Even ice still has some heat energy, in fact energy is always present until the value of ‘absolute zero’ is reached some -273.16°C, which is why the Kelvin scale has its start point at absolute zero (and hence freezing point is +273.16 Kelvin).
We should all be familiar with a heat pump since we most likely have one at home! A domestic refrigerator (or even freezer) is a heat pump – it pumps heat out of the device, thus cooling the inside.
