The direct expansion system in HVAC has been growing rapidly due to its ability to get rid of most duct work and piping. The popularity of this system is because the installation work has been made easier hence reducing the cost of the overall system. The DX System works in such a way that the evaporator is located in the space to be refrigerated. When the refrigerant in the evaporator coil expanded, it will cool the space by absorbing the heat from it. The mini splits, window air conditioner and packaged units are examples of such system. In the direct expansion or DX types of air central conditioning plants the air used for cooling space is directly chilled by the refrigerant in the cooling coil of the air handling unit. Since the air is cooled directly by the refrigerant the cooling efficiency of the DX plants is higher. However, it is not always feasible to carry the refrigerant piping to the large distances hence, direct expansion or the DX type of central air conditioning system is usually used for cooling the small buildings or the rooms on the single floor.