Influence of Sun Shading Devices on Energy Efficiency, Thermal Comfort and Lighting Comfort in a Warm Semi-Arid Dry Mediterranean Climate

Abstract

The dry Mediterranean climate (BShs) is the European region with the highest number of hours of sunshine per year. The high annual solar radiation makes sun shading devices necessary to comply with current energy efficiency standards. However, these standards do not sufficiently consider their effect on the indoor lighting comfort of buildings. The objective is to qualitatively and quantitatively determine how movable sun shading devices jointly influence the energy efficiency, thermal comfort and lighting comfort of buildings in BShs climate. The scientific novelty of the work consists of demonstrating the limitations of the sun shading systems commonly used in southeastern Spain and determining the optimal technical solution in this climate to simultaneously improve thermal and lighting comfort. This research comparatively studies the influence of various movable sun shading systems on the daylighting and thermal performance of an educational building. This study conducted on-site measurements, user surveys and computer simulations to study how to improve the thermal and lighting performances of the building. This work demonstrates that interior solar shading provides little improvement in thermal comfort and reduces the cooling demand by only 25%. External movable sun shading improves thermal comfort and reduces the cooling demand by more than 60%, but only adjustable blinds or awnings achieve adequate and homogeneous illuminance values as they diffuse daylight. The paper concludes that energy efficiency standards should be modified to ensure adequate lighting comfort in buildings.