Heat And Heat Transfer Flashcards
Change in heat energy
Mass x specific heat capacity x change in temperature
How storage heaters work
Bricks with high specific heat capacity are heated overnight by passing an electric current through a heating coil in the bricks
They are heated at night as electricity is cheaper
The system is closed in but it has a cover which can be opened when needed
The brick have a high shc so they can absorb a lot of heat without increasing to much in temperature
Latent Heat
At the melting and boiling points, the energy taken in is used to change the state of the substance rather than causing an increase in temperature
Specific Latent of Fusion
The amount of heat energy needed to change 1kg of the substance from a solid to a liquid
Specific Latent of Vaporisation
The amount of heat energy needed to change 1kg of the substance from a liquid to a gas
Formula for latent heat
Mass x specific latent heat
The heat pump
A device that extracts available heat from one area and transfers it to another to either heat or cool an interior space e.g fridge/ perspiration
Conduction
Movement of heat energy through a substance without the movement of the particles of that substance
U- value
The rate of heat loss to its surroundings
Convection
Transfer of heat through fluid by the movement of particles
Radiation
Movement of energy in straight lines from the surface of a hot body, without the need for a medium to pass through
The Specific Heat Capacity
Of a substance is the heart energy needed to change 1kg of the substance by 1 kelvin
Thermometric property
A physical property that changes measurably with changing temperature
Solar constant
The amount of solar energy per second falling in 1m2 of area
