JPH06323639A - Method for controlling chilled water supplying device - Google Patents

Abstract

PURPOSE:To prolong the service life of a compressor by a method wherein an operating state of the compressor is judged in reference to information got from a suction pressure sensor and a discharge pressure sensor, an amount of pressure reduction of an electronic expansion valve is computed in reference to the operating state and a temperature of chilled water and it is corrected until its operating state of the compressor coincides with its condition of use. CONSTITUTION:There are provided a chilled water inlet temperature sensor 9 and a chilled water outlet temperature sensor 10 as control means. Information got from them are inputted to a controller 11. An operating frequency of a compressor 1 is computed, the compressor 1 is controlled by an inverter 12 and then a cooling capability of a freezing cycle is controlled. Information got from the discharging pressure sensor 13 and a suction pressure sensor 14 are inputted to the controller 12 and it is judged whether the condition of use of the compressor 1 is sufficient. If the condition is satisfactory, it is not necessary to adjust an electronic expansion valve 3. If the condition of use of the compressor 1 is not satisfactory, the amount of reducing pressure of the electronic expansion valve 3 is corrected in compliance with the state of not-filling and then the correction is carried out until its condition of use is fulfilled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a computer cooling device that requires cold water at a constant temperature and a general industrial cold water supply device, and more particularly to a method for controlling a refrigeration cycle.

[0002]

2. Description of the Related Art As a conventional technique, in Japanese Patent Laid-Open No. 2-4165, an inverter controls the refrigerating capacity of a refrigerating cycle in order to absorb the heat load of a heating element and cool the chilled water returned to a refrigerating apparatus. , A method that makes it possible to supply cold water at a stable temperature is described.

[0003]

In the above technique, the output frequency of the inverter is controlled on the basis of the temperature of the return chilled water returned from the load, the operating frequency of the compressor is controlled according to the value, and the cooling capacity of the refrigeration cycle is controlled. This is a method of cooling the chilled water that circulates between the load and the load.In this method, the inverter output frequency is controlled, but it is not taken into consideration in the usage conditions of the compressor. There is a problem that the life is shortened.

An object of the present invention is to satisfy the usage conditions of the compressor, to control the refrigeration cycle in a stable manner, and to supply a stable cold water.

[0005]

To achieve the above object, the present invention measures a discharge pressure sensor and a suction pressure sensor for monitoring the operating state of a compressor, a discharge temperature, a suction temperature sensor, and the temperature of cold water. The operating condition of the compressor is monitored by the temperature sensor, and the electronic expansion valve is adjusted according to the usage conditions of the compressor.

[0006]

The operation state of the compressor is judged from the information from each sensor, and the electronic expansion valve is adjusted to satisfy the usage condition of the compressor. As a result, the usage conditions of the compressor can be satisfied and the service life is not shortened.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. Figure 1
FIG. 3 is a system diagram of a cold water supply device according to this embodiment. The refrigerating cycle of this cold water supply device is constituted by the compressor 1, the condenser 2, the electronic expansion valve 3, the evaporator 4, and the refrigerant pipe 5 connecting them, and the cold water cooled by the evaporator 4 is pumped by the pump 6 Water is sent to the load 8 through the cold water pipe 7. A chilled water inlet temperature sensor 9 and a chilled water outlet temperature sensor 10 are provided as control means, and information obtained from them is input to a controller 11, which calculates an operating frequency of the compressor 1 and controls the compressor 1 by an inverter 12. , Control the cooling capacity of the refrigeration cycle.

Discharge pressure sensor 13 and suction pressure sensor 14
The obtained information is input to the controller 12 and it is determined whether the usage conditions of the compressor 1 are satisfied. The usage conditions of the compressor 1 are that the suction pressure is 1 to 7 kg / cm ² G, the discharge pressure is 11 to 25 kg / cm ² G, and the pressure ratio ε is between 1.8 and 8. The pressure ratio ε is calculated from the equation 1.

[0009]

[Equation 1]

When the operating condition of the compressor 1 is out of the operating condition, for example, when the suction pressure is low, the decompression amount of the electronic expansion valve 3 is reduced to increase the suction pressure. If the suction pressure is high, the pressure reduction amount of the electronic expansion valve 3 is increased to reduce the suction pressure.

When the discharge pressure is high, the electronic expansion valve 3
Decrease the amount of pressure reduction and reduce the discharge pressure. If the discharge pressure is low, the pressure reduction amount of the electronic expansion valve 3 is increased to increase the discharge pressure.

If the pressure ratio is small, the decompression amount of the electronic expansion valve 3 is increased to increase the discharge pressure and decrease the suction pressure,
Try to increase the pressure ratio. If the pressure ratio is high, reverse the adjustment to reduce the pressure ratio.

The electronic expansion valve 3 is adjusted to adjust the refrigeration cycle so that the usage conditions of the compressor 1 are met.

If the conditions are satisfied, it is not necessary to adjust the electronic expansion valve 3, but if the usage conditions of the compressor 1 are not satisfied, the electronic expansion valve 3 is adjusted according to the unsatisfied state. The amount of pressure reduction is corrected until the usage condition of the compressor 1 is satisfied. If the cold water temperature is high, the operating frequency is increased to increase the refrigeration capacity. At that time, the electronic expansion valve 3 is adjusted to a pressure reduction amount corresponding to the operating frequency. By keeping the previously corrected amount as it is, the change in the corrected amount can be suppressed small. Then, the operating state of the refrigeration cycle is observed to determine whether the usage conditions of the compressor 1 are satisfied. If the usage condition is satisfied, the condition is left as it is, and if not satisfied, the decompression amount of the electronic expansion valve 3 is adjusted.

By constantly monitoring the state of the refrigerating cycle and maintaining the operating state of the refrigerating cycle within a certain range, a stable refrigerating cycle state can be obtained, stable cold water can be supplied, and the operating conditions of the compressor 1 can be controlled. Can be satisfied.

[0016]

According to the present invention, since the usage conditions of the compressor can be satisfied, the product can be used without shortening the life of the compressor. Further, cold water having a stable temperature can be supplied.

[Brief description of drawings]

FIG. 1 is a system diagram of a cold water supply device to which the present invention is applied.

[Explanation of symbols]

1 ... Compressor, 2 ... Condenser, 3 ... Electronic expansion valve, 4 ... Evaporator, 5 ... Refrigerant piping, 6 ... Pump, 7 ... Cold water piping, 8 ... Load, 9 ... Cold water inlet temperature sensor, 10 ... Cold water Outlet temperature sensor, 11 ... Controller, 12 ... Inverter, 13 ... Discharge pressure sensor, 14 ... Suction pressure sensor.

Claims (1)

[Claims] 1. A compressor having a variable capacity by capacity control, a condenser, an electronic expansion valve capable of adjusting a decompression amount from the outside, a refrigeration cycle in which an evaporator is sequentially connected by a refrigerant pipe, and heat exchange by the evaporator. In a method for controlling a cold water supply device having a cold water pipe and a pump for circulating cold water between a load and a pump, capable of measuring suction pressure and discharge pressure of the compressor, and a temperature sensor for measuring cold water temperature. A chilled water supply device characterized in that a condition of the refrigeration cycle is grasped and a decompression amount of the electronic expansion valve is adjusted to satisfy a usage condition of the compressor and to control a stable refrigeration cycle. Control method.