Daylighting in Riyadh and Los Angeles: comparison of cultural factors in potential market penetration

Choosing an effective daylighting mechanism for a home is a function of its environment: both the climate and the culture. Two distinct locations, Los Angeles, California and Riyadh, Saudi Arabia, are used to compare the use of light tubes to improve the amount of daylight penetrating a residential space. During the daytime in Los Angeles (Latitude 34 N), people receive natural light through the windows of their homes. As a consequence of this preference, lighting systems such as daylighting tubes are often unnecessary because the daylighting through the traditional windows exceeds the minimum design level. In contrast, the residential building interiors in Riyadh (Latitude 24 N) do not achieve the minimum illuminance from the daylight from the windows due to issues and concerns with glare and privacy. Because of the discomfort caused by glare and the culturally-founded concerns regarding privacy, the windows in Riyadh are commonly small and people often keep the curtains closed at all times. Daylighting tubes would allow the residential interiors to achieve the minimum illuminance from daylighting, while also addressing the issues of glare and privacy. Although lighting tubes can be used in any climate and country, certain circumstances make the use of lighting tubes more beneficial. To determine this, four elements were studied, tested, and compared. The four factors were glare, privacy, heat gain, and energy. There are multiple computer programs available to test glare. Hdrscope was chosen because it is one of the best glare programs. A survey was used to analyze and compare the differing levels of the privacy needs of both cities. Heat and energy were examined by using the energy modeling program Integrated Environmental Solutions (IES). The objective is to provide an overview of all common daylighting systems and prove that lighting tubes are more efficient in certain cities and cultures. The effectiveness of a daylighting system relies on more than just climate and sun exposure; cultural norms and traditions also play an important role in determining the optimal lighting system, (Alam, n.d.).住宅高效采光方案的选择取决于其所处的环境——涵盖气候与文化双重维度。本研究选取美国加利福尼亚州洛杉矶与沙特阿拉伯利雅得两处迥异的地域作为案例，对比日光导光管（light tubes）提升住宅空间自然采光量的应用效果。地处北纬34度的洛杉矶，居民日间可通过住宅窗户获取自然光。出于采光偏好，传统窗户的自然采光量往往已超出最低设计标准，因此日光导光管这类采光系统通常并无必要。与之形成鲜明对比的是，地处北纬24度的利雅得，其住宅室内空间因眩光与隐私问题的困扰，无法通过窗户自然光达到最低照度标准。由于眩光带来的不适感，以及基于文化层面的隐私顾虑，利雅得的住宅窗户普遍尺寸偏小，且居民往往全天拉闭窗帘。日光导光管既能够让住宅室内达到自然采光的最低照度要求，同时也可妥善解决眩光与隐私相关的问题。尽管日光导光管可在任意气候与国家中应用，但特定场景下其应用优势会更为显著。为明确这一点，本研究针对四项核心要素展开研究、测试与对比，分别为眩光、隐私、得热与能耗。目前有多款可用于眩光测试的计算机程序，本研究选用Hdrscope，因其属于当前最优的眩光测试程序之一。本研究通过问卷调查分析并对比两座城市居民不同层次的隐私需求。得热与能耗情况则通过能耗建模软件集成环境解决方案（Integrated Environmental Solutions, IES）进行分析。本研究的目标在于梳理所有主流自然采光系统，并论证日光导光管在特定城市与文化场景中具备更高的能效表现。自然采光系统的能效不仅取决于气候与日照条件，文化规范与传统习俗同样对最优采光方案的选择具有重要影响（Alam，无出版日期）。