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.

Molds manufacturing to produce chloroprene rubber product with carbon steel over time the mold surface will wear. From the original. The practice in the industry often uses surface coatings (Hard chrome method) or change materials to create molds. Therefore this research is to study the effect of corrosion or wear. To see the size of surface mold changed in the experiment. Based on a tolerance of 0.1 millimeters at the molding point and after molding in the actual work conditions of a 2-3 weeks sample and mold size measurement. At less than 10 times the permissible coordinate value is 0.01 millimeters. The experiment found that. The wear of carbon steel molds was formed with chloroprene rubber. It has a very small value when referenced to the tolerance coordinates which is not significantly reduced when the rubber specimen size is determined. The allowance range is 10 μm to 100 μm. Therefore the design of chloroprene rubber to make molds with carbon steel. It can help reduce production costs. Without replacing with corrosion-resistant materials or adding coatings.

The ORC power plant is a promising technology to generate electricity from low-temperature heat sources. However implementation of the ORC for low capacity electricity generation is unattractive at the commercial level. Scroll compressors are massively produced to be used in refrigeration and air-conditioning applications. Using a scroll compressor in reverse as an expander can reduce the investment cost of low-capacity ORC power plants. In this study 2 scroll compressors that are available in the automotive air-conditioning market of Thailand were modified and used as the expander of a 1 kW ORC power plant. The performances of these 2 scrolls were compared and the plant performance was investigated. A heat source temperature from 100°C to 150°C was supplied to the plant. It was found that the gross power is higher by 18-35% for the larger expander (110 cc/rev) than for the smaller expander (85.7 cc/rev). The larger one provides the isentropic efficiency of 37-76% and the gross power of 806-1926 W. In addition the effects of check valve installation were examined and compared with those of the tests without check valve installation. It was revealed that the isentropic efficiency increases by 18% while the gross power decreases by 4-22% when the check valve was installed.

The purposes of this research were to investigate the factors consisted of a temperature different parts of the lemongrass and a size of chopped lemongrass that affected to distillation of lemongrass essential oils. There are two experiments in this work. The first experiment investigated the factors by defining 1) temperature at 105 oC and 110 oC 2) different parts of the lemongrass (Leaves and trunk) and 3) sizes of chopped lemongrass at 1-2 cm and 15-20 cm respectively. 2k Factorial designs method was used for this experiment. In the second experiment the appropriate parameters from experiment 1 were used for 3 replicates to find an average of lemongrass essential oils. The results of first experimental analysis showed that the appropriate parameters were temperature parts of the lemongrass and sizes of chopped lemongrass at 110 oC leaves and 1-2 cm respectively. For the result of experiment 2 it was found that the average of lemongrass essential oils was 30.36 ml.

This thesis presents the design and construction of an experiments of the power flow in the power systems. For the operating system of the power flow in the power systems. Comprise with the real power Reactive power Voltage in the power system. To guide the planning and operation of power systems. The results of the experiment to calculate the pressure at various points in the Power loss of system. As well as finding solutions to problems. Occurring in the system such as under voltage or short circuit in the system. This is the basic of stability analysis of power system operation and planning