|
|
Post by RiftandRend on Mar 5, 2017 23:50:48 GMT
Quick question for the more scientifically minded, would a material still exhibit thermoelectric properties when molten? Because if so then graphene encased coated Selenium-Bismuth thermocouples might be incredibly effective.
|
|
|
|
Post by teeth on Mar 6, 2017 0:00:19 GMT
If this were implemented, it'd be about five minutes until people start asking for gaseous thermocouples.
|
|
|
|
Post by David367th on Mar 6, 2017 1:11:13 GMT
If this were implemented, it'd be about five minutes until people start asking for gaseous thermocouples. How long have we been asking for nuclear lightbulbs now? |
|
|
|
Post by Easy on Mar 6, 2017 1:16:41 GMT
Resistivity and conductivity do change by orders of magnitude with temperature so I would not expect the thermoelectric sensitivity to remain constant. Especially not through a state change.
How about them gas turbines? WHRRRRRRRR
|
|
|
|
Post by n2maniac on Mar 6, 2017 1:40:59 GMT
Quick question for the more scientifically minded, would a material still exhibit thermoelectric properties when molten? Because if so then graphene encased coated Selenium-Bismuth thermocouples might be incredibly effective. They aren't going to be any better then a Carnot engine, the existing materials strangelysuspiciously are really friggin close to a Carnot engine, and the delta T we can use (~500K) is in the neighborhood of the optimum for radiator sizing (3100/4 = 775 K, so 2325K exhaust temperature) and could only see ~10% radiator area reduction. What are you hoping to optimize for here? |
|
|
|
Post by RiftandRend on Mar 6, 2017 2:46:09 GMT
Quick question for the more scientifically minded, would a material still exhibit thermoelectric properties when molten? Because if so then graphene encased coated Selenium-Bismuth thermocouples might be incredibly effective. They aren't going to be any better then a Carnot engine, the existing materials strangelysuspiciously are really friggin close to a Carnot engine, and the delta T we can use (~500K) is in the neighborhood of the optimum for radiator sizing (3100/4 = 775 K, so 2325K exhaust temperature) and could only see ~10% radiator area reduction. What are you hoping to optimize for here? I was just wondering if we could get high efficiency thermocouples running at 4900K. |
|
|
|
Post by David367th on Mar 6, 2017 2:55:38 GMT
They aren't going to be any better then a Carnot engine, the existing materials strangelysuspiciously are really friggin close to a Carnot engine, and the delta T we can use (~500K) is in the neighborhood of the optimum for radiator sizing (3100/4 = 775 K, so 2325K exhaust temperature) and could only see ~10% radiator area reduction. What are you hoping to optimize for here? I was just wondering if we could get high efficiency thermocouples running at 4900K. If you mean the outlet temperature, probably not. If you were getting good efficiency tho, you'd probably be seeing some nasty waste heat. |
|
|
|
Post by RiftandRend on Mar 6, 2017 5:20:00 GMT
I was just wondering if we could get high efficiency thermocouples running at 4900K. If you mean the outlet temperature, probably not. If you were getting good efficiency tho, you'd probably be seeing some nasty waste heat. I was able to get 46 % efficiency with 2400K outlet temp and ~4900K core temp assuming materials don't change their thermometric properties during state changes. |
|
|
|
Post by newageofpower on Mar 6, 2017 5:39:06 GMT
If this were implemented, it'd be about five minutes until people start asking for gaseous thermocouples. But then what would we use as the solid-side machinery/material? |
|
|
|
Post by n2maniac on Mar 6, 2017 5:41:36 GMT
If you mean the outlet temperature, probably not. If you were getting good efficiency tho, you'd probably be seeing some nasty waste heat. I was able to get 46 % efficiency with 2400K outlet temp and ~4900K core temp assuming materials don't change their thermometric properties during state changes. If you are going for efficiency, great! If you are going for smaller radiators, crank up the heat! If you are going for maximum power on the ship... there is an optimization problem I'll step back from for now. |
|
|
|
Post by Enderminion on Mar 6, 2017 13:10:13 GMT
If this were implemented, it'd be about five minutes until people start asking for gaseous thermocouples. But then what would we use as the solid-side machinery/material? for a second I read that as "but why use solid-side machinery/material?" |
|
|
|
Post by kelarkir on Mar 20, 2017 20:23:47 GMT
To answer the question, yes you can do it, you can even use it to measure the temperature. If I remember correctly, the problem is the time during phase change. Oh and linearity isnt really a given anymore but who needs puny linearity?  |
|
|
|
Post by n2maniac on Mar 21, 2017 7:17:24 GMT
If this were implemented, it'd be about five minutes until people start asking for gaseous thermocouples. But then what would we use as the solid-side machinery/material? is not quite gaseous, but probably a considerable contender on a smaller scale system (or in a universe where thermocouples don't get carnot efficiencies at 3000K....). |
|
