A while back we wrote about the performance of our refrigerator and presented the power details. However, one item was probably missing in the data. That is, how much power does that thing take when its summer?
I pulled out our trusty Kill-o-watt power monitor and set up the test a couple days ago, and began recording . Unfortunately, we are not in the middle of a hot spell which would raise the ambient temperature in in the kitchen to 80F or more. For this test I’d say the average temperature remained between 70-72F. This is better described as a middle temperature data point, but more information will always help others decide if this is right for them.
Here are the test conditions:
- Frigidaire 18 cubic foot freezer/refrigerator (ice maker not used)
[ Label inside reads Electrolux model FRT18IL6JW1 ] - Measurement time of 39.5 hours. Timer has unit off 7hrs at night.
- Power measured was 640 Watt Hours total. 115-130W when compressor running, 44W light when door open.
- Test conditions: “Normal” family of 4, 2 adults, 2 teens. Kitchen temperature mostly 70-72F its a cool summer spell.
- Primary power is the output from our Modified Sine Wave Inverter, a Trace DR2412.
The total power was 1470 WH, and that averages out to 893 WH per day. Compare that to 640 WH from the winter measurment and there seems to be a big difference. Still this number is far better that the 3120 WH per day with 100% duty cycle.
There are probably human factors involved here. I didn’t puppy guard the refrigerator door to “monitor” its use this time. That may have resulted in the door being open more. In fact, Jackie made a delicious pie yesterday using the leftover apples and fruit in the fridge. She was trying to clean out the fridge for next week when we’re gone mostly to the county fair with the kids 4H projects. Yep, that’s it. We’ll be back again on this one to get a better data point for comparison.
The lesson from this number is clear, don’t leave that fridge door open, you’re spilling power all over the floor! 
Related posts:
Boaters who cruises mainly in tropical heat have found they can decrease power consumption of their fridge in two ways. Add insulation to exterior shell and provide additional ventilation to back radiator. The external insulation is cosmetically unsightly but with the adittion of thin sheets of panelling can be disguised. Looking at our own and friends fridges I notice the top of the fridge is cluttered with stuff that partially fills the gap between the shell and the cabinets above. Tis gap is essential for ventilation. In extreme situations adding a computer fan powered by a small solar panel will greatly improve air flow.
Have a look at the newest energy efficient fridge interiors. Notice the bottoms have drawers with sides so the drawers catch the cold air instead of letting it spill out the front opening. See if you can somehow alter the interior to do something similar if you are not planning to upgrade and replace it.
If it becomes a problem having a fridge door open for prolonged time, places like Harbor Freight sells hour meters, elapsed timers and mechanical counters that would count how many times a door is opened and how long it stays open. Harbor Freight is known for offering low cost products.
Not sure if I want to go there. That is, with the data logging device on the refrigerator door. The family enough from me about leaving stuff on, excellent idea, just not one for me
I was just discussing this very aspect with another off gridder who also reads you website. Family members often get downright uptight about energy savings if it inconveniences them. Smart meters in the regular grid world have prompted a lot of negative comments about ‘spying’ on their energy use.
yes, the whole smart grid technology promoted by the utility companies has a real downside/darkside to it. In the off grid world, only my family complains.
I’ve often wondered if having a refrigerator against a north wall with a seasonal ventilation panel would save enough power to justify it. The idea is to have the radiators cooled by outside air in warm times and have the radiators warm inside air when it is cold out. It could be accomplished by enclosing the radiators in a box with top and bottom holes that open either to inside or outside.
In desert climates it should be day/night as well.
The cooler the air (possibly down to some limit) cooling the refrigerant, the more efficient the process.
I have also seen old buildings in the cool micro-climates of San Francisco that had built in cooler boxes, sealed from the inside but open to the outside air.
Thoughts?
While I’m asking, I also recall that gas powered refrigeration is slightly more energy efficient than electrically powered. Does using lp gas count as being off-grid?
TJ
Wow, this post is nice, my younger sister is analyzing these things,
so I am going to convey her.
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