Dairy Refrigeration:

Most of the dairy plants pre-cool milk to 2.5°C previous to processing for the separation of cream & blending for manufacturing standardized quality. There are warm as well as cold milk separators. Afterwards, the separation procedure occurs at a temperature of 4°C. After the process of separation and blending, the milk is sent for pasteurization that is done by heating followed by the chilling of milk. Heating is performed either by hot water or steam and storing the milk at 62°C for approximate 3 minutes. The milk is then cooled up first by water from a cooling tower and after then by chilled water. The rate of flow of chilled water ought to be such that its go up in temperature is not more than 5.5°C. While a direct-expansion system is utilized for cooling, the refrigerant flow is controlled through an automatic expansion valve therefore the temperature does not drop below - 2°C lest the milk can freeze. Water chilling apparatus generally consists of an ice-bank kind's water chillers containing of an insulated tank along water, direct-expansion coil & pump. This system ensures a stable temperature of chilled water of 0 - 1°C. It also takes care of load fluctuations by permitting excess refrigeration to be stock up in the appearance of ice on immersed coils.

Refrigeration is also needed for cooling the cream before churning & the mechanical separation of butter. For the stock up of butter, a temperature of 0 to 4°C is suitable. However for storage for 6 months or more, - 23 to - 18°C temperature ought to be utilized. This is the similar as for some of the frozen products. Therefore butter might be kept in freezer of refrigerators for storing up further than a period of six months or more.

Ice-cream make up is another industry that makes high use of refrigeration. The ice-cream freezer ought to whip in a sure amount of air in the mix, simultaneously with freezing. The product is 0 to 100 per cent frozen between the temperature approximate ranges of - 2.5 to - 55°C.