54W

At the cold end of the pipe, the

water vapour condenses and

releases heat to its surroundings.

The water is drawn back along the

inside of the pipe

At the hot end of the pipe, the water evapo-

rates, taking heat away from the area. Due

to the pressure difference, the water vapour

moves towards the colder end

Thin-walled copper pipe

Interior lining with capillary effect

There is a small amount of water in

the pipe which evaporates at low

temperature due to the low pressure

6