The present work considers parametric analyses that examine the attempts of capturing heat from the exhaust gas of 500-kVA power generator. The heat capturing is performed through the use of counter flow concentric tube heat exchanger. The captured heat is utilized to heat water. Therefore, various geometrical configurations of heat exchangers are considered and supplied to heat transfer equations. Two flow-patterns are considered, flow-pattern I where the exhaust gas is streamed in the inner tube while the water is flowing in the annulus, and flow-pattern II where exhaust gas is streamed in the annulus while the water is flowing in the inner tube. The appropriate heat transfer modeling is briefly presented. It was found that the most efficient geometrical configuration is found in flow-pattern II, where water flows in the inner tube with an inner to outer diameter ratio of 0.75. The corresponding captured average heat rate of the aforementioned case is 26 kW.
Khaled, M., Ramadan, M., & Hage, H. E. (2015). Parametric Analysis of Heat Recovery from Exhaust Gases of Generators. In Energy Procedia (Vol. 75, pp. 3295–3300). Elsevier Ltd. https://doi.org/10.1016/j.egypro.2015.07.710