adding support in crawlspace
"My question is whether that would be sufficient, and what materials I should use for the beams." --------- The beams could be solid wood, structural steel, or manufactured wood, LVL, etc. Are you asking the minimum beam size for the span?
"add some support beams across the floor joists and 4x4 posts sitting in those concrete holders"----- Would that sufficient? Depends on the loads, floors, walls, roof, point (concentrated) loads, etc. Without one being there to examine what is built on what, it is pretty impossible to give you an exact answer. As Greg said, you may need a S.E.
Clothes taking longer to dry?
Clean the dryer screen in HOT water if using fabric softener sheets.
They leave a residue that impedes air-flow, costing you money.
Clean the ducting in the last six months? 17,000 dryer fires annually!