Daylighting has the potential to significantly improve life-cycle cost, increase user 1) _____, reduce emissions, and reduce operating costs:
· Improved Life-Cycle Cost: At an 2) _____ incremental first cost increase of from $0.50 to $0.75 per square foot of occupied space for dimmable ballasts, fixtures and controls, daylighting has been shown to save from $0.05 to $0.20 per square foot 3) _____.
· Increased User Productivity: Daylight enlivens spaces and has been shown to increase user satisfaction and 4) _____ comfort leading to improved performance.
· Reduced Emissions: By reducing the need for electric 5) _____ for lighting and cooling, the use of daylight reduces greenhouse gases and slows fossil fuel depletion.
· Reduced Operating Costs: Electric lighting accounts for 35 to 50 percent of the total electrical energy consumption in commercial buildings. By generating waste heat, lighting also adds to the loads imposed on a building's mechanical cooling 6) _____. The energy savings from reduced electric lighting through the use of daylighting strategies can directly reduce building cooling energy usage an additional 10 to 20 percent. Consequently, for many institutional and 7) _____ buildings, total energy costs can be reduced by as much as one third through the optimal integration of daylighting strategies.
As with all energy-efficient design strategies, there are some costs associated with the use of daylighting. 8) _____ must be sure to avoid glare and overheating when 9) _____ windows. More windows do not automatically result in more daylighting. That is, natural light has to be controlled and distributed properly throughout the workspace. Also, for cost savings to be realized, controls have to be in proper functioning order. Poor 10) _____, commissioning, or Operations and Maintenance (O&M) practices can all lead to sub-optimum performance.
(by Gregg D. Ander, FAIA)
STRATEGY POINT: Introduction to Summary Writing
· Before doing anything, read the summary question carefully.
· Next read the two texts and underline any information which is relevant to the summary question.
· When writing your summary, avoid using exact words from the texts. Always try to paraphrase the information, using synonymous phrases and different structures.
· Make your summary easy to comprehend by using sequence words (firstly, finally, etc.).Remember that spelling and grammatical mistakes which interfere with communication will lose your points, so always check your work.
15 a) Read the texts and summary questions below:
1. What does capacity for change lead to?
2. What natural changes are mentioned?
3. What is said about modelling of a shape?
4. What is the most usual daylight modelling derived from?
5. What is the role of change and modelling in daylighting?
Capacity for change leads to the infinite variety in appearance of the daylit interior. Change is at the heart of daylighting, the human body has a capacity for adaptation, particularly in vision, and the need to exercise this response.
Perception reacts to a degree of change; it is the natural order of things that the appearance of interior spaces alter with time; an entirely different measure of experience to the static qualities of spaces lit entirely by artificial sources of light during the day; or where there is no access to the daylight outside.
There is a natural process of renewal in the photochemical processes of the eye as it adapts to accommodate changes in daylight. First there is the natural change from day to night, from first light until dark and the need for artificial sources to take over when daylight fades. Then there are the changes associated with changes of the weather; from bright sunny days to dark and cloudy or rainy days, there is little doubt that the human spirit soars when rising in the morning on a bright day, an experience which is less likely to happen when it is dark and gloomy outside. Closely associated with changes in the weather are those of the changes of season, from the winter snows to summer sunlight. The world outside, as experienced through the window, provides necessary information of the variety of the exterior world; whilst leading to subtle changes in the appearance of the interior.
Modelling of a shape derives from its physical form, whether round, square or otherwise, coupled with the way in which light plays on its surfaces. This is referred to as its modelling and when this derives from daylight or sunlight, giving light from a single direction, this provides a form which is perceived by the eye as having meaning, unambiguous. This is a different experience again from the form of an object or space resulting from a room lit by artificial light, where the overall light may be received from a multitude of light sources. The most usual daylight modelling is that derived from vertical windows at the side of a room, giving light from a single direction; this may be helped by windows from an adjacent wall which adds to the modelling; as the light will still be from the same overall direction, but adding to the total modelling. Two examples might be used to emphasize this, the first, a Greek Doric column where the light of day gives modelling to the entasis on the rounded surfaces of the column; light which emphasizes its particular rounded quality together with its verticality. The second example is the original David statue by Michelangelo seen in its setting in the art gallery in Florence, lit from daylight above, where the form changes in time as the day goes by. Daylight by its nature gives meaning and aids our understanding of a shape or space by its directional flow. Interior spaces are judged to be pleasant, bright or gloomy as a result of the effects of modelling and interiors are judged by the way in which the spaces and the objects within them are seen during the day to be natural, or accord to our experience of the natural world.