ICT2014 Abstracts

Thermoelectric generator (TEG) is a promising technology for heat and power generation applications. TEGs are especially attractive for micro combined heat and power (CHP) generation due to its solid-state and compact nature. In this work, a micro CHP boiler is developed using a high-temperature TEG based on our nanostructured bulk Half-Heusler thermoelectric materials of significantly enhanced thermoelectric figure of merit. In the core of our TEGs is a thermoelectric module of unique device-packaging architecture that enables device operation at 500 ^oC temperature differences with 10% heat-to-electricity conversion efficiency. Meanwhile, we developed a multi-physics model to simulate the heat exchanger and thermoelectric devices using finite volume and finite element method. Using our model, both the heat exchanger design and the thermoelectric module have been optimized in order to obtain the maximum thermal efficiency and electric power output, and minimum pressure drop and thermal stress. The TEG was installed on a 30 KW residential boiler adjacent to the combustion flame in order to utilize the above 1000 ^oC temperature difference between the hot flame and the water, converting a portion of the heat into electricity with the remaining heat contributing to water heating. Our initial thermoelectric generator prototype shows the electric power output of about 100 W. The total heat and electricity generation efficiency of 95% can be achieved using condensing boilers. CHP boilers will not only reduce building electricity cost by about 50% compared with electricity cost from the grid, but also greatly enhance the energy security during natural/artificial disasters. Working with the boiler OEMs, our future work is focused on system level integration of TEG into boilers that can ultimately lead to a commercial path of micro CHP technology using high-efficiency thermoelectric generators.