จำนวน Repository ( 36 )

การศึกษาเชิงเปรียบเทียบระหว่างโรงไฟฟ้าโออาร์ซีแบบซับคริติคัลโรงไฟฟ้าโออาร์ซีแบบซุปเปอร์คริติคัล และโรงไฟฟ้าแรงคินไซเคิลแบบไตรแลทเตอรัลสำหรับแหล่งความร้อนที่อุณหภูมิ 210-250 องศาเซลเซียส
การศึกษาเชิงเปรียบเทียบระหว่างโรงไฟฟ้าโออาร์ซีแบบซับคริติคัลโรงไฟฟ้าโออาร์ซีแบบซุปเปอร์คริติคัล และโรงไฟฟ้าแรงคินไซเคิลแบบไตรแลทเตอรัลสำหรับแหล่งความร้อนที่อุณหภูมิ 210-250 องศาเซลเซียส

The performance investigations of subcritical ORC supercritical ORC and trilateral Rankine cycle (TLC) power plants with the heat source temperatures of 210-250°C were conducted and compared in this study. Several working fluids were evaluated. A MATLAB code was developed and used in this study. The thermodynamic properties of the working fluids were calculated by using NIST REFPROP program. The justification of the code was validated with a result taken from the literature. The optimal operating conditions were searched using the golden-section technique. The maximum net output power of 141.72 kW was obtained when using the supercritical ORC plant with R141b as its working fluid and the heat source temperature was at 250°C. The corresponding cycle efficiency was 16.25%. When using the subcritical plant at the same heat source temperature the maximum net output power of 133.40 kW and cycle efficiency of 15.70% are obtained when pentane is used as the working fluid. Furthermore the net output power of 133.82 kW and cycle efficiency of 14.90% are obtained when using R141b as the working fluid in the TLC power plant. According to the off-design simulations an appropriate adjustment of the working fluid flow rate can mitigate the variation of the net output power.

2563
การอบแห้งพริกด้วยเครื่องอบแห้งอุณหภูมิต่ำที่เสริมการทำงานด้วยเครื่องอุ่นอากาศเทอร์โมอิเล็กทริค
การอบแห้งพริกด้วยเครื่องอบแห้งอุณหภูมิต่ำที่เสริมการทำงานด้วยเครื่องอุ่นอากาศเทอร์โมอิเล็กทริค

This research objective was to apply thermoelectric module model TEC12710 as a preheater and dehumidifier for red chilies dryer. The heat side and cool side of Thermoelectric module affected by supplied electricity were used to produces the low humidity and warm air in preheater before charging to the main electric heater of dryer. Fresh red chilies were selected as a sample in the prototype testing during the use of preheater assisted main heater and using only main heater. The test results are compared with the sample dried under the natural sun drying. The experimental results show that the preheater can condense the moisture in air with the highest MER of 0.083 kgwaterh-1 at cold side of thermoelectric module and can heat the air up in 10°C of temperature with hot side of thermoelectric module. The final moisture content of sample is only 10%wb with the slightly changed in color when compared with the sample from sun drying. The using of preheater with main heater gives a higher specific moisture extraction rate lower specific energy consumption 14 MJ energy used and can dry faster than 10 h when compared with the using of only main heater.

2563
การพัฒนาบรรจุภัณฑ์เพื่อสิ่งแวดล้อมจากวัสดุคอมโพสิตเส้นใยผักตบชวา แกลบ และใยมะพร้าว สำหรับรักษาอุณหภูมิ
การพัฒนาบรรจุภัณฑ์เพื่อสิ่งแวดล้อมจากวัสดุคอมโพสิตเส้นใยผักตบชวา แกลบ และใยมะพร้าว สำหรับรักษาอุณหภูมิ

The research was to develop environmental packaging from composite materials hyacinth fiber rice husk and coconut fiber for temperature preservation to replace the use of foam packaging that cannot be degraded naturally. In the composite materials water hyacinth fiber rice husk and coconut fiber at the ratios 7: 1: 2 1 : 1 : 2 and 1: 1: 1 were extruded by heat using isocyanate glue as a solder and testing the physical and biological properties of composite materials as fiberboard. For testing of temperature preservation of the bio packaging heat transfer test to obtain the bio-packaging for the environment the composite materials of fiber water hyacinth rice husk and coconut fiber at the ratio of 7 : 1 : 2 was the most appropriate type. Since it had a density of 0.7 grams per cubic centimeter strength of 26.76 MPa moisture content of 3.8 percent ages and swelling of 26.63 percent ages. In dry condition at room temperature it could store heat for 2 hours and could retain the cold temperature as shown for the temperatures rising from 4 to 30.7 degree Celsius within 2 hours. This research therefore presents a new alternative method of natural fiber composite materials application for temperature preservation in order to reduce the use of foam containers and increase cost value to natural bio waste materials.

2563
การวิเคราะห์พฤติกรรมของวัสดุผสมภายใต้สภาวะอุณหภูมิต่างๆของผ้าเบรก
การวิเคราะห์พฤติกรรมของวัสดุผสมภายใต้สภาวะอุณหภูมิต่างๆของผ้าเบรก

Brake system is used the friction between disk and pads. In the driving conditions the brake behavior from the driver is difference. Based on this reason the damage on disk and pads are occurring. Nowadays the ratio of compound materials in pads is several and involved automotive industry has not available enough to experiment. Thus it is difficult to brake pads damaged analyzing in several driving conditions. In this problem the mechanical property tester is main tool for experimenting. And test procedure based on the Brake lining and disc brake pads compressibility JIS D 4413 [7]. The experiment emphasizes on the flexibility behavior and internal energy by volume with 3 types of brake lining and pads. For the experiment focused on conditions by normal apply brake repeat apply brake and suddenly apply brake. The results revealed the normal apply brake condition the maximum and minimum of flexibility behavior was appeared on brake lining and pads type A and type C with testing temperature at 2000C. By the repeat and suddenly apply brake conditions the brake lining and pads type C and type A with 300C is given to the maximum and minimum flexibility behavior. In case of internal energy by volume the maximum and minimum energy was appeared on pads type C and B at the 300C of testing temperature. For the testing temperature at 200 and 4000C the pads type A and type B were got the maximum and minimum energy respectively. On the other hand at the high flexibility behavior is given to high internal energy at the high temperature of the apply brake condition.

2561
The study on high temperature degradation of AISI 1020 low carbon steel  in the carburization state
The study on high temperature degradation of AISI 1020 low carbon steel in the carburization state

This research was aimed to study the high temperature degradation of AISI 1020 carbon steel pipe under the carburizing atmosphere. This environment was prepared by a mix of powdered charcoal and CaCO3 catalysts and then simulated at temperature of 1000C for 1 2 and 4 hours. The variation in the weight of the aged steel specimens was obtained by the measured metal loss at various working periods. The light optical microscope was used to observe the microstructural changes of aged steel samples. The results revealed that the prolonged operating period decreases the weight of samples and the degradation occurs on the outer surface of the pipes. The study also indicated the microstructural difference between the inner and outer wall of the steel pipe which is resulted from the changes in chemical compositions during the carburizing process.

2560