A Liquid Filled Prismatic Louver (LFPL) system, which combines
both energy saving strategies is experimentally demonstrated. The LFPL
system was installed in a south-facing building façade in New York City
and evaluated for indoor daylight penetration and potential for thermal
energy harvesting. Daylight redirection is achieved through the prismatic
louver geometry and proper orientation, whereas thermal energy harvesting
is achieved through IR absorption from the liquid (e.g., water) within
the prisms. Daylighting performance was evaluated by illuminance
measurements at key locations within the space, whereas thermal
harvesting performance was evaluated through temperature measurements and
thermal imaging analysis. We show that the LFPL system, with all
prismatic elements oriented at the same angle, achieved effective
daylight redirection to the ceiling and provided 2-fold and 8-fold enhanced illuminance, at prism orientations of 10° and 20°, respectively.
We also demonstrate the system's capability to adjust to specific
lighting needs, within the space, through the dynamic individual
orientation of prismatic elements; thus, achieving a concentrated ceiling
illuminance enhancement of ~100 times and ~200 times at 2.5 and 4.3 m
away from the window sill, providing work plane illuminance enhancement
of 6- and 2-times more than in the case of the control room with regular
windows. Furthermore, we show a reduction of potential heating loads at
locations close to the window from the combination of infrared absorption
in the water volume and the redirection of the incoming solar radiation,
leading to a reduction of the work area temperature by an average of 8
°C.
Revised: February 10, 2021 |
Published: February 3, 2020
Citation
Alva M.E., E. Vlachokostas, and N. Madamopoulos. 2020.Experimental demonstration and performance evaluation of a complex fenestration system for daylighting and thermal harvesting.Solar Energy 197.PNNL-SA-144824.doi:10.1016/j.solener.2020.01.012