CFD Modeling of a Semi-transparent PV-PCM Façade Window with Embedded Water Cooling

¹ Technical University of Cluj-Napoca, AtFlow Research Centre, 400641 Cluj-Napoca, Romania
² Technical University of Cluj-Napoca, Building Services Department, 400604 Cluj-Napoca, Romania.

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Urban decarbonization can benefit from façades that both generate power and manage heat. This study examines a semi-transparent PV glazing coupled with a phase-change layer (PCM, ~25 °C melt) and an embedded water loop as a tri-functional façade element suitable for dense cities. A steady state CFD was built with radiation baseline (pressure-based RANS, k–ω SST viscous model, fully conjugate heat transfer) with Discrete Ordinates in participating media to resolve solar transport through PV–PCM–glass and quantify heat flux partitioning. At a summer design point, the sunlit face absorbs ~780 W/m² on average; ~200 W/m² are rejected immediately to ambient (~21% radiative, ~79% convective), while the remainder is routed into the laminate. Results show strong cooling footprints over the serpentine on the PV side and “cold stripes” on the room side (~12–31°C), evidencing effective heat draw toward the coil and reduced indoor loads. Water-side removal derived from outlet temperature yields ~190 W for the numerical simulated panel, and a closed local energy balance corroborates the optical–thermal setup. This study delivers design-relevant metrics (PV operating temperature, exterior/room-side fluxes, useful heat recovery) and highlights levers, like coil pitch, PCM thickness, flow rate, and film coefficients.