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.

This research project presents about the design and construction of a five-phase generator for producing magnetic force along the shaft axis that there are various important elements which should be considered in the processes of the design and construction such as flux per pole number of poles number of turns rotor speed and winding coefficient of coils. The experiment result is found that the five-phase axial flux permanent magnet generator along the shaft axis can produce DC voltage by the efficiency without load and with load. Furthermore this contribution can be used to produce electricity with other renewable energy such as electricity from wind energy.

This research aims to develop the waste heat energy conversion device to generate electricity through a thermoelectric generator (TEG) which is called “CHEU. This device is applied to the LPG cookstove that serves as a waste heat source. The thermoelectric generator with 4 modules in series connection is used to convert heat energy to electricity. The present research shows a modification of the CHEU based on two concepts as follows: (1) re-design the structure for heat transfer improvement and (2) select the high capability of TEG to support a high temperature from a heat source as a result of (1). In this study the modified CHEU is called “MCHEU”. A heat-load condition is set as the gas pressure of LPG which varies in a range of 0.1 - 0.6 kg/cm2 and the throttle valve is fixed approximately at 40% of a fully opened throttle while the air entrainment is fully opened throttle. Also the water-cooling system is used for heat dissipation. Base on the performance evaluation of MCHEU the interesting results are drawn as follows: 1) the maximum temperature difference is on an average value of 278.5oC at a maximum heat load condition while a maximum voltage current and power are on an average value of 18.83 V 5.67 A and 107 W respectively. 2) The temperature difference of MCHEU is higher than that of CHEU with an average value of 50%. 3) The output power obtained by MCHEU is higher than that of CHEU with an average value of 52% and takes less time about 40% for fully charging a battery (12V 7.5Ah). Nevertheless MCHEU usage does not affect the thermal efficiency of a cookstove. 4) The efficiency of an energy conversion obtained by MCHEU is 20% which is higher than that of CHEU about 2%.

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