Technology of appliances Based on Electro Mechanical

 The main objective of this section is to describe the basic principles and modes of operation of refrigerators and air conditioners. The common mechanical refrigerators and air conditioners have electric motors that utilize electrical energy to produce mechanical work required for space or air conditioning. Hence they are referred to as electro mechanical systems. Refrigerator is the process of lowering the temperature in a space, and maintain it for the purpose of cooling foods or providing comfort. This is achieved by using a liquid, which is referred to as refrigerant. To appreciate the principles of refrigeration, we will discuss the relationship between heat and and the different states of matter.