Fan on fridge coils

simmtron

I have to say I am happy with my results from my latest project. Living in the tropics daytime temperatures are about 90f. Last year we bought Samsung inverter fridge for our off grid system and have been very happy. The coils for this fridge are integrated into the skin of the side of the fridge . So I thought how could I get more ventelation to cool the coils. I had an old 12 volt panel that puts it very low amps so directly hooked up a 5 inch computer fan to the side wall blowing on the fridge. The fan only comes on during the day, but kwh consumption dropped from 1.2 kwh per day to .9 kwh per day. This was over a week period ,with and without fan.

jonr

A little higher than I would expect.  Just to be sure, I'd check it on and off for a couple more weeks.

Estragon

Ideally the fan would be switched by a thermostat so it would run only when skin temp > ambient. How warm does the skin get?

simmtron

> @jonr said:
> A little higher than I would expect.  Just to be sure, I'd check it on and off for a couple more weeks.

Sorry, what is a little higher than you expect?

simmtron

> @Estragon said:
> Ideally the fan would be switched by a thermostat so it would run only when skin temp > ambient. How warm does the skin get?

The skin gets very hot. The fan seems to keep it a lot cooler and the compressor does not run for as long or as often. Don't have it on a thermostat as it does not use and battery power as is connected directly to a panel, which runs from about 7am till 6pm.

Estragon

Pity you couldn't run the fan with heat from the skin, like a woodstove fan that runs on electric power from a thermoelectric generator.

jonr

The .3 kwh/day improvement over say an 8 hour period (fan hours/day guess) is a hard to believe ~75% drop in power draw for those 8 hours.    I'd do some more checking.    Also, power reduction while the sun shines does nothing to reduce wear on the batteries.  IMO, kwh/day during non sun hours (ie, from battery) is a more important metric.   It might lead you to other kwh saving strategies (like turning the refrigerator off from 2am to 8am).

simmtron

I think the savings is because of the 90 degree temps here during the day. When the temps were lower in January (75f) the kwh use was a lot lower.

simmtron

> @Estragon said:
> Pity you couldn't run the fan with heat from the skin, like a woodstove fan that runs on electric power from a thermoelectric generator.

Although the panel I am using does not work for anything else but a low watts fan. Not costing me anything.

Estragon

I was thinking more about using the heat to run the fan at night, with lower ambient temps.

It would probably create more problems than it solves though as they aren't all that efficient and may not move enough heat off the skin where it's mounted. The woodstove fans need pretty high temps to run.