Efficiency Impact of Defrosting a Chest Freezer
 

This entry is part 1 of 1 in the series Freezer Efficiency About a year ago when I bought my house, the previous owners offered the chest freezer that was downstairs for a reasonable price. We gladly accepted. Ever since, it has been chugging away eating up whatever amount of electricity it needs to [...]Post from: EcoRenovator.org

Efficiency Impact of Defrosting a Chest Freezer



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I gotta say, I was really hoping to see more then 5% from the defrost job. I think the main reason it wasn't as horrible as I thought was because the ice wasn't covering the entire inside surface. It was built up very thick, but just in a smaller area.

Hopefully the next idea will help out more. :)

Has anyone else ever measured their freezer power consumption and seen what tweaking will do for you?

Anyone want to test the effect of salting the ice and leaving the freezer unplugged while it melts with the food still inside?

Adding salt to ice allows it to absorb more heat faster, which means that things will freeze when subjected to salted ice... since the food is already frozen, you can rest assured that it will stay frozen for some time as long as the freezer isn't opened frequently, and the salted ice will most likely help to keep it frozen and keep the freezer's internal temp low enough to help keep the food frozen, while the salt melts the ice.

I'm not sure if the ice has to be in somewhat direct contact w/ the food for this to work, though.

It's how you make home-made ice-cream... add cream and sugar to a pail that rotates inside another pail that has ice and road salt in it, and mix the cream and sugar constantly while rotating the pails against each other.

0.05032kw/h. Not a bad stat. Good to see a comparison for a chest freezer.
We (the house I live in) recently acquired a brand new upright freezer (space reasons dictated). Manual of course. Over the past 80 or so hours, it racked up 0.04817kw/h. And its empty. I'm looking forward to filling it with a few quad legged animals. Hopefully we can get that 0.048 down to 0.045 average. But I have no idea how low it can go.

I traded an old standup freezer for a new standup. The new freezer paid for itself the first year. My electric bill dropped at least $50 month. If I had the space I would have gotten a chest style. If you have an old freezer you may want to invest in a newer pump and door seals for it if the chest itself is in good condition. I wish I would have thought of that when I made my change. The new one would have fit inside the old one.

Welcome to the site fishaholic! Good to see a fellow Wisconsinite. :) We'd love to learn a little about you if you'd post an intro in the introductions forum.

I'll have to check the age of the freezer. I don't think its incredibly old, but I'll need to see to be sure. Thankfully, the energy usage from it isn't that bad even when looking at the new freezers. EnergyStar has a list of freezers and their energy consumption listed on their site. I don't have the link handy off hand though.

Would salt+water=corrosion? Just guessing, maybe at those temperatures it's not a problem.

Here is how I defrost the freezer:
I wait for winter. When the forecast says it will be -10*C or lower in the morning I unplug the freezer in the evening. The inside usually doesn't get warmer than -10*C thru the night (starting at -20*C). Around 5am I take everything out and leave it outside, preferably in a place where local cats can't get at it. Leave the freezer door wide open and put a small standing fan in front. The circulation of air melts the ice 5-10 times faster, no scraping. After 1-2 hours the ice is gone, clean any debris, wipe clean, close door, turn on, 10-15 minutes later put stuff back in.

Very little work, and unplugging the previous evening allows you to save some energy by coasting until morning. The pulse stage is lowering the temperature of only the freezer, not what's in it. Using the fan takes some energy, but makes it much quicker.

Look up home made ice cream recipes.

You put salt and water in the tub together, and that allows the ice to impart more of it's energy (cold) to the cream, bringing it below 32degF (the freezing point of water).

While doing so, of course, the salt acts as a catalyst upon the ice, melting it faster.

The basic idea is that as long as your freezer has a drain in it, and you can keep the water from damaging anything inside/outside the freezer, you could probably just put salt on the ice buildup a few times a day, and it would just melt on it's own. You might have to turn your freezer down a bit, but not so low that it won't keep your food frozen.

Aaahhhh, the drain is the key. A lot of freezers don't have a drain (probably to reduce loss of cold air). But this idea with salt is good :)

IIRC, 1 cubic foot of ice equals about 1 cubic inch of water.. In most defrost cases, a towel would work just fine.