Experimental investigation on the performance of an impinging jet solar air heater

Investigation on an impinging jet solar air heater is performed and reported in this work. The air is supplied through an impinging jet pipe which contains the nozzles to distribute the air in the solar air heater. The air is released from the jet strikes the absorber plate which increases the heat transfer rate by creating turbulent flow in the collector. This study is focused on the parameters that affect the heat transfer characteristics and compared with conventional solar air heater. The system is examined by varying the angle of attack (0°, 10°, 20°, 30°, 60° and 90°) and the nozzle diameter (3 mm, 5 mm and 7 mm) in the air mass flow rate range of 0.012–0.016 kg/s. The study revealed that the highest performance is achieved with the 30° angle of attack, and the lowest performance is recorded with the 0°. The reduction in jet diameter increases the pressure loss in the collector. The better system performance is observed with the 5 mm diameter hole. The maximum thermal enhancement factor of 2.19 and efficiency of 55.8% are reached with the flow rate of 0.016 kg/s

An investigation

This paper discusses the performance of the sawdust and neem powder briquette and its blends. In the first set of experiments, the sawdust and neem powder briquettes are produced by manually operated hydraulic pelletizer in the pressure range of 7–33 MPa. The strength of briquettes is investigated by the shatter index, impact resistance, durability index and water resistance test. The calorific value and water boiling tests have been also conducted to study the performance of the briquettes. The result shows that the neem powder briquette has significantly higher strength, but lower calorific value compared with the sawdust briquette. Also the performance of the briquettes increases with increase in pressure. Thus the maximum pressure of 33 MPa is used for the second set of experiments. In the second set of experiments, the neem powder is blended with the sawdust in the ratio of 100:0, 75:25, 50:50, 25:75, 0:100 (Sawdust:Neem powder). The study shows that the sawdust with neem powder as binding agent has considerably increased the strength of the briquette with a little reduction in burning rate