My frigeumrator dont kul gooder

[WME]

 

Now that the English lit majors have picked themselves up off the floor and starting breathing again , here's the deal. An airflow mod to improve overall cooling of an RV refer.

Basic rule to remember our refers ( AC too) don't make cold, they move heat from one place to another.  If you can move enough heat, the lack of heat means things get cold.

The problem is what to do with the extra heat you have moved. Our units have cooling fins and coils that dump the heat into the air outside of the refrigerator and depend on gravity air flow to  vent it to the air. In hotter weather you lose air flow and all of a sudden your beer is warm. People add fans to try to boost the cooling in hot weather and it helps.

Here's my better idea. Instead of just blowing air around in the duct behind the refer I planned to cool the entire space. This will keep the space behind the refer from superheating in the direct sun, the air flow will make the condenser cool better and of course keep the beer colder . My RV has the side inlet  and roof outlet.

I removed the cap and bug screen. Then cut a piece of FRP the size of the exhaust duct. Cut 2 holes in the FRP panel and mounted 2, best quality, 120mm computer cooling fans, then glued the panel into the vent. This pulls air into the cavity and keeps all of the tubes and fin cooler. making the refer cooler.

Odd bits the fans are mounted with machine screws and t-nuts. The t-nut will bite into the FRP and a dab of sealer also glues the nut to the FRP. This way if I have to change a fan it should be easy, as the nuts will stay inplace on the bottom of the FRP. The wiring is all above the FRP, with wire nuts, for the same reason, easy change.

In 85 degree weather the propane flame is on for long periods of time. The cooling fans seem to cycle on and off much more often. I guess that means that the condenser is cooling off and dropping below 130 deg

A pictures is worth a thousand words so here is a bunch.

Here's the "kit"  fans are 120mm, 75 cfm ea and draw .25 amps ea. The white thingie is the thermostat 5 amps, 130 deg turn on point. The clamp and black clip are mounting choices, I use a different method.

 

FPR panel, cut to size and with holes for fans

 

Thermostat installed between condenser fins

 

FRP panel and fans installed in vent duct.

 

The big picture of things. Cheap roof vent covers, 360 black water vent, two 100w glue down solar panels

Edited August 1, 2017 by WME

[redskinman]

Excellent project,looking forward to see if it helps.I bought a small fan from Walmart and stuck it in there and it didnt help me unfortunately

[Scarlett O'Hara]

Perhaps later on, when I've tackled simpler puzzles, this fix won't appear so intimidating.   Ingenious!  But what less could be expected from a man who speaks in tongues.

Scarlett

[WME]

Well got to test things a bit. I wish I had a set of before numbers of time vs temp, but alas no such thing.

Test today outside starting temp 86, Starting temp in refer 86 deg On 110v. 2 gallon of water bottles in freezer and 3 gallons in refer all in 16 oz water bottles. Water 86 degrees. Thermostat #5

2 hr in freezer 33 deg refer 54.  4 hr freezer 28 deg, refer 48 outside temp 95.  6hr freezer 18, refer 42.out side temp 91. Bed time, next morning Freezer 4, refer 36. After 2 days things seem stable, freezer -4, refer 36. So does it work gooder ???, but it does work very good. Now I just need some 110 temps to properly evaluate its performance

 

[sweetleon]

-4℉ seems unnecessarily cold, no? Water freezes at 32℉

[WME]

A freezer should be below 0, even your house freezer. In very hot weather the RV refers lose efficiency and the temps will go up quickly.

Like I wrote I need some 110 deg temps to see how much cooler the fans make things Last summer at 117 deg, with a stock unit, the freezer temp was 24 deg, that makes soggy ice cream