Effect of micro-channel technique on solar collector performance

Abstract

The use of the micro-channel technique is available in many applications, but its applications in the solar collectors are very few, so this research makes a clear contribution in this field. The heat transfer to the flowing air is improved by using micro-channel technique. Numerical and experimental of the impact of micro-channel technique on solar air collector performance is investigated. Navier Stokes and energy equations is solved by using 3D forced convection laminar model inside rectangular micro-channels of absorber plate in solar air collector. The numerical calculations are extended to analyze the performance of a solar air collector by using micro-channel absorber plate. Experimentally, an absorber plate was manufactured from Aluminum metal with 30 rectangular micro-channels (length 0.9, width 0.004, height 0.0008 m) is constructed with measurements facilities of velocity, temperature, and differential pressure to achieve the experimental results. The tests are carried out indoor utilizing a solar simulator. Validation is achieved by using comparing the numerical results with experimental outcomes and a good agreement is executed among them, it is approximately (3-4%). Both factors air flow rate and solar irradiance have been studied as one of the essential factors in solar collectors. The numerical and experimental parameters studied are air flow of 0.0019, 0.0029, 0.0044 and 0.0053 kg/s and irradiance of 200, 400, 600 and 800 W/m2. The performance was investigated by measuring outlet air temperature. The micro-channel absorber shows good performance, the maximum outlet air temperature reaches 72.5°C.