JPH07218005A - Air conditioner - Google Patents

Abstract

PURPOSE:To reduce a frequency of ON and OFF of a compressor by switching an opening of a motor operated expansion valve provided in a refrigerating cycle in proportion to a temperature difference between a set temperature and a room temperature. CONSTITUTION:An indoor controller 9 calculates a temperature difference between a set temperature and a room temperature, and the opening of a motor operated expansion valve 6 is obtained. When a temperature difference between a set temperature when an air conditioner is started to be operated and the room temperature is large, an opening of the valve 6 is increased, a refrigerant circulating amount is increased to increase its capacity. On the contrary, when the room temperature approaches the set temperature to reduce the difference, the opening of the valve 6 is decreased to reduce the circulating amount, thereby decreasing its capacity. Thus, the capacity of the conditioner can be varied to reduce a frequency of ON and OFF of the compressor 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner with variable capacity.

[0002]

2. Description of the Related Art Normally, an air conditioner is selected so as to have sufficient ability to perform air conditioning at the maximum air conditioning load, but the time ratio at which it is operated at the maximum load is small, and most of the air conditioner is air. It is operated with an air conditioning load that is less than the capacity of the air conditioner. Therefore, the air conditioner has an excessive capacity with respect to the air conditioning load, and the compressor is ON-OFF controlled to keep the room temperature at the set temperature. However,
To keep the room temperature close to the set temperature, turn the compressor ON-OF.
F control must be performed frequently, and there are the following problems. The first is the problem of restarting the compressor. That is,
When the compressor is stopped and restarted, the pressures on the discharge side and the suction side are not balanced, so the compressor starts up against the differential pressure, which may cause a start-up failure. The second is an increase in heat loss that occurs each time the compressor is stopped. That is, when the compressor stops, the low-temperature low-pressure side refrigerant and the high-temperature high-pressure side refrigerant move until they are balanced in pressure, which causes heat loss. As a means for solving such a problem, there is, for example, Japanese Patent Publication No. 3-19469.

[0003]

Although the above-mentioned problems are solved in the air conditioner according to the prior art, since the capacity of the air conditioner is constant and the ON / OFF control of the compressor is performed,
There was a problem that comfort was not improved due to room temperature fluctuations near the set temperature.

An object of the present invention is to solve the above problems and provide an air conditioner in which the frequency of ON / OFF of the compressor is reduced and the comfort is improved.

[0005]

In order to achieve the above object, the present invention opens and closes the opening of an electric expansion valve provided in a refrigeration cycle in proportion to the temperature difference between a set temperature and room temperature.

[0006]

[Function] By opening and closing the opening of the electric expansion valve in proportion to the temperature difference between the set temperature and the room temperature, the refrigerant circulation amount of the refrigeration cycle is made variable, the capacity of the air conditioner is controlled, and the O of the compressor is controlled.
Reduce the frequency of N-OFF.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an air conditioner according to the present invention. 1 is a compressor, 2 is an S tank, 3 is an indoor heat exchanger, 4 is an outdoor heat exchanger, 5 is a switching valve, and 6 is an electric expansion valve, which constitutes a refrigeration cycle. Also,
Reference numeral 7 is an indoor blower, and 8 is an outdoor blower. 9 is an indoor control open circuit, 10 is a room temperature setting circuit, 11 is a room temperature measuring circuit, 12
Is an outdoor control circuit, and 13 is an electric expansion valve drive circuit. The indoor control circuit 9 compares and calculates the set temperature set by the room temperature setting circuit 10 and the room temperature measured by the room temperature measuring circuit 11, and the ON-OFF control of the compressor 1 and other indoor units 14 and the entire air conditioner. Control. The outdoor control circuit 12 controls the outdoor unit 15. For example, in the cooling operation, the compressor 1 is turned on when the room temperature is higher than the set temperature, and is turned off when the room temperature is low. Here, the capacity of the air conditioner is mainly determined by the refrigerant circulation amount of the refrigeration cycle, and the refrigerant circulation amount of the refrigeration cycle depends on the suction pressure and discharge of the compressor 1 when the compressor 1 is driven at a constant rotation speed. Determined by pressure and displacement. Therefore, the capacity can be controlled by changing the opening degree of the electric expansion valve 6 in proportion to the temperature difference between the set temperature and the room temperature, the room temperature is controlled near the set temperature, and the compressor 1 is turned on and off. The frequency of can be reduced.

The indoor control circuit 9 calculates the temperature difference between the set temperature and the room temperature, and obtains the opening degree of the electric expansion valve 6 from the relationship shown in FIG. When the temperature difference between the set temperature and the room temperature is large such as when the air conditioner starts operating, the opening degree of the electric expansion valve 6 is increased to increase the refrigerant circulation amount to increase the capacity. On the contrary, when the room temperature approaches the set temperature and the temperature difference becomes small, the opening degree of the electric expansion valve 6 is reduced to reduce the refrigerant circulation amount and the capacity is reduced. The calculated opening of the electric expansion valve 6 is transmitted from the indoor control circuit 9 to the outdoor control circuit 12, and the expansion valve drive circuit 13 drives the electric expansion valve 6.

[0009]

According to the present invention, since the opening of the electric expansion valve can be controlled in proportion to the temperature difference between the set temperature and the room temperature, the capacity of the air conditioner can be varied and the frequency of ON / OFF of the compressor can be reduced. can do.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an air conditioner according to the present invention.

FIG. 2 is an explanatory diagram of electric expansion valve control according to the present invention.

[Explanation of symbols]

 1 ... Compressor, 2 ... S tank, 3 ... Indoor heat exchanger, 4 ... Outdoor heat exchanger, 5 ... Switching valve, 6 ... Electric expansion valve, 7 ... Indoor blower, 8 ... Outdoor blower, 9 ... Indoor control open circuit , 10 ... Room temperature setting circuit, 11 ... Room temperature measuring circuit, 12 ... Outdoor control circuit, 13 ... Electric expansion valve drive circuit, 14 ... Indoor unit, 15 ... Outdoor unit.

Claims (1)

[Claims] 1. A compressor for compressing a refrigerant, an indoor heat exchanger,
In an air conditioner that constitutes a refrigeration cycle from an outdoor heat exchanger, a switching valve, an electric expansion valve, an indoor blower and an outdoor blower, and the indoor unit and the outdoor unit each have a control circuit, the opening of the electric expansion valve is performed. An air conditioner that opens and closes in proportion to the temperature difference between the set temperature and room temperature.