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.

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 aims to develop the gypsum refractory board mixed with corn leaf coir. The 5 ratios of gypsum plaster: corn leaf coir: tap water: sodium silicate are equal to 1: 0: 1: 0.03 1: 0.100: 1: 0.03 1: 0.150: 1: 0.03 1: 0.200: 1: 0.03 1: 0.250: 1: 0.03 และ 1: 0.300: 1: 0.03 by weighted. The gypsum refractory boards were produce by casting in normal temperature (30 – 35 degree of Celsius). The properties testing of gypsum refractory board mixed with corn leaf coir followed the TIS 219-2009 standard (gypsum plasterboard) included: breaking load nail pull resistance deflection water absorption density and thermal conductivity coefficient. From the results 1: 150: 1: 0.03 is the most suitable ratio of gypsum refractory board mixed with corn leaf coir. This developed gypsum refractory boards can reduce the quantity of corn leaf waste and get the good thermal insulation gypsum refractory board products.