The energy performance of the Central Sunlighting System (original) (raw)
Related papers
Climate-based daylight analysis of fixed shading devices in an open-plan office
Lighting Research and Technology, 2016
Office buildings consume large amounts of energy and are responsible for large amounts of greenhouse gas emissions worldwide. Among building energy efficiency measures, solar shading plays a significant role in reducing building energy consumption for cooling. This study analysed the influence of solar protection on daylighting of an open-plan office. Climate-based daylight modelling was used to predict such metrics as daylight factor, daylight autonomy and useful daylight illuminances. The results obtained showed that overhangs, and horizontal and vertical louvres have similar behaviours and sidefins have no relevance to indoor daylight conditions. In all cases, it has been proven that excessive obstruction may yield an excessive reduction in a range of illuminances between 500 and 2000 lux, increasing lighting energy consumption.
Evaluation of daylighting in office buildings
Harvesting daylighting can significantly cut energy use in office buildings. However it requires careful design to counterbalance heat gain or loss, glare and variations in daylight availability. Designers with proper planning can not only improve the visual environment and create a higher-quality space but also lower energy costs for buildings. Lighting control with photosensors can take full advantage of daylighting by dimming light output so that no more light is produced than necessary. As a result, occupants tend to be more productive, comfortable and efficient. This paper focus on the occupant satisfaction and acceptance in relation to the daylighting in offices with automated daylight control. Three office buildings with automated lighting control were examined. These buildings were chosen because of their installed daylight responsive system. A questionnaire was given to the occupants and a study of their preferences in regard daylight was conducted.
Reducing energy consumption while maintaining acceptable environmental quality in buildings has been a challenging task for building professionals. In office buildings, artificial lighting systems are a major consumer of energy and can significantly contribute to building cooling load. Furthermore, although reliable, artificial lighting does not necessarily provide the required quality of lighting. Significant improvement in lighting quality and energy consumption can be achieved by proper integration of daylight and artificial lighting. The objective of this study is to investigate the energy performance of office buildings resulting from daylight and artificial lighting integration in hot climates. A parametric analysis is conducted to find the impact of different window design parameters, including window area, height and glazing type, on building energy performance. Results have shown that as much as 35% reduction in lighting energy consumption and 13% reduction in total energy consumption can be obtained when proper daylighting and artificial lighting integration is achieved.
Daylighting is considered one of the main passive strategies for enhancing indoor spaces quality. Shading device is usually used to prevent excessive sunlight from delivering into the building, especially in clear-sunny sky environment. The use of a per-formative shading device can help in reducing both cooling and lighting loads, as well as improving the quality of the space. Nevertheless if such devices are not designed with care it may cause to admitting more sun rays than needed or result into poor daylit spaces. Sun breakers are believed to enhance the performance of southern faced spaces, as it provides protection from the excessive solar rays which have direct effect on the cooling loads. This paper investigates the effect of using sun breakers on both daylighting and energy performance. Year-round daylighting and energy simulations were conducted for a south oriented office space, located in the city of Cairo, Egypt. Diva-for-Rhino a plug-in used to interface Radiance and Daysim was used for calculating the annual Daylight Availability of the space. While Viper another plug-in for rhino and used to interface Energy-Plus was used for annual energy consumption simulations. Sun breakers with different settings and parameters were compared and the results were analyzed for achieving the needed balance. Results showed that the performance of sun breakers is tremendously related to its position, depth and rotation angle. The daylighting performance could be significantly enhanced; the 'Daylit' area percentage can reach more than 72% of the space, while the savings in the annual energy consumed had also reached up to 34%. The results also showed that there is a satisfactory balance between the daylighting solutions and the thermal ones.
Many contemporary office buildings are characterized by large glazed surfaces, often located without any consideration about orientation. Without a suitable solar control strategy, this fact implies several problems related to visual comfort, thermal comfort and energy demand, which is mainly related to HVAC and, to a smaller extent, to artificial lighting. Moreover, if the office room is large, the values of physical parameters influencing comfort are relevantly variable from point to point, mainly as a function of the distance from glazed surfaces. Typically, daylighting requirements of occupants located far from the windows can conflict with the thermal comfort requirements of occupants located next to the windows. In this work a case-study is analysed. It consists in a medium size office room located in a typical office building, in an urban context of the Northern Italy. Different solar control devices and related control logics are compared; their effects on global comfort conditions and energy demand are assessed. The considered devices consist of different kinds of movable external slats, some of which incorporating PV cells. This analysis is performed by means of a specific software: "Ener_Lux", already presented in previous PLEA Congresses. Once defined the kind of devices and the related operating logic, the program simulates the dynamic thermal and luminous behaviour of the physical system, provides various comfort assessment index values and calculates the primary energy demand for HVAC and lighting.
2010
Nowadays, many working environments are located within facilities that are not visually connected with the exterior. This is due to the new architectural paradigms as regards the design, based on the possibility to substitute natural light for artificial lighting even in daytime. Accordingly, the need of reducing energy costs and the user's wish to optimize lighting and visual comfort levels raises the option of innovative natural lighting systems implementation. For a luminous retrofitting case, located in Mendoza, Argentina, a specific methodology used determined that the more adequate natural lighting strategy would be redirecting direct sunlight, working on the reflected light design. The methodology proposed is formed by an analysis of the initial situation, conditions modelization and design resolving proposals, through luminous evaluation, real and virtual scale model construction, and performance evaluation using heliodon and simulation software. This work points to use natural lighting to reduce energy consumption and get better luminous ambient through the application of a low-cost daylighting system. In the mentioned case, strategies of redirection of the solar component capable of optimizing indoor lighting levels up to a 40% were applied.
Daylight in Existing Office Buildings: An Untapped Retrofit Resource
2012
Daylight in existing buildings represents a vast untapped resource for energy and demand savings, however estimating these savings is not a trivial task. Daylighting savings are influenced by multiple aspects of building design, window properties, climate, orientation, electric lighting and operation. Savings are also importantly a function of operation of window blinds or shades for glare control. This paper describes the results from the recently completed California Energy Commission, Public Interest Energy Research (CEC PIER) project on Office Daylighting Potential (Saxena 2011), that estimated the demand and energy savings potential from adding photocontrols to existing office spaces in California, and quantified how much further those savings could be improved with additional daylighting enhancements. The California Commercial End-Use Survey (CEUS) dataset of 536 existing office premises provided the basis for the analysis. A Radiance-based annual daylighting simulation and a ...
Daylighting for Visual Comfort and Energy Conservation in Offices in Sunny Regions
Office buildings in regions with abundant sunlight may still fail to make effective use of daylight: the difficulty in controlling variations in natural illumination, which may be substantial, often results in extensive use of artificial lighting. A solution to this paradox was sought by means of a controlled experiment designed to investigate the effect of several strategies to reduce glare and to achieve visual comfort in a test room configured to represent a typical side-lit office. Subjects performed office tasks such as reading or operating a computer, and completed a detailed questionnaire about their work environment, whose physical parameters were monitored in great detail. The study showed that if the window is exposed to direct sunlight, the use of tinted glass may not be an adequate response. Internal Venetian blinds, if deployed correctly, may prevent glare and provide visual comfort to workers near the window – but they require frequent adjustment and reduce the depth a...
Energy Saving Through the Sun: Analysis of Visual Comfort and Energy Consumption in Office Space
Energy Procedia, 2012
Energy demands for heating, cooling and lighting can be dramatically prejudiced by the façade configuration, solar exposition and typology of openings trying to maximize use of natural light. Office buildings are often field of experimentation of materials and innovative components, by the way a consolidated design market promotes façade layouts strongly transparent introducing a primary need to shading and protection of the users privacy. Building Automation Systems (BAS) can reduce users' intervention on indoor condition control; on the other hand users want to be capable to fix conditions in their working space avoiding problems of visual discomfort, specifically disturbing and intolerable levels of glare. Systems to evaluate visual comfort parameters to improve consciousness in use of daylighting are fundamental in design to realize a façade which permits real energy saving during operation time.
Evaluation of Daylight in Buildings in the Future
2015
Building regulation requirements and traditional engineering practice for daylight calculations is often outdated and unsynchronized with the advance and needs of modern sustainable building design. State-of-the-art calculation tools provide accurate results on daylight conditions using methods as simple as calculating the useful daylight illuminance. These methods facilitate sustainable building design that also works in practice. This is illustrated with an example where the daylight conditions in an office with different types of solar shading is examined.