Thermal performance of a box-window double-skin façade with semi-transparent photovoltaics

Abstract

This research investigates using a box-window double-skin facade with semi-transparent photovoltaics in an office building located in Iran's cold and dry climate to reduce energy consumption. Simulations were conducted using EnergyPlus and LadybugTools to analyze the facade's impact on heating, electricity generation, thermal comfort, and daylighting, with two air gap depths of 0.25 m and 0.5 m. Findings show that decreasing the air gap depth from 0.5 m to 0.25 m results in higher interior temperatures. During hot periods, the Outdoor Air Curtain mode of the box-window facade achieves greater indoor temperature reduction than the Air Exhaust mode. The study found that a 20% transparent PV configuration on the exterior of the façade generates less AC power than a 40% PV position inside. The AC power output for the whole year and the lowest amount of illuminance in June are 2099 kWh and 311 (20-Ex). For optimal daylighting throughout the year, the study recommends the 20% transparent PV setup, which results in 5.6% more energy savings compared to reference glass. This configuration achieved a maximum Predicted Mean Vote (PMV) of 1.04 in July while shading devices effectively reduced overheating.