You been reading your science books again. LOL!Never seen the point really as there is open ventilation within the caravan, so all you are doing is trying to take the moisture out of the atmosphere, not the caravan, and trust me, there is a lot of atmosphere out there.
What do you refill a dehumidifier withI know some consider dehumidifiers a waste of time and money in a caravan, but if you do use them I spotted 2.5kg bag refill in The Range for £5.79 yesterday which as far as I can see is a good bit cheaper than Ebay or Amazon suppliers.
These crystals are absorbent chemicals intended to keep the inside of the caravan dry. But as said in an above post they reality is that in a well ventilated caravan with cupboards and lockers open there is no point in the crystals or even an electric dehumidifier. All you are doing is drying the global atmosphere.What do you refill a dehumidifier with