SHADING COEFFICIENT OF A VERTICAL GREENERY SYSTEM

Abstract

Urban Heat Island (UHI) has been a major concern in Singapore and has been closely monitored since 1982. This phenomenon has proved changes to the climate in which we live in. The causes are attributed to the rapid urban shift to urbanization and industrialization which remove vegetation cover. One of the ways to mitigate this impact is vertical greenery.

The objectives of this study are to determine the shading coefficients (SC) of the 23 types of green plants and the correlation between SC and Leaf Area Index (LAI). An equation between SC and LAI is to be formulated to find the SC of any plant with a given LAI or vice versa.

The SC is then substituted to the Envelope Thermal Transfer Value (ETTV) to quantify the amount of thermal reduction by these green plants. The SC and LAI experimentations were conducted on 23 plants at HortPark for a period of 2 weeks in July 2008. The results show that the vertical greenery can reduce temperature on the exterior wall effectively. There is also a relative correlation between SC and LAI which means the effectiveness of green plants depends on the leaves‟ density and thickness. The equation between SC and LAI has been determined to extrapolate the results. The ETTV of a building with vertical greenery proves to be lower as compared to one without. The experiments conclude that vertical greening can reduce the temperature of the façade and thereby helps in lowering the urban heat island effect.

Although not all the plants were experimented, the 23 plants should provide a substantial amount of data for analyzation. The measurements that were repeated 2 to 3 times should have minimized the possible human and experimental errors as are common in all experiments.