Just to give you bit of an idea, the receiver/drier is the filter for your aircon.Works in the same manor as your oil & fuel filters.It just stops shit getting through the system and going to the TX valve.
The TX valve is similar to a needle and seat set up.If junk gets in there it keeps it blocks the system and stops it from working.
So really being next to the extractors wont really matter that much, and the heat from them won't effect the system dramatically.

Hope this helps.