Thermal Conductivity and Insulation Flashcards
What is Thermal Conductivity?
Thermal Conductivity is a property of a material allowing heat to pass through it.
How does Heat travel?
- Conduction - Heat traveling through solids
- Convection - Heat traveling through liquids
- Radiation - Heat traveling through a vaccum
A vacuum = A region with no particles
What is Thermal Insulation?
Thermal Insulation is to reduce the rate of heat energy transfer.
What are some examples of poor Thermal Conducters and what are they therefore used for?
Wood, Brick, Air..
They are poor Thermal Conductors of Heat, therefore they are insulators as the rate of heat energy transfer across the material is low.
What are some examples of insulation in the home?
- Draught Excluder
- Double Glazed Windows
- Blocking the Chimney
- Boiler Jacket
- Loft insulation
- Cavity Wall Insulation
- Curtains
- Carpet / Rugs
How do you calculate payback time (in years)?
Payback time = Cost to install / Saving each year
E.g.
Cost of fitting = £30
Annual Saving = £15
Payback time = 2 years
What is Infrared Radiation?
The radiation emitted by an object due to the heat of a body
What is Black body Radiation?
Black body Radiation is the radiation emitted by a body that absorbs all the incident implemented upon it.
What is a Black body emitter?
An object that absorbs all radiation hits it and does not reflect it
