Circulating fluid circuit With the circulating pump, circulating fluid will be discharged to the customer’s machine side. After the circulating fluid will heat or cool the customer’s machine side, it will be returned to the main tank via the heat exchanger. A sub-tank is not used under the normal operation. It will be used when a circulating fluid is recovered from the customer’s machine side. The internal pump is used to transfer a circulating fluid from the sub-tank to the main tank. (Refer to “Circulating fluid automatic recovery function” on page 1316.) Refrigeration circuit When the circulating fluid temperature is rising higher than the set temperature, open the expansion valve (a) to introduce refrigerant gas at a lower temperature to the heat exchanger. With this, the circulating fluid will be cooled down. Oppositely, when the circulating fluid is getting lower against the set temperature, open the expansion valve (b) and introduce refrigerant gas at a high temperature without going through the water-cooled condenser to the heat exchanger. With this heat, the circulating fluid will be heated. Construction and Principles Refrigeration circuit Facility water circuit Injection valve Expansion valve (a) Expansion valve (b) Compressor Water control valve Facility water outlet Water-cooled condenser Facility water inlet Refrigerant dryer Highpressure gauge Highpressure shutoff pressure switch Flow rate sensor Circulating fluid circuit Internal pump Circulating pump Level switch Level switch Heat exchanger Main tank Temperature sensor Pressure sensor Circulating fluid outlet Circulating fluid return inlet Sub-tank 1318