The Transient Heat Flow In The South & West Facing Hcb Wall Of Condominium Building In Adama City,Ethiopia.

Abstract

In most of tropical regions of the world the major challenges in creating thermal friendly indoor space is heat. Heat is among one of the major determinant of thermal comfort that passes and leaves through the building facades; which the focal interface is between indoors and outdoors. This research aims to find the reaction of South and West facing façade of condominium building to the external environment as well as identify if the facades do fit for handling the warm climate of Adama city. Ambient temperature(indoor &outdoor) , surface temperature( exterior & interior) and humidity of the room within 2hrs interval (5 times a day) for four consecutive days in three months(March, April & May) were measured and used alongside the thermal conductivity values of the facade layers derived from literatures. MS Excel and formulas retrieved from literatures were used to analyze the data. Comparatively high thermal transmittance (1.2w/m2 k) ,low thermal insulance (0.83m2 k/w) & low absolute thermal resistance (10.406k/w , 9.756k/w is due to air gap) were among the results from the analysis , which indicate low performance of the facades. Relative humidity and room temperature results also do not completely fall inside the thermal comfort zone of Adama city: which depicts the existing facades are incapable of fulfilling thermal comfort throughout the daytime period. Heat transfer rate as low as -34.4J/sec (in April) & -45.29J/sec (in April) and as high as 73.3J/sec (in March) & 96.4J/sec (in March) were recorded for South and West facades respectively. Both facades do start gaining heat after midday, though the West facade receives quite more rapidly than South façade. Overall the existing facades do need optimization to enable them cope up with warm climate of Adama city. The research suggested optional facades by changing the existing air gap (16cm) of the facades to 20(+4cm) & 24(+8cm) in order to increase thermal performance of the facades with minor intervention. The results found were ,23.44% & 46.8% increase in absolute thermal resistance ,19.17% & 15.8% decrease in thermal transmittance for an extra 4 & 8cm air gap respectively.. This modification will enable the facades to have slower heat gain and faster heat loss, which is basic for maintaining thermal comfort in warm climates of Adama city.