Defrosting at evaporator panel is one of working cycles in freezer. Power consumption in defrosting does not meet the objective of using freezer therefore the approach to decrease power consumption in defrosting is one strategy for energy saving. Normally the cycle of defrosting in freezer is a constant time that specify by referring to the highest humidity period. With this control concept the problem of temperature exchange is not occurred from ice accumulation at evaporator panel but it makes the over necessity of defrosting process in the low humidity season and cause the unnecessary power usage in freezer. This thesis presents the control approach for defrosting by using the difference of the temperature at evaporator and the temperature at chilling area. By using this approach the defrosting process is operated depend on load and the fan is on or off relate to defrosting time. Test results demonstrate that about 12% of power can be saved by this control approach when compared to constant time control.

Defrosting at evaporator panel is one of working cycles in freezer. Power consumption in defrosting does not meet the objective of using freezer therefore the approach to decrease power consumption in defrosting is one strategy for energy saving. Normally the cycle of defrosting in freezer is a constant time that specify by referring to the highest humidity period. With this control concept the problem of temperature exchange is not occurred from ice accumulation at evaporator panel but it makes the over necessity of defrosting process in the low humidity season and cause the unnecessary power usage in freezer. This research presents the control approach for defrosting by using the difference of the temperature at evaporator and the temperature at chilling area. By using this approach the defrosting process is operated depend on load and the fan is on or off relate to defrosting time. Test results demonstrate that about 12% of power can be saved by this control approach when compared to constant time control.

This research was aimed to study the participation behaviors in the electrical energy saving the factors affected to the participation behaviors and the promotion of the participation behaviors in electrical energy saving of the undergraduate students of the Faculty of Science and Technology Rajamangala University of Technology Phra NaKhon. The participants of 150 students from the Faculty of Science and Technology was also performed based on systematic sampling. The questionnaire was used. The statistical evaluation was also analyzed based on the percentage mean and standard deviation. A 85% of participants is male a range of age to be 19-20 years old (62.7%) second academic years by about 37.3% and a 65.3% of participants has been studying in the major of computer science. Knowledge levels in the electrical energy saving of the most participants are high (13.33%) moderate (62%) and low level (24.67%). The four participation behaviors in the electrical energy saving were analyzed including electrical lighting system air conditioner and ventilator system office electrical system and electrical equipment maintenances resulting in very high level with the average mean of 4.25 and standard deviation of .547. First the participation behavior in the electrical equipment maintenance was very high level with 4.31 and S.D.=.870. Second the participation behavior in the office electrical system was to be 4.27 with S.D.=.828. Third the participation behavior in the air conditioner and ventilator system was to be 4.21 with S.D.=.549. Finally the participation behavior in the electrical lighting system was very slow level with 4.21 and S.D.=.672. By comparing the participation behaviors in the electrical energy saving with the different of academic major of students the participation behaviors in the electrical energy saving did not significant different.

The study objectives of the electrical energy saving behavior of student in faculty of business administration Rajamangala University of Technology Phra Nakhon 1) to study psychological trait factor psychological state factor and situational factor in overall group and subgroup of the students’ electrical energy saving behavior in faculty of business admimistration RMUTP 2) to study the interaction effect between psychological trait factor psychological state factor and situational factors related to the students] electrical energy saving behavior in overall group and subgroup. The sample size was 361 students of bachelor’ s degree. The study factors were 7 independents future orientation and self-control) 1 psychological state factors (appropriate model from family knowledge on the electrical energy saving and the information about electricity saving). The dependent factor was the electrical energy saving behavior. Frequency percentage arithmetic mean and standard deviation were used for descriptive statistic while stepwise multiple regression and two-way ANOVA were used for inferential statistics in overall group and subgroup according to social demographic characteristics. The research findings were as follows : Firstly all 7 factors of psychological trait factors psychological state factor and situational factoe could predict 52% of variance of the electrical energy saving behavior. The most prediction power factors were appropriate model from family positive attitude towards saving behavior receives electricity saving information and well-being respectively. Secondly the interaction effect was found well-being and electricity saving information with the electrical energy saving behavior of student which was male and female group and freshman and sophomore group junior and senior group G.P.A above 3.00 and parents’ income lower than 30000 thb Thirdly the interaction effect was found the future orientation and self-control and knowledge on the electrical energy saving behavior with the group of student who mother has an education lower than undergraduate.

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