Primary And Secondary Refrigerants:

Prime refrigerants are those that can be directly utilized for the cause of refrigeration. If the refrigerant is permitted to freely flow into the space to be refrigerated and there is no risk of possible injury to human beings, then primary refrigerants are utilized. The refrigerants utilized in home refrigerators as Freon-12 are primary refrigerants.

Alternatively, there can be definite situations in which we cannot permit the refrigerant to come in direct contact through the items being refrigerated, and then the refrigerant utilized is termed like a secondary refrigerant. As for instance, we cannot permit a toxic refrigerant to be utilized for air conditioning in residential buildings. There are some refrigerants that are highly inflammable and so their direct use is prohibited for safety reasons. Again, it can so happen that if direct refrigeration, such like in cooling a large cold storage, is permitted, then the amount of refrigerant needed can be so large that its expense becomes prohibitively high. These are some distinctive situations for which we take favour the use of secondary refrigerants. Water and brine solutions are ordinary examples of secondary refrigerants.