Page 16 – The Cooler

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Let’s say that a particular engine will run with 100^oC temperature difference between
the hot cap and the cold end.

So, when the hot cap reaches 120^oC and the air temperature is 20^oC, the shaft will turn.

As the heat rises, say to 220C, a 200^oC differential makes the engine run more vigorously.

Likewise, a 300^oC, or 400^oC differential just keeps raising the engine power.

But, heat flows in all directions - and the bigger the differential, the faster it flows.

One comment is:- “Other than the burner, everything else in the engine is a cooler.”

When the differential is say 500^oC, then the reality is that the so called cold end is actually
getting quite hot.

The engine will still run with a hot end at 500^oC and the cold end at 400^oC.

With the natural heat loss from the metal of the engine, a 500^oC top could reach
thermal equilibrium with the bottom at say 250^oC.

But if we were to cool the bottom end down to say 150^oC, that would widen the differential
and improve the engine.

Thus the water cooler.

But how to make the cooler?

One method is to route the gas through a large quantity of small pipes
in a water chamber.

100 pipes need 200 gas tight welds. A lot of work.

Alternatively, let’s pass the gas through slits on one side of an aluminium wall.

The other side of the wall has the cooling water circulation.
No need for gas tight welds.