Near-Vacuum Hydrogen Airlock

[clickrush]

This is really nice.

An alternative would be the beforementined naphtha lock. If you do a double napththa lock with a vacuum in between then you can achieve perfect termal isolation as long as the naphtha doesn't freeze or evaporate.

For super cold areas one probably needs to add a bunch of automation to it and a double airlock so the vacuum after the liquid lock is garuanteed.

But this technique has the unique advantage that you could go down in temperature w/o having to worry about that and w/o using power. The only caviat is that you cannot use hydrogen on either side, which is normally the gas you are filling cold rooms with.