JPH0359349B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure adjustment control method for an air conditioner in which an on-off valve for capacity control such as a solenoid valve is provided between high and low pressures in a refrigeration cycle. By keeping the on-off valve open for a certain period of time when the power switch is opened, the high-low pressure balance of the refrigeration cycle is promoted, thereby preventing damage to the on-off valve, and in particular, a pilot type solenoid valve is used as the on-off valve for capacity control. One of the purposes is to reduce noise caused by vibration inside the solenoid valve.

Conventionally, the refrigeration cycle of this type of air conditioner and its operation control device have been constructed as shown in FIGS. 1 and 2.

In the figure, reference numeral 1 denotes an indoor unit, which is equipped with an indoor heat exchanger 2, an indoor fan 3, and the like. 4 is equipped with an outdoor unit, a compressor 5, an outdoor heat exchanger 6, an outdoor fan 7, an electromagnetic switching valve 8, an electromagnetic valve 9 for capacity control, and a pressure reducer 11.

13 is an operation switch, and 17 is a pressure switch for controlling the ability to open and close the solenoid valve 9.

In the above conventional air conditioner, the electromagnetic switching valve 8
The system performs switching between cooling and heating, and performs capacity control using a bypass circuit 12 constituted by a solenoid valve 9. This bypass circuit 12 is connected between the discharge pipe 5a and suction pipe 5b of the compressor 5. Further, 18 is a refrigerant heater that heats the refrigerant, and is equipped with a heat source such as an electric heater or an oil boiler.

Reference numerals 19 and 20 are on-off valves for controlling refrigerant flow, and during cooling operation and normal heating operation, on-off valve 1 is used.
9 opens, and the on-off valve 20 closes. Further, when the refrigerant is to flow into the refrigerant heater 18, the on-off valve 19 is closed and the on-off valve 20 is opened.

Then, when the electromagnetic switching valve 8 is energized, the inside of the electromagnetic switching valve 8 becomes the circuit shown by the broken line in the figure, and heating operation is started, the pressure inside the indoor heat exchanger 2 increases and the outdoor heat exchanger The pressure inside 6 will drop. In this state, when the operation is stopped by the operation switch 13 and the electromagnetic switching valve 8 is no longer energized, the inside of the electromagnetic switching valve 8 becomes the circuit shown by the solid line in the figure, and the pressure in the indoor heat exchanger 2 increases. is compressor 5
The pressure is transmitted to the suction side of the compressor 5, and the pressure becomes higher than the discharge side of the compressor 5, and a reverse pressure is applied to the solenoid valve 9 in the bypass circuit 12 with the valve closed.

In pilot-type solenoid valves, when the valve is closed and reverse pressure is applied and the differential pressure decreases, noise similar to electromagnetic noise is generated, so for air conditioner users, it is important to The sound that can be heard after the machine is turned off creates a sense of unease.

As a countermeasure to this problem, it is possible to surround the solenoid valve 9 with soundproofing material, but this increases the temperature rise of the solenoid valve coil, which is not preferable and is not a fundamental countermeasure.

It is also conceivable to install a check valve in series in the bypass circuit 12, but the check valve will leak when the differential pressure disappears, so similarly, the solenoid valve 9
More noise is generated.

Furthermore, it is conceivable to use a reversible solenoid valve or a solenoid valve with a check valve as the solenoid valve 9, but this type of structure increases the cost and the bypass circuit 1
2, the port diameter of the solenoid valve 9 must be increased, and reversible solenoid valves with large port diameters and solenoid valves with check valves have the disadvantage of high cost. There is.

Therefore, in order to solve the above conventional problems, the present invention reduces the load on the solenoid valve 9 and prevents noise by opening the solenoid valve 9 for a certain period of time even when the operation switch 13 is opened. It is something.

Hereinafter, one embodiment of the present invention will be described with reference to FIG. 3 of the accompanying drawings. Note that the refrigeration cycle diagram is the same as the conventional example, so it will be omitted. In FIG. 3, the same parts as in FIG. 2 are given the same numbers and their explanations will be omitted.

In the figure, 14 is a timer device, and 15 is an interlocking switch that works in conjunction with the operation switch 13, which operates to “close” and “open” in reverse to the “open” and “close” operations of the operation stop switch 13, and Controls power supply to the device 14. 16a is a contact of the timer device 14, and the contact 16a becomes "closed" at the same time as the timer device 14 is activated. Then, after a predetermined time has elapsed, contact 1
6a becomes "open".

Next, the behavior of the refrigerant from heating operation to stop will be explained. During heating operation, the electromagnetic switching valves 8 are connected as shown by broken lines, and the refrigerant pressure in the indoor heat exchanger 2 increases and the pressure in the outdoor heat exchanger 6 decreases. At this time, the solenoid valve 9 may be opened or closed by the pressure switch 17 for capacity control depending on whether capacity control is to be performed or not.

When the operation switch 13 is closed from this state, the electromagnetic switching valve 8 is switched as shown by the solid line in FIG.
5 is closed, the timer device 14 is energized at the same time, and the contact 16a is "closed" for a certain period of time, so that the solenoid valve 9 is also opened. Therefore, the high-pressure refrigerant in the indoor heat exchanger 2 flows through the electromagnetic switching valve 8 and the electromagnetic valve 9 to the outdoor heat exchanger 6. Note that the contact of the pressure switch 17 for capacity control opens when the pressure decreases at the same time as the operation is stopped.

This eliminates the pressure difference between the discharge pipe 5a and the suction pipe 5b.

As a result, the problem of back pressure being applied to the electromagnetic valve 9 and noise generation after the operation is stopped can be solved, and failures of the electromagnetic valve 9 can also be eliminated.

Although the refrigeration cycle of this embodiment has been described for the heating case of a normal heat pump type refrigeration cycle, the same applies to the case of cooling, and the same applies to a heat transfer type refrigeration cycle having the refrigerant heating device 18. Can be implemented. Further, the present invention relates to a pressure adjustment control method for an air conditioner, and the control device can be similarly implemented using an electronic control circuit or the like. Further, in this embodiment, the electromagnetic valve 9 for capacity control also serves as a valve device for pressure adjustment, but similar effects can be obtained even if a valve device for pressure adjustment is provided separately. Further, the position where this valve device is installed is not particularly limited as long as it is a position that short-circuits the high pressure side and the low pressure side of the refrigeration cycle.

As is clear from the above embodiments, the pressure adjustment control method for air conditioning according to the present invention includes a refrigeration cycle configured by connecting a compressor, an electromagnetic switching valve, an outdoor heat exchanger, an indoor heat exchanger, and a pressure reducer, respectively.
Further, an electromagnetic on-off valve is connected between the discharge side and the suction side of the compressor to communicate or disconnect between the two,
The electromagnetic switching valve is opened for a certain period of time after the power switch that enables energization to the compressor and the electromagnetic switching valve is opened to eliminate the pressure difference between the discharge side and the suction side of the compressor. By opening the solenoid valve for a certain period of time even if the switch is opened and operation is stopped, the pressure difference between high and low pressures in the refrigeration cycle is smoothly eliminated, and in addition, reverse pressure is applied to the solenoid valve when it is closed. Therefore, the solenoid valve is always protected, and there are no noises caused by the movement of refrigerant when the solenoid valve is closed. Compared to normal heating operation in which refrigerant flows through an outdoor heat exchanger, the back pressure applied to the pilot type solenoid valve after the refrigerant heating operation is stopped is high. will definitely be prevented.

[Brief explanation of drawings]

FIG. 1 is a refrigeration cycle diagram of an air conditioner, FIG. 2 is an electric control circuit diagram showing a conventional example, and FIG. 3 is an electric control circuit diagram of an air conditioner according to an embodiment of the present invention. 2... Indoor heat exchanger, 5... Compressor, 5a...
Discharge pipe, 5b... Suction pipe, 6... Outdoor heat exchanger,
8...Solenoid switching valve, 9...Solenoid on-off valve.

Claims (1)

[Claims] 1. A refrigeration cycle is constructed by connecting a compressor, an electromagnetic switching valve, an outdoor heat exchanger, a pressure reducer, and an indoor heat exchanger in order, and connecting a refrigerant heater in parallel to the outdoor heat exchanger and the pressure reducer, In an air conditioner in which the discharge side and suction side of the compressor are connected by a bypass circuit having a pilot type electromagnetic switching valve, after opening a power switch that enables energization to the compressor and the electromagnetic valve switching valve, a constant A pressure adjustment control method for an air conditioner in which the pilot type electromagnetic on-off valve is opened at certain times.