A Comparative Analysis of the Visual Comfort Performance between a PCM Glazing and a Conventional Selective Double Glazed Unit

Abstract

The performance of a Double Glazing Unit (DGU) with a Phase Change Material (PCM) layer embedded in the cavity was analyzed in terms of the visual comfort perceived by the occupants. The analysis was carried out through a set of simulations, performed by the Radiance engine managed through Honeybee. As an input for the simulations, the visible transmittance Tv of PCM in solid (diffusing) state was used, based on previous laboratory measurements. The simulations were run for several specific times of the year: The two solstices and the autumn equinox, for different hours during the day. Other variables investigated were the site (Östersund, 63.2° N; Turin, 45.2° N; Abu Dhabi, 24.4° N), the room orientation (south; west), and the sky conditions (clear sky with sun; overcast). For comparative purpose, the simulations were repeated for the same boundary conditions in a room equipped with a selective glazing, with a Tv of 0.5. For each case, the visual comfort perceived by the occupants has been analyzed in terms of Daylight Glare Probability (DGP) in two different points in the room and of “Spatial Useful Illuminance” (percent of work plane points where the illuminance lies in the range 100–3000 lx). The results showed that the glazed package with PCM in most cases admits more daylight into the room, resulting into an increased glare (DGP values), but also in lower Spatial Useful Illuminance values.

Experiment on the Uniformity of Internal Lighting in Zigzag Photovoltaic Greenhouses by Grating Plates

“…As shown in Figures 14-19, the variation of the illuminance of each material over time is distributed over time and appears in a "W" shape, assuming that cloud interference is excluded [19][20][21][22]. The illumination intensity of each dot zone of each material will reach a small peak at 12:30 because the solar altitude angle is the highest and the light intensity is strongest at noon, and the illumination of each dot zone at 11:30 and 13:30 is lower than the value of 12:30.…”

Uso de materiais de mudança de fase em sistemas construtivos: revisão integrativa de literatura

“…Alguns autores apresentaram aplicações vantajosas para essa característica, como a utilização do sistema como proteção solar (GOIA; PERINO; SERRA, 2014). Porém, mesmo a utilização apenas de iluminação difusa deve ser avaliada, já que pode acarretar desconforto luminoso interno e ofuscamento (GIOVANNINI et al, 2018).…”

Dynamics of Melting Process in Phase Change Material Windows Determined Based on Direct Light Transmission

“…The energy performance of PCMs was investigated for a standard window component [10], as well as for unusual applications such as thermotropic glazing [14] or double skin facades [15]. Moreover, some authors showed a beneficial effect on daylight provision [2] and visual comfort [16]. In some cases, the PCM glazing can be treated as an alternative to dynamic shading systems like exterior perforated louvers [17] or other types of blinds [18].…”