5TH International Congress on Technology - Engineering & Science - Kuala Lumpur - Malaysia (2018-02-01)

Experimental And Numerical Study Of A Double Pass Solar Air Heater

Solar thermal technologies have been applied widely in which the Solar Air Heaters (SAH) play an important role. The main applications of the solar air heaters are drying of agricultural-products and heating of building [1-2]. SAH are simple in design and maintenance, less expensive than other solar collectors and they use less material [3]. The flat plate solar collectors absorb the solar energy and convert it into thermal energy by means of an absorber and the collected heat energy is transferred to the fluid flowing through the collector [4]. A model of a double pass solar air heater has been prepared to produce hot air by consuming solar energy in day time. We investigate the experimental and the numerical methods of a double pass solar air heater with forced convection in delivery mode side the insulation under the meteorological conditions of Tunisia. The double pass solar air heater has designed and realized in our LASEM laboratory. In this type of collector, air enters at ambient temperature and warms up as it moves along the channel. The air circulates between the absorber plate and the insulation base, corresponding to the first channel, and turns back flowing between the transparent cover and the absorber plate, corresponding to the second channel, where a fan is installed side the insulation in delivery mode. The results of the experimental study showed that the temperature increases from the bottom of the SAH. The velocity of the airflow is high in the outlet of the collector and it decreases along the absorber which is influenced by the temperature. The temperature inside the collector increases with increasing of the solar radiation that allows the increase of the efficiency of the collector. For the numerical simulation, we have used the commercial CFD code Ansys Fluent 17.0. The realizable k-ε model has adopted for taking into account the turbulence effect. A good agreement has been obtained between the numerical and the experimental results that assures the validity of our numerical model.
Oumaima Eleuch, Badis Bakri, Zied Msaed, Zied Driss