Foundation Level Exam Flashcards
HAAS
House As A System: building concept defines a house as an energy system made up of four interdependent components.
A. Environment
B. Building Envelope
C. Mechanical Systems
D. Occupant Activities
What are the HAAS principles?
Four HAAS elements work-balance, in order to:
A. provide affordable shelter (doesn’t exist)
B.Occupant Health and Safety
C.Minimize energy consumption
D. Minimize environmental impact
Thermal Comfort Factors?
A. Temperature
B. Humidity Levels
C. Air Movement
D. Surface temperature (mean radiant temperature - MRT)
Impact Occupant Behaviour
A. Moisture Added
B. Ventiliation Requirements
C. Internal heat gain
D. Increase electrical loads, water and energy use
What are the conditions that cause Heat Flow?
Conduction
Convection
Radiation
Define Conduction.
Transfer of heat across a temperature gradient: warm –> cool
In houses, conduction happens between solid objects in direct contact.
The rate of heat transfer depends on temp. difference between surfaces and R-Value of material
Define Convection.
Transfer of heat by circulation of currents from one part to another, in a gas or liquid.
In houses, convection circulates from warm side of wall to cold side of wall, resulting in heat transfer.
Mixing warm and cold air also transfers heat.
Examples: condensation on window with cold outside temp
condensation when cooking with poor ventilation
Define radiation.
Energy emitted as particles or waves that are absorbed by another body.
ie. waves of heat transmitted across an open space
Name building practices/materials that control heat flow.
- Insulation: roof, wall, foundation
- Vapour barrier: limits movement humidity/vapour into structure
- Air Barrier: Poly, Airtight Drywall, External Insulation and House Wrap
- Improve Windows/Doors to limit air infiltration
- Weather barrier (ie Tyvek)
- Building Codes: NBC requires min insulating values build assemblies
- Heating-Degree days determines level of insulation required
Data required to evaluate heatflow/conductive heat loss?
- Type of material
- Location in building assembly
- Area
- Thickness
- Spacing
- Conductivity
Effect of heat flow on thermal comfort?
- Raise or lower air temp (dry bulb effect)
- Heat or cool surfaces
- Create air movement
- Increase/decrease relative humidity
Effect of heatflow on energy consumption?
Increase the need for heating/cooling to maintain optimum temp levels
Heat loss sources?
Windows Doors Walls Chimneys Foundations Ceilings Exposed floors Infiltration
Explain thermal bridging.
Occurs when thermally conductive materials (wood framing) conduct heat through building envelope, bypassing insulation in the framing cavity.
Reduces thermal resistance wall assembly.
Any solid material that connects the warm side of the envelope to the cold side (wall studs)
Define the nominal insulation value.
Insulating value of the insulation material. Does not account for building assembly performance.