Fun with Fans and Fridges

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by fred...
OK, so I got OCD. Can't help that. I am obsessed with getting as much cold out of my fridge as I can. I really like steaks I can freeze and eat a week to ten days into trip. And we consume an above normal amount of cold milk and white wine, cheeses and spreads and jellies and jams (not at the same time).

I prefer running fridge on propane and am a pro at disassembling, cleaning and reassembling the propane system. Still, when ambient temps reach 90+ and I'm not using the AC, it struggles. If sun is hitting pod in those temps it struggles even with the AC running. By that I mean, fridge rises above 40 (42-45) and freezer about 15 or so or even 20. Opening frequently, of course, makes it much worse. At night, it's never really a problem and by AM the fridge is back down to mid to upper 30's and freezer 5-10 or so. This past summer I have been watching and documenting closely (see OCD above). BTW, the above observations are all @ 4 bars (hot weather setting for us).

BTW, I do carry a Coleman thermoelectric (12volt) cooler which works great for storing 12 oz. adult beverages and other frequently requested items. 

Sooo, it's obvious that ambient temp has a lot to do with fridge efficiency. After all, the fridge is absorbing heat from inside the fridge and dumping in back outside to the back of the fridge. The hotter the back of the fridge, the less room for heat to be dumped and the warmer the fridge gets. Simplistic, but makes sense to me. That's why it works better at night - because there is more room for the hot air to dump and because my frequent trips for adult beverages are made to the cooler.

Yep, we pulled off the vent covers to make it easier for the absorbed hot air to escape and have even played with "heat shields" to try and block sun from heating compartment. Both help, but still not the solution I think I have been looking for.

About a year or so ago I was reading all these people on the internet saying that circulating air in the fridge was *the* solution. Sorta made sense and since everything on the internet is true I bought one. Didn't make any difference as far as I could tell. Maybe in a larger fridge, but I didn't see any difference in the little pod fridge. I put the fan(s) in one of my gadget boxes. (Cleverly hidden from OCD wife who suffers from anti-clutterism!!).

You've seen them

Repurposed as...

Cool, huh? Get it? Cool.

The last four days have been perfect testing right here in my driveway. First day was sunny and mid 90s. Started up the fridge about midday and put a bunch of bottles of cold water, a half gallon container of water and half a dozen freezer packs. About as full as we would have it camping. I did leave the freezer empty. The fridge and freezer temp @ start were both about 87. I started the vent fan above as well as jumping the pancake fan to circulate as much air as possible. Slideout was in, AC off. Windows closed. Alec Guinness would appreciate the conditions in the pod (any Bridge On The River Kwai fans?). I turned off the pancake fan and left my new vent fan on late afternoon. I left the vent fan on for the duration of the test.

Day two and three were ridiculous. Pod in full sun. Daytime highs 92-95 and high humidity. I still can't believe I lived in Florida for 25 years. Nuts. I closely monitored fridge temps. I use one of this AccuRite things that seems to be pretty accurate. So both mornings I started out with 2 and 6 in freezer and 36 in fridge. Surprisingly close and pretty encouraging. During the day, the temps rose. I did open the fridge for about thirty seconds or so both days just cuz I want to stick my finger in the water to see if it really was that cold. When I saw freezer hit 12 degrees and fridge about 38, I jumped the pancake fan to move some more air. It helped and temp dropped back a couple of degrees. I could feel the hot air pouring out of the top vent. Interestingly, I measured the switch that is supposed to kick on the pancake fan and it never seemed to get much above 130 (IR and Thermopen).

Over the first two days the fridge maxed out @ 40. Considering the "I'll tell you anything!!" conditions inside the pod, I was impressed. BTW, I put the AccuRite sensor below the metal shelf and on top or the crisper in the center of the fridge.

Last night was cool and today the temps were mid-seventies and overcast. Measured temps were 1 in freezer and 32 in fridge this AM. By the time I concluded test this afternoon, temp in freezer was 2 and fridge 32.

If you got this far, cheers!! 

I'm pretty comfortable in concluding that the most effective way to make your fridge more efficient is to get rid of the hot air behind it. And, maintain it, of course. If your ambient temps don't exceed mid seventies and your having a problem, there are other issues.

 I also ordered a switch that supposedly opens @ 125-130 instead of the 158 that come with the fridge. Might be better than putting a manual switch on pancake fan. We'll see.

Pod On!!

fred