I'm looking into building an absorption chiller as a decidedly non-professional DIY project. For safety reasons and because temps. > 0°C are sufficient, I won't be using ammonia but some saline solution as absorber and water as cooling agent. The obvious choice for the salt would be LiBr, as this is used in comercial installations. However, I'm not sure I can procure it (chemicals suppliers don't sell to private persons in germany) and it's not cheap (~ 30€/100g). What other salts are strongly hydroscopic and commonly availible? Alternativly, where can I find a concise list with the physical properties of many common (=household) salts?
Have you looked into silica gel or zeolites? Both are non-toxic, and thus likely obtainable by private persons. Zeolites are used in self-refrigerating beer kegs.