The Effect of Water and Plants on Climatic Performance of Indoor SkylightsCase Study: Residential Buildings of Tehran

Indoor skylights or patios are considered one of the pervasive spaces in Tehran's residential buildings. Patios play a significant role in modifying the climatic conditions and bringing the environment closer to humane conditions with a passive approach, thereby reducing energy consumption. The environmental benefits of these spaces were raised as a new response to the energy consumption of buildings after the energy crisis of the 1970s and since then, atrium spaces have been used in modern architecture. Research shows that the climatic performance of skylights is different from and affected by the surrounding conditions and they reduce the need for cooling, heating and mechanical ventilation. On the other hand, they reduce relative humidity, particularly in winter. The purpose of this paper is to obtain the temperature conditions, WBGT (Wet Bulb Globe Temperature), relative humidity of skylights, and its effect on comfort achievement. For this purpose, a skylight of a roofed five-storey residential building in the north of Tehran with plants and injection of pool moisture into the central skylight space. This is a field work in which simulation was done with indoor skylights with cover, water and plants and indoor skylights with the cover but without water and plants. Field measurements were done by temperature and humidity data loggers, and WBGT device in summer and winter for four and five consecutive days, respectively.  In order to record the air temperature in different layers of the patio, three data loggers were installed on the odd floors of the building and a data logger was installed on the roof of the building in the shadow to collect local temperature data every 30 minutes. Then, the building was simulated using the DesignBuilder software and after the results and graphs were obtained, a comparative analysis of the samples was performed and the validity of the simulation results was proved. The results show that the skylights roofed with the plant and injection of the moisture content of the ponds caused a moderate climatic condition in the skylight space, reducing the air temperature to 4° C in the warm season and increasing it to 11.7° C in the cold season. By closing the pool door several times during the field measurements in winter, it was found that the temperature difference in the patio floors increased after the removal of the pool moisture from the skylight. In addition to reducing humidity, the moisture stratification in the floors changed and the humidity decreased from the first to fifth floors. As the skylights were roofed, sunny or cloudy weather conditions in the cold season had little effect (on average 0.5° C) on the internal temperature of the patio. A comparison of the results of simulation and field studies showed that the removal of plant and pool moisture led to an increase in the temperature difference in the skylight. Examining the WBGT index also showed that the fifth-floor patio will be in the caution heat zone during the daytime maximum temperature and will be in the extreme caution zone in the middle of summer.