# Reduction in Carbon Dioxide Emission and Energy Savings Obtained by Using a Green Roof

Lu Cai, Xiao-Ping Feng , Jing-Yan Yu, Qian-Chao Xiang, Rui Chen

School of Environmental and Civil Engineering, Jiangnan University, Wuxi, Jiangsu 214122, China

Revised: September 24, 2019
Accepted: October 5, 2019

Cai, L., Feng, X.P., Yu, J.Y., Xiang, Q.C. and Chen, R. (2019). Reduction in Carbon Dioxide Emission and Energy Savings Obtained by Using a Green Roof. Aerosol Air Qual. Res. 19: 2432-2445. https://doi.org/10.4209/aaqr.2019.09.0455

## Highlights

• Using green roof experiment simulation method to obtain energy savings 11.53 kWh.
• The new plant Buddha grass is used as a research material for green roof.
• Using the green roof to get the carbon reduction of 1.79 kg.
• The green roof benefits described in this paper are comprehensive.

## ABSTRACT

Green roofs have good heat preservation and insulation performance, which plays an important role in reducing air-conditioning load and reducing carbon dioxide emissions. Experimental research and numerical simulation analysis on the energy-savings and ecological benefits of green roofs in hot summer and cold winter areas in Wuxi, China (31°N, 120°E) are carried out. The experimental results show that a new type of Buddha grass can absorb 1.79 kg of CO2 and release 1.3 kg of O2 per square meter per year. In addition, the annual carbon emission reduction of the green roof in Wuxi was 9.35 kg m–2, and the emission reduction benefit of the green roof was calculated to be USD $1.02 m–2 a–1. The energy consumption simulation shows that the green roof per unit area can save 11.53 kWh per year, and the annual quantitative ecological benefit of a green roof is USD$3.37 m–2. The calculated dynamic investment return is 10 years. A green roof has the benefits of heat preservation and insulation; meanwhile, it can reduce energy consumption. It is also worth mentioning that its energy-saving potential and ecological benefits are substantial, and the investment payback time is short, which makes it worth promoting in a large area.

Keywords: Carbon dioxide emission; Green roof; Equivalent thermal resistance; Energy-savings; Ecological benefits.

Impact Factor: 2.735

5-Year Impact Factor: 2.827