Effect of heating elements types on air preheater performance: Review

In the air conditioning, steel industry, and power plants, rotating heat exchangers are utilized to preheat air for use in waste heat recovery or steam generators. In this article, various rotating heat exchangers that are utilized in thermal power plants have been presented to preheat the air supplied to the steam generators. The heat transfer between two fluid streams is accomplished in these devices via a rotating matrix that functions as a thermal accumulator by alternatingly coming into contact with the two fluid streams. Although a considerable number of studies have investigated the influence of types of heating elements on the performance of air preheaters, there is a scarcity of exhaustive review articles that encompass the latest developments in this domain. This paper provides a comprehensive review of recent available studies that investigate the impact of flow configuration, material, and geometry of the heating elements on the air preheater thermal hydraulic performance. It found that the replacement of the air preheater's baskets with new ones featuring distinct profiles increased the heat transmission rate. Also, the resistance coefficient and Nusselt number increased in tandem with the corrugation angle. The heat regeneration temperature and the heat exchanger's efficiency were observed to decrease as the matrix's rotating speed and the hot flow's mass flow rate increased, according to the results.