JPH0828971A - Controlling method of air conditioner - Google Patents

Abstract

PURPOSE:To prevent seizure due to a shortage of oil supply by detecting pressures at a discharge part and a suction part of a compressor, by executing a blower control of an air cooled type condenser with a difference between the detected pressures used as a variable to be controlled and by of ensuring thereby a lower limit value or above of a pressure difference allowing oil to be supplied in the compressor. CONSTITUTION:After passing through a check valve 2, a gas refrigerant of high temperature and high pressure compressed by a compressor 1 exchanges heat with air in an air cooled type condenser 3 and becomes a high-pressure refrigerant. The high- pressure refrigerant is depressurized in an expansion valve 4 to exchange heat with cold water and becomes a gas refrigerant of low temperature and low pressure and it returns to the compressor 1, thus a refrigerating cycle being formed. In this case, pressure detecting ports 6 and 7 are provided at a discharge part and a suction part of the compressor 1 respectively. A blower control of the air cooled type condenser 3 is executed with a difference between the detected pressures used as a variable to be controlled and thereby a lower limit or above of a pressure difference allowing oil to be supplied in the compressor 1 is ensured. Thereby seizure due to a shortage of oil supply is prevented and a smooth operation of the refrigerating cycle is conducted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner control method.

[0002]

2. Description of the Related Art In the conventional steady operation, the blower was sometimes controlled using the discharge pressure Pd and the outside air temperature as variables in order to secure a difference in the oil supply pressure of the compressor.
The variable of (Pd-Ps) at this time is not taken into this control as s.

[0003]

In the prior art, when the pressure difference ΔP between the discharge pressure and the suction pressure is larger than the lower limit value Po of refueling possibility to some extent, there was no problem, but a refrigerant having a small pressure is used as the physical property. In such a case, ΔP <Po is likely to occur, and seizure may be caused due to insufficient oil supply to the compressor.

An object of the present invention is to provide an air conditioner equipped with an air-cooled condenser having one or a plurality of blowers and a compressor of a type that replenishes discharge pressure by utilizing a pressure difference of suction pressure. It is possible to prevent seizure due to shortage.

[0005]

In order to achieve the above object, the present invention provides an air-cooled condenser having a blower or blowers and a compressor of a type that refuels by utilizing a pressure difference between a discharge pressure and a suction pressure. In an air conditioner equipped with a compressor, pressure detection ports are respectively provided in the discharge part and the suction part of the compressor, and the pressure difference (ΔP between the pressure Pd detected from the discharge part and the pressure Ps detected from the suction part during operation of the compressor = Pd-Ps)
Is used as a variable when controlling the blower for the condenser. That is, (1) When the pressure difference ΔP (= Pd−Ps) becomes close to or lower than the refuelable differential pressure lower limit value Po, control for stopping the rotation of the condenser blower is added.

(2) When the pressure difference ΔP (= Pd-Ps) is close to or lower than the lower limit value Po of refueling possible, control is performed to reduce the rotation speed of the condenser blower.

(3) When the pressure difference ΔP (= Pd-Ps) becomes close to or below the lower limit value Po of refueling possible pressure, the group control operation of the condenser blower is also added to the control.

[0008]

According to the present invention, by adopting the above-mentioned means, the refrigerant pressure in the air-cooled condenser rises, that is, the discharge pressure Pd rises. Therefore, the oil supply differential pressure ΔP (= Pd-
The value of (Ps) becomes large, and it is possible to secure the refuelable differential pressure lower limit value ΔP or more.

[0009]

1 is a refrigeration cycle system diagram of an air conditioner of the present invention. In the figure, a high-temperature, high-pressure gas refrigerant compressed by a compressor 1 passes through a check valve 2 and is heat-exchanged with air in an air-cooled condenser 3 to become a high-pressure liquid refrigerant. The high-pressure liquid refrigerant is decompressed by the expansion valve 4 and heat-exchanged with cold water in the evaporator 5, becomes a low-temperature low-pressure gas refrigerant, and returns to the compressor 1 in the refrigeration cycle. ，
The pressure detection port 7 is arranged in the suction part, and the blower control of the air-cooled condenser 3 is performed by setting the variable for detecting each pressure and controlling the pressure difference, and the lower limit of the refuelable pressure difference of the compressor 1 is controlled. Secure a value Po or more. Now, the lower limit value Po of the refuelable pressure difference of the compressor 1 is set to 3 kg / cm ² . During operation of the compressor, the difference ΔP (= Pd−Ps) ≦ 3 kg / cm ² between the pressure Pd detected by the discharge part 6 of the compressor 1 and the pressure Ps detected by the suction part 7 during the unloading operation of the compressor, etc. In this case, the operation of the air-cooled condenser 3 is stopped or the rotation speed is reduced. At this time, the refrigerant pressure rises inside the air-cooled condenser 3 due to a decrease in heat exchange capacity. That is, the pressure Pd on the discharge side rises to secure ΔP> 3 kg / cm ² or more.

FIG. 2 shows an example in which an air-cooled condenser 3 having a plurality of blowers is mounted. It is assumed that, while the compressor is operating, four air-cooling type condenser blowers 8, 9, 10, and 11 are operating together, and ΔP is also 5 kg / cm ² or more. When ΔP becomes 4.0 kg / cm ² or less due to compressor unloading operation, the blower 11 is stopped. Further, when ΔP is 3.5 kg / cm ² or less, the blower 8 is stopped, and ΔP is 3.0 kg / cm ²
In the following cases, the rotation speeds of the blowers 9 and 10 are reduced. Thereby, the lower limit value Po of the refuelable differential pressure of the compressor 1 Po
The above can be secured. That is, it is possible to prevent seizure due to insufficient oil supply of the compressor 1.

[0011]

According to the present invention, a compressor for an air conditioner equipped with an air-cooled condenser having one or more blowers and a compressor of a type that refuels by utilizing a pressure difference between a discharge pressure and a suction pressure. It is possible to secure a value equal to or higher than the lower limit value of the refuelable differential pressure, and to prevent seizure due to insufficient refueling and to perform a smooth operation of the refrigeration cycle.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle system diagram of an air conditioner according to an embodiment of the present invention.

FIG. 2 is a perspective view of the present invention having a plurality of condenser blowers.

[Explanation of symbols]

1 ... Compressor, 2 ... Check valve, 3 ... Air-cooled condenser, 4 ... Expansion valve, 5 ... Evaporator, 6 ... Pressure detection port (discharge pressure), 7
... Pressure detection port (suction pressure), 8-11 ... Blower for condenser.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takeo Takemoto 390 Muramatsu, Shimizu City, Shizuoka Prefecture, Hitachi Air Conditioning Systems Division (72) Inventor Masanori Uekura 390, Muramatsu, Shimizu City Hitachi, Ltd. Air Conditioning Systems, Hitachi, Ltd. Within the Business Department (72) Inventor Ken Kaneko 390 Muramatsu, Shimizu City, Shizuoka Prefecture

Claims (1)

[Claims] 1. An air conditioner equipped with an air-cooled condenser having a blower or blowers and a compressor of a type that refuels by utilizing a pressure difference between a discharge pressure and a suction pressure, the discharge section of the compressor. The pressure detection port is provided in each of the suction and suction parts, and the difference between the pressure detected by the discharge part during operation of the compressor and the pressure detected by the suction part is close to the lower limit of the refuelable pressure difference, or In this case, the method for controlling the air conditioner has a function of stopping the rotation of the blower for the condenser.