Building Applications, Opportunities and Challenges of Active Shading Systems: A State-of-the-Art Review

Joud Al Dakheel,Kheira Tabet Aoul

doi:10.3390/en10101672

Abstract

Active shading systems in buildings have emerged as a high performing shading solution that selectively and optimally controls daylight and heat gains. Active shading systems are increasingly used in buildings, due to their ability to mainly improve the building environment, reduce energy consumption and in some cases generate energy. They may be categorized into three classes: smart glazing, kinetic shading and integrated renewable energy shading. This paper reviews the current status of the different types in terms of design principle and working mechanism of the systems, performance, control strategies and building applications. Challenges, limitations and future opportunities of the systems are then discussed. The review highlights that despite its high initial cost, the electrochromic (EC) glazing is the most applied smart glazing due to the extensive use of glass in buildings under all climatic conditions. In terms of external shadings, the rotating shading type is the predominantly used one in buildings due to its low initial cost. Algae façades and folding shading systems are still emerging types, with high initial and maintenance costs and requiring specialist installers. The algae façade systems and PV integrated shading systems are a promising solution due to their dual benefits of providing shading and generating electricity. Active shading systems were found to save 12 to 50% of the building cooling electricity consumption.

Highlights

Daylighting in buildings provides multidimensional benefits that have been widely reviewed in the specialized literature [1]
As discussed earlier, rotating shading systems consist of a shading device made of either glass, metal, fabric or timber and is designed to rotate around either a horizontal or vertical axis depending on the position of its slates [91]
Primary energy consumption ofcooling the building was reduced by 50% lower than a similar building as modeled

Summary

Introduction

Daylighting in buildings provides multidimensional benefits that have been widely reviewed in the specialized literature [1]. The provision of daylight through building openings permits views to the outdoors [2], which concurrently contributes to visual [3], psychological comforts [4], health [5], and productivity [6]. Daylighting has many benefits, it has undesirable side effects such as heat gain and glare [9]. Successful daylighting designs will consider the use of shading devices to reduce glare and excess heat gain in buildings [10]. Shading devices are used in buildings to provide a healthy balance by reducing the excessive glare and heat gain and providing privacy [11]

Objectives

Methods

Findings

Conclusion