Assessment of Light Transmission for Comfort and Energy Efficient Insolation by “Green Structures”

Abstract

Insolation is one of the most important factors of human comfort and health in premises. Nevertheless, in a cooling period, the solar radiation brings additional heat gains decreasing the energy efficiency of buildings. The best practice is to allow the maximum solar radiation in heating and transition periods, and to limit it to the minimum permissible level during a cooling period. Usually, the problem is solved by technical measures, such as automated sun-blind-transformers, automatic jalousie or south orientation of glazing, equipped by a non-transformed canopy. In a previous work of the authors, a solution using “green structures” with deciduous plants was proposed. It avoids automation, allows using the most of orientations for glazing, does not decline the view, provides emotional comfort by the most natural appearance, and also improves the sanitary conditions by phytoncides. The goal of the work is the provision of minimum normative insolation in a cooling period by the design of a “green structure”. A geometric model is used for the sunrays, which passed through the planting. The model considers the shape of plant crowns and light transmission through them avoiding direct simulation of the shape of each leaf. An approach for the simple determination of the light transmission through different plants without special apparatus is proposed. The light transmission through different plant crowns was determined for different plants, which can be used in “green structures”. The best practice is a combination of plants with dense and openwork crowns.