An Experimental Evaluation of the Thermal Performance of Felt Type Vegetated Facade System

Abstract

Vegetated facade systems (VFS) have been used as green building envelope systems in recent years. Using VFS for ecological strategies and evaluating thermal performance of these sytems are not a new concept. However, there is not any experimental study in literature which evaluates thermal performance of felt type VFS applied on an insulated existing building wall which is located in Csa climate during cooling and heating periods. Hence, an experimental study was conducted to measure thermal performance of felt type (type which used felt material as growing media) VFS in Kocaeli (under Csa climate). Test results indicate that in day time with high amount of solar radiation, felt type VFS decreased exterior surface temperatures of an insulated existing wall by maximum of 30°C. Also, interior surface temperatures of vegetated facade were lower than interior surface temperatures of reference facade with the maxiumum difference of 1.8°C. Although high differences between exterior surface temperatures of vegetated and reference walls were observed, there was no significant difference between interior surface temperatures of vegetated and reference walls. This is due to the fact that existing building exterior wall assembly includes 5 cm thickness expanded thermal insulation material which enchance thermal performance of brick wall. In addition, indoor air temperatures behind both facades were close to each other, and were not suitable according to ISO 7730 and ASHRAE 55 Standards comfort range for representative summer days with high ambient air temperatures. Nevertheless, indoor air temperatures behind vegetated facade were in the comfort range in the fall representative day which required cooling, while indoor air temperatures behind reference facade were not in the comfort range in summer representative day.

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