Lecture 10 - Daylighting

Question 1

What are the 5 measurements of Light?

Answer 1

1. Luminous Intensity (I) [cd]
2. Luminance (L) [cd/m^2]
3. Luminous Flux (F) [lm]
4. Daylight Factor (DF) [%]
5. Illuminance (E) [lux = lm/m^2]

Question 2

Define Luminous Intensity

Answer 2

Quantity of power of a light source to emit light in a given direction

Question 3

Define Luminance

Answer 3

Luminous intensity of a surface in a specific direction (brightness of a surface)

Question 4

Define Illuminance

Answer 4

Luminous flux received per unit area of surface (orientation must be stated)

Question 5

Define Luminous Flux

Answer 5

If a lightsource has no preferred direction of emission it is ISOTROPIC and the Luminous Intensity in any direction multiplied by 4pi is equal to Luminous Flux

Question 6

Define Daylight Factor

Answer 6

Ratio of local illuminance at a point INDOOR to the SIMULTANEOUS OUTDOOR horizontal illuminance due to an unobstructed sky.

Question 7

What are the 4 benefits of Sun access?

Answer 7

1. Thermal comfort
2. Visual comfort
3. Free heat energy
4. Health and psychological benefits

Question 8

What are 4 Health and psychological benefits of sun access?

Answer 8

1. Improved mood and emotional state
2. Improved productivity
3. Vitamin D
4. Metabolism, Endocrine, and Hormones - Body clock