h a l f b a k e r yI think this would be a great thing to not do.
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This is a proposed cooling and air moving system with no moving
parts (except the air, which isn't a part).
In solar fruit driers the hot air moving upward creates a strong
draft pulling after it the air from the bottom. The same happens
in smoke stacks and chimenies. So this idea is about
an effect
similar to "moving lights" that work by switching on LEDs or
flaurecent lights in sequence only here we use electric heat
elements or infra-red LEDs. This creates a draft of hot air
moving out of the pipes and pulling cold air in.
The cool air could pass first in a heat exchange chamber where
it collects heat from the units that need cooling, especially the
CPU. The dissipation of heat into the chamber could be assisted
by a peltier device, although not very efficient, but sufficient
enough in our case to quickly move the heat off the unit and
into the coper fins for quick dissipation.
This could
Heat art?
https://www.deviant...sturbance-245646124
This would be interesting as a heat-xel if real [wjt, May 12 2018]
[link]
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Of course it could. He said so. |
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Now I can't.
ever erase that mistake. |
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OK, so you want to electrically heat air, so that it rises by
convection and cools things? |
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would the coanda effect work with this? |
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//electrically heat air// |
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No, I think the electrical heat is already a given, such as, for
example, the heat from your laptop. |
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I think the idea here is to add a convenient chimney to your
laptop, in place of the fan. But it might |
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I think a laptop chimney would |
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The interesting bits would be the heat-xels and their workable sizes. Aah, the beauty of the informational driving patterns and the motions of painted smoke. |
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Except for the trailing "This could" which was supposed to
be replaced by the current text and instead got pushed
down to the end, the rest is quite clear, me thinks. |
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Yes I do want to electrically heat a pipe's sections in a way
that causes the air to flow one way, leading the air out and
away from the laptop. Once the flow is established, it can
take the heat from the laptop parts and take it away
through convection, just like a fan does. |
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Not a magical notion, and not something that is wishful
thinking, this is a practical and doable thing pending the
problems and flaws that the ever watchful HB team will
find, of course. |
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Of course this might startle giraffes, but what are they
doing in the laptop in the first place. |
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As a second thought I could probably |
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So, [pash], what you're suggesting is that a simple six-foot
chimney, connected to the laptop, and with strategically-
placed heaters consuming only a few hundred watts of power,
could replace the cumbersome half inch-tall fans that gobble
up perhaps a watt of electricity? |
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Why, the benefits seem absolutely enormous. |
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Solar updraft towers work with a roughly constant and
uniform application of heat to the collection area. So what's
your goal in trying to peristalt the heat? |
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Let's think about the power requirements. |
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Let's assume your computer fan is about 2W, and moves
about 3 cubic metres of air per minute. |
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Now we replace it with this heated cooling tower (the
name, there, gives you pause for thought). Let's also
assume that the heater in the tower raises the air
temperature by 10°C in order to achieve a reasonable flow. |
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So, we're heating 3 cubic metres of air per minute by 10°C.
That's about 3kg of air, with a heat capacity of about
1kJ/kg, meaning you need about 30kJ/min for the heating.
That's about 500W of power. |
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So, this system would be on the order of 250 times less
efficient than a fan. |
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//So, this system would be on the order of 250 times less efficient than a fan//
You could be a bit more 'glass half-full' about it - e.g. "...this system would be only 250 times less efficient than a fan!" |
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Also, just moving air about is an inefficient answer to the problem of cooling. A cooling system like this has hot things in it which require cooling, and a cooling medium which ideally has a reasonably high heat capacity (unlike air) and a high thermal conductivity (unlike air).
The two reasons to move air about are (1) to move hot air away once it has absorbed some heat and (2) because the air will absorb more heat the higher the temperature difference between the thing that needs cooling and the air is. Moving air faster and faster might seem like you're doing something but beyond a certain point it probably only changes the temperature of the air near the thing that needs cooling by a fraction of a degree (outweighed by all the heat being transmitted by the fan motors), and the limiting factor is actually the thermal conductivity of the cooling medium. I.e. no matter how cool the air, there is a limit to the amount of heat it can absorb per second and carry away.
It is for these reasons that people use water-cooling on very hot computers or even exotic alloys of indium and gallium (which conveniently are liquid) for more specialist cooling jobs. Even with these though, the limiting factor is thermal conductivity, not your ability to pump the cooling medium around. |
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In fact, consider how woefully inefficient air is as a coolant: You're outside on a winter's day walking along with a freezing gale blowing in your face. Your face is putting out only a few 10's of watts of heat (at the most) but still doesn't get frozen by the gale, because air is a very poor conductor of heat. |
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//What's a xel?// That's 'heat-xel' and it's a Maxwell demon swinging forging hammer to heavy music. |
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Heat pipes get most of their effect from phase changes, i.e.
evaporation of liquid at the hot end, and condensation at the
cold end. |
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//the air will absorb more heat the higher the temperature difference
between the thing that needs cooling and the air is// |
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So, if we make the thing hotter, it'll be cooled more efficiently by the
air. |
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There's an idea in the making! |
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{starts working on a steam driven punkah-wallah} |
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Anyway I think this is a situational wossernames. |
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I presume that pashute lives in a sunny place. So a
metal chimney can be painted black, sunlight heats
chimney, convection occurs etc etc |
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In England, you'd just end up with a black metal chimney,
with the paint drying out sometime the heavy, cold rain
stops. |
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I though this idea was about better controlling the heat transfer medium. Designing it's flows to a more complex level with little subunits rather than just globbing heat at one end and taking the resultant cooling effect at the other. |
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