VARS

I think this is a bit larger than the average RV absorption refrigerator. Wild guess 200 pounds and 5 ft³ for the "high side." This assumes that the evaporator ("low side") is contained within the 20 ft³ box. This will depend on the configuration of the exhaust gas heat exchanger. The normal refrigerant choice is ammonia with water as the absorbent, plus a buffer charge of hydrogen on the "low side" to nearly equalize total pressure throughout the system.

Household refrigerators used to be mfd by Electrolux and Servel, and maybe still are. One RV mfr is Dometic. There are others as well.

We have a small Dometic absorbtion refrigerator in our small 10 year old RV camper. It can be switched between propane, 12VDC and 120VAC for heat source. From the owner's manual we have it sounds like the refrigerant pairing is ammonia and hydrogen.

Unit is approximately 21.5 inches high, 19.5 inches wide, and 21.5 inches deep. The manual does not provide refrigeration capacity, but based on experience this year (we purchased the camper used) the performance is less than 0.5 TR. Check these sites

http://www.dometic.com/enie/

http://www.dometic.com/enus/Americas/USA/RV-Products/refrigerators/

If you are looking for a model for outside the USA, use the first link to find the correct ccountry.

This sounds about right, along with the tonnage estimate.