This paper presents about the defrosting time of evaporator in refrigerator by using the temperature different between evaporator and chilling area. This temperature different concept could control the defrosting system to operate according to the load. It also helps controlling the operation of fan motor to be able to operate in accordance with the defrosting time. In general system the timer is set at the highest humidity season which cause the unneccessary defrosting cycle even in low humidity season. This general system create the west of power usage colling system. These can cause time-consuming in defrosting process in the low humidity season and cause the unnecessary usage of power to cooling system. This research is to develop the controller for the defrosting system at evaporator from the investigation. As the results we have found that the defrosting system at evaporator according to its load made the refrigerator can decrease the power about 8% when comparing to constant time evaporator system

This paper proposes a study of an Ozone generator. The generator under the study is designed using the electrode with uniform field. The electrode is constructed in the plane shape with positive potential. The transformer oil is used as insulating materials to prevent discharges around the electrode discharges in the air void depends on the size the types of dielectrics and level of applied voltage. Between the electrode and the air void there is acyclic dielectric. The stainless electrode with water is used as a ground potential. The breakdown depends on the electric field intensity. It is found that there is sufficient amount of ozone due to the ionization Development and design ozone generator this research electric field intensity on the water type and this can be used as a principle to construct a new type of ozone generator.