Abstract
In this study, the reduction of energy demand in the building taking into account the climatic conditions of Riyadh (24.7136° N, 46.675° E) was evaluated through the installation of PCM. By adding sink term in energy and momentum equations, the phase change was modeled. Heat transfer was determined transiently on the inner surface of the envelopes and the results were reported monthly and annually. Considering Riyadh's climate, due to the setpoint temperature interval of 23–25 °C, the addition of RT-23 led to an undesirable PCM performance during the warm months. The results showed that In July, August and September, PCM-23 was not effective, but in the other months, the heat exchange decreased so that in one year, energy consumption decreased by 3984 kWh. The amount of PCM that is injected into the wall and ceiling affects the heat exchange. At thicknesses of 10, 20 and 30 cm, the presence of PCM due to phase change reduced the heat transfer by 25.7%, 35% and 47.1%. Hence as much as 3674, 3984 and 4469 kWh less energy is consumed to set the temperature in interior space.
•Using PCM, energy demand in Riyadh's buildings were reduced.•Taking into account of annual average temperature for Riyadh, PCM-23 was selected.•The results showed that In Jul, Aug and Sep, PCM-23 was not effective.•PCM-23 reduced the annual energy usage by 3894 kWh.•At PCM thicknesses of 10, 20 and 30 cm, energy usage reduced by 25.7%, 35% and 47.1%.