Photovoltaic Warm Façades with Phase Change Materials in European Climates

Abstract

Since facade-integrated photovoltaic (PV) modules heat up greatly, which reduces the efficiency of thePV, facade panels with PV and phase change materials (PCM) were developed. PCMs absorb a significantamount of thermal energy during the phase transition from solid to liquid, while maintaining a specificmelting temperature. This cools down the PV and increases the electrical yield. Numerical studies onPV-PCM warm facades without rear-ventilation have so far been missing. Therefore, a thermal andan electrical simulation model for PV-PCM warm facades were developed and validated. They werethen used to analyse the yield increase of two PCM-types and -quantities in PV warm facades facingeast, south, and west in Athens, Potsdam, and Helsinki. An annual yield increase of 1.2% to 8.5% formonocrystalline PV modules was determined. The maximum monthly yield increase is 8.0% in Helsinki,11.4% in Potsdam, and 11.3% in Athens. The study shows that a case-specific selection of the appropriatetype and quantity of PCM is necessary. Using the models, a design tool for PV-PCM warm facades will bedeveloped. It will be validated with real monitoring data from PV-PCM facade test rigs at the TechnischeUniversitat Dresden and the National Technical University of Athens