Refrigeration principle of ethylene glycol chiller

Ethylene glycol chiller, as its name implies, is a chiller with ethylene glycol as the coolant of the chiller.

Sometimes the cooling liquid needs to be below 0℃. If water is used for cooling, it will freeze. Adding some antifreeze liquid can avoid freezing, and ethylene glycol can prevent freezing.

In the all-air system, it is not easy to use the cooling tower to directly cool the inner area when the outdoor temperature is too low in winter. At this time, outdoor cold air can be used as cold source, and ethylene glycol solution can be used as cold carrier, and outdoor natural cold source can be introduced into the room to provide cooling for the inner area. When it is necessary to supply heat to the outer zone and cool the inner zone, turn off the water chiller and still use the boiler or city hot water as the heat source to supply heat to the outer zone.

Working principle of ethylene glycol solution refrigeration;

Install a plate heat exchanger outdoors, introduce outdoor cold air into the plate heat exchanger by a fan, and exchange heat between ethylene glycol solution and outdoor cold air in the plate heat exchanger. The cooled glycol solution enters the air conditioning unit in the inner zone, where it exchanges heat with mixed air (air mixed with fresh air and return air). The mixed air is cooled, and then enters the room in the inner zone to provide cooling for the room in the inner zone. When the temperature of ethylene glycol solution rises, it returns to the outdoor plate heat exchanger again to exchange heat with the outdoor cold air, and continues to circulate after the temperature drops. This heat exchange method is often used in heat recovery systems. Ethylene glycol exchanges heat with high-temperature exhaust air, and after the temperature rises, it enters the fresh air cabinet to preheat the fresh air. Therefore, the heat in the exhaust air is recovered to heat the fresh air, which saves electric energy and operation cost.

It is a very energy-saving air conditioning method to use ethylene glycol solution as cooling agent and introduce the cold energy from outdoor cold air to provide cooling for the inner area. Only need to install a plate heat exchanger outdoors, when running, the water chiller is turned off, and only the fan and air conditioning unit can be turned on to introduce natural cold source to provide cooling for the inner area, which saves electric energy and reduces operating costs. However, in the process of using outdoor cold energy to provide cooling for the inner zone, cold air should exchange heat with ethylene glycol, and ethylene glycol should exchange heat with mixed air. After two heat exchanges, the cold energy loss is large and the heat exchange efficiency is not high, generally lower than 60%.