heat Flashcards
What are some ways you can gain heat?
- People
- Boilers
- Electric devices
- Movement
- Insulation
- Solar
- Cooking
- Lighting
These methods contribute to the overall heat gain in a building.
What are some ways you can lose heat?
- Ventilation
- Cracks
- Air conditioning
- Single glazing
These factors lead to heat loss in a building, affecting energy efficiency.
What is trickle ventilation?
A form of ventilation found in every home, ensuring there is always ventilation around the windows of a building
Trickle ventilation allows for a constant flow of fresh air, improving indoor air quality.
What does U-Value measure?
The ability of a material to transfer heat by conduction
A lower U-value indicates better insulating properties.
What is the formula for calculating U-Value?
1/RT = U-value, where RT = RSI + (brickwork thickness/conductivity) + (insulation thickness/conductivity) + (Blockwork thickness/conductivity) + RSO
This formula accounts for various resistances in the material layers.
What units are used to measure thermal conductivity?
W/mk
Thermal conductivity indicates how well a material conducts heat.
At what wind speed must work stop on site?
50 m/s
High wind speeds pose safety risks on construction sites.
What does the Venturi effect describe?
Wind cannot go through buildings and instead goes around, causing wind speed to increase
This effect can lead to increased wind pressure on buildings.
What is thermal resistance?
A measure of whether a material will allow heat to pass through easily or offer resistance
Higher thermal resistance indicates better insulation properties.
What factors contribute to thermal resistance in building materials?
- Material thickness
- Irregularities in materials
- Air trapped in stationary layers
These factors create insulation layers both internally and externally.
What is the significance of thermal resistance in air spaces like cavity walls?
It is due to the low thermal conductivity of the air
Air serves as an effective insulator when trapped in cavities.
What does the U-value represent in terms of heat transmission?
The amount of heat energy that flows per second through one meter of a building element when the temperature difference is one Kelvin
It quantifies the efficiency of insulation in a building.
Fill in the blank: The total heat loss can be calculated using equations for _______ and ventilation heat loss.
[key learning term]
Understanding both heat loss types is crucial for energy efficiency.
