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270 Kwh Per Year = 30 Watts / Hour, Right?


paulnptld

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Here's why I'm asking. In looking for energy efficient refrigerators (EcoSolarCool, etc.) I found that most of them were 40 watts and more. On a forum someone pointed out that Kenmore makes an Energy Star model for $199 that they've powered entirely with a single 100 watt solar panel. Seemed impossible, but here's the model:

http://www.kenmore.com/kenmore-3.1-cu-ft-2-door-compact-refrigerator/p-04695693000P?prdNo=1&blockNo=1&blockType=G1

Looking at the Energy Star rating it seems he might be right though: http://c.shld.net/assets/docs/spin_prod_931511512.pdf

Any thoughts on this? I want to yank out my battery sucking Norcold ASAP if this $199 refrigerator could really work.

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A 100 watt solar panel cannot run that refrigerator steadily on a daily basis.

270 KWh per year is average for a small fridge. Nothing unique about it. That is a little over 2 amps per hour if run directly on 12 volts DC which you can't do. Adding an inverter makes more loss. Brings it to around 3 amps per hour @ 12 volts.

Note that a 120 watt solar panel in the northeast - only averages around 1 amp per hour, @ 14 volts per day. Somewhat more in the southwest IF pointed correctly and following the sun throughout the day.

Just about any small DC refrigerator on the market can run on 2 amps per hour @ 12 volts.

There are large 5.8 cubic foot 12-24 volt DC refrigerators that are custom made for solar and run on much less. I have one. Sundanzer 5.8 chest refrigerator uses 1/3 of an amp per hour @ 70 degrees F. Way more efficient then anything like you're talking about. My Sundanzer will run all summer hooked to a single 120 watt solar panel and one 120 AH battery. Has 6" of insulation and a Danfoss 12-24 volt compressor.

Here's a list of some of the most efficient small AC refrigerators. All pretty much the same.

Avanti 2.4 AR2412B 277 KWh per year, Avanti 3.1 BCA319*** 259 KWh per year


Avanti 2.4 RM2411B 252 KWh per year, 17.8 x 18.5 x 25 inches38 lbs., 25” tall, 18.5” X 17.8”

C-Series HC24R Refrigerator Only – Single Door 5.3 281 KWh

Cuisinart 043-1894-4 Refrigerator Only – Single Door 4.2 218 KWh

Cuisinart 043-1893-6 Refrigerator-Freezer – Single 5.3 266 KWh

Danby 1.8 Model # DAR195BL 19.7” tall X 19.6” deep X 17.5” wide, $120 at Home Depot, 302 KWh

Danby DCR326BSL Top Freezer 3.1 337 KWh

Danby Designer DAR259BL Refrigerator Only – Single Door 2.5 309 KWh

Danby Designer DAR340W Refrigerator Only – Single 3.3 316 KWh

Emerson CR519BE Refrigerator Only – Single 4.2 218 KWh

Frigidaire CFPH25M4LB Refrigerator Only – Single 2.4 253 KWh

Frigidaire FFPH25M4LB Refrigerator Only – Single 2.4 253 KWh 26.125” tall, 18.8” wide, 17.8” deep

The Igloo FR180 small freezer, 1.7 18.5” X 17.5” X 19.25” tall $85 Walmart

Magic Chef HMBR265WE Refrigerator Only – Single 2.6, 256 KWh

MicroFridge MFR-3 Top Freezer 2.9 290 KWh

Midea 4135198 Top Freezer 3.2 270 KWh, also Midea MRD311S Top Freezer

PREMIUM PRF3150MW Top Freezer 3.2 270 KWh

Sanyo SR-369* Refrigerator Only – Single 3.3 310 KWh 33.3” high, 18.6” wide and 19.8” deep

SPT RF-314W Top Freezer 3.2 270 KWh

Sub-Zero, Inc. 249RP* Refrigerator Only – Single 4.9 278 KWh

Sub-Zero, Inc. 700BR Refrigerator Only – Single 5.3 254 KWh 34.5” H X 27” W X 24” D

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Here's a detailed report of one old Samsung AC refrigerator I messed with five years ago - using an inverter and adding insulation. This old frig I paid $25 for at a yard sale tests at using less power then the new one you cited. It is still in one of my RVs and has worked fine for years. I certainly would not want to "dry camp" with it on a long term basis. For an RV that we only sleep in at night and drive in during the day - it has worked great. Note that this RV is 4WD and we've done a lot of off-roading in mountains. Old refrigerator never skipped a beat. We have a pair of Trojan T-105 "house" batteries. Many times we have left the RV for 5-6 hours parked with two fans running (for our dog) and the refrigerator on and never had any low battery issues. Also camped many nights - from 7 PM to 7 AM with lights, refrigerator, watched a 24" LCD TV with a DVD player and also had no low-battery issues.

Dorm sized, Samsung. 17.5” X 18.5” X 26.5” tall exterior (little AC Samsung fridge). Once cool, with some water bottles in it, it used: .12 KWh in 5 hours, and .27 KWh (270 watt hours) in 12 hours. That comes to 197 KWh per year @ 70 degrees F. Draws 1 amp at 120 VAC when running. I added insulation (1”) 4.06 hours = .08 KWH (20 watt-hours per hour. Checked again - 18.33 hours and .35 KWH. That’s .018 KWH (18 watts) in one hour.

Hooked to two batteries with a mod-wave inverter (220 amp hours collectively)

1:15 PM battery voltage 12.97 100% charge
10:30 PM battery voltage 12.22 VDC 60% charge
8:15 AM (next day) battery voltage 12.09 VDC 49% charge
1:45 PM battery voltage 11.94 38% charge
3:15 PM battery volage 11.9 38% charge

Read-out says - 24 hours and 30 minutes .43 KWH was used.
Checked it again while installed in camper with added insulation.
In 21.20 hours it used .45 KWH. .021 KWH per hour. It was around 70 F degrees outside.

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My Norcold is ancient and is 12v/120. No propane. It's also poorly insulated and seems to cycle on frequently.

I suppose buying a propane refrigerator would be cheaper than buying additional solar panels or a $1,100 solar refrigerator.

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A standard 1.8 cubic foot Norcold DC RV refrigerator (compressor type model DC-254) like used in Winnebago Lesharos and Phasars draws 6 amps @ 12 volts when running. Runs around 20 minutes per hour at 70 degrees F. I.e. an average of a 2 amps per hour. A single 120 AH house battery can easily run it for over a full day before down to a 50% discharge. Many are used in boats besides RVs.

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And as soon as you open the door to get a cold beer all the numbers are shot to hell. Add a kid to the mix and you'll see why most rv come with propane refers.

That's also why the super DC refer JD wrote about is a chest type.

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My Norcold is ancient and is 12v/120. No propane. It's also poorly insulated and seems to cycle on frequently.

I suppose buying a propane refrigerator would be cheaper than buying additional solar panels or a $1,100 solar refrigerator.

I don't know how big a refrigerator you need? I see the little 12 volt Norcolds fairly often for $100. Great little refrigerators. Model DC-254. Norcold also made a bigger one that used an AC compressor and a built-in DC to AC inverter. Used in a lot of big class A motorhomes and a pig on energy usage.

Lots of good working three-way absorption refrigerators around for $100-$200. The killer is trying to ship them if you cannot pick up.

I've got piles of them here (good 3-ways). If you are driving distance to central NY - come and take your pick for $200. I got two more good ones last week from a couple of truck campers I'm scrapping out.

My vote is for a 12 volt DC if you do a lot of stop and go RV use. If you camp long-term with no electric power - then propane or a DC chest unit with solar is the way to go.

Note that if stop-and-go - a cheap AC refrigerator from Walmart works fine. Just hook it to a 1500 watt inverter. $75 for a refrigerator, $100 for an inverter - and you're all set.

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And as soon as you open the door to get a cold beer all the numbers are shot to hell. Add a kid to the mix and you'll see why most rv come with propane refers.

That's also why the super DC refer JD wrote about is a chest type.

That chest refrigerator also has 6" of foam insulation that makes a huge difference. But yeah - chest units are always more efficient then vertical units - in an RV or in someone's house.

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