Refrigeration is a process that operates under two main criteria, namely pressure and temperature. This process uses a special type of liquid called Refrigerant which is able to withstand very high and very low temperatures. Refrigerant changes its state from liquid to vapour and back to liquid as it travels through the mechanical refrigeration circuit. The purpose of refrigerant is to absorb heat inside the refrigerated space and to release that heat into the ambient air or into the atmosphere. When the refrigerant increases to a certain temperature it evaporates and absorbs heat and when the refrigerant decreases to a certain temperature it condenses and releases heat. This process of absorbing heat and releasing heat continues until the desired temperature is reached within the refrigerated space and at this point the refrigeration unit will temporarily switch off. When the temperature begins to rise above the set point temperature the refrigeration unit will switch on and the refrigeration process will begin until the desired temperature is reached.