Sem 2 - Fabric & Performance Flashcards
To meet the targets of the climate change act in 2050 the UK will need to reduce by at least what a year
3%
What is Heat Conduction.
The transfer of heat from one substance to another due to direct contact..
What part of the building regulations applies to heat loss in commercial construction.
L2A
What is the optimum building orintation to reduce solar gains.
East - West. This orintation lets you harness daylight and control glare along the faces of the building.
What are the units for thermal conductivity
w/mk
Contribute to global emissions reductions to limit global temperature rises is the work of the…
Paris climate agreement.
What are two examples of Outstanding BREEAM design for thermal admittance
Bloomberg Building, London (Norman Foster design)
The Bullitt Center, Seattle (Zero Carbon Building)
What has the Goverment committed to within the Climate Change Act
Reduce emissions by at least 80% of 1990 levels by 2050
Demonstrating that a building has appropriate passive control measures to limit solar gains is the requirtments of what part of the building regs.
L2A
How do you calculate an R-Value
Thickness of material divided by the thermal conductivity of that material. If material is in mm divide that by a 1000 before dividing by the thermal conductivity.
In domestic construction, what is the biggest consumption of energy and what percentage is the usage
Space Heating - 61%
What are the units for R-Values
m2k/w
In Commercial construction, what is the biggest consumption of energy and what percentage is the usage
Space Heating - 45% although lighting is much higher than domestic at 21%
What are the units for fabric heat loss
Watts
What does R-Value represent and mean
Resistence to heat transfer
What does R-Value represent
Thermal resistance; how much of a fight the material puts up against the heat passing through it, for a given thickness and area.
What is the best way to even out temperature swings from the suns heat.
More glazing to the east (where sun rises) to allow for solar gains. More thermal mass in the west (where sun sets) to absorb the heat.
What is the Part L Uvalue limit for windows
2.20w/m2k
Thermal bridging equates to roughly what percentage of the heat loss within a building
15-30%
What is the Part L Uvalue limit for roofs
0.25w/m2k
Thermal admittance (or heat transfer) is what
The ability of a material to absorb and release heat from an internal space, as that space’s temperature changes.
What is the term used to describe the resistance to the passage of heat.
Thermal Resistance.
Increased heat loss at the floor and ceiling junctions can what.
Lead to cold spots which will increase the risk of condensation and mould.
What is the Part L Uvalue limit for floors
0.25w/m2k
How is a Uvalue measured
The Uvalue of a building component (roof, wall, window) measures the amount of energy (heat) is lost through a square meter of that material for every degree (k) difference in temperature between the inside and outside.
What is the Part L Uvalue limit for AOVs
3.5w/m2k
What is the Part L Uvalue limit for walls
0.35w/m2k
Using components with the recommended UValues doesn’t necessarily mean compliance with L2A. Compliance needs to be demonstrated by meeting what 5 seperate criteria
The calculated CO2 rate for the building or building emission rate (BER) must not be greater than the target emission rate (TER) Demonstrate the building has appropriate measure of passive control to limit solar gains. The necessary provisions put in place for enabling energy efficient operation of the building.
What is the calculation for fabric heat loss
U-Value x Area (m2) x Temp Difference
Why does heat loss occur?
Energy always wants to be stable so the warmer air inside a building is looking to move outside into the cold to neutralise
R-value is expressed as
m2K/W
The amount of heat loss within a building depends on what three things
The Conductivity of the component. The area of the component and the temperature difference across the component.
What building component is the biggest contributor to heat loss and what percentage does this equate to.
Windows - 26%
What is the calculation for U-Value
1 divided by the sum of all R-Values
Reduce emissions by at least 80% of 1990 levels by 2050 is the modus of the…
Climate Change Act laid down by Parliament
What is the mean ojective of the Paris climate agreement
To limit the amount of greenhouse gases emitted by human activity to the same levels that trees, soil and oceans can absorb naturally.
What are the units for U-Values
w/m2K
What are the specs for a passivhaus
- Super insulation; all elements of envelope should not have a uValue greater than 0.15 w/m2K.
- Space heating; Heat recovery from ventilation.
- Triple glazed windows; Uvalue no greater than 0.8 w/m2k
- complete airtightness; Air leakage should be less than 1m3/h/m2 @ 50pa
- MVHR units; recovery rate no less than 80%
- Some use of solar gains, thermal mass & renwable energies.
What is the order of the Energy Hierarchy
- (1) Reduce the need
- (2) Use energy more efficiently
- (3) Use renewable energy
- (4) fossil fuels should be clean & efficient
