Experimental study and multi-objective optimisation of a novel integral thermoelectric wall

Abstract

The development of a high-performance building envelope is critical to the improvement of building energy efficiency. As the building-integrated thermoelectric envelope (BITE) has a complex structure, development of a simple and practical thermoelectric wall is relevant. Therefore, this study proposes an integral thermoelectric wall (ITEW) with a simple structure that can easily be integrated into a building wall. The ITEW not only eliminates the heat losses or gains of the wall but also provides indoor cooling and heating capacity. A theoretical model of the ITEW was first established and verified using detailed experiments. To realise the highest performance of the ITEW, the optimal ranges of five key parameters—the direct current, number of PN couples, thermoelectric element leg length, thermoelectric element cross-sectional area, and heat dissipation condition—were determined. Thereafter, taking these value ranges as constraints, the Non-dominated Sorting Genetic Algorithm-II was used to perform a multi-objective optimisation in summer and winter conditions. The results show that the cooling and heating performances of the ITEW can be simultaneously improved. The cooling coefficient of performance ranged from 2 to 7, and the cooling capacity per unit area ranged from 2 to 70 W/m2. Meanwhile, the heating coefficient of performance ranged from 1 to 8 and reached values greater than 4 under conventional building heat load demand. The results of this study, therefore, establish a foundation for the development and application of the ITEW system.