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 20oC, 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 400oC differential just keeps raising the engine power.

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

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 400oC.

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

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.