JPS62202967A - 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 an air conditioner, and particularly to defrosting during heating operation of the air conditioner.

[Prior art]

Figures 9 and 10 are for example Utility Model Publication No. 57-49093
FIG. 9 is a refrigerant circuit diagram and an electric control circuit diagram during defrosting of a conventional heat pump type air conditioner shown in FIGS. 8 and 9 of the publication.

In the figure, 1 is a compressor, 2 is a four-way valve operated by a drive coil 2A, 3 is an indoor heat exchanger, 4 is a pressure reducing device, and 5 is an outdoor heat exchanger, which are connected in a ring through a refrigerant pipe 6. A refrigerant circuit 7 through which refrigerant is passed is configured. 8 is an indoor fan that blows air into the indoor heat exchanger 3 and sends it indoors;
9 is an outdoor fan that blows air into the outdoor heat exchanger 5 and sends it outside; 10 is provided at the inlet pipe of the outdoor heat exchanger 5;
A defrosting condition detector generates an output when the temperature of this part falls below a predetermined temperature, and ti is a switching device that switches from contact 11a to contact 11b when the defrosting condition detector 10 generates an output, and contact 11a is connected to the power source 1 through the drive coil 2A of the four-way valve 2 and one contact point of the heating switch 13.
5, contact 11bC:! : Connected to the power supply 15 via the relay 12 and the other contact of the heating switch 13. In addition, between both ends of the voltage = 1 s, there is a series circuit consisting of the normally closed contact 12a of the relay 12, the indoor fan 8, and the air speed switch 14 connected to the speed terminals of the indoor fan 8 and a plurality of (three in the figure) speed terminals of the indoor fan 8. is connected.

A conventional air conditioner is configured as described above, and the contact 11a of the switching device 11 is normally closed.

Then, when the heating switch 13 is closed during heating operation,
The drive coil 2A is energized and the four-way valve 2 is set to the heating cycle side. As a result, the high-temperature, high-pressure gas discharged from the compressor 1 flows as shown by the arrow, and is supplied to the indoor heat exchanger 3 through the four-way valve 2, and is forcedly ventilated by the indoor fan 8. Hot air is blown out. On the other hand, the gas refrigerant cooled by the forced draft becomes a condensed liquid and adiabatically expands in the pressure reducing device 4 to become a low-pressure refrigerant.

Then, it is heated in the outdoor heat exchanger 5 by the forced ventilation of the outdoor fan 9 and evaporates, becoming a low-pressure gas and being sucked into the compressor l via the four-way valve 2.

Here, when the outside temperature decreases, the amount of heat sucked up from the outdoor heat exchanger 5 to the refrigerant circuit 7 decreases, and when the evaporation temperature decreases to below the zero point temperature, frost formation begins on the outdoor heat exchanger 5.

As a result, the ability to absorb heat decreases, and the input pipe temperature of the outdoor heat exchanger 5 further decreases, and when the temperature falls below a predetermined temperature, the defrosting condition detector 10 generates an output. This output opens the contact 11a of the switching device 11, so the drive coil 2A is deenergized and the four-way valve 2 is switched, the refrigerant flow direction is opposite to the arrow, and the refrigerant circuit 7 is in cooling operation. Become. Also, at the same time as the contact 11a is opened, the contact 1
1b is closed, and accordingly, the relay 12 is energized and the contact 12a is opened, so that the indoor fan 8 stops blowing air. This prevents cold air from being blown to the occupants.

In this way, the four-way valve 2 is switched to enter the cooling operation, and the high-temperature, high-pressure refrigerant gas discharged from the compressor 1 enters the outdoor heat exchanger 5 after passing through the four-way valve 2, and is deposited there. The frost is melted by the heat of the refrigerant. This is the defrosting operation.

When the input pipe temperature of the outdoor heat exchanger 5 rises with the end of defrosting, the defrosting condition detector IO returns to normal and the switching switchgear 1
The first contact 11b opens and the contact tta closes. As a result, the relay 12 is deenergized again and the contact 12
a is closed, and the indoor fan 8 starts blowing air. Further, the drive coil 2A is energized again and the four-way valve 2 is switched, thereby returning to heating operation.

[Problem that the invention seeks to solve]

Conventional air conditioners are configured as described above.
There is a problem that heating is not performed during the defrosting operation and for a while after the heating operation is resumed, and the indoor temperature decreases, causing discomfort to the occupants.

Furthermore, switching from heating operation to defrosting operation causes rapid movement of refrigerant, which causes noise and liquid return to the compressor, resulting in lower reliability.

This invention was made to solve the above-mentioned problems, and is an air conditioner that prevents the indoor temperature from decreasing even during defrosting operation so as not to cause discomfort to the occupants, and also improves the reliability of the equipment. The purpose is to provide a machine.

Another object of the present invention is to provide an air conditioner with a simpler device in addition to the above object.

[Means for solving problems]

The air conditioner according to the present invention includes a solenoid valve connected between the discharge side of the compressor and the inlet side of the outdoor heat exchanger during heating operation, and a defrosting condition detector provided on the outdoor heat exchanger. When the defrosting condition detector detects the defrosting condition, the solenoid valve is opened (a solenoid valve opening/closing means and an expansion valve control means which closes the valve of an electric expansion valve provided in the refrigerant system for a certain period of time and then opens the valve) It was established.

[Effect]

In the air conditioner according to the present invention, when defrosting conditions are established, the electric expansion valve is closed to stop the refrigerant circuit that performs heating operation, and then the solenoid valve is opened to allow high temperature refrigerant gas to flow into the outdoor heat exchanger. Therefore, after a certain period of time has elapsed, the electric expansion valve is opened to adjust the refrigerant and perform defrosting operation.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, numbers 1 to 3, 5 to 7, and 10 to 15 are the same as those in the conventional apparatus shown in FIGS. 9 and 10. 17 is an electric expansion valve inserted in the position of the pressure reducing device 4 shown in FIG. 8, and controls a valve body (not shown) from fully closed to fully open or from fully open to fully closed by an input signal; 18 is a compressor
This is a solenoid valve connected between the discharge side of the outdoor heat exchanger 5 and the inlet side of the outdoor heat exchanger 5 during heating operation. However, the indoor fan 8 and outdoor fan 9 in FIG. 9 are omitted from illustration.

FIG. 2 is an overall configuration diagram of an air conditioner, and as is clear from FIG. The valve opening degree of the valve 17 is controlled, and the solenoid valve 18 is opened and closed by the solenoid valve opening/closing means 21.

3 and 4 are electrical circuit diagrams showing the electrical connections of the embodiment of FIG. 2 and a block circuit diagram of the defrosting control device.

In the figure, 23 is a defrosting control device, which is composed of a microcomputer (hereinafter referred to as microcomputer), and has a CPU
23A, memory 23B, input circuit 23C and output circuit 2
It has 3D. A defrosting condition detector IO is connected to the input terminal 11 of the input circuit 23C. Output circuit 23D
The contact 24 connected to the M1 magnetic valve 18 is connected to the output terminal 01 of the
A driving device (not shown) is connected to the output terminal 02,
03 is connected to an electric expansion valve 17.

Next, the operation of the air conditioner having the above configuration will be explained using FIG. 5 and FIGS. 6(a) to 6(c). FIG. 5 is a flowchart showing the operation program stored in the memory 23B of the defrosting control device 23, and FIGS. 6(a) to (c) are time charts showing the operation.

First, perform heating operation in step 31 shown in FIG.
2, the output of the defrosting condition detector 10 is monitored and waiting until the defrosting condition is reached. When the conditions are satisfied, the process proceeds to step 33, in which an output is generated from the output terminal 02 of the defrosting control device 23, and the electric expansion valve 17 is driven in the closing direction to be fully closed or almost fully closed. After that, in step 34, when the time ΔS has elapsed, the process moves to step 35, and the electromagnetic valve 18 is caused to be fully closed or almost fully opened by issuing a signal from the output terminal 01 of the defrosting control device 23. At this time, the high temperature refrigerant gas generated by the compressor 1 is transferred to the solenoid valve 18.
It passes through the outdoor heat exchanger 5 and melts the frost attached thereto. At this time, the electric expansion valve 17 is closed, so
The refrigerant that had accumulated in the indoor heat exchanger 3 does not flow and the compressor 1
No liquid returns to the tank. Then, in step 36, when a certain period of time ΔS has elapsed, an output is generated from the output terminal 01 of the defrosting control device 23, and the electric expansion valve 17 is opened (driven in the direction to be fully open or almost fully open. At this point, During the heating operation, the high-temperature refrigerant stored in the indoor heat exchanger 3 flows into the outdoor heat exchanger 5 to shorten the defrosting time.Also, since the solenoid valve 18 is already open, the discharge of the compressor 1 is reduced. Since the pressure has also decreased, there is no sudden movement of refrigerant, and the compressor l
It is possible to prevent liquid from returning to the tank.

Next, in step 38, when the defrosting condition is canceled, step 39
After proceeding to Step 40 and closing the solenoid valve 18, the process returns to step 40, thereby returning to the original heating operation. The operation of the solenoid valve 18 and the electric expansion valve 17 for the defrosting conditions explained in the flowchart of FIG. 5 is shown in a time chart.
The result will be as shown in the figure.

FIG. 7 is a flowchart showing another embodiment of the present invention, and FIGS. 8(a) to 8(c) are time charts thereof.

In the embodiments described above, the electromagnetic valve 18 is opened after the electric expansion valve 17 is fully closed or almost fully closed at the start of the defrosting operation.
In this embodiment, after opening the solenoid valve 18, the electric expansion valve 17 is controlled to be fully opened or almost fully closed. Effects similar to those of the embodiment can be obtained.

That is, after the electromagnetic valve 18 is opened in step 41 of FIG. 7, the electric expansion valve 17 is brought into a fully closed or almost fully closed state in step 42. Thereafter, after the time ΔS3 has elapsed in step 43, the electric expansion valve 17 is fully opened or almost fully opened in step 37.

In this embodiment, the operating program is simplified compared to the previously described embodiments, and the capacity of the memory 23B inside the defrosting control device 23 can be reduced.

〔Effect of the invention〕

As described above, according to the present invention, since the defrosting control device is provided with the expansion valve control means for controlling the electric expansion valve and the solenoid valve opening/closing means for opening and closing the solenoid valve, it is possible to enjoy comfortable This has the effect of shortening the defrosting operation time without sacrificing performance, and further improving the reliability of the air conditioner.

[Brief explanation of drawings]

1 to 6 are diagrams showing one embodiment of an air conditioner according to the present invention, in which FIG. 1 is a refrigerant circuit diagram, FIG. 2 is an overall configuration diagram, FIG. 3 is an electric circuit diagram, and FIG. 4 is a block circuit diagram of the defrosting control device of FIG. 3, FIG. 5 is a flowchart showing the operation of FIG. 4, and FIGS. 6(a) to (c) are time charts showing the operation of FIG. 5. FIG. 7 is a flowchart showing the operation of another embodiment of the present invention, FIGS. 8(a) to (c) are time charts showing the operation of FIG. 7, and FIGS.
The figure is a refrigerant circuit diagram and an electric circuit diagram showing a conventional air conditioner. In the figure, 1 is a compressor, 2 is a four-way valve, 3 is an indoor heat exchanger, 5
is an outdoor heat exchanger, an exchanger, 6 is a refrigerant pipe, 7 is a refrigerant circuit, 10
17 is an electric expansion valve; 18 is a solenoid valve; 21 is a solenoid valve opening/closing means; 22 is an expansion valve control means; 23
is a defrost control device. Note that the same reference numerals in the figures indicate the same parts.

Claims (2)

[Claims] (1) A compressor, a four-way valve, an indoor heat exchanger, an electric expansion valve, and an outdoor heat exchanger are connected in a ring through refrigerant piping to pass the refrigerant, and the four-way valve directs the refrigerant to the indoor heat exchanger. a refrigerant circuit that performs heating operation by flowing the air into the air, a solenoid valve connected by refrigerant piping between the discharge side of the compressor and the inlet side of the outdoor heat exchanger during the heating operation, and the outdoor heat exchanger. a defrosting condition detector for detecting a defrosting condition of the equipment; an expansion valve control means for closing the electric expansion valve when the defrosting condition detector outputs an output; An air conditioner comprising a solenoid valve opening/closing means that opens the solenoid valve after a lapse of time, and wherein the expansion valve control means opens the electric expansion valve after a predetermined time has elapsed from the opening of the solenoid valve. (2) A compressor, a four-way valve, an indoor heat exchanger, an electric expansion valve, and an outdoor heat exchanger are connected in an annular manner by refrigerant piping to pass the refrigerant, and the four-way valve directs the refrigerant to the indoor heat exchanger. a refrigerant circuit that performs heating operation by flowing the air into the air, a solenoid valve connected by refrigerant piping between the discharge side of the compressor and the inlet side of the outdoor heat exchanger during the heating operation, and the outdoor heat exchanger. a defrosting condition detector for detecting the defrosting condition of the equipment; a solenoid valve opening/closing means that opens the solenoid valve when the defrosting condition detector outputs an output; An air conditioner comprising an expansion valve control means that closes an electric expansion valve and opens it after a certain period of time.