Building Engineering Sustainable Building Design and Energy Efficiency 2 — Questions and Answers
Question 1: What does the R-value of insulation measure?
- Resistance to heat flow — higher R-value means better insulating performance (Correct answer)
- The density of insulation material in pounds per cubic foot
- The flammability rating of the insulation product
- The moisture absorption capacity of the insulation
Correct answer: Resistance to heat flow — higher R-value means better insulating performance
R-value quantifies a material's thermal resistance; doubling the thickness of insulation approximately doubles the R-value and halves heat flow through the assembly.
Question 2: What is greywater and how is it used in sustainable building design?
- Lightly contaminated wastewater from sinks and showers reused for toilet flushing or irrigation (Correct answer)
- Rainwater collected from roofs for domestic water supply
- Treated blackwater suitable for non-potable reuse
- Industrial process water recovered for building cooling
Correct answer: Lightly contaminated wastewater from sinks and showers reused for toilet flushing or irrigation
Greywater from lavatories, showers, and laundry contains minimal contaminants and can be treated and reused for toilet flushing or landscape irrigation, significantly reducing potable water demand.
Question 3: What is net-zero energy building (NZEB) design?
- A building that generates as much renewable energy annually as it consumes from the grid (Correct answer)
- A building with zero energy costs due to utility rate arbitrage
- A building designed with no mechanical heating or cooling systems
- A building that produces no carbon emissions from occupant activity
Correct answer: A building that generates as much renewable energy annually as it consumes from the grid
NZEBs balance annual energy production from on-site renewables (typically solar PV) against total energy consumption, achieving a net annual energy balance of zero.
Question 4: What is the purpose of a green roof (vegetated roof) on a building?
- To reduce stormwater runoff, improve insulation, and mitigate urban heat island effect (Correct answer)
- To provide agricultural production for building occupants
- To replace conventional roofing membranes with lower-cost vegetation
- To generate electricity from photosynthesis in the plant layer
Correct answer: To reduce stormwater runoff, improve insulation, and mitigate urban heat island effect
Green roofs slow and reduce stormwater runoff, provide insulation, reduce cooling loads through evapotranspiration, extend membrane life, and reduce urban heat island temperatures.
Question 5: What does fenestration refer to in building envelope design?
- The placement, size, and type of windows, doors, and other glazed openings (Correct answer)
- The ventilation strategy for a building
- The foundation type used for below-grade construction
- The staircase design and configuration
Correct answer: The placement, size, and type of windows, doors, and other glazed openings
Fenestration encompasses all glazed openings in the building envelope and their performance characteristics including solar heat gain coefficient (SHGC), U-factor, visible transmittance, and air leakage.
Question 6: What is the Solar Heat Gain Coefficient (SHGC) of a window?
- The fraction of incident solar radiation that enters the building through the glazing (Correct answer)
- The ratio of heat conducted through glass to outdoor temperature difference
- The percentage of visible light transmitted through the glazing
- The insulating value of the window assembly
Correct answer: The fraction of incident solar radiation that enters the building through the glazing
SHGC ranges from 0 to 1; lower SHGC blocks more solar heat gain and is preferred in cooling-dominated climates, while higher SHGC aids passive heating in cold climates.
Building Engineering Sustainable Building Design and Energy Efficiency 2
What does the R-value of insulation measure?