The Refrigeration Principle of the Glycol Refrigeration System

Glycol refrigeration system is a refrigeration system using glycol as refrigerant carrier of water cooler.

Sometimes the refrigerant carrier needs to reach the temperature below 0 C. If the ice is carrying the cook, it will freeze, so adding some anti-freezing liquid can avoid freezing, and glycol can prevent freezing.

In system full of air, it is not easy to use cooling tower to directly supply cooling to the inner area of the air conditioning system when the outside temperature is too low in winter. At this time, the outdoor cold air can be used as a cold source, and the glycol solution can be used as a refrigerant to introduce the outdoor natural cold source into the indoor area for cooling. When it is necessary to supply heat to the outside area while to supply cooling to the inner area, the chiller unit should be shut down and the boiler or urban hot water should still be used as heat source to supply heat to the outside area.

Plate heat exchangers are installed outdoors, and cold outdoor air is introduced into the plate heat exchanger by fan. The glycol solution and cold outdoor air do an exchange in the plate heat exchanger. The cooled glycol solution enters the air-conditioning unit of the inner zone. It exchanges heat with the mixed air (fresh and return air mixed) in the unit. The mixed air is cooled. After the temperature is lowered, it enters the inner zone room and supplies cooling to the inner zone room. When the temperature of glycol solution increases, it returns to the outdoor plate heat exchanger and exchanges heat with the outdoor cold air. After the temperature decreases, it continues to circulate. This heat exchange method is often used in heat recovery systems. Ethylene glycol and high temperature exhaust air exchanges for heat. When the temperature rises, they enter the fresh air cabinet and preheat the fresh air. Thereby, 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 that the glycol solution is used as a refrigerant to introduce the outdoor cooling air to the inner zone. Only one plate heat exchanger is installed outdoors, and when running, the chiller is closed, and only when the fan and air conditioning unit are turned on can the natural cold source be introduced to the inner zone for cooling, which saves electricity and reduces operating costs. However, the cold air should be exchanged with ethylene glycol in the process of using outdoor cooling capacity to supply cooling to the inner zone, which then exchanges with mixed air. After two heat exchanges, the cooling loss is large and the heat transfer efficiency is not high, which is generally less than 60%.