Materials which need to gain lots of energy
to warm up also release lots of energy
when cooling down – ‘store’ lots of heat.
When substance is
heated, temp depends on:
Amount of energy
supplied to it
Mass of substance
What substance is
Specific heat capacity of a substance:
energy needed/transferred to 1kg of
substance needed to raise its temp by 1°C.
Unit for specific heat capacity is joules per kg per °C.
Formula: E = m x c x θ
Where E = energy
transferred in J
m = mass in kg
c = specific heat capacity in J/kg °C
θ = temp change in °C.
To find specific heat capacity –
rearrange equation: c = E/m x θ
Materials used in them usually
have high specific heat
capacities to store lots of energy.
Water has high specific heat capacity
+ is liquid so can be pumped in pipes
– ideal for central heating.
Uses electricity at night (off-peak) to heat special
bricks/concrete blocks in heater. Energy transfer
from bricks keeps room warm – have high specific
heat capacity - store lots of energy. Warm up slowly
when heater element is on + cools slowly when off.
Some are filled with oil which has specific
heat capacity that’s lower than water – often
not as good as water -based systems.
However oil does have higher boiling
point – oil filled heaters can safely reach
higher temps than water-based ones.
Electricity consumed at off-peak
times sometimes charged at
cheaper rate – storage heaters
designed to be effective.