Solar radiation and illumination

Automated control of lighting and fenestration

“…Glare and local overheating could be minimized by setting a maximum limit on transmitted solar radiation, so that the reflective film would be used whenever a high level of direct beam solar radiation was incident upon the window. A typical value for the maximum limit would be 500 w/m^, since diffuse radiation rarely exceeds this value [8] . This limit could be set and adjusted by the building occupants as required.…”

“…The effect of direct beam daylight possibly being less effective than diffuse daylight at providing workplane illuminance could be handled by derating. Levels of incident diffuse illuminance rarely exceed 60,000 lux [8]; if the incident illuminance exceeded that amount, the calculation of interior daylight could be made using a lower value for the incident illuminance. The adjusted value could be chosen conservatively to be 60,000 lux, or perhaps chosen to be 60,000 lux plus a percentage of the illuminance over 60,000 lux.…”

Electric power from shadows and indoors: solar cells under diffuse light conditions

“…For example, at least 10% of incident light is diffuse light even when the sky is clear. 19 The fraction of diffuse light increases to more than 30% in urban environments [13][14][15][16][17][18][19] and becomes almost 100% in the shadow. In addition, dust particles in the air, clouds, fog, humidity, buildings or civil structures, and even trees along streets can affect the diffuse-light conditions in urban environments by scattering or reecting light.…”

“…13,25,27,31,[40][41][42][43] The increasing adoption of photovoltaics in urban life necessitates a better understanding of the operation of photovoltaics under diffuse light. [16][17][18][19] However, studies on diffused lights and their effects on photovoltaics are not enough to be applied during our life yet and, in some cases, proper analysis procedures or protocols with reasonable physical models that account for various wavelengths and angles of incidence (AOIs) of light have been difficult to establish because of the unlimited range of possible illumination conditions. [13][14][15][16][17][18] Diffuse light incident on a solar cell can be assumed to be modeled as a sum of rays from various directions.…”

“…16,52 However, the response of PV in diffuse light is still insufficient than that under the STC. 19 When photovoltaics generate power in a wide-open location that lacks objects (other than the atmosphere) that produce shadows or reect or scatter light, such as a desert or the ocean, the diffuse light has a minor effect because of the small amount of diffuse light under clearsky conditions, which is ∼10% when the air is clear without dust. 19 However, because photovoltaics are being installed closer to urban areas, we should consider the diffuse light caused by reections from surrounding objects and the scattering of light by dust or other large molecules in the atmosphere.…”