Daylighting Performance of Solar Control Films for Hospital Buildings in a Mediterranean Climate

Abstract

One of the main retrofitting strategies in warm climates is the reduction of the effects of solar radiation. Cooling loads, and in turn, cooling consumption, can be reduced through the implementation of reflective materials such as solar control films. However, these devices may also negatively affect daylight illuminance conditions and the electric consumption of artificial lighting systems. In a hospital building, it is crucial to meet daylighting requirements as well as indoor illuminance levels and visibility from the inside, as these have a significant impact on health outcomes. The aim of this paper is to evaluate the influence on natural illuminance conditions of a solar control film installed on the windows of a public hospital building in a Mediterranean climate. To this end, a hospital room, with and without solar film, was monitored for a whole year. A descriptive statistical analysis was conducted on the use of artificial lighting, illuminance levels and rolling shutter aperture levels, as well as an analysis of natural illuminance and electric consumption of the artificial lighting system. The addition of a solar control film to the external surface of the window, in combination with the user-controlled rolling shutter aperture levels, has reduced the electric consumption of the artificial lighting system by 12.2%. Likewise, the solar control film has increased the percentage of annual hours with natural illuminance levels by 100–300 lux.

In-Service Thermal and Luminous Performance Monitoring of a Refurbished Building with Solar Control Films on the Glazing System

“…The research findings of the present work suggest that SCFs are more effective in the presence of clear sky conditions (higher outdoor incident solar radiation levels) than of overcast sky conditions (higher outdoor diffuse solar radiation levels). This supports the fact that scientific research and promotion of these window films are more common in hot [20][21][22]24] and temperate [16][17][18]23,[25][26][27][28][29][30] climates since they present longer and more severe cooling seasons, successfully promoting the reduction in excessive solar heat gains through the windows.…”

“…Similarly to previous findings of research studies reported in the literature review [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30], the installation of SCFs makes it possible to significantly decrease the indoor illuminance levels and temperature values due to the modification of the properties of the glazing system, with a greater emphasis for highly reflective solar control films. However, special attention should be given when choosing SCFs with application to the internal glass surface since it promotes the absorption and consequent reflection of heat towards the indoor environment, increasing the greenhouse effect of the space.…”

“…When analyzing the performance of glazing systems with SCFs in office rooms, significant reductions in the solar radiation income (up to 60%), the indoor illuminance (up to 65%), the cooling energy needs (up to 29%) and consumption (up to 13.1%) were obtained in the presence of films by previous studies [16][17][18][26][27][28]. Considering previous studies of the performance of single- [29] and double-glazing [30] systems with SCFs conducted in the city of Lisbon, Portugal, a better performance was obtained for SCFs installed on the external glass surface, and films with low solar transmittance made it possible to significantly reduce the cooling energy use (up to 86%).…”

“…The relatively scarce studies that investigate the impact of SCFs on the performance of buildings through experimental [16][17][18][19] or numerical [20][21][22][23][24][25] approaches, or both [26][27][28][29][30], generally conclude that the installation of SCFs can promote better thermal and visual performances and result in energy savings.…”

Performance of a Solar Spectrum-Selective Absorption Film as a Building Energy-Saving Retrofit in China

“…The solar control film is considered suitable for the retrofitting of the glazing system of existing buildings due to its low cost, excellent thermal insulation performance, easy installation, and minimal disruption to building occupants. , The solar spectrum selective absorption film (SSAF), a kind of solar control films, is mainly composed of transparent conductive oxides such as antimony tin oxide and indium tin oxide . It can strongly absorb solar near-infrared (NIR) radiation, and some of the absorbed energy may end up to outdoor space ultimately, reducing the transmission of solar radiation through the window. , …”