Indoor Daylighting and Thermal Response of a Passive Solar Building to Selective Components of Solar Radiation

Ochuko Overen,Golden Makaka,Edson Meyer

doi:10.3390/buildings11010034

Abstract

Solar radiation provides the most significant natural energy in buildings for space heating and daylighting. Due to atmospheric interference, solar radiation received at the Earth’s surface consists of direct beam and diffuse radiation, where diffuse can be further broken down into longwave and visible radiation. Although each of these components co-occurs, their influence on the indoor visual and thermal conditions of a building differ. This study aims to analyze the influence of the various components of solar radiation on the indoor thermal and daylighting of a passive solar building. Thus, a pyrheliometer, pyranometer, shaded-pyranometer, and pyrgeometer mounted on a SOLYS 2 (Kipp & Zonen, Delft, Netherlands) dual Axis sun tracker, were used to monitor direct, global horizontal, diffuse and downward longwave radiation, respectively. The seasonal indoor air temperature and relative humidity were measured using an HMP 60 temperature relative humidity probe. A Li-210R photometric sensor was used to monitor the indoor illuminance. The summer and winter indoor air temperature, as well as relative humidity, were found to be influenced by diffuse horizontal and global horizontal irradiance, respectively. In summer, the indoor air temperature response to diffuse horizontal irradiance was 0.7 °C/ħW/m2 and 1.1 °C/ħW/m2 to global horizontal irradiance in winter, where ħ is 99.9 W/m2. The indoor daylighting which was found to be above the minimum office visual task recommendation in most countries, but within the useful daylight illuminance range was dominated by direct normal irradiance. A response of 260 lux/ħW/m2 was observed. The findings of the study support the strategic locating of the windows in passive solar design. However, the results show that north-facing clerestory windows without shading device could lead to visual discomfort.

Highlights

The building sector consumes over 30% of the total final energy, having increased by more than 35% since 1990
The office space entrance door was always open during operation hours, which was observed to be 8:00 to 17:00 weekdays
The indoor air temperature and relative humidity which served as the thermal parameters of the office space were monitor

Summary

Introduction

The building sector consumes over 30% of the total final energy, having increased by more than 35% since 1990. The building sector is responsible for 30% of greenhouse gas (GHG) emission. It accounts for half of the world electricity demand, with some region electricity consumption increased by 500% [1,2,3]. Building designs have been transformed to reduce the energy consumption in buildings and mitigate the resultant GHG emission. They are designed to harness solar energy to enhance indoor thermal and visible conditions [5]. Uncontrollable admittance of solar radiation to the inner space of a building can result in overheating and visual discomfort. A selective admittance of solar radiation is required for the effective utilization of solar energy in the built environment

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Conclusion