Daylight and thermal harvesting performance evaluation of a liquid filled prismatic façade using the Radiance five-phase method and EnergyPlus

Abstract

A dynamic liquid filled prismatic louver (LFPL) façade is evaluated both as a daylight redirecting and an energy harvesting system. The LFPL performs daylight redirection due to its transparent daylight redirecting geometry, whereas it performs thermal harvesting due to its heat absorbing water medium inside the transparent prisms. We evaluate the illuminance levels and daylight glare probability (DGP) of the LFPL system through the Radiance simulation tool, and in particular using the Radiance five-phase method for complex fenestration systems (CFS). In addition, we assess the thermal harvesting potential of the LFPL system and the impact of the enhanced daylight penetration on the reduction of heating, cooling, and fan energy consumption through EnergyPlus simulations. Our study shows that (a) the LFPL system enhances the indoor natural light by 9% and reduces the glare by 20% and (b) although the façade elements have the potential to be rotated, a fixed position of the LFPL works equally well as the dynamic rotation scenarios. A fixed LFPL position is a passive design and thus does not require powering for controlling the façade, which makes the approach simpler. Furthermore, in terms of energy harvesting, the LFPL system shows (c) a 52.4% enhanced solar radiation absorption at the façade level, compared to the baseline glass glazing and (d) a reduction in cooling, heating, and fan requirements by 6.5%, 1.5%, and 5.7%, respectively.