Analysis of Thermal Effectiveness in Sri Lankan Context a Research based on Vertical Greeneries of Multi-storied Buildings

Abstract

Thermal energy, which comes from the heat, makes the great influence state-of-the-art of global climate simulations. This effect feels especially for multi-stored buildings and concept of greenery has been introduced as a tool for mitigating the thermal effect directly by shading heat-absorbing surfaces and indirectly through evapotranspiration cooling. These greeneries can be placed either horizontal or vertical or both surfaces, which are having the direct exposure to the heating sources. Vertical greens, the key concern of this research, especially gives more benefits by make use of natural processes such as lighting and temperature control. It has been observed that vertical greenery reduces thermal effect up to some extent and reduce energy consumption of the building for air conditioning. Studies have shown that vertical greenery systems are able to reduce thermal heat transfer into the building which in turn reduces energy consumption for air conditioning. This research is carried out as a case study based work. Three case study areas are selected, which are having the great exposure to the sunlight. Two main categories of vertical greens layers can be observed basically in Sri Lanka and the selected sites as case study areas covers both categories of vertical green layers. First category is wall vegetation that is the green layer on the wall and the rest category is the green facades, which is the green layer not having any contact with the wall and vegetated by using a separate support. The spot temperatures on both sides of different walls with and without green layer using Infrared thermometer is observed, compared and analysed. A significant temperature reduction is observed between inside and outside of a room of a building is able to obtain the effect of vertical green vegetated wall when compared to the bare wall. This reduction tends to decrement the cost of energy for air conditioning of a building. Literature expresses, to reduce the room temperature from a single degree of Celsius using a split air conditioner requires the almost 5% of its total energy consumption per day. Thus it has been observed the significant amount of energy can be saved due to the vertical greenery, when validating the above criteria for the research findings. Concluding the research, the choice of design parameters for vertical greenery is an essential to make sure its contribution for energy saving, since the direct relationship exist the energy reduction and vertical greenery.