Genetic-Algorithm Based Controls for Daylighting

Solar Energy ◽  
2006 ◽  
Author(s):  
Abderrezek Khlifi ◽  
Moncef Krarti

This paper describes a daylighting control strategy suitable to operate the electrical lighting fixtures in order to maintain a desired illuminance level for one or several specific working locations. The control is based on genetic algorithm to minimize energy use of electrical lighting systems. The algorithm has been developped using experimental data obtained for an office space in Boulder, Colorado. The GA-based control can be coupled with any switching settings to operate the electrical lighting systems such as on-off, stepped, and dimming. The analysis indicated that the GA-based control can save up to 70% of total electrical lighting energy use for the case study of the office building in Boulder, Colorado.

2021 ◽  
Vol 27 (4) ◽  
pp. 156-165
Author(s):  
Jeffrey Y C Cheng ◽  
Nancy C Y Wong ◽  
Tony W L Ho ◽  
Hiu Fai Kwong ◽  
Roger T H Ng ◽  
...  

Lighting retrofit is a common technique to reduce lighting energy use and to improve lighting quality. It is usually performed by replacing the lamps in the existing luminaires with more efficient lamps. Despite the high potential to enhance lighting performance by improving other parts of the luminaires such as reflectors, lighting retrofits usually keep their designs unchanged and focus on the change of the lamps. In this case study, an alternative lighting retrofit method - the replacement of reflectors using a nano optical coating - was tested in a typical office in Hong Kong. The case study used a luminaire with a highly reflective nano optical coating. The pre- and post-retrofit illuminance level, illuminance uniformity, glare and lighting energy use were measured. The results show that the use of the nano optical coating enables the reduction of light tubes in the office and thus the lighting energy consumption without lowering the lighting quality. The lighting retrofit enhances the illuminance uniformity in the office by 14.6% while keeping the illuminance level and discomfort glare within the satisfactory level. It also lowers the lighting energy use of the office by 37.5%.


Solar Energy ◽  
2004 ◽  
Author(s):  
Kelly Kissock

This paper describes data and algorithms to estimate typical average interior illuminance from daylighting using a hybrid of Hay, Davies, Klucher, Reindl (HDKR) method for calculating total solar radiation on a tilted surface and the Illuminating Engineering Society (IES) Lumen Method for estimating interior illuminance from daylighting. This hybrid algorithm, in conjunction with typical meteorological data, directly accounts for shading and typical local cloud cover effects on an hour-by-hour basis, which is difficult to do using the IES sky-cover or sky-ratio methods. Several experiments show reasonable agreement between measured and calculated results. Case study examples demonstrate of use of the method, when incorporated into software, to quickly analyze daylighting potential in industrial facilities, and the use of this information to develop specific recommendations for cost-effectively reducing lighting energy use in industrial facilities by improving the utilization of natural lighting.


Solar Energy ◽  
2005 ◽  
Author(s):  
Abdelkarim Nemri ◽  
Moncef Krarti

This paper provides a simplified analysis tool to assess the energy saving potential of daylighting for commercial buildings through skylights. Specifically, the impact of daylighting is investigated for various fenestration opening sizes, glazing types, control strategies, and geographic locations. A top floor of a prototypical office building has been considered in the analysis. The results obtained for the office building can be applied to other types of buildings such as retails stores, schools, and warehouses. Based on the simulation analysis results, it was determined that skylight to floor ratio more than 0.3 does not affect significantly the lighting energy savings. An optimum value of skylight to floor area ratio was found to be 0.2 to minimize the annual total building energy use.


Author(s):  
Brian James ◽  
Paul Delaney ◽  
Doug Avery

The Office of the Future (OTF) program is a new energy efficiency approach supported by a consortium of some of the nation’s largest and most progressive energy utilities. OTF targets existing multi-tenant commercial office buildings with packages of advanced energy efficiency strategies that can be applied at the tenant level for building owners. The overall goal is to assemble technical guidelines to office renovation projects that specify performance requirements for different attributes of the office (lighting, plug loads, etc.) and whole building that result in 25% and 50% savings better than code. Three pilot projects were conducted: 1. Executive office space 2. Open area office space 3. Office space with five private offices, a conference room, lobby, kitchen, and corridor The executive offices provided an opportunity to measure energy use in a 1,360 square-meters (m2) office and to undertake a relighting project that met the architectural, aesthetic, and functional demands of the space while employing current energy-efficient products and design techniques. The open area office space consisted of 745 m2 of primarily cubicle office space — half of the 12th floor of a federal building in Santa Monica, CA. The project was highly representative of the challenges and complications faced in retrofit projects in everyday office buildings. The office space with private offices involved renovating the lighting and lighting controls in a 147 m2 office space in the 41,156 m2 building, and summarized the performance of the lighting design in accordance with the OTF Technical Guidelines. In addition, this project included details regarding the pre- and post-lighting systems and controls, compares the actual metered power and energy performance of the 2008 Title 24 code baseline, presents the code calculation basis, and reveals some of the complexities associated with this approach. These pilot projects had three primary goals: 1) examine the performance characteristics of highly-controlled lighting systems in a real office environment compared to existing lighting and applicable codes, 2) monitor plug load energy use, and 3) provide measured and technical data back to OTF consortium members to inform the OTF process. The measured results of the open area office space project revealed that a high-performance lighting design with controls delivers savings considerably beyond code-calculated estimates. In fact, results show that during daytime occupied hours, the average site usage is 43% less power than code calculations. The new system reduced the connected load by 56%. Similar results were found for the other two pilot projects.


2019 ◽  
pp. 41-48
Author(s):  
Idil Bakir Kucukkaya ◽  
Ebru Alakavuk

The progress in industrial and technological areas, which started with the Industrial Revolution, has deteriorated the ecological balance and depleted the natural resources. Sustainability, which initially seemed as a solution within this concept, became an important part of Interior Architecture as in disciplines related to design. The lighting systems of the offices that are the secondary living areas should be evaluated in terms of sustainability as well. In this paper, the energy savings and loss of the artificial office lighting systems has been calculated according to the ASHRAE/IES standard 90.1Ц20078?1 which are included in the Leadership in Energy and Environmental Design (LEED) certificateТs lighting criteria [1]. The wattage of the artificial lighting systems has been calculated while the systems were in use. The results of these measurements have been compared with lighting wattage and thus the lighting energy savings and loss have been configured. The office has been comparatively analyzed according to LEED criteria.


Author(s):  
I. Yang ◽  
Sung-Im Kim ◽  
Jin-Gyeong Kang ◽  
Hye-Sun Jin ◽  
Bo-Hye Choi ◽  
...  

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5541
Author(s):  
Andrea Ferrantelli ◽  
Helena Kuivjõgi ◽  
Jarek Kurnitski ◽  
Martin Thalfeldt

Large office buildings are responsible for a substantial portion of energy consumption in urban districts. However, thorough assessments regarding the Nordic countries are still lacking. In this paper we analyse the largest dataset to date for a Nordic office building, by considering a case study located in Stockholm, Sweden, that is occupied by nearly a thousand employees. Distinguishing the lighting and occupants’ appliances energy use from heating and cooling, we can estimate the impact of occupancy without any schedule data. A standard frequentist analysis is compared with Bayesian inference, and the according regression formulas are listed in tables that are easy to implement into building performance simulations (BPS). Monthly as well as seasonal correlations are addressed, showing the critical importance of occupancy. A simple method, grounded on the power drain measurements aimed at generating boundary conditions for the BPS, is also introduced; it shows how, for this type of data and number of occupants, no more complexities are needed in order to obtain reliable predictions. For an average year, we overestimate the measured cumulative consumption by only 4.7%. The model can be easily generalised to a variety of datasets.


2019 ◽  
Vol 193 ◽  
pp. 111-126 ◽  
Author(s):  
Jie Xiong ◽  
Athanasios Tzempelikos ◽  
Ilias Bilionis ◽  
Panagiota Karava

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