Simulating the CO sub(2) reduction caused by decreasing the air conditioning load in an urban area

• Published in: Energy and buildings Vol. 114; pp. 87 - 95
• Main Authors: Hirano, Yujiro, Fujita, Tsuyoshi
• Format: Journal Article
• Language: English
• Published: 15.02.2016
• Subjects: Air conditioning; Albedo; Energy conservation; Energy consumption; Joining; Mathematical models; Reduction; INW, Japan
• ISSN: 0378-7788
• DOI: 10.1016/j.enbuild.2015.06.033

In this paper, measures such as planting urban greenery and using high-albedo paint to mitigate the urban heat-island effect, conserve energy, and reduce CO sub(2) emissions were assessed. As a typical energy-saving method for buildings, reducing the internal heat sources and increasing the insulation are also assessed. We used a coupled urban canopy and building energy model to predict the heat loads of buildings in city districts, the effects of air-conditioning on energy consumption, and air temperature changes. In this model, a vertical one-dimensional local atmospheric model is coupled with an air-conditioning load calculation model for buildings, making it possible to assess the interaction between anthropogenic heat release due to air-conditioning usage and the outside thermal environment. In this study, we selected a target study region in the city of Kawasaki, Japan. When typical city districts were assessed, planting greenery or increasing albedo achieved temperature reductions of 0.6-1.0 degree C and 0.1-0.5 degree C, respectively, and energy savings of 40-80 and 70-90 kJ/m super(2)/day (per unit floor area) on a typical summer day. The results from the large-scale assessment show that urban greening or albedo increases achieved the highest energy savings, of up to 400 t-CO sub(2)/day, in the entire target study region.