R=Pod refrigerator cooling issues...

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   There has been alot of discussion here about refrigerators not cooling well, so I thought I would start a thread that may help some people understand these fridges better, and maybe help with efficiency and food cooling on the road.

Firstly, the Dometic units that are used in the R-Pod are ammonia units that do not have pumps. They cool with a chemical reaction between hydrogen and ammonia, using gravity and heat instead of a pump. The thing that is imerative for this system to work is airflow through the coils on the back of the fridge. If the air does not circulate through the coils and cool them, there is no transfer of heat from inside the unit to the outside, and they just do not work efficiently.

The trick is to route the air through the coils and out the upper vent, which means limiting the space between the coils and the back wall to less than 1", and routing the air at the top of the back through the cooling fins of the condenser.

R-Pods are built with way too much room behind the refrigerator, and since air takes the path of least resisiance, the air goes around the coils and cooling fins, instead of through them. Once I fixed this, my fridge works fine :)

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Ziggydog Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 16 Jun 2020 Location: Berllingham WA Online Status: Offline Posts: 3	Topic: R=Pod refrigerator cooling issues... Posted: 20 Jul 2020 at 10:29pm
	There has been alot of discussion here about refrigerators not cooling well, so I thought I would start a thread that may help some people understand these fridges better, and maybe help with efficiency and food cooling on the road. Firstly, the Dometic units that are used in the R-Pod are ammonia units that do not have pumps. They cool with a chemical reaction between hydrogen and ammonia, using gravity and heat instead of a pump. The thing that is imerative for this system to work is airflow through the coils on the back of the fridge. If the air does not circulate through the coils and cool them, there is no transfer of heat from inside the unit to the outside, and they just do not work efficiently. The trick is to route the air through the coils and out the upper vent, which means limiting the space between the coils and the back wall to less than 1", and routing the air at the top of the back through the cooling fins of the condenser. R-Pods are built with way too much room behind the refrigerator, and since air takes the path of least resisiance, the air goes around the coils and cooling fins, instead of through them. Once I fixed this, my fridge works fine :)

offgrid Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 23 Jul 2018 Online Status: Offline Posts: 5290	Posted: 21 Jul 2020 at 5:58am
	Good point. The COP of an ideal absorption fridge is (Te/(To-Te)*(Tg-To)/Tg where Te is the evap temp, Tg is the heat generator temp (the temp where the gas flame is heating the refrigerant) and To is the condenser temp. The evap temp is what you're trying to reduce, so once you get the gas flame set right there's really nothing left to play with other than trying to get the condenser to run cooler. Getting more airflow through the fins by redirecting airflow or adding a fan, or maybe extending the fins are about the only options. If you could direct a small water mister on the condenser fins without damaging things that might help too.
	1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold