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EN
In this work a simple new type of flow sensors was developed; the double coil flow sensor. In this sensor two coils are magnetically coupled due to the flow of pure water inside them. The first coil, the primary coil, was supplied by AC voltage in the frequency range 0.5-1 MHz which is the coupling range of frequency for water. The voltage in the second coil, was found to be directly proportional with the volumetric flow rate of the water flowing inside the coils. The two coils can only be coupled in the laminar flow region. In the turbulent region, due to the turbulent chaos and fluctuation the two coils cannot be effectively coupled, and therefore the sensor cannot be used. The temperature of the water was found to have a negligible effect on the coupling, which add a good advantage to the simplicity of the double coil sensor. The working fluid used in this work was pure water. Other fluids are believed to be working as well, most probably at different frequency range, and this will be the subject of future work.
EN
The pressing need for reducing the global warming effects from the emission of greenhouse gases necessitates the use of renewable energy where possible. Solar distillers are devices with a promising future. In this work, an experimental setup (solar distiller) was constructed and equipped with a mirror, basin, glass cover, compressor, sensors and controllers to study the partial evacuation effects on different solar distillation parameters and the production capacity under the Jordanian climate. The test rig was tested for three different water levels (1, 2 and 3 cm), and four pressure values (1, 0.9, 0.8 and 0.7 atm) under the Jordanian climate. The detailed experimental results strongly correlate with the results previously published in literature. The modifications performed on the system doubled the previously attained efficiency. These improvements in the solar distiller will favor the application of the vacuum pressure principle in many different applications, such as the water extraction from the atmospheric air.
EN
Hot water storage tanks are devices with high energy consumption, used widely in residential, industrial and commercial sectors. The hot storage tank is a key device in numerous applications such as electrical heaters, solar thermal storage, solar electrical energy production and many others. Its superior technology is favorable for the designers and has a great impact on the market competition. Hot water storage tanks were studied under continuous usage feature, for different inlet types, flow rates, thermal stratification in static and dynamic modes, both experimentally and numerically. The real discrete usage feature has not been analyzed in a proper way. In this study, the experimental and performance analyses with frequent discrete usage of the hot storage tank were performed. Different flow rates of 3, 6, and 9 l/min with 5, 10 and 20 min discrete usage waiting periods were studied. It was found that the thermocline thickness and mixing number increases for both increasing the flow rate due the increment in turbulent mixing potential and increasing the waiting period due to the increase in heat transfer time available between the hot and cold layers. The real data was drawn as is to permit further analyses and data comparison to other researchers. The effect of waiting periods can be used in solar HST to maximize the efficiency of solar collectors as the solar collector efficiency is high at low temperatures.
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