Concentration solar dryer water-to-air heat exchanger: Modeling and parametric studies

In this paper we present a modeling and parametric studies of a water-to-air heat exchanger. This exchanger is formed of a fan blowing the air to be heated through a battery of smooth tubes where the hot water—coming from solar concentrators—circulates. The heated air is injected into a thermal room to dry the clay bricks.In the first part, we study the most used models in the estimation of the heat transfer and air flow pressure drop across a tube bundle, and subsequently calculate the required transmitted power to the air.In the second part, we focus on the parametric study of the influence of the different geometric parameters of the exchanger on the heat flow rate, the air outlet temperature, the pressure drop and the requested transferred power to the air. The considered parameters are: The water heat flow rate, the heat exchanger compactness, the rows arrangement, the tube diameter, the transverse pitch, the total number of tubes, the number of rows and the air velocity.Simulations have shown that the heat exchanger performance could be improved essentially throughout the design and manufacturing process by modifying the different geometrical parameters and filling certain conditions.