[sawwit]

Perhaps they use the heat very efficiently?

[sethrin]

No dice. Conservation of energy and other thermodynamic laws say that [a] there are limits to efficiency, and [b] if you absorb energy you must re-radiate it. Among other things. There's no point in speculating about the blatantly unphysical. @Sharlin is right, it's just "Goddidit" dressed up.

[stevejones]

Do any of them say it must be re-radiated omni-directionally as infra-red light?

[marcosdumay]

Pretty much.

You can make it cooler than infra-red light (like microwaves), and you can irradiate for half a sphere, or even a bit less. But that's all.