Buildings account for 36% of worldwide energy consumption, with the Heating Ventilation and Air Conditioning system representing up to 55% of a building's consumed energy.
The most thermally inefficient building envelope elements are the glazing units, causing (28-36) % of the total heat inputs during summer.
The project aims to study the efficiency of translucent phase change material (PCM) layers in the structure of photovoltaic (PV) skylights, that provide a level of daylighting.
PCMs store high amounts of thermal energy through phase change (latent heat), are classified into organic and inorganic substances, and are commercially available, with a wide range of properties, such as phase change temperatures, latent heat values, etc. It is estimated that a PCM with a phase change temperature of 25 °C will be adopted, for nighttime solidification to occur in the climate of Cluj-Napoca. PCMs have less effective thermal insulation properties compared to air/argon and can cause overheating after daytime melting. Thus, within the PCM layer, a coil manufactured out of transparent tubes will be immersed. The extracted heat will be transferred to the domestic hot water (DHW) heating system, to preheat the DHW. Therefore, the final product will obtain Building Integrated PV thermal (BIPVT) system features, increasing buildingsâ energy efficiency by reducing cooling load and boiler energy production, and increasing PV power generation, with the disadvantage of decreasing daylighting.
