I never thought about this until reading the comments below this answer. To radiate something like 150W (a very conservative lower limit of human + suit systems heat production - see @Uwe 's comment below) I think a radiator would have to be conspicuously visible, wouldn't it? I don't remember seeing heat sink fins sticking out of the astronauts packs while walking on the moon or doing ISS maintenance though. In fact I think everything was/is pretty much white all around - which minimizes heating from the sun but for essentially the same reason will not radiate efficiently.
How is the heat actually dissipated?
note: see the answer - the total heat is probably much larger than 150W I mention here.