Evaluation of thermoelectric power generated through waste heat recovery from long ducts and different thermal system configurations

摘要

This paper presents the impact of Thermoelectric Generator (TEG) performance for recovering waste heat from long flue gas ducts with different thermal system configurations such as constant fluid temperature, counter flow, parallel flow and cold heat sink exposed to ambience. The counter flow configuration showed a good agreement with reference study for 2 m length of the duct at a high heat transfer co-efficient of 100 W/m(2)K. The increase in duct length showed an adverse effect on TEG power generation due to the temperature drop of fluid along the duct rather than a constant temperature and hence the efficiency of TEG decreased in comparison with a constant fluid temperatures of flue gas and fresh air. Analyzing the performance of different thermal system configurations, results showed that cold heat sink exposed to ambient configuration has a potential to generate maximum TEG power output of 172.34 kW with an efficiency of 4.3% which are 40.22%, and 20.74% lower than the constant fluid temperature configuration respectively for 50 m duct length at a practical heat transfer coefficient of 25 W/m(2)K. The cold sink exposed to ambient configuration is economical whereas counter flow configuration is recommended for regenerative purposes after TEG power generation. (C) 2019 Elsevier Ltd. All rights reserved.