Observations from existing passive buildings can provide indications on new approaches that are required to design with “a changing climate”. Jaalis are perforated façade shading screens which are one of the most suitable climate- responsive design strategies for buildings in the Indian subcontinent. This work reports on the eld study observations from a passive, Jaali shaded tomb chamber at Sarkhej Friday mosque in Ahmedabad, India ( figure 5). The 1600 sq.ft. tomb chamber was designed to be entirely shaded by Jaalis on its north, south and west facades ( figure 2).
Indoor environmental thermal data consisting of dry bulb temperature, relative humidity and surface temperature; was recorded for the duration of two days in late January (2019). Moreover, activities of visitors who spent more than two- three hours of their time in the tomb chamber were captured. The thermal data recorded at three levels (6”, 3’, 6’ from oor) from SE, SW, NW and NE corners of the building was analyzed for PMV-PPD metrics and surface temperature comfort range (ASHRAE Standard 55 recommendations) ( figure 3). The PMV values at all the locations were within neutral (0) to slightly cool (-1) range and the PPD values were within the 20% acceptable limits; which predicted the Jaali shaded zones to be thermally comfortable. Visitor activities, however, were concentrated in areas that received solar radiation from the screen-less parts (where broken Jaali was replaced by grilles) of the façade (figure 4). Floor temperature of these areas suggested local thermal discomfort. These observations suggest requirement of “thermally dynamic and nonuniform” environments, as advocated by Brager et.al (2015) and Parkinson and de Dear (2015).