refrigerant for water distiller

What refrigerant do water distillers use? I heard they use to use R11, R113, etc. but what do they use nowadays? (I've heard about a design that uses the water itself as the refrigerant but it'll be a long time before that becomes practical.)
Of course, a water distiller has to operate at high temperatures, so the refrigerant must have reasonable condensing pressures at those temperatures and if the water is for drinking, must not be hazardous in case of a leak.
Now, are there any designs that first pull a weak vacuum in the water chamber so the boiling temperature of the water will be lower and thereby reduce the refrigerant condensing temperature?