Význam zelených střech při zmírňování efektu městských tepelných ostrovů v rozdílných klimatických podmínkách

Abstract

Green roof infrastructure is gaining popularity in European countries as well as in other countries all over the world. Green roof is more than just soil and plants on a roof but consists of specialized membranes and drainage system to support vegetation on top of buildings. The mitigation of the urban heat islands and the reduction of cooling loads in buildings are the main advantages of this roofing system. Therefore, green roofs can play a significant role in helping cities to adapt to climate changes. In order to demonstrate this role, it is essential to conduct experimental and modeling studies to provide consistent results. The objective of this research is to evaluate the effects of the green roofs on reduction of excess heat in three urban areas with different climate conditions; Prague, Rio de Janeiro, and Sydney, based on the evidence of occurrence of the heat islands. The effect was examined at a precinct scale; 600 m x 600 m. Modelling testes three scenarios; conventional roof, extensive green roof, and intensive green roof. The methodology consists of seven steps: software validation, modeling, simulation, energy requirement calculation, discounted payback period, data analysis, and conclusion. Data from this simulation is used to demonstrate potential energy savings in case of reduction of energy demand for space cooling. The results of this research shows that implementation of green roofs is an effective strategy in tackling excess heat on the local neighborhood scale and also in reducing energy demand for cooling during summer period. The data demonstrates that green roofs have a beneficial effect on the urban heat islands by lowering the air temperature within the cities during the summer, in case of Prague by 0.49 °C, Sydney by 0.72 °C, and Rio de Janeiro by 0.92 °C. The most significant reduction was achieved in Sydney and Rio de Janeiro due to their climate condition and urban form. Given these results, green roof infrastructure should be considered as an effective tool by local authorities and city councils in order to improve the quality of living in urban areas and create energy efficient cities.

Green roof infrastructure is gaining popularity in European countries as well as in other countries all over the world. Green roof is more than just soil and plants on a roof but consists of specialized membranes and drainage system to support vegetation on top of buildings. The mitigation of the urban heat islands and the reduction of cooling loads in buildings are the main advantages of this roofing system. Therefore, green roofs can play a significant role in helping cities to adapt to climate changes. In order to demonstrate this role, it is essential to conduct experimental and modeling studies to provide consistent results. The objective of this research is to evaluate the effects of the green roofs on reduction of excess heat in three urban areas with different climate conditions; Prague, Rio de Janeiro, and Sydney, based on the evidence of occurrence of the heat islands. The effect was examined at a precinct scale; 600 m x 600 m. Modelling testes three scenarios; conventional roof, extensive green roof, and intensive green roof. The methodology consists of seven steps: software validation, modeling, simulation, energy requirement calculation, discounted payback period, data analysis, and conclusion. Data from this simulation is used to demonstrate potential energy savings in case of reduction of energy demand for space cooling. The results of this research shows that implementation of green roofs is an effective strategy in tackling excess heat on the local neighborhood scale and also in reducing energy demand for cooling during summer period. The data demonstrates that green roofs have a beneficial effect on the urban heat islands by lowering the air temperature within the cities during the summer, in case of Prague by 0.49 °C, Sydney by 0.72 °C, and Rio de Janeiro by 0.92 °C. The most significant reduction was achieved in Sydney and Rio de Janeiro due to their climate condition and urban form. Given these results, green roof infrastructure should be considered as an effective tool by local authorities and city councils in order to improve the quality of living in urban areas and create energy efficient cities.