Integrated TEG-TEC and variable coolant flow rate controller for temperature control and energy harvesting

The thermoelectric (TE) device enables a conversion interface between the heat transfer and the electricity domain. Heat can be converted to electricity via the thermoelectric generator (TEG) effect and conversely, electricity can be converted to heat via the thermoelectric cooling (TEC) effect. In the meantime, varying the flow rate of coolants in a liquid cooling system is another common technique that is used to achieve temperature control. This paper proposes a fuzzy logic controller (FLC) that integrates both the combined TEG-TEC control method and the variable coolant rate techniques to achieve both the active temperature control (in TEC mode) and the energy harvesting capability (in TEG mode) of the TE device. The most significant control objectives are that the TEC mode is used to improve the temperature transient response whereas the variablant flow rate's purpose is to drive the system towards operating in the TEG mode. Temperature control of a fuel cell stack is chosen as example study application and an experimental verification involving a heat emulator is presented to highlight the positive influence of the variable flow rate technique for improving the temperature transient and increasing the energy harvesting capability of the TEG-TEC control technique. (C) 2018 Elsevier Ltd. All rights reserved.