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academic:climate-based-daylight-modelling [2013/10/18 09:51]
cbdm
academic:climate-based-daylight-modelling [2017/07/11 12:41] (current)
cbdm
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 UDI achieved therefore is the defined as the annual occurrence of daylight illuminances that are between 100 and 3,000 lux. The UDI range is further subdivided into two ranges called UDI-supplementary and UDI-autonomous. UDI-supplementary gives the occurrence of daylight illuminances in the range 100 to 300 lux, depending of the design level illuminance. For these levels of illuminance,​ additional artificial lighting //may// be needed to supplement the daylight for common tasks such as reading. UDI-autonomous gives the occurrence of daylight illuminances in the range 300 to 3,000 lux where additional artificial lighting will most likely not be needed. The UDI scheme is applied by determining at each calculation point the occurrence of daylight levels where: UDI achieved therefore is the defined as the annual occurrence of daylight illuminances that are between 100 and 3,000 lux. The UDI range is further subdivided into two ranges called UDI-supplementary and UDI-autonomous. UDI-supplementary gives the occurrence of daylight illuminances in the range 100 to 300 lux, depending of the design level illuminance. For these levels of illuminance,​ additional artificial lighting //may// be needed to supplement the daylight for common tasks such as reading. UDI-autonomous gives the occurrence of daylight illuminances in the range 300 to 3,000 lux where additional artificial lighting will most likely not be needed. The UDI scheme is applied by determining at each calculation point the occurrence of daylight levels where:
-  * The illuminance is less than 100 lux, i.e. UDI '​fell-short' ​(or UDI-f).+  * The illuminance is less than 100 lux, i.e. UDI not achieved ​(or UDI-n).
   * The illuminance is greater than 100 lux and less than 300 lux, i.e. UDI supplementary (or UDI-s).   * The illuminance is greater than 100 lux and less than 300 lux, i.e. UDI supplementary (or UDI-s).
   * The illuminance is greater than 300 lux and less than 3,000 lux, i.e. UDI autonomous (or UDI-a).   * The illuminance is greater than 300 lux and less than 3,000 lux, i.e. UDI autonomous (or UDI-a).
-  * The illuminance is greater than 3,000 lux, i.e. UDI exceeded (or UDI-e). +  * The illuminance is greater than 3,000 lux, i.e. UDI exceeded (or UDI-x). 
-For those cases where solar gain in summer must be controlled to minimise overheating/​cooling,​ careful attention should be paid to the degree of occurrence of the UDI-metric. ​+For those cases where solar gain in summer must be controlled to minimise overheating/​cooling,​ careful attention should be paid to the degree of occurrence of the UDI-metric. ​
  
 Application of the UDI approach is described in detail in a study carried out for the [[http://​preview.thenewsmarket.com/​Previews/​VLUX/​DocumentAssets/​281927.pdf|VELUX corporation]]. Application of the UDI approach is described in detail in a study carried out for the [[http://​preview.thenewsmarket.com/​Previews/​VLUX/​DocumentAssets/​281927.pdf|VELUX corporation]].
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 The useful daylight illuminance (UDI) approach includes a measure of the occurrence of some set upper-limit being exceeded, in addition to the occurrence of illuminances in the preferred ranges. Thus UDI provides a measure of the effectiveness or otherwise of the architectural form to temper the daylit environment. The UDI scheme has had some tweaks since it was first proposed, and the range limits are to a degree flexible depending on the application. It is the basis of the scheme rather than the exact values assigned to the range limits that is important. The useful daylight illuminance (UDI) approach includes a measure of the occurrence of some set upper-limit being exceeded, in addition to the occurrence of illuminances in the preferred ranges. Thus UDI provides a measure of the effectiveness or otherwise of the architectural form to temper the daylit environment. The UDI scheme has had some tweaks since it was first proposed, and the range limits are to a degree flexible depending on the application. It is the basis of the scheme rather than the exact values assigned to the range limits that is important.
  
-Useful daylight illuminance is fundamentally different from, say, continuous daylight autonomy because, in separating out the occurrence of excessive illuminances,​ the measure for UDI autonomous, by default, includes a penalty for the occurrence of those illuminances that are deemed too high. It remains to be determined what occurrence of UDI exceeded is considered acceptable. It may be that the penalty effect needs to be amplified by further subtracting the UDI-occurrence (or some multiple of it) from the occurrence of UDI-a.+Useful daylight illuminance is fundamentally different from, say, continuous daylight autonomy because, in separating out the occurrence of excessive illuminances,​ the measure for UDI autonomous, by default, includes a penalty for the occurrence of those illuminances that are deemed too high. It remains to be determined what occurrence of UDI exceeded is considered acceptable. It may be that the penalty effect needs to be amplified by further subtracting the UDI-occurrence (or some multiple of it) from the occurrence of UDI-a.
 ====== The '​Well-tempered'​ Daylit Environment ====== ====== The '​Well-tempered'​ Daylit Environment ======
  
academic/climate-based-daylight-modelling.txt · Last modified: 2017/07/11 12:41 by cbdm