Advances in Building Energy Research

Volume 4

Mat Santamouris

• Publisher: Routledge
• Year: 2010
• eBook ISBN: 9781136532771
• Topic: Technology & Engineering
• Subtopic: Civil Engineering
• Index: Technology & Engineering

Advances in Building Energy Research (ABER) offers state-of-the-art information on the environmental science and performance of buildings, linking new technologies and methodologies with the latest research on systems, simulations and standards. As stringently reviewed as a journal but with the breadth of a book, this annual volume brings together invited contributions from the foremost international experts on energy efficiency and environmental quality of buildings. Spanning a broad range of technical subjects, this is a 'must have' reference on global developments in the field, suitable for architects and building engineers, environmental engineers, industry professionals, students, teachers and researchers in building science, technical libraries and laboratories.

1

Research on heating and cooling requirements of buildings with solar louvre devices

Ana I. Palmero-Marrero and Armando C. Oliveira

Abstract

External louvres have been increasingly used to provide solar protection for a building’s glazed surfaces. In this work, a general study of the effect of louvre shading devices applied to different façades of a building is carried out for different locations (latitudes). Building energy requirements for a building in the cooling and heating seasons are quantified for different window and louvre areas, under different climatic conditions (Europe, Africa and America). Shading geometry is studied with EES software, while indoor air and operative temperatures are calculated through simulations with TRNSYS. Both horizontal and vertical louvre layouts are considered. The results show that the use of louvre shading devices in the building leads to indoor comfortable thermal conditions and may lead to significant energy savings, in comparison with a building without shading devices. The potential of integrating solar thermal collectors into horizontal solar louvres is also addressed, by considering possible active solar heating and cooling systems.

■ Keywords – building simulation; EES; energy requirements; solar louvres; TRNSYS

INTRODUCTION

Glazed areas and shading devices have an important role in a building’s energy consumption. Highly glazed façades have been increasingly used in new buildings, allowing access to daylight and an external view. However, the risk of a high cooling and heating demand in the building must be considered (Hien et al, 2005; Poirazis et al, 2008).

The most effective way to reduce the solar load on fenestration is to intercept direct radiation from the sun before it reaches the glass. The energy performance of buildings using different shading designs, such as overhangs (Lee and Tavil, 2007), external roller shades (Tzempelikos and Athienitis, 2007) and venetian blinds (Simmler and Binder, 2008), has been studied. Glazed areas that are fully shaded from the outside reduce solar heat gain by as much as 80 per cent (ASHRAE, 1997). In all exterior shading structures, the air must move freely to carry away heat absorbed by the shading and glazing materials. This is the case with external louvres.

Louvres are currently widely used, providing solar protection for glazed spaces and reducing loads during the cooling season. Some studies on the effect of louvres on a building’s thermal performance (Datta, 2001) and daylighting performance (Freewan et al, 2009) have been carried out. The integration of a solar thermal collector into an existing louvre design, using horizontal louvres (overhang type), was assessed (Palmero-Marrero and Oliveira, 2006). In all these cases, only south-oriented windows and horizontal layout louvres were studied. However, louvres have been applied to other façade orientations, and also with vertical layouts. Applications extend to a variety of vertical glazed façades, atria roofs, windows and conservatories – see Figure 1.1.

Figure 1.1 Use of louvres to protect glazed surfaces (horizontal layout in a south façade and vertical layout in east or west façades)

In the Northern Hemisphere, due to solar incidence angles, horizontal layouts can considerably reduce the solar heat gain on south, southeast and southwest exposures, during late spring, summer and early autumn. On east and west exposures, during the entire year, solar altitude is generally so low that, to be effective, horizontal layouts would have to be excessively long (ASHRAE, 1997). In these cases, a good solution could be the use of adjustable vertical mechanisms to control direct solar radiation (Ciemat, 2001).

Since a building may have glazed façades that are not south-oriented, the effect of shading devices in other orientations must be studied. In this work, the performance of louvre shading devices applied to the east, west and south façades was evaluated for different latitudes. Both horizontal and vertical layouts were considered. The energy required in the building for space coolin...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• List of Acronyms and Abbreviations
• 1 Research on heating and cooling requirements of buildings with solar louvre devices
• 2 On the evaluation of heating, ventilating and air conditioning systems
• 3 Climatic change and the built environment
• 4 Chromogenic technologies: Towards the realization of smart electrochromic glazing for energy-saving applications in buildings
• 5 Overview of natural cross-ventilation studies and the latest simulation design tools used in building ventilation-related research
• 6 Comfort models and cooling of buildings in the Mediterranean zone
• 7 Cool materials and cool roofs: Potentialities in Mediterranean buildings
• 8 Artificial intelligence for energy conservation in buildings
• Index