Development and Energy Savings Analysis of Active Thermal Switches with Thermal Storage for Dynamic Building Envelopes in Residential Buildings

This study presents the design, experimental evaluation, and energy savings potential of an active thermal switch technology for building envelopes, enabling variable thermal resistance. The switch incorporates a low-power motor and a Raspberry Pi-based control for programmable switching, real-time monitoring, and fault detection. The effective thermal conductivity of a switch inserted into a 10 in × 10 in (0.064 m2) insulation is measured to ∼0.046 W/m-K in the OFF state and 0.258–0.316 W/m-K in the ON state. Cyclability tests over 225 thermal cycles show no performance degradation. Outdoor tests using scaled-down models demonstrate improved performance of wall-integrated phase change materials (PCMs). Building energy simulations on single-family residential homes across various US cities’ climates indicate that integrating these switches with PCM-based thermal storage can reduce annual heating and cooling energy use by up to 1,090 kWh and energy costs by up to $286, with average savings of 738 kWh (24%) and $130 (24%), respectively.