The Study on the Evaluation of Thermal Insulation Efficiency with Typical Plant Species of Roof Greenery in Kaohsiung

Abstract This research focuses on the buildings with relevant landscape engineering, and taking the public building as the targets including the sustainable campus project in Kaohsiung. Relevant studies and cases regarding roof greening are also collected and compiled as references for this research. Temperatures of the surface layers, soil layers and ceiling surfaces of different greening types are simultaneously measured in different locations on a 24-hour basis to explore the price-performance ratio of an effective heat-insulation green roof that meets users’ demands. Through filed experiment from real projects, the study compares the highest temperature of the top floors and ceilings with different roof greening types, with the data analyzed through the time-lag effect. The results show that factors influencing the heat capacity of greening types in their performance of temperature reduction and heat dissipation are surface temperature, solar radiation, height of the greening installations, shade and ventilation. Ranking of the most effective types from the best to the worst is: solar panel>planting at a certain height>soil with a certain thickness>planting>stony building materials>wood plastic composite path>soil>original surface. The one with the best price-performance ratio is planting at a certain height and a large shade, which can create a temperature difference by 10 Celsius degrees and achieve a constant indoor temperature. The test result is expected to serve as a reference to create an effective roof greening type in energy saving, temperature reduction and heat insulation. It can be applied to cities with overheating problems, and thus improve the comfort of the urban space in the future by creating a sustainable green space for living.