NOVEL CONFIGURATION FOR DIRECT ABSORPTION SOLAR COLLECTOR WITH NONE-CIRCULATED NANOFLUID

Abstract

Novel configuration for direct absorption solar collector has been developed. In the new configuration none-circulated nano-fluid absorbs solar radiation through glass wall. The absorbed heat directly transfers to circulated water flowing inside copper tube submerged into the nano-fluid. Numerical model has been developed for flowing water, nano-fluid annular region and the copper tube which separates the two different fluids. Heat absorption of concentrated solar arrays reflected by parabolic trough is simulated as a heat source in the energy equation solved in nano-fluid region. The efficiency of one meter of solar receiver unit with glass-to-copper tube size ratio of (½) increases significantly with flow rate up to 65%. However the receiver wasn’t covered by evacuated tube to reduce losses, circulating water restricts the raising of nanofluid temperature and in turn reduces thermal losses. Since, water flow rate changes increasingly affect the efficiency, the depth of absorption in nano-fluid and characterized length of natural convection are not inconveniently selected. However, further investigations are planned to be done to optimize heat absorption and convection in nano-fluid region. Temperature rising per one meter decreases with flow rate despite of performance enhancing.