Solar chimney for a real building considering both energy-saving and fire safety – a case study

Abstract

This study presents the world-first design of solar chimney for a real building considering both energy-saving and fire safety. Typical designing factors on both functions were investigated by a numerical tool after it was validated by experiments. It was obtained that solar chimney can be adopted for both functions with 7.42 air changes per hour natural ventilation under normal conditions and at least 6.52 times extension of available safe egress time for occupants under typical fire conditions. It was also known that the previously obtained optimized cavity gap of 0.2–0.3 m is no longer applicable for a big space, where the optimum gap is 1.2 m considering both functions for a big space. A consistency coefficient is also proposed here that a positive consistency coefficient means the increased parameter can enhance the performance of both functions, while a negative coefficient represents the performance enhancement of one function will compromise the other. The consistency coefficient of those designing parameters are: cavity gap (30.91) > air supply area through top vent (12.47) > air supply area through bottom door (5.4) > cavity height (3.09) > 0 > solar radiation (-0.47) > cavity height below the roof (-40.04). The parameters with negative consistency such as cavity height below the roof should be considered carefully when both functions are planned.