จำนวน Repository ( 24 )
การจำลองและการทดสอบระบบเติมอากาศแบบน้ำไหลเวียนด้วยพลังงานแสงอาทิตย์
The amount of dissolved oxygen (DO) in aquaculture ponds is considered to be one of the most important aspects for the survival of fishes. The water in aquaculture ponds is stratified into distinct layers with different DO caused by differences in temperature. This temperature difference occurs when the surface layer of water heated by the sun becomes hotter than the lower water layer. Since the top layer is in contact with the air it contains the most DO. On the other hand the deepest layer is isolated from the air it contains the lowest amount of DO. This study proposed an aeration system called a Solar Circulating-Water Aeration System (SCWAS). The SCWAS uses solar thermal energy to create a natural water circulation. In other words it provides an upward current of water from the bottom to the pond surface and a downward current from the surface to the bottom. This circulation creates the movement of surface water and then increases the DO content of the surface water. This water circulation moves highly oxygenated surface water to the bottom layer forcing low oxygen water from the bottom up to the surface where it can absorb oxygen. To evaluate this design concept the numerical simulations of the system were conducted using ANSYS Fluent software. According to the simulation results the SCWAS can provide the natural water circulation. It was found that a flow rate of 2.24 L/s is obtained when the ratio between the draft tube inlet (r) the draft tube outlet (R) the base (L) is 1: 2: 3. In addition an SCWAS prototype was built and installed in a tilapia aquaculture system. A calibrated measuring system was installed to investigate the prototype performance. The experimental results indicate that the average DO values at the water surface and at the bottom of the pond increased by 1.45 and 1.40 times respectively compared with those of a pond without SCWAS. Economic analysis shows that the payback period of SCWAS is 4.58 years and its investment cost is 17.49% less than that of the paddle-wheel aerator.
การศึกษาเชิงทดสอบการใช้น้ำสำหรับระบายความร้อนออกจากแผงเซลล์แสงอาทิตย์
This research aimed to experimentally study of solar panel efficiency with water cooling. Three mono-crystalline solar panels with the capacity of 80 W (for each panel) were used for this test. The first panel was a solar panel without water cooling. The second panel was a panel with water spray cooling. The last panel was a solar panel with water drop cooling. The cooling water flow rate was varied to 50 75 and 100 LPH. From the test it was found that the temperatures of all solar panels had the similar trends. The solar panel efficiency decreased when the temperature of solar panel increases. The solar panel efficiency increased when the cooling water flow rate was increased for both of water spray cooling and water drop cooling. For all water cooling flow rates the water spray cooling solar panel performed higher efficiency than water drop cooling solar panel. The highest solar panel efficiency in this test occurred when the water spray cooling flow rate of 100 LPH.
การออกแบบการทดลองเพื่อปรับปรุงกระบวนการเชื่อมลวดวงจรไฟฟ้าของวงจรรวม
Using copper wire instead of gold wire can reduce a lot of cost in IC production of semiconductor industrial. However the circuit stability (Circuit Reliability) is less than the use of goal wire. Therefore the study to improve the production of integrated circuits in the part of the wire bonding process by increasing the baking process. It is an important process to improve the quality of the integrated circuit between Cu wire and chip. For this experimental study of baking process it was performed by comparing IMC values at 175 ˚C and 200 ˚C. The quality of workpiece was tested and measured by Scanning Electron Microscope (SEM) machine every 30 minutes. The research experiment found that the temperature with effect to the workpiece quality to stabilize the IMC value was 175 ˚C for 9 hours nevertheless the new temperature at 200 ˚C it has been applied with only 3 hours. Finally the IMC testing result is higher than the average of the at 60% standard acceptable level as other research reviews and it also higher than the acceptable level of the industry level at 80%. Hence this result can reduce time cost of IC and workpieces production and it also including the higher quality of the products.
Experimental investigation of a thermosyphon economizer to recover waste heat in the electronics industry
A case study was conducted to design construct and test a thermosiphon economizer for increasing the temperature of feed water by using waste hot water. The simulation of the thermosiphon economizer (heat exchanger) for the establishment of the optimum size was performed using the thermos-economical method. The thermosyphon was made of a total of 80 copper tubes (outside diam.19.05 mm) with evaporative adiabatic and condensation lengths of 300 10 and 300 mm respectively. The working fluid was R-134a filling ratio was 50% by evaporative volume and the thermosiphon was arranged in a staggered form. In testing performance flow rate of the inlet hot water was set at 10 L/min and the controlled inlet temperature of cold water at 25oC. The average flow rate of the cold water was set at 5 7 and 10 L/min respectively. Results showed that the maximum of rate of heat transfer from the condenser section occurred at the flow rate of the cold water of 10 L/min. When test the inlet temperature of hot water of 4555 and 65 o C were used at the inlet volume flow rate of cold water of 10 L/min maximum heat transfer rates from the condenser 4626 8260 and 8790 W were achieved. Moreover the outlet temperature of the cold water which was initially 25o C changed to 311 34 and 37o C respectively. Therefore increasing the outlet feed water temperature reduced energy consumption. The effectiveness of the thermosiphon economizer with the inlet temperatures of hot water of 45 55 and 65o C was 0.47 0.48 and 0.49 respectively.
การศึกษาเชิงทดลองการเพิ่มประสิทธิภาพแผงเซลล์แสงอาทิตย์โดยใช้ท่อความร้อนแบบแบน
The purpose of this research was to improve the efficiency of solar cell modules by cooling with heat pipes. The test set consisted of three 80 watt solar modules that were made of mono-crystalline. The first module did not install heat pipes while the second module installed heat pipes using ethanol as the working fluid and the third module installed heat pipes using R-11 as working fluid. Solar radiation intensity electrical energy produced by the solar modules and temperature of the solar modules were recorded. The results showed that the average temperature of the first solar cell module was 52.9oC and the case of not install heat pipes on module. For the units with heat pipes it was found that unit with ethanol heat pipe had an average temperature of 50.7oC and efficiency at 10.2% whereas the unit using R-11 heat pipe had an average temperature at 49.2oC and efficiency at 11.8% From the experiments it was concluded that the installation of heat pipes could increase the efficiency of solar cell mokules.