the coolant look radioactive
The idea of RFRG is to use its properties as a refridgerent to cool things, not use something (ln2) to get it cold and transfer heat, glow does that great. Refridgerent work with pressure, remove heat while it's under pressure, let it expand (low pressure) and it cools down, then vaporizes and takes heat with it. Wikipedia is better at explain than me, search it.
I have tried it with RFRG, but makes a strange effect when the gas gets cold. You can find the new save as "RFRG fridge by Popy36" (2222131)
have you tried using RFRG? this is kind of what it is designed for.