pvc should be sufficient but copper would probably be better.. you could even consider burying larger pvc and pulling some 3/4" or 1" flexible tubing thru for serviceability..
burial depth and materials may vary by location so may want to consult with local plumber for advice, code info, etc.. especially if your trenching for any other utilities..
may also want to consider a storage tank in the new building to stabilize temp and air delivery.. of course good FR(L as applicable) and any number of modular plastic quick connect tubing options for distribution manifolds.. various options for mounting couplers..
I even ran full copper distribution in a building once that owner fully polished afterwards
I had this same idea for the farm and I'll probably do it when I trench the ducts for underground power.. good luck!