high-temperature, high-pressure liquid refrigerant is sealed inside the indoor heat exchanger by the flow control valve and the second on-off valve during defrosting operation, and heating capacity is quickly ramped up after defrosting is completed. .

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 2 to 4.

FIG. 2 is a refrigeration cycle according to an embodiment of the invention, FIG. 3 is an electric circuit diagram thereof, and FIG. 4 is a diagram showing changes in heating capacity and a control method thereof.

In Fig. 2, 1 is a compressor, 2 is a four-way valve, and 13 is a second
1 is a solenoid valve, 3 is an indoor heat exchanger, 12 is an electric expansion valve, 5 is an outdoor heat exchanger, 6 is an accumulator, and the refrigerant pipe 1 is connected in sequence.
8 are connected to form a refrigeration cycle. Also, during heating, the outlet of 5 electric expansion valve 12 and the accumulator 6
The first electromagnetic valve 10 and the inlet of the valve are connected by a Z-circuit 19 via a pressure reducer 9. In addition, 2
0 is a temperature sensor, 7 and 8 are indoor heat converters 3, respectively.
゜The blower of the outdoor heat exchanger 5, 11 is the frost detector, and p1
The electric expansion valve 12 has a throttling action and a function of simultaneously closing the pipeline.
The motor 1a of the compressor 1 is connected in series via a stop switch 18.

Reference numeral 16 denotes a control device which operates/stops the compressor 1 and defrosts it based on signals from the temperature detector 20 and the frost detector 11, and switches between the heating operation and the defrosting operation by turning on the switch 1. Contact points 17a and 17b of the switch 17 are connected to a motor 1 for the blower for the electromagnetic coil internal heat exchanger 3 for driving the four-way valve 2, a motor 8a for the blower 8 for the outdoor heat exchanger 5, and a motor 8a for driving the first electromagnetic valve 10. and electromagnetic coils 10a are connected to each other. By switching the switch 17, the contacts 17& and 17b are connected to the power source 14 via the operation switch 16, respectively.

Next, the operation of this embodiment will be explained with reference to Fig. 4, which shows the relationship between the change in heating capacity over time, the defrosting cycle, and each valve control.〇First, the temperature of the air-conditioned room during heating is set to the desired setting. When the operating switch 16 is closed when the temperature is lower than the temperature, the control device 16 operates the switch 18 to close based on the signal from the temperature detector 2o, and at the same time operates the contact 17a of the switch 17 to close the closed contact. As a result, motors 1a, 7
a and 8a and electromagnetic coils 21L, 12a and 13a
is energized, the four-way valve 2 enters the heating cycle, and the electric expansion valve 12 and the second solenoid valve 13 become open.
Compressor 1. The blower 7 for the indoor heat exchanger 3 and the blower 8 for the outdoor heat exchanger 5 are started.

As a result, the gas refrigerant compressed to a high temperature and high pressure by the compressor 1 is condensed in the indoor heat exchanger 3 to form high temperature and high pressure liquid refrigerant and potash, as shown by the solid line arrow, and is depressurized by the electric expansion valve 12 to become low temperature and low pressure. It becomes a two-phase refrigerant of gas and liquid, flows into the outdoor heat exchanger 5, evaporates, passes through the accumulator 6, and returns to the compressor 1.
At this time, the indoor heat exchanger 3 exchanges heat with the surrounding indoor air, and the blower 7 for the indoor heat exchanger 3 blows warm air toward the air-conditioned room. That is, in FIG. 4, by closing the operation switch 15 at time O to start heating, the heating capacity increases over time and the temperature of the air-conditioned room rises. After that, it remains in a steady state for a certain period of time, but especially in low outside temperature conditions, the moisture condensed in the outdoor heat exchanger 5 forms frost, which reduces the heat absorption capacity, so it is necessary to remove the frost. .

Therefore, the formation of frost is detected by the frost detector 11 and a signal is sent to the control device 16 to perform defrosting operation.
The control device 16 operates in response to the signal from the frost detector 11 so that the contact 17b of the switch 17 is closed. As a result, motors 7a and 8a and electromagnetic coils 2a, 1
2a and i3a are de-energized, the four-way valve 2 enters the cooling cycle, and the electric expansion valve 12 and the second solenoid valve 13
is in a closed state, and the blower 7 for the indoor heat exchanger 3 and the blower 8 for the outdoor heat exchanger 5 are stopped. At the same time, since the electromagnetic coil ICJ& is energized, the first electromagnetic valve 1o is in an open state. In this way, the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 is condensed in the outdoor heat exchanger 6 as shown by the broken line arrow, and is formed in the outdoor heat exchanger 5 due to the heat radiation effect in the process of becoming a high-temperature, high-pressure liquid refrigerant. Thaw the frost. The refrigerant flowing out from the outdoor heat exchanger 5 passes through a pressure reducer 9 provided in a bypass circuit 19 and returns to the compressor 1 from the accumulator 6. At this time, the electric expansion valve 12 and the second electromagnetic valve 13 confine the liquid refrigerant, which was at high temperature and high pressure during the heating operation, in the indoor heat exchanger 3. After a certain period of time has elapsed, when a signal indicating the end of defrosting is sent by the frost detector 11, the control device 16 operates so that the contact 17a of the switch 1 closes. In this way, the four-way valve 2 is switched to the heating cycle, the first solenoid valve 1o is closed, the electric expansion valve 12 and the second expansion valve 13 are opened, and the blowers A and 8 are started to resume heating operation. be done.

As described above, in the present invention, when the indoor heat exchanger 3 is defrosted, the electric expansion valve 12 and the second solenoid valve 13 are used to maintain the refrigerant state close to that during steady heating, that is, the indoor heat exchanger 3
By keeping the indoor heat exchanger 3 at high temperature and high pressure and by sealing in the liquid refrigerant, the heat capacity required to raise the indoor heat exchanger 3 to high temperature and high pressure when defrosting is restored is small, and the liquid refrigerant is immediately Since the heat passes through the electric expansion valve 12 and flows into the outdoor heat exchanger to exert an endothermic effect, the heating capacity increases quickly.

In addition, some percentage of the total amount of refrigerant charged in the refrigeration cycle is confined within the indoor heat exchanger 3 by two valves during defrosting operation, so the liquid that could not be evaporated during defrosting in the past Although there has been a problem in which refrigerant accumulates in the accumulator 6 and overflows, being sucked into the compressor 1 and causing liquid compression, it is thought that such a problem will not occur with the control method described above.

In this embodiment, the main circuit is closed during the defrosting operation by using an electric expansion valve 12 that has both a throttling function and a circuit closing function, but instead of the electric expansion valve 12, a capillary tube and a solenoid valve The electric expansion valve 1 as a combination
There is no problem with anything that has the same functionality as 2. Further, the pressure reducer of the bypass circuit is not particularly necessary as long as it can be used in common with the pressure reducer of the main circuit.

1. In this embodiment, the switching of the four-way valve 2 and the control of the other valves are synchronized, but these controls may have a certain degree of time difference. However, at the same time as switching four-way valve 2,
Or, some time ago, the flow control valve 12 and the second solenoid valve 13
It is more effective to close it.

As described in detail, the air conditioner defrosting device of the present invention has the following features:
A refrigeration cycle is constructed by sequentially connecting a compressor, a four-way valve, an indoor heat exchanger, a flow control valve, and an outdoor heat exchanger with refrigerant piping, and branching from between the flow control valve and the outdoor heat exchanger, A first on-off valve is provided in a conduit connected to the suction side of the compressor, and a second on-off valve is provided in a conduit connecting the four-way valve and the indoor heat exchanger. A defrosting device for an air conditioner, comprising a control circuit that closes the flow rate control valve and the second opening/closing valve, opens the first opening/closing valve, and switches the four-way valve during frost formation. In this way, by maintaining a refrigerant state close to that of steady heating in the indoor heat exchanger during defrosting operation, the heating capacity can be increased quickly after the removal of the box, and comfort can be improved. . In addition, it exhibits a soaking effect, such as being able to prevent liquid compression.

[Brief explanation of drawings]

Fig. 1 is a refrigeration cycle diagram of an air conditioner showing a conventional example;
FIG. 2 is a refrigeration cycle diagram of an air conditioner having a defrosting device according to an embodiment of the present invention, FIG. 3 is an electric circuit diagram of the defrosting device of an air conditioner according to an embodiment of the present invention, and FIG. The figure shows changes over time in the heating capacity of the air conditioner and the control of each valve. 1... Compressor, 2... Four-way valve, 3...
・Indoor heat exchanger, 12...Flow rate control valve, 5...
...Outdoor heat exchanger, 10...First on-off valve, 13...Second on-off valve, 16...Control circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A refrigeration cycle is constructed by sequentially connecting a compressor, a four-way valve, an indoor heat exchanger, a flow rate control valve, and an outdoor heat exchanger with refrigerant piping, and a refrigeration cycle is constructed by connecting a compressor, a four-way valve, an indoor heat exchanger, a flow rate control valve, and an outdoor heat exchanger, and branching from between the flow rate control valve and the outdoor heat exchanger to A first on-off valve is provided in the pipe line connected to the suction side of the compressor, and a second on-off valve is provided on the pipe line connecting the four-way valve and the indoor heat exchanger. when the flow control valve and the second on-off valve are in a closed state,
The defrosting device for an air conditioner is further provided with a control circuit for opening the first on-off valve and switching the four-way valve.