The dried (in the sun) peels break down into a superabsorbant polymer that holds water. Works better if you throw in avocado peels according to a girl from South Africa that made a super absorbent biodegradable polymer from dried orange and avocado peel that works as well as commercial water storage crystals for soils:

Combatting drought with a Low-Cost, biodegradable Superabsorbent Polymer made out of ORANGE PEELS https://www.googlesciencefair.com/projects/en/2016/deb654bce83b15eed364f52fa8685634649014602eca78858c58fec00aa6041a

You have to be careful with dry orange peels, if they catch fire they’ll smoulder and flame and stink to high heaven. I’ve seen people light dried peel to start their wood stoves instead of paper.