2014 IES Street and Area Lighting Conference
September 14-17, 2014 | Nashville, TN
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The accuracy of lighting simulations depends on the physically based modeling of the building and site properties, as well as the algorithmic reliability of the computational tools. Despite many developments in lighting simulation in the past decades, faithful representation of the sky luminance distributions at a specific location and time continues to be a challenge.
This paper details a field-measured assessment of a digital daylighting system. Two offices were retrofit with fixtures, lamps, controls, and automated data acquisition hardware, and system performance was evaluated throughout a twelvemonth period. This work was motivated by a desire to accelerate the adoption and acceptance of automated dimming controls in the US commercial buildings market. In spite of dramatic energy saving potential, automated dimming controls are rarely implemented, comprising only a small portion of the market share. While researchers and experts are able to successfully implement the technology, there is strong evidence and anecdotal knowledge that real world installations have not fared well. Photo-controlled lighting is perceived as risky and difficult to implement, with challenges concerning user acceptance and satisfaction (Bierman & Conway 1999; Christoffersen and others, 1997; Doulos and others, 2007).
Successful daylight designs of office buildings can provide significant energy savings when properly integrated with daylight sensing electric lighting control systems. However, previous research shows that spaces [excepting large volume toplit spaces (McHugh and others, 2004)] designed to integrate daylight with electric lighting controls rarely produce the energy savings purported during design stages (Heschong and others, 2005). Discrepancies in realized savings are attributed to complicated specification, installation, and commissioning (Rubinstein and others, 1997; 1998), and are compounded by operational issues associated with suboptimal manual blind (or shade fabric) operation and user dissatisfaction, resulting in systems being disabled (Heschong and others, 2005). In fact, users that intentionally disable daylight harvesting systems account for over 70 percent of nonfunctional systems (Heschong and others, 2005).
Commercial refrigerators and freezers that are used in grocery stores around the world to keep frozen foods, dairy products, meats, and many other foods fresh require lighting fixtures inside the cases in order to illuminate the products inside. These lighting fixtures are often located between the refrigerator doors across from the food. This area inside the case is called a mullion. The mullions can be seen below in Fig. 1. There are mullions located between doors and there are mullions located at each end of the case. In a three door case, as seen in Fig. 2, there would be a total of four lighting fixtures, two at each end and two in the center.