Refrigerant properties and selection

Refrigerant is used to accept the cold amount of refrigerant and then cool other substances, also known as refrigerant. It plays the role of transferring the cold amount of refrigerant in the indirect refrigeration system.

First, refrigerating motor requirements for refrigerant

Factors should be considered when choosing refrigerant: freezing point, specific heat, corrosion to metal and price.

1. The specific heat is larger than the specific heat, and the cooling capacity is larger, which can reduce the circulation amount of refrigerant.

2. Low viscosity and high thermal conductivity.

3. The freezing point is low and should be appropriate, because the freezing point is too low will lead to the decrease of specific heat and the increase of viscosity.

4. Odorless, non-toxic, safe to use, and less corrosive to metal.

5. It's cheap and easy to buy.

2. Common refrigerant and properties

There are many types of refrigerants, which can be gas, liquid or solid. Common refrigerants are air, water and brine solutions.

1. Air and water

Air or water is the cheapest and most readily available refrigerant. All have the advantages of low density, safety and harmlessness, almost no corrosion to the equipment, etc. But the specific heat of air is small, so air is used as refrigerant only when it is used for direct cooling. Although water has the advantage of high specific heat, but the freezing point of water is high, so water can only be used as a refrigerant above 0℃. Brine should be used as the refrigerant below 0 ° C.

2. Brine solution

Brine, the most common refrigerant, is made of salt dissolved in water. The commonly used brine is sodium chloride aqueous solution and calcium chloride aqueous solution.

The properties of salt water depend on the amount of salt in the solution. In particular, the freezing point of brine depends on its concentration.