An investigation into the impact of movable solar shades on energy, indoor thermal and visual comfort improvements

Buildings are huge energy consumers and are responsible for a large part of greenhouse gas emissions in the world. Among building energy efficiency measures, solar shading plays a significant role in reducing building energy consumption, especially in hot summer and cold winter zone of China. This paper carried out a field measurement of shading performance of movable shades installed on the south-facing facade of a residential building in Ningbo city of China. The field tests show that external movable solar shades have a good shading performance that can reduce solar transmittance to about 8% and keep indoor illuminance at about 1000 lux with little fluctuations, indicating a suitable level for indoor environments. A building simulation study on energy, indoor thermal and visual performance of movable solar shades was further carried out. Several important indexes were adopted to give an in-depth analysis, including energy performance, room base temperature, transmitted solar radiation, PMV-PPD and its distribution as well as Discomfort Glare Index (DGI). Results show that movable solar shades used for south-facing windows not only reduce building energy demand by 30.87%, but also improve indoor thermal comfort by 21% in summer as well as reduce dramatically extremely uncomfortable risks by 80.4%, and meanwhile the visual comfort condition is also improved by 19.9%. (C) 2013 Elsevier Ltd. All rights reserved.