On the sunny side of Mercury it gets up a balmy 427C. The dark side reaches a slightly nippy -183C. A mercurian day equals ~59 earth days, but it does turn. Now, if one were to install a bunch of very large heat engines there we could get a massive amount of energy.

Now, what do we do with all that energy? That's up to another halfbaker to figure out - beam it back to earth, store it chemically, a big wire, or something far more zany.

What kind of heat engine could we use? I'm not sure, but I'll start out with an idea - since this is the halfbakery - and you can all let me know I'm missing something. Let's start with a refrigerant. We can use water - there is some in crater shadows on the north pole. We pump it into giant containers on the surface. When the sun comes out, the water boils, which increases the pressure. There's a turbine connected to these containers. The other end of the turbine runs to an underground tube, which is cold (since it stays relatively cool underground). This condenses the steam into water, which is pumped back into the containers above.
-- Worldgineer, Mar 20 2003

Mercury Engine http://www.mercurym...c_dry-sump_-_850_hp
;-) [bristolz, Oct 05 2004, last modified Oct 21 2004]

Ocean Thermal Energy Conversion http://www.nrel.gov/otec/
for st3f, and everyone else, really. [rapid transit, Oct 05 2004, last modified Oct 21 2004]

How is solar energy absorbed on Mercury any different than on earth, or in space?
-- roby, Mar 20 2003


[Worldgineer], I love your ideas, but haven't we done this before...many times? Something about NASA heat pipes (cooling) or stirling engines/peltier plates (physical/electrical transduction). The common idea is to use the thermal differential between the blazing unfiltered sun's rays and the cold of space.

Bring the idea down to earth (literally) and make it's energy economical by bringing down capital costs and you'll have my croissant.
-- FloridaManatee, Mar 20 2003


Change this idea to a mercury vapor Stirling cycle engine, and I'll vote for it. Promise.
-- pluterday, Mar 20 2003


rob, Mercury is a large mass close to the sun. Why it's important that it's a large mass is so it can provide materials for construction. Why it's important that it's close to the sun is because the intensity of the radiation emitted from the sun varies with the squared distance from the source (it's sunnier there).

tj, Sure - that would work well. The problem is, even though the temperature swing seems large in Death Valley, it's not really big enough to generate much energy without a very large machine.

Florid, I don't know - I've looked around and even tried a few searches. Please link if you find this halfbaked.

pluter, Split the difference? I could change it to Stirling cycle vapor engine on Mercury for your bun.
-- Worldgineer, Mar 20 2003


Why, you toy with me, sir!
-- pluterday, Mar 20 2003


Oh pluter. I do want to please, but a mercury vapor Stirling cycle engine would clearly be your idea and I wouldn't want to tarnish it with my course descriptions. Perhaps if you know of a source of mercury on/near Mercury we could team up?
-- Worldgineer, Mar 21 2003


So you're saying that the intensity of the solar energy available at Mercury distance would solve the efficiency issues of capture, storage, and transport?
-- roby, Mar 21 2003


Capture yes. Storage and transport, as I said, is left to another fine halfbaker.
-- Worldgineer, Mar 21 2003


Put it in a stupendously large water mattress and kick it toward earth.
-- roby, Mar 21 2003


zany, but what do you mean by "it"?
-- Worldgineer, Mar 21 2003


The Buran, of course.
-- bristolz, Mar 21 2003


// mercury vapor Stirling cycle engine //

You could make an amazing lamp with that. Direct the power from the Stirling engine into a generator. Feed the electric current though a transformer back into the mercury vapour, causing it to fluoresce.

What a "feature lamp" that would be ... heat into light ... wicked .....
-- 8th of 7, Mar 21 2003


Has anybody harnessed the temperature difference between day and night on Earth? I'm intrigued.
-- st3f, Mar 21 2003


Sure, but they use larger machines - our atmosphere. Examples: wind power, hydroelectric.
-- Worldgineer, Mar 21 2003


[st3f] Not that I know of. They've done it with the ocean, though. see link.
-- rapid transit, May 11 2003


But Worldgineer, surely the rarity of water on Mercury, and our human need for it makes that material less than ideal for use in any sort of reciprocating engine. Losses would build up quite quickly with such large differentials, and such low gravity, wouldn't they?

Mercury on the other hand is much less essential to life, and far less likely to be heated up to escape velocity. It probably would be a superior material for the stirling engines...

Of course, I'm pretty sure lead reaches the melting point, so you could use that too, although as everyone knows, what we really want is a stirling engine powered by silver vapor.
-- ye_river_xiv, Sep 04 2006



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