VARIABLE-CAPACITY CONTROL FOR REFRIGERATING CYCLE

摘要

Variable-capacity control is reliably carried out without using a large pressure control valve while maintaining sufficient pressure resistance in a refrigerating cycle in which carbon dioxide is used as its coolant. A pressure sensor for measuring the pressure on the low pressure side of this refrigerating cycle is used. The electromagnetic coil of the pressure control valve is controlled so that the measured pressure approaches the target value. Low pressure is applied equally to both ends in the direction of movement of the valve disc of the pressure control valve, so that the valve disc can be moved by a light load, and hence the size of the electromagnetic coil can be small.