Investigating the role of thermal comfort in the assessment of building energy performance using a spatial model

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Lighting controls: evolution and revolution

The basic function of a lighting system is to provide a defined amount of light to a space according to context-appropriate design criteria while minimising energy use. Lighting control strategies based on occupancy and daylight adaptation have been consistently shown to substantially lower lighting energy use compared to fixed systems, and are now ubiquitous in building energy codes. The adoption of light emitting diodes and the integration of information and communication technologies enable lighting control systems to become smarter with a greater integration of sensing, data processing and connectivity, and to evolve into a platform for both lighting and non-lighting applications. We describe different lighting control strategies and their evolution with a focus on commercial office applications. To illustrate emerging approaches, we then discuss two particular smart lighting systems – a wireless, distributed lighting control system and a power-over-Ethernet, centralised lighting control system, with cloud connectivity. The role that a connected lighting system can play in the overall building eco-system is then discussed, and new applications and services that are enabled are presented. Finally, we discuss the challenges to the market adoption of connected smart lighting systems, and the arising opportunities for researchers and practitioners to realise one more round of high-value returns offered by lighting systems

Physical and psychological discomfort in the office environment

Office employees spend a lot of time inside buildings, where the physical conditions influence their well-being and indirectþ influence their employers' business performance. With data from a field study conducted in the Netherlands in April-May 2003, we used path analysis to further elucidate the relationship between personal (gender and seasonality of mood shifts), building (view type, view quality, window distance, and social density), and environmental conditions (light quality, and office impression) and physical and psychological discomfort, sleep quality, and hindrance. The results show that window views of nature, and those that are rated as being more altractive, are beneficial to building occupants, reducing discomfort. However, being close to a window and rating the lighting as being of lower quality can result in thermal and glare problems (hindrances). Reduced discomfort at work can improve sleep quality, indicating that physical conditions at work influence home life

Linking lighting appraisals to work behaviors

Among those concerned with practical matters of office design, demonstrations that the work environment affects employees' well-being and work behaviors are thought to be important to support client decision making. Veitch, Newsham, Boyce, and Jones developed a conceptual model in which lighting appraisal and visual capabilities predicted aesthetic judgments, mood, and performance. This article extends that model to include measures of work engagement, using experimental data originally reported by Newsham, Veitch, Arsenault, and Duval. Structural equation modeling showed strong fit to a model in which lighting appraisals indirectly influenced work engagement through aesthetic judgments and mood. This evidence that providing a satisfactory work environment can contribute to employee effectiveness merits further study by environmental and organizational psychologists

Linking lighting appraisals to work behaviors

Among those concerned with practical matters of office design, demonstrations that the work environment affects employees' well-being and work behaviors are thought to be important to support client decision making. Veitch, Newsham, Boyce, and Jones developed a conceptual model in which lighting appraisal and visual capabilities predicted aesthetic judgments, mood, and performance. This article extends that model to include measures of work engagement, using experimental data originally reported by Newsham, Veitch, Arsenault, and Duval. Structural equation modeling showed strong fit to a model in which lighting appraisals indirectly influenced work engagement through aesthetic judgments and mood. This evidence that providing a satisfactory work environment can contribute to employee effectiveness merits further study by environmental and organizational psychologists

Individual control of electric lighting in a daylit space

Participants (N=40) occupied a glare-free, daylit office laboratory for 1 day, and were prompted every 30 min to use dimming control over electric lighting to choose their preferred light level. Illuminances and luminances were recorded before and after each control opportunity; luminance maps were generated using a calibrated, high-dynamic range digital camera. Although there was a wide variation in chosen light levels between individuals, results showed a significant negative correlation between prevailing desktop illuminance and change in dimmer setting. This indicates that, from the perspective of occupants, daylight does displace electric lighting. Surprisingly, we did not find any luminance-based measure that was as good a predictor of participant dimmer choice as illuminance measured on the desktop. On average, manual dimming control in this situation reduced energy use for lighting by 25% compared to a fixed system delivering 500lx of electric lighting on the desktop

POEs for green buildings

Peer reviewed: YesNRC publication: Ye