Refrigerator power

Re: Refrigerator power

as a matter of fact, yes, it has been done successfully before. do a search and you should find it or somebody may have it and can give you the link to the page.

here's one i found,
http://forum.solar-electric.com/showthread.php?t=9&page=6

i don't remember if there were more.

edit to add that bb and i both came up with the thread pretty much at the same time.

Re: Refrigerator power

Go to the Energy Star web site and look at fridges for a start. You can download an excel spread sheet of about 1300 models from various manufacturers.

You should be able to get down in the 250 kWh/year range.

Re: Refrigerator power

Icarus - On your Nov 22 2008 comment I think I can shed some light on why fridges are as they are.

Back in the good old days, refrigerators had one large door and the freezer was mounted in the top. All the cold air came from the freezer alone. Since the freezer was inside the fridge, the fridge area was kept cold by leakage from the freezer into the fridge area. Since cold air falls, it made sense to have thefreezer in the top. Warm air at the bottom would rise, where the freezer would chill it, making a natural convection inside the fridge. This also catered to the level of technology. It wasn't until later that technology progressed to where they could use two separate boxes with one compressor and be able to keep both boxes at the correct temperature. By then, we were all used to top mount freezers. We converted a little over a year ago from a Maytag non-estar top freezer to a Fridgidaire side by side estar unit, and I've been missing that top freezer.

On the compressor location, a compressor is heavy so they want it at the bottom for safety. A top heavy fridge with a lot of stuff in the door might tip over when the top door is opened. So, compressor goes in the bottom to the back.

Sunfrost has a concept that uses cold to transfer heat through the wall, listed here. I always thought this was a neat concept. However, ever since discovering the whole absorption cooling stuff, I'd have to wonder if there would be a way to build an absorption fridge and use solar heated water for it. If there were that would be amazing because I'd just be able to run everything off a combination of solar heated water and solar panels.

No idea if an existing gas-fired absorption fridge would be able to be modified to run off a hot water source instead of a flame since a flame setup would be using a hotter heat source. I understand the concept but have never actually seen one in action or seen an actual diagram of the setup. Anyone know if this would be a feasable thing to do? I'm not in a position to do any experimenting, right now I'm hard at work trying to get my McMansion sold so I can get to a place more suited to two people now that both kids are pretty much out of the house. Had both gone for about 6 months but circumstances forced them to start fouling my nest again.

I'd still love to do a chest fridge, but after long discussions with the 'ol lady she isn't having it. I've got to use conventional firepower on this. She likes the idea of going offgrid and using the sun for as much as possible, but she's not wanting to give anything up either. Making it tough...

Re: Refrigerator power

lotek wrote: »

Dayton Ohio, My sister-inlaw lives there, and its FREEZING that time of yr.
Just put the frig on the porch and you wont have a power bill for it.
Back in the day. when I lived in the north Ga mountains, we did this, and had to put the milk inside the house at night to keep it from freezing. The house would get down to around 45 at night after the fire whent out, but warmed rapidly after the cook stove was stoked for morning coffee.

You don,t want to put some of the newer refrigerators in the cold now. The computerboard shuts them down and you lose your food. The GE model I had previously says in the owners manual to keep the fridge in the house. I gave it to my daughter as an extra fridge as the side by side she had is limited in width. I always wanted a side by side till I saw the disadvantages of them. She put the GE in the garage before in her other house and lost all her frozen food. She moved again and put the ge in the garage and lost all the frozen food again. Thought she would have learned the lesson from the first time. When that fridge shuts down because you put it in the cold the computer board in it has to be reset. Vic

Re: Refrigerator power

There is nothing in a fridge/freezer in the 18-19CF range that is rated in the 250's. I wish there were!!

I looked at the ESR matrix and if you want an upright in the 18-19CF range you can get as low as ESR 335 but that's for a hotpoint.

Hotpoint, GE, Frigidaire are lowest in energy consumption.

I prefer the reliability of a whirlpool and you can get their ESR as 343 as mentioned in Mikeo's post. It's a very basic 19CF whirlpool.

I am willing to give up 8W of 'calculated' wattage for what I think is the more reliable product.

Kim

Re: Refrigerator power

That would be WONDERFUL!

Kim

Re: Refrigerator power

I have a 2003 KitchenAid ~25cu ft fridge. Without defrosting it consumes 1.18 kWh per day average. It has auto-defrost which has been running about once a week. I have logged and plotted the fridge power consumption during two defrost cycles (see attached). The first defrost required 251 Wh of extra energy to defrost and re-cool fridge/freezer back to normal temps. The second defrost (8 days later) used 247 Wh. Indoor temp at time of defrosts was 66F and 40% humidity.

Re: Refrigerator power

The economics of propane are complicated. If you are full time, conventional energy star is far and away the best way to go. If you only use weekends, and the occasional holiday week, then propane wins hands down. Somewhere in between the lines cross, and everyone must make their own choices.

LP fridges can be had reasonably priced if you shop carefully, especially RV types in RV wrecking yard. They are also prone to failure if they are not run exactly level, ergo buying a used one comes at some risk. LP fridges can also be made more efficient if you add evaporator and condenser fans, and add rigid foam to the outside of the cabinets. They also are smaller than most conventional fridges. My only experience with large sized LP fridges has been bad! I believe it was "explorer" who took a conventional full sized fridge case, and installed a cooling unit off a large size LP fridge. The results were terrible. We couldn't keep them cold in the summer unless we covered them with a blanket, and kept fans on the condensers.

Tony

Re: Refrigerator power

I'm going to have to go with BajaGringo on this one. We live off grid where sunlight is a precious commodity four months of the year and the extra $1000 to get a large LP fridge was well worth not having to double the size of the battery bank and add more panels. LP consumption is hardly noticeable above what the water heater, central heating, and stove use.

Re: Refrigerator power

Dave,

I find myself both agreeing and disagreeing with you. I think it is really an individual choice, but one that is indeed hard to quantify. My only point is that the numbers begin to favour a conventional the more it is used.

If you factor in purchase cost, KWH used/LP used, the price of that LP effect on battery life etc IMHO conventional makes sense for full time, understanding that there is more upfront PV system cost, but lower fridge purchase cost (typically)

Comparing new to new, LP fridges are nearly twice as expensive as a good energy star model. The spread get greater as the LP fridge gets bigger. I figure that my fridge, that uses 1500 btu/hour, and has a duty cycle of ~25%on a annual basis will therefore use ~9000 btu/day,, or about 1/8 of a gallon in round numbers. My current cost for LP is ~$4 gallon, plus what it costs me to haul it. (No delivery here thank you very much!) This makes 45 gallons of fuel per year +-. at a cost of ~$180.

An energy star fridge would use ~.75kwh/day. to generate that power I would need, by my calculation, ~ 400 watts of PV more, plus another 30 amps worth of controller, plus perhaps another pair of T-105s. So, 400*2=$800 for Pv, $300 for controller, $200 for batteries, for a total increase cost of say $1300, (with a 5 year battery cost of $40/per year).

For that, I would get a bigger fridge, with a cost savings of ~$300 maybe. so at the end of ten years, a reasonable life expectancy the numbers might look like this.

Battery cost, 10 years @ $40=($400)
Fridge cost savings 300
Fuel savings 1800
Total savings over 10 years $1700

One can run what ever numbers one thinks are real and come to ones own conclusion. I still suggest, that over time if you are going to live full time, a conventional wins at some point.

Tony

Re: Refrigerator power

icarus wrote: »

Dave,



We run a generator (to charge batteries) perhaps 5 days a year. We have a fairly well balanced system such that we have several days reserve without drawing the batteries down more than ~30% and one good sun day will bring them back to 100%.
My point is, if I wished to add ~750 wh/day of capacity, I know quite well how much bigger my PV system would need to be to stay in that balance. Like I said in the previous post, in my case ~$1300

Hey Tony,
And my point is if you did this, you would be running the generator alot more. If you had to leave for a week, or you were busy building a home, you would one day come home to spoiled food and deeply discharged batteries. Your golf carts would be wrong for the job. In your location one would have to program an unattended generator if you were not home. Your solar for charging in December and January would go way up in your location. After doing fire insurance investigations on these strategies I keep small systems easy. One day the owner can go electric when they understand what is involved.

One would also find out that in a small system that they can conserve and get by (like you do) in bad weather with propane. You will give that up with an electric and yes we are saying the same things. I am taking the chance of failure to a level that is acceptable to ME! I think Marc is correct in his 8K$, which is low down here to make your system relaible for electric.

In the end, in these small systems, you will either be lifting batteries or paying for more fuel. In your location, I think you will be paying for fuel either way in the deep winter. Maybe this discussion will help someone! There are not too many of us!