Use of Aluminum Oxide sponges made by polyurethane polymer sponge method in manufacturing of a waste heat recovery heat exchanger

Waste heat recovery heat exchangers have been used to recovery of thermal energy from hot flue gasses of devices. In this paper, to enhance the efficiency of a regenerative heat exchanger, the Aluminum Oxide sponges have been used as core of the matrix. This ceramic sponges is made by polyurethane polymer sponge method with porosity and pore density of ۰.۸۵ and ۱۰ppi, respectively. The sponges play the role of heat transfer elements in the matrix of heat exchanger and recovers and stores the thermal energy in waste gasses then release to the cold inlet air. The sponges have been used and thermal efficiency of heat exchanger have been investigated. According to results, the ceramic sponges had a positive effect on efficiency of the heat exchanger and with an increase in matrix thickness, increases the overall thermal efficiency, however, at high thicknesses, the negative effects of pressure drop reduces the thermal efficiency. The ceramic sponge heat exchanger recovers more than ۳۱% of waste thermal energy. Use of the Aluminum Oxide sponges as heat transfer elements in heat recovery heat exchangers is recommended due to high stiffness, strength, compactness particularly in humid and corrosive processes, particularly in humid and corrosive processes.