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Post by Pttg on Nov 13, 2016 18:37:10 GMT
What are the limitations on adding heat pumps and subsystems to the game?
Lots of our systems are limited in operating temperature by the functional limits of the materials. Lasers like to be below the melting points of their mirrors. Crew modules like to be below the boiling point of water. That sort of thing.
It seems reasonable to hook up a household AC unit to our crew modules and compress and heat outward-flowing coolant to a nice cherry-red before sending it to the radiators. Then the radiator can be extremely tiny and slow-flowing, run back through a decompressor, and refrigerate our crew modules however you like. I don't see a physics violation in the loop, although I can understand why the ISS doesn't use a system like that since it might be very power-intensive. For our 10 Mw reactors, though, a few extra kw won't break the bank.
I'm especially curious if self-pumping power plants make thermodynamic sense; can we get enough power from a powerplant to step its coolant up a few hundred K before it hits the radiators?
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Post by n2maniac on Nov 13, 2016 21:46:29 GMT
What are the limitations on adding heat pumps and subsystems to the game? Lots of our systems are limited in operating temperature by the functional limits of the materials. Lasers like to be below the melting points of their mirrors. Crew modules like to be below the boiling point of water. That sort of thing. It seems reasonable to hook up a household AC unit to our crew modules and compress and heat outward-flowing coolant to a nice cherry-red before sending it to the radiators. Then the radiator can be extremely tiny and slow-flowing, run back through a decompressor, and refrigerate our crew modules however you like. I don't see a physics violation in the loop, although I can understand why the ISS doesn't use a system like that since it might be very power-intensive. For our 10 Mw reactors, though, a few extra kw won't break the bank. I'm especially curious if self-pumping power plants make thermodynamic sense; can we get enough power from a powerplant to step its coolant up a few hundred K before it hits the radiators? It should be possible. For a rough idea of what it would take, it can be modeled as a Carnot engine operating in reverse (this is allowed since all steps in the Carnot process are reversible!). If we wanted to take 10kW of waste heat at 300K and bump it up to, say, 1200K, we would need 30kW of electrical power and it would reject 40kW of heat at the high temperature radiator. Since the radiator is operating 4x hotter, it will radiate 4^4 = 256x more W per m2. With the 4x higher heat, it would need to be only 1/64th the size. Do keep in mind the radiator area needed for the 30kW of electrical power, though if you run them at ~2400K with 15% efficient reactors the 180kW of heat needs less area than the 40kW at 1200K. A real refrigeration unit will be less efficient, and the magnitude of this "less efficient" will take the edge off of this benefit. If anyone knows of a real device designed to refrigerate with this extreme output temperature, we could get a better idea of realistic ranges. Typical refrigeration units operate between 250 or 200 and 300K.
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