This was from my chemical engineering – but I can't figure it out.
We have two halves of a cupboard (Easiest way to describe it) and down one side, we pass a hot gas – like steam we need to cool. It enters and is cooled, so flow down the slat, which is angled.
At the end it passes down a hole, and flows back along a flat in the other direction.
So the the left, to the right, to the left – all the time giving up its heat. Within the confined space, the gas swirls as it cools, sucking in more gas. So some of the gas is actually sucked up wards, as the gas is cooled.
It emerges at the base, as cold gas – or in the case of steam, liquid water.
Up the other side we pass cold gas, which is heated, and rises up. Until it also tacks backwards.
So it emerges at the top, as heated gas. All the time within a section, the gas is heated, and sucks more cold gas up the heated plane.
I have talked before about a helical turbulence heat exchanger, were one gas is descending a helix, the other rising up a helix.
What we have done is flatten out the helix. So the slats force the gas up or down. It is a lot simpler top build – so a lot cheaper. It takes up a lot less room.
So we can build a fusion steam train. Where we add heat to water from steam plasma tubes – a 50x1cm steam plasma tube at 4 atmospheres develops 1.2 MW of heat – enough to generate 120kW of electricity. This is enough for a conventional steam engine. https://en.wikipedia.org/wiki/Steam_engine#Steam_locomotives
So we fire the boiler with no wood or Fossil Fuels burn. And no external power. Two such tubes will out perform the most powerful electric train of today. They are only 150 kW.
So 2.4 MW is more than the 60kW of Mallard at full steam. It is easiest and lighter just to convert the steam into electricity, and use power electronics to drive the train.
So we use two steam plasma tube to generate the steam to provide 240kW – 4 times the power of Mallard, with no fuelling cost. We then pass the steam into two slatted heat exchangers, on each side of the train.
This gives us back our liquid water at 90oC, and hot gas containing 85% of the thermal energy of our used steam. That we loop back to our boiler.
Suddenly our boiler is getting over 4MW of heat – and we generate 400kW of power – enough for 4 towns.
All with no fuel use. A 100 mile journey will use 7x10-16cc of regular water. Far less that the fluid loss from our system.
So no overhead power lines. No fuel burn. So no global cO2. And a hypersonic train. And all the maths is first year undergraduate engineer level.
So we could yet see a new steam age for the trains. Only this times we do not output the steam to the air. They already run regenerating seam engines. See http://www.google.co.uk/patents/US7080512
But they have missed the idea of using a Carnot system to remove 85% of the heat, and 100% of the working fluid. It does use 4% of the generated power, but nearly doubles the power produced by the engine.
Tourist lines still run steam engines, so it would be a nice first year project to develop a Carnot heat recovery system – but no 'puff-puff' from the engine. Loud speakers and a recording would put this right.
The tourists would probably demand we still vent 5% of the steam – t ogive that authentic effect. But we reduce the water use by 95%.
We eliminate the fuel burn. And increase the engine power by 80%.