LBNL Report Number
During the last ten years, daylighting has become an increasinglysimportant consideration for lighting designers,sarchitects, and building owners. Besides the amenities thatsdaylight it may significantly contribute to the reductionsof electric lighting loads, especially in commercialsbuildings, where the largest portion of the lighting requirementssoccurs during the day. However, it is important thatsdaylight admittance is controlled to prevent glare and negativesimpacts on cooling loads.
As with electric lighting design, successful daylightingsdesign requires means for predicting the luminous performancesof fenestration systems. In other words, we need tospredict daylights contribution to the illuminance and luminancesof interior surfaces. Daylight must be of sufficientsquantity and quality for building occupants visual comfort,svisual performance, and aesthetic needs. Consideration ofsadditional design criteria, such as thermal comfort and energy/costsimplications, requires means for predicting the thermalsperformance of fenestration systems, so designers cansbalance and optimize the contribution of fenestration systemssto lighting and thermal loads.