Heat in the Home and Specific Heat Capacity Flashcards
What makes a method of insulation cost-effective?
A low payback time or the biggest annual saving
What is cavity wall insulation?
Foam in the gap between bricks to reduce convection and radiation. The foam’s air pockets reduce conduction
What is loft insulation?
A thick layer of fibreglass will on the loft floor and ceiling to reduce heat loss by conduction and convection
What is draught proofing?
Foam and plastic around doors and windows to reduce heat loss by convection
What does a hot water tank jacket do?
Reduce conduction and convection
What heat transfers do thick curtains reduce?
Radiation and conduction
What is a U-Value?
A material that is a good conductor has a high U-Value, meaning that heat travels faster through it
How do you find payback time?
Initial cost / annual saving
What is specific heat capacity?
The amount of energy something can store, and the amount of energy needed to raise the temperature of 1kg of a substance by 1•c
What is the equation for specific heat capacity?
E (energy transferred - J) = M (mass - kg) * C (sp. heat capacity - J/kg•c) * θ (temperature change - •c)
E=MCθ
Why is water ideal for central heating systems?
Its specific heat capacity is very high
It is a liquid
How do storage heaters retain heat?
It is kept in concrete and bricks, as they have high specific heat capacities
Why might an oil heater be used instead of a water heater?
It has a higher boiling point, so higher temperatures can be safely reached
What is the purpose of having a higher specific heat capaticty?
Storing more energy
