Experimental analysis of a rotary heat exchanger for waste heat recovery from the exhaust gas of dryer

In this paper, a rotary heat regenerator is fabricated to preheat the inlet air of the air jet impingement food dryer for by recovery of flue's energy. This regeneration heat exchanger is a rotary matrix made of zigzag shape aluminum sheets with a thickness of 0.5 mm. The effect of thermal recovery on efficiency of air jet impingement dryer is investigated. In addition, the influence of the temperature of the input air, the rotation speed of the matrix and the flow rate of the hot air is investigated on the temperature of fresh air entering at ambient temperature. The experiments are carried out at three levels of parameters. Results show that increasing the rotational speed of the matrix and discharge flow result in decrease of both the outlet temperature of the hot fluid and the efficiency of the heat exchanger. It can conclude that the hot air inlet temperature has the most significant effect on matrix efficiency and heat storage. The efficiency of heat recovery is improved up to 42.2%.