Passive Daylighting Research Articles

Comprehensive analysis of active and passive daylighting towards power savings in an office room

A comprehensive method is presented to simulate illuminance distribution for two office room designs with same area of 7.8 m2 each: room 1 has a window whilst room 2 has no window. The integration of passive daylighting system and light emitting diodes (LEDs) is adopted for illuminating room 1, while the integration of active daylighting system and LED lighting is adopted for illuminating room 2. The effectiveness and power savings are analysed for the aforementioned two cases. The impact of using LED lighting to control the illuminance and light distribution (uniformity) of light is also studied. For both cases, simulation was performed for a selected day under three sky conditions: clear sky, mixed sky and overcast sky using a software called DIALux 4.13 to obtain the average illuminance in the rooms and the power saved via the use of active and passive daylighting systems. Results obtained showed that active and passive daylighting systems are both effective for power savings depending on the location of rooms and time of the day. Also, active daylighting system is more effective under clear sky, while passive daylighting system can be effective under clear or mixed sky.

Construction Technology and Strategy of Natural Light Environment in Urban Underground Space

In underground space, daylighting plays an important role in increasing the spacious sense, improving the ventilation effect, and more importantly, reducing the negative visual and psychological effects brought by the underground space, such as enclosed monotony, unknown direction and isolation. In this paper, the technical means of utilizing natural light in underground space were elaborated from the two aspects of passive daylighting method and active daylighting method, aiming to bring natural light into the underground as much as possible so as to fully satisfy people's longing for nature for those who work and live in the underground space.

Improving visual comfort and energy efficiency in existing classrooms using passive daylighting techniques

In classrooms, light levels are directly related to energy consumption; due to the use of artificial lighting. Hence, this study aims to improve the visual comfort and energy efficiency in existing classrooms, by investigating various retrofit methods for passive daylight techniques, in northerly oriented classrooms at Jordan University of Science and Technology (JUST). Data of this research are obtained using computer simulation and real measurements. The combination of the clerestory window and the anidolic ceiling directed toward the south provided about 62% of the lighting level required in the classroom, and it decreased the energy consumption required for lighting, heating, and cooling by 16.3%.

Daylight Transmission Analysis In Experimental Building Envelope Assemblies

In light of the fact that building envelope design and construction are critical for building performance as well as the fact that architects and engineers rarely collaborate in the early phases of design processes, the Facade Laboratory at The University of Texas at Austin was established. The laboratory exists as a physical chamber to allow testing in the areas of daylighting, thermal exchange, ventilation, and the use of direct and indirect solar energy. The full-scale size of the Facade Laboratory helps provide particularly accurate data, as the prediction of a structure’s lighting and thermal behavior is inherently dependent on the use of real-scale testing facilities. Simultaneously, the data collected through experimentation with the Facade Laboratory is used in the calibration of energy simulation software. Physical facade mock-up tests inspire new speculative simulated tests and vice versa. An initial shading structure, Prototype 1, was designed, built, and tested virtually and physically. A second scheme, Prototype 2, tested only virtually thus far, expands upon the fi rst scheme by proposing speculative hybrid light/ventilation fi lters which incorporate passive daylight to optimize building energy consumption, thus allowing for improved interior lighting conditions while simultaneously creating improved indoor air quality. The Facade Laboratory offers the opportunity to develop an integrated approach to problem solving by an interdisciplinary team of architectural and engineering students as well as professionals. Initial facade construction design and mock-up experiments as well as corollary virtual experiments have yielded interesting qualitative and quantitative results, warranting a larger discussion regarding their implications.

방위각 추적식 프리즘형 집광조명시스템 성능평가

This thesis introduced an azimuth tracking prismatic daylighting system. The system improved several issues of the previous passive prismatic daylighting system: low efficiency at sunrise and sunset, glare effect and polarized. The system was developed to track the movement of sun with azimuth tracking device, and it has its own power from the attached solar cells. We compared the with previous passive one in terms with system efficiency and daylighting factors(DF).

Engineering Daylight into Commercial Buildings

The daylighting of commercial buildings offers the opportunity to reduce energy consumption and improve occupant appraisal of the quality of their interior environment. The focus of this paper is the assessment of a light-redirecting device designed for use in a passive daylighting system for conventional, high-rise building facades. This paper presents an introduction to how performance parameters can be defined and performance analysis conducted at the design stage of this daylighting device using ray tracing software. The device is judged on its potential to redistribute light throughout the depth of a typical room without causing discomfort glare to occupants. A proposed definition of optimal device performance, derived using geometric considerations, is also presented.

THE HIGH-RISE OPPOSING FACADE IN CLEAR SKY CONDITIONS—NOT ALWAYS AN “OBSTRUCTION” TO DAYLIGHT

The opposing building facade is an omnipresent feature for buildings in the urban commercial setting. In clear sky conditions, there are large surfaces of building facades that have the potential of reflecting sunlight incident on them. When the sun is behind a building (so that the solar facade azimuth is greater than 90°), the building opposite potentially acts as a passive daylighting device to it. The work discussed in this paper shows that the performance of this device varies for each floor and for different building densities. Using the ADELINE simulation software, a street with high rise buildings opposite each other is modelled in clear skies, and daylighting is calculated in rooms at different floor levels. Comparisons are made with daylighting of the same rooms without an obstructing building in order to observe the effect of the “obstructing building” to daylighting. Preliminary results indicate that the opposite facade of high rise buildings has the potential to be considered a passive daylighting device in particular contexts. As a passive device, the opposing facade could be given attention by urban designers and planners, as well as by those drawing up building legislation for the urban built environment. It would be desirable and important for users of the built environment, to determine future developments from the point of view of how opposing facades affect daylighting. This approach could have implications for energy efficiency and conservation and would utilise the free resource of solar radiation more effectively.

Use of diffuser in passive daylight solar lighting

A passive solar lighting system that mimics conventional electrical lighting systems has been developed. The system consists of a filon light collector with a boxlike system of diffusers. It has been applied to an office area in Trinidad and Tobago and its effectiveness evaluated. Results obtained indicate that on clear days average illumination levels above 300 lux are obtained during the period 8.00 am to 3.30 pm. The system can be integrated with conventional electrical systems.

The Passive Daylighting of Building Interiors

This study investigates collection, concentration, and transport systems, and their applicability to the transmission of daylight. Systems to transmit concentrated natural light to deep interiors, and the concept of an ideal collector with high capture and concentration ability need further examination. Reflective hollow light guides and optic fibres have shown considerable potential in terms of their luminous efficacy. Other design issues investigated include the intelface between the concentrator and the light guide, and the combining and coupling of different transport systems. The analyses are carried out primarily in terms of concentration and transmission effciency as a basis for assessing the technical and economic feasibility of daylighting deep interiors.