Thermal Performance Flashcards
How climate change is affecting he world today
What can pass through the green house gas layer which heats the Earth surface?
Short wave radiation.
What is absorbed by green house gasses or re-radiated back to the Earth’s surface?
Long wave radiation.
What happens when long wave radiation is absorbed by green house gasses?
More heat is retained which heats up the atmosphere.
What does the UK Government aim to do by 2050 about emissions?
Reduce emissions by at least 80% of 1990 levels.
What percentage is required yearly in order to achieve the reduction of 80% emissions by 2050?
3%
At what percentage were the emissions in the year 2017?
43%
What is the total energy use in the UK for services?
16%
What is the total use of energy in the UK for industry?
16%
What is the total use of energy in the UK for transport
40%
What is the total energy use in the UK for domestic?
28%
Where do building heat losses occur?
Roof - 22% Windows - 26% Walls - 6% Floor - 8% Ventilation and air infiltration - 35%
Where does heat loss occur?
In buildings where there is a temperature difference between the inside and the outside of the building.
What 3 things does the amount of heat loss depend on?
The conductivity of the component.
The area of the component.
The temperature difference across the component.
What does thermal insulation provide resistance to?
The passage of heat.
What does the level of resistance depend on?
The type of insulation.
What does thermal insulation do?
Maintains stable temperature to improve thermal comfort.
Reduces energy use.
What is Thermal Bridging?
It is an area of a building construction which has a significantly higher heat transfer than the surrounding materials.
Where is thermal bridging mostly typical?
Where there is either a break in the insulation.
Less insulation or the insulation has been penetrated by an element with higher thermal conductivity.
What is the units of measurement for calculating thermal performance?
W/m²K
What does the K stand for in the W/m²K measurment?
Kelvin, unison measuring a temperature
It is same as degrees C
If a structure is insulated well, is the U Value higher or lower?
Lower.
What type of heat transfer is from one heat substance to another due to direct contact?
Conduction
What does Kelvin measure?
Temperature
Heat will naturally travel from a colder to a hotter object, true or false?
False
Which U-value is better 0.25 or 0.35
0.25
