Thermal performance evaluation of an active building integrated photovoltaic thermoelectric wall system

Active building envelope is an evolved and enhanced version of traditional envelope which received extensive attention. This paper presented a novel and promising active building integrated photovoltaic thermoelectric (BIPVTE) wall system that can use the electric power converted from solar energy by PV cells directly serves for the operation of thermoelectric radiant panel. This active system is highly self-adaptive to ambient thermal environment and can reduce heat gain by considerable scale. A dynamic-state systematic model was established and validated through experiment data. Three analytic sub-models related to the electric and thermal model of PV panel, heat transfer in air duct and model of thermoelectric radiant panel were coupled to describe the thermal behavior of BIPVTE wall system. The electric model of PV panel was solved by Lambert W function to deliver an explicit expression; the thermal model equations of PV panel, air duct and insulation board were solved in a matrix form by adopting state-space method; the analytic model of thermoelectric radiant panel was derived from previous study. After model validation, the traditional wall was taken as the reference to evaluate thermal performance of BIPVTE wall system. The simulation results showed that when indoor air temperature is 24 °C, the thickness and thermal conductivity of insulation is 0.04 m and 0.05 W/m K, BIPVTE wall can reduce about 70% daily heat gain compared with traditional wall in typical day simulation.