Solar Refrigerator

cfcw · August 2010

Re: Solar Refrigerator

I've got some data that may be useful for this thread. I'v got an Engel MT45 with insulating cover. I set the unit outside on my back porch in the shade. Current temps we're experiencing are highs in the mid 90's and lows in the upper 70's At the 40 hour mark the unit has used 460 watt hours of energy, as measured through my Doc Watson meter.

I have not been opening this case so . I'm sure that in an extended power outage this unit would be opened multiple times per day and asked to store and cool other items such as drinking water. A better test would be for me to place a couple gallons of room temp water in this case every day. I may do that and report back in a few days.

Holling · August 2010

Re: Solar Refrigerator

cfcw wrote: »

I've got some data that may be useful for this thread. I'v got an Engel MT45 with insulating cover. I set the unit outside on my back porch in the shade. Current temps we're experiencing are highs in the mid 90's and lows in the upper 70's At the 40 hour mark the unit has used 460 watt hours of energy, as measured through my Doc Watson meter.

I have not been opening this case so . I'm sure that in an extended power outage this unit would be opened multiple times per day and asked to store and cool other items such as drinking water. A better test would be for me to place a couple gallons of room temp water in this case every day. I may do that and report back in a few days.

Awesome data. Thanks for your input. For storing insulin it would be opened once every few weeks in the winter and once every three days if it was over 80 degrees.

dmiller · August 2010

Re: Solar Refrigerator

cfcw wrote: »

I've got some data that may be useful for this thread. I'v got an Engel MT45 with insulating cover. I set the unit outside on my back porch in the shade. Current temps we're experiencing are highs in the mid 90's and lows in the upper 70's At the 40 hour mark the unit has used 460 watt hours of energy, as measured through my Doc Watson meter.

I have not been opening this case so . I'm sure that in an extended power outage this unit would be opened multiple times per day and asked to store and cool other items such as drinking water. A better test would be for me to place a couple gallons of room temp water in this case every day. I may do that and report back in a few days.

That's running through an inverter. The numbers using 12v input would be better.

dmiller · August 2010

Re: Solar Refrigerator

BB. wrote: »

Holling,

You could go with "maintenance" free AGM batteries (they are really nice--and will probably last at least as long), but they are much more expensive (Sun Xtender PVX-2580L AGM Sealed Battery is ~$585). Frequently, first time solar/off-grid folks buy a cheap(er) "training set" of batteries first--then spend more for the next set).

.

If it's a backup system definitely go with AGM. Too much chance of error with a little used FLA battery.

niel · August 2010

Re: Solar Refrigerator

just a note,
i decided to place this thread into the energy use and conservation thread. though it can fit in nearly any category i feel the move is needed for a few reasons,
1> there's technically no such thing as a solar refrigerator.
2> it is more inline with a use of power by an appliance.
3> there are many more threads of this type here and we don't want to look everywhere for them do we?

cfcw · August 2010

Re: Solar Refrigerator

I have collected data for the past few days on a Engel Mt-45 hooked to a 12V battery with a doc watson meter. Here's some of my data

Unit draws ~35 watts while compressor running- only .3W when not running.

Unit initially was placed outside in shade to simulate a non-power environment. High in 90s, lows in the 70's

As mentioned earlier with the unit closed up, insulator zipped up it was quite efficient it used 460 watt hours in 40 hours without opening or about 275 watt hours per day. However, I felt this was unrealistic load because most people have every intention of using their refrigerator. So, every twelve hours I opened it up and placed two gallons of room temp water in there to give the refer something to do. As expected, the results were much different. To cool that water off in the Summer environment used 330 watt hours every twelve hour period, or about 660 watt hours per day.

I had painters coming to the house, so I moved the unit off my rear porch back to my basement. Temps in the 70s. It used less power for the same task, around 250 watt hours per twelve hour period.

So to recap-

Closed, insulated in hot environment 275 wh/day
Opened twice daily and used to cool four gallons water 660 watt hours per day

Dave Angelini · August 2010

Re: Solar Refrigerator

At 660 watt hours you could run my Stecca. Might be out of the budget but an amazing piece of gear. It runs off sunlight only in the winter and almost can do that in the summer.

Sparkletron · October 2010

Re: Solar Refrigerator

Holling wrote: »

I'm looking for an efficient refrigerator along with what ever it will take to run it.

I set up exactly what you're looking for. I have a Sundanzer fridge hooked up to a small 12V battery bank. The Sundanzer normally runs off AC. If it detects a loss of power, it switches to the batteries. If AC is restored, it switches back. A smart charger keeps the batteries charged and happy. You don't need solar panels unless you expect to lose power for more than a week. Anecdotally speaking, a single 110 amp-hour battery will keep a Sundanzer running for days--even at the coolest setting, even in your area (105+ temps in the shade). I would recommend you get at least two batteries to extend the runtime and for redundancy. Later, if you decide you still want to add PVs to the mix, the option is there for you. But I would rely more on the battery bank than on PVs since the outage might occur during a cloudy rainy monsoon event.

Solar Refrigerator

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