Here's something I stole from another site...
Just to clarify a few things about the RV absorption refrigerator -
The heat source, meaning the propane flame or the electrical heating element, is used to "elevate" the amonia/water mixture to the top of the cooling unit. There after it is gravity and the PHYSICAL change of state of the chemicals that does the rest of the cooling work.
The air flow across the back of the refrigerator is also gravity controlled - hot air rises and flows out the roof vent. Cooler air is drawn in through the bottom or side vent to replace this rising air. This rising air collects heat from the evaporator fins as it passes by, thus removing heat from the cooling unit.
Any assistance, especially in HOT weather, will help with this heat dissipation. A fan to move the air need not be a large one to effect a higher efficiency. Also, the addition of sheet metal baffles to direct the moving air through the evaporator fins can be very effective.
Use a mirror to look up into the back of the refrigerator compartment. There should be a maximum of one inch clearance between the evaporator coils and the facing wall. If the clearance is more than this then your refrigerator will benefit by the addition of baffles. It may be necessary to remove the refrigerator to install the baffles, but that is not a hard task to do and may result in a very much improved cooling efficiency.