Heat pumps, refrigerators and freezers all move heat from one place to another, which is where the term “heat pump” comes from.

In a refrigerator, the heat is moved from inside the fridge to the outside, making the inside colder while the heat is discharged from the heat coils on the outside of the back.

The physics are as follows. When a substance changes from a liquid to a gas (through evaporation or boiling), it absorbs heat (making its environment colder). When it changes from a gas to a liquid (condensation), it gives off heat (making its environment warmer). The change of state is accomplished by spraying the substance, referred to as a refrigerant, causing it to evaporate. The refrigerant is compressed in a different part of the cycle, causing it to condense.

The synthetic compounds industry started to use in the 1930s were chlorofluorocarbons (CFCs). In the 1970s, scientists discovered CFCs were broken down in the atmosphere by the ultra-violet wavelengths in sunlight, releasing chlorine atoms that were part of their structure. The chlorine atoms interact with ozone, transforming it into oxygen.

Ozone in the atmosphere protects the living organisms on the Earth including us, from much more........

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