Well, Arty's a tier 5 and he can expend enough energy to power a city for two seconds, but he's not at the top range of energy projection. I'd say probably half a minute would be okay. 

You probably just missed it, but there was a blurb about the assimilation in the absorption section.

And as Lalliman said, cold is a lack of energy. Absorbing anything from it would just make it worse.