Energy and Exergy Analysis of Heat Recovery from the Accumulating Tanks of a Central Heating System by Employing a Sample of Thermoelectric Generators

Abstract

Heat recovery using a series of thermoelectric generator (TEG) samples improved and studied previously is investigated in this paper. For this, such TEGs are connected to the accumulating tanks (ATs) of a geothermal central heating system assisted by natural gas to recover all waste heat from those devices. The study was carried out based on energy and exergy analysis. In the energy analysis part of the study, the proposed energy conversion efficiency of the TEG sample for the temperature difference in an AT-TEG system in this current study, which is 2%, was applied to find power output and energetic efficiency. As a result, total net power production was 9.888 kW, while overall energy efficiency was 7.717%. It can be observed that this amount of net power generation is sufficient to supply 61.262% of the electrical power needed for the circulating pumps in the remaining parts of the central heating system. This research reveals that TEG application in heat recovery is a promising way forward, but there is still a need to enhance the conversion efficiency of such devices.