Integration of a solar air heater to a building equipped with PCM to reduce the energy demand

Abstract

The main focus of the article is to investigate the effects of radiation on PCM advantageousness in buildings. Numerical methods were used to estimate the intensity of radiation on horizontal (roof) and vertical (walls) surfaces and then its effect was applied as heat flux in boundary conditions. To examine PCM, the heat exchange (HE) through horizontal and vertical surfaces was determined and compared with the surfaces without PCM. For surfaces without PCM, the highest HE was for roof (4348 kWh/year) and followed by east (3919), west (3906), north (3656) and south (3520 kWh/year) walls. By adding a 5 cm layer of PCM to the outermost layer, HE through roof dropped by 34% while this figure was 23.4% for east wall and followed by 23.2% (west), 18.9% (north) and 16.7% (south). To enhance the effect of PCM, its installation location was examined in four cases and it was found that if PCM is mounted in the outermost layer, there is the most energy-saving (i.e., 4576 kWh/year). Finally, adding a solar air heater was led to more energy-saving by 325 kWh/year.