Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
25 Cards in this Set
- Front
- Back
|
What are the goals of a daylit commercial building?
|
1) Meet design objectives and adopt holistic design
2) Maximize comfort and productivity of occupants 3) Maximize value of building (energy savings, reduced OPEX, higher rents) |
|
|
What 2 types of light cause heat gain?
|
Visible
Infrared |
|
|
Light output is measured in ________________.
|
lumens
|
|
|
The amount of light falling on a particular surface is measured in ____________.
|
lux
or footcandles |
|
|
A measure of the amount of visible light that passes through the glazing material of a window
|
Visual transmittance
|
|
|
Low-E clear glass has a VT of ___________, which means that ____% of the visible light passes and ____% is reflected.
|
0.70
70%, 30% |
|
|
What is light efficacy?
|
Relationship between light output and the heat value associated with the light. High efficacy means lots of light without much heat - like blue sky.
Incandescent bulb puts out light with heat, lower efficacy. |
|
|
Adding direct sunlight to interior space - pro and con.
|
1) Adds sparkle and excitement, movement (shadows)
2) Very intense light source - too much for task lighting, although very high efficacy |
|
|
In terms of real estate, the portions of solar radiation that are of highest importance are the visible spectrum and infrared.
TRUE OR FALSE |
TRUE
|
|
|
____________ ___________ (VT) is the measure of the amount of visible light that passes through a window.
|
Visual transmittance
|
|
|
Which of the following has the highest efficacy?
Fluorescent Sky, average Sun at 7.5 deg Sky, clear Sun at 25 deg Incandescent |
Sky, clear
|
|
|
The _________ exposure is the most important in terms of source for bringing daylight into a commercial building.
|
south
|
|
|
Name two locations in buildings most suitable for daylighting.
|
Single story
Top story of multi-story building |
|
|
What is the 15/30 rule?
|
Daylight can be used for task lighting in 15 ft perimeter of building adjacent to windows.
From 15 to 30 ft can be partially daylighted, with supplemental electric lights. Beyond 30 ft, use electric lights. |
|
|
The window above a light shelf is called _____________.
|
Clearstory
|
|
|
The daylighting zone can extend about ______ times the height of the window.
This can be extended to up to ______ times using a light shelf, or up to _______ times using a highly reflective light shelf. |
1.5
2.0 2.5 |
|
|
What is the importance of light reflectance values?
|
Used when selecting the finishes for ceilings, walls, furniture and floors. To reflect daylight, need high values on ceiling and walls, decreasing for furniture, floors.
|
|
|
What is the main advantage of adding a light shelf?
|
Reducing the glare near the window.
|
|
|
Explain how to properly wallwash a room and why.
|
1) Install downlights 2 ft from back wall.
2) Use cooler temperature light, above 4000k deg, to avoid 'gloomy' feeling in room. For daylit rooms deeper than 14 ft |
|
|
For daylighting systems, lighting should be installed ____________ to daylight source (windows, skylights).
Parallel or perpendicular |
Parallel
|
|
|
When a light shelf is NOT incorporated into window design, the height of the window (from the floor) is multiplied by ______ to determine the approximate room depth that could be effectively daylit.
1.0, 1.5, 2.0, 2.5, 3.0 |
1.5
|
|
|
If, however, the window design includes a highly reflective light shelf, the window height to room depth multiplier would be:
1.0, 1.5, 2.0, 2.5, 3.0 |
2.5
|
|
|
In order to get the most 'bang for the buck' in terms of daylight being directed inside, ALL surfaces (ceiling, walls, floors and furniture) should have high reflectance values (i.e. whilte or near white).
TRUE OR FALSE |
FALSE
|
|
|
In order to best match the distribution of daylight, the coordinated artificial lighting should be:
Direct Direct/indirect Indirect All equally suitable |
Direct/indirect
|
|
|
Split-wiring (or stepped switching) is in between conventional switching and dimming in terms of cost and occupant satisfaction.
TRUE OR FALSE |
TRUE
|
