Experimental Investigation on Waste Heat Recovery from a Cement Factory to Enhance Thermoelectric Generation

Abstract

This work investigated the potential for waste heat recovery from a cement factory using thermoelectric generation (TEG) technology. Several TEGs were placed on a secondary coaxial shell separated from the kiln shell by an air gap. The performance of the system was tested and evaluated experimentally. Two cooling methods, active water and forced air, were considered. A forced closed-loop water cooling system with a heat exchanger was considered for the active-water cooling method. A heat exchanger was inserted before the water tank to improve cooling efficiency by reducing the inlet temperature of the cooling water tank, in contrast to forced-air cooling, in which a heatsink was used. The obtained results indicated that the closed-loop water-cooled system equipped with a radiator, i.e., active water, has the highest conversion efficiency. The maximum absorbed heat for the forced-air and active-water cooling systems were 265.03 and 262.95 W, respectively. The active-water cooling method improves the power of TEG by 4.4% in comparison with forced-air cooling, while the payback periods for the proposed active-water and forced-air cooling systems are approximately 16 and 9 months, respectively.