Evaluation of a prototype active solar thermoelectric radiant wall system in winter conditions

• A novel active solar thermoelectric radiant wall was developed and reported.
• The novel wall can control the heat flux of wall by using solar energy or DC power.
• The performance of the active solar thermoelectric radiant wall operating in winter condition was investigated.
• The optimum operating current and the operation strategy for the ASTRW have been proposed.

Active solar thermoelectric radiant wall (ASTRW) system represents a new solar wall technology that uses solar energy to compensate for passive heat losses or gains through building walls. In ASTRW system, electrical energy obtained from photovoltaic cells or DC power is used to power thermoelectric modules, which can control the heat flow through the wall. In order to assess the practical feasibility of the ASTRW system, we have developed a prototype ASTRW system and conducted experiments in different modes. Results show that the ASTRW system can not only eliminate conventional building envelop thermal loads but also provide a heating capacity for space heating. The COP can reach 2.3 and the thermal efficiency can reach 34.2% when the system is powered directly by PV system during the daytime of a sunny winter's day. During the daytime hours of a cloudy or rainy winter's day, the system is powered by a DC power and works as an air source thermoelectric heat pump, and the COP can be about 2.0 for space heating. In order to get an excellent performance of the ASTRW system, the optimal operating current for ASTRW system has been analyzed using a simplified analytical model and the optimum operation strategy for ASTRW has been determined and proposed based on the experimental results.