What gas has the highest specific heat?

[CTH2004]

So, I want to make a “thermal battery” that stores massive amounts of gases at my desired tempature, so if something goes wrong, I can quickly lower/ raise the tempature to the target. Due to the volume and heat capacity, it’s tempature barely changes!

So, what gas takes the most energy to increase by one degree? I know “x” is the best coolants, but I’m not sure if it’s a good colant due to a high specific heat (what I want) or a low specific heat (not what I want)

Just wondering, thanks!

[G-Man]

Water has the highest specific heat by far at 72 Joules per mol Kelvin followed by nitrous oxide and carbon dioxide at 37.2 and 28.2 respectively. Water is the best at storing heat, I use a hot water tank connected to a furnace for heating my Mars base.

[CTH2004]

Originally posted by G-Man:

Water has the highest specific heat by far at 72 Joules per mol Kelvin followed by nitrous oxide and carbon dioxide at 37.2 and 28.2 respectively. Water is the best at storing heat, I use a hot water tank connected to a furnace for heating my Mars base.

Thanks!

Will probally use water for my main base, (how do you heat it via a furnace though?) but I have some things I want absurdly high temperatures for (aiming for multiple thousand degrees) (designing a sort of flame-thrower). So, does steam have the same capacity, or does nitrous become better?

Also, come to think of it, does this mean “x” is such a good coolant for the opposite reason?

[G-Man]

I think pollutants were used as coolant because it was easy to get a lot of it and it had little other purpose. The phase change update gave it utility again with a convenient phase diagram for making heat pumps.

To heat the water I run the hot furnace exhaust through a heat exchanger with the hot water tank. The tank stores the heat so I only need to turn on the furnace every once in a while to heat it back up.

All the molecules have the same specific heat in gas and liquid form. Latent heat is a factor though. One benefit of using water is its super-high latent heat of 8 kilojoules per mol (how much energy it takes to turn liquid into gas), which keeps the temperature stable at around 300-360 degrees Celsius (what I want). High latent heat sounds bad for you though. It will take a lot more energy to heat up water to super-high temperatures. You'll have to spend a lot of energy turning it into steam with no real benefit. Maybe you could use the combustor to make hot steam directly instead of boiling water, you'd have to test it. You only really need to worry about latent heat for Water since it's the only molecule that's liquid when you melt it.

[CTH2004]

Originally posted by G-Man:

I think pollutants were used as coolant because it was easy to get a lot of it and it had little other purpose.

Makes sense. Instead of of using the more effective ones that you need for other porpuses, use something thats still okay, but you have lots of!

Originally posted by G-Man:

The phase change update gave it utility again with a convenient phase diagram for making heat pumps.

How so? I mean, isn't that really just a modified heater/ cooler?

Originally posted by G-Man:

To heat the water I run the hot furnace exhaust through a heat exchanger with the hot water tank. The tank stores the heat so I only need to turn on the furnace every once in a while to heat it back up.

neat!

Originally posted by G-Man:

All the molecules have the same specific heat in gas and liquid form. Latent heat is a factor though. One benefit of using water is its super-high latent heat of 8 kilojoules per mol (how much energy it takes to turn liquid into gas), which keeps the temperature stable at around 300-360 degrees Celsius (what I want).

How's it still liquid at that temp?

Originally posted by G-Man:

Why do you need temps that high?

To mess around with changing pressure from temps, and makig a canister that as soon as you open it bursts into flames, super heating any base! (I might have creative mode on)

Originally posted by G-Man:

High latent heat sounds bad for you though.

Why though?

Originally posted by G-Man:

It will take a lot more energy to heat up water to super-high temperatures. You'll have to spend a lot of energy turning it into steam with no real benefit. Maybe you could use the combustor to make hot steam directly instead of boiling water, you'd have to test it. You only really need to worry about latent heat for Water since it's the only molecule that's liquid when you melt it.

Hmm... there's a gas output for the H2 combuster?

[G-Man]

Originally posted by CTH2004:

How's it still liquid at that temp?

As the water vaporizes into steam, pressure starts to build in the tank which increases the boiling point. At about 364 degrees the water will be entirely steam. The good part is that, as I use the steam to heat the base, it will cool down and condense into liquid water and release the 8 kJ/mol of latent heat back into the system. This makes water an even better storage of heat! Because you want very high temperatures I'm guessing you won't be letting the steam get cold enough to condense so you will never get that latent heat back. It's just something to consider.

Originally posted by CTH2004:

Hmm... there's a gas output for the H2 combuster?

I haven't touched the combustor since the phase change update, but it used to output extremely hot water, too hot for liquid water to form now. The combustor will give you hot steam from O2 and volatiles while just burning them in a furnace will give you hot CO2 and pollutants. You might want to try both options and see what works best for you.

[CTH2004]

Originally posted by G-Man:

Originally posted by CTH2004:

How's it still liquid at that temp?

As the water vaporizes into steam, pressure starts to build in the tank which increases the boiling point. At about 364 degrees the water will be entirely steam. The good part is that, as I use the steam to heat the base, it will cool down and condense into liquid water and release the 8 kJ/mol of latent heat back into the system. This makes water an even better storage of heat! Because you want very high temperatures I'm guessing you won't be letting the steam get cold enough to condense so you will never get that latent heat back. It's just something to consider.

True. I also plan on using this same tech to cool my base, so maybe I'll do both!

Originally posted by G-Man:

Originally posted by CTH2004:

Hmm... there's a gas output for the H2 combuster?

I haven't touched the combustor since the phase change update, but it used to output extremely hot water, too hot for liquid water to form now. The combustor will give you hot steam from O2 and volatiles while just burning them in a furnace will give you hot CO2 and pollutants. You might want to try both options and see what works best for you.

Thanks!