Cooling Benefits of an Extensive Green Roof and Sensitivity Analysis of Its Parameters in Subtropical Areas

Yu Zhang, Lei Zhang, Luyao Ma, Qinglin Meng and Peng Ren
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Yu Zhang: School of Chemistry and Chemical Engineering, State Key Lab of Subtropical Building Science, South China University of Technology, Guangzhou 510641, China
Lei Zhang: School of Architecture, State Key Lab of Subtropical Building Science, South China University of Technology, Guangzhou 510641, China
Luyao Ma: School of Architecture, State Key Lab of Subtropical Building Science, South China University of Technology, Guangzhou 510641, China
Qinglin Meng: School of Architecture, State Key Lab of Subtropical Building Science, South China University of Technology, Guangzhou 510641, China
Peng Ren: School of Architecture, State Key Lab of Subtropical Building Science, South China University of Technology, Guangzhou 510641, China

Energies, 2019, vol. 12, issue 22, 1-22

Abstract: The present study aims to further demonstrate the cooling benefits of an extensive green roof (EGR) and fill the gap existing in the literature in terms of a sensitivity analysis of an EGR, especially in subtropical areas. First, onsite measurements were performed. The results indicated that the peak air temperatures in the chamber with the EGR were 4.0 °C and 1.9 °C lower, respectively, compared to those in the chamber with a bare roof on sunny and rainy days. Moreover, the EGR decreased the daily electricity consumption from air conditioning by up to 16.7% on sunny days and 6.7% on cloudy days. Second, the measured values were employed to validate the green roof module (GRM) in EnergyPlus. The results demonstrated that the GRM yielded accurate results in quantifying the cooling benefits of the EGR. Finally, we selected 16 factors of the EGR, each with four levels, to perform the sensitivity analysis. Range and variance analyses revealed that the factors that most significantly impacted the EGR performance were the R -value of roof construction, substrate (soil) thickness, the thermal conductivity of dry substrate, the leaf area index, leaf emissivity, and the solar absorptance of the substrate. These factors contributed 90.8% to the performance index.

Keywords: extensive green roof; cooling benefits; onsite measurements; numerical simulation; sensitivity analysis; subtropical area (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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