# 2 dollar/watt solar panels,refer and freezer costs



## mightybooboo (Feb 10, 2004)

Soooo....just got another 800 watts approx. of panels at 2 dollars/watt off of Craigslist.Let me just say this,used panel prices are outrageously cheap right now,just spend some time looking and reap huge savings!

So now its time to crunch some usage/cost numbers in putting them to use.

OK,solar refer and freezers.Look at this,the standard voltage mains/grid powered whirlpool(made by Woods in Canada) is almost twice as large as sundanzer but costs 500 bucks(todays price) and only uses 345 kw/hrs vrs 140 for sundanzer.So would need about 200 watts panels for almost twice the size vrs 75 for sundanzer.Panels would be 250 dollars more(extra 125 watts),including inverter losses, pretty close at 2 dollar/watt panels.

So 750 for whirlpool vrs 1200 for sundanzer and almost twice the size.

These cheap panels really are skewing the numbers for costs of appliances.The newest energy star freezers/refers are INCREDIBLY efficient,our 1999 freezer,same size as sundanzer 8.1 cf uses 297 kwhrs.Its a whirlpool too(Woods in Canada)

These conclusions sound about right?
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http://www.enn.com/top_stories/article/37711
Whirlpool Chest Freezers
Whirlpools makes a very energy efficient chest freezer, model number EH151FXR (similar models are EH151FXQ or EH150FXQ). This 14.8-cubic-foot freezer is rated at 354 kWhrs per year. The average cost to run this freezer for year is $29, according to Energy Star.

Though it requires manual defrosting, it sport a number of other features including an interior light and a temperature alarm. Its key-eject lock means that the freezer can only be opened when the key is pushed in and turned &#8212; a safety feature helpful in homes with small children. Four baskets (two upper, two lower) make it easier to organize the contents &#8212; especially on the lower level.

It&#8217;s available from Amazon for $405.

Sundanzer Freezers
The most efficient DC-powered chest freezer is the SunDanzer. This eight-cubic-foot capacity freezer has an exceptionally low energy consumption &#8212; it uses around 140 kWhr / year. It incorporates the highly efficient Danforst compressor. It also has a super-insulated cabinet that is wrapped in four inches of polyurethane. Because it runs on either 12 or 24 volts DC, the SunDanzer freezer is mostly used in off-grid homes or in remote locations, because a 75 watts solar panel and and two six-volt golf cart batteries can power the freezer.


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## Jim-mi (May 15, 2002)

And if the grid or my inverter has a *major* hickup......

My Sundanzer will still keep on a tickin..........

I do like that . . . . . . . .

Do I regret spending the $$$$ for my Sundanzer . . . . .not at all.


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## mightybooboo (Feb 10, 2004)

Yep.

I think once we get into this having a backup inverter,and back up charge controllers would be a wise thing to have.You are going to need them eventually.May as well get em now.

Beyond that though,do my numbers crunch pretty close?Ive always had trouble crunching the electrical numbers,not being an EE or alt. energy pro,just someone who plays with it as best I can.

Im a little excited about being able to go beyond the cost/size limitations of the Sundanzer which is indeed a real concern.And the costs are a real concern to people.If Lower cost panels are making the expensive hyper efficient appliances no longer cost effective then thats where Im going to be heading.

I feel in fairness if the cost/benefit structure is changing we need to be honest about it and change along with it.

Example,Bud complains his sundanzer limit is 10 degrees.My Woods freezer....Zero degrees F.Thats also important.Very important how much longer zero degrees allows you to store products,meat goes to years from 6 months.

*I love the Sundanzer*,its a great product.
I also loved my Fastenal stock but I had to move beyond it because it wasnt cost effective in a rapidly changing world.Emotional ties and cold hard reality,we have to face em.The world moves along and we have to move with it.

Energy Star has made huge inroads in appliance efficiency.Recently the refers/freezers have undergone another 10-20 percent increase in efficiency.*Thats big news*.

Anyhow,looks like solar at 2 dollars/watt really changes what we can do.
Just imagine how a dollar a watt could skew what we do now.

Maybe someday we will see it? Thanks to the Depression Im seeing an honest 2 dollars/watt,its blowing my mind away the potential of solar at this cost.

Have I mentioned I love Solar,LOL!

BooBoo <-----"It'll NEVER Work"


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## mightybooboo (Feb 10, 2004)

Stay away from RV refrigerators!

Unless they got way more efficient Bud and I both looked up our refers today.I have a Dometic and he has a Sibir.

They both use the same power,at 120 volt use 3,900 watt/hrs DAILY,or use .27 gallons propane daily!

Hows that for HUGELY inefficient.

We were SHOCKED at what energy hogs they are!

You can get a 14.8 cf freezer at Lowes for 398.00 delivered that uses less than 1000watt/hrs a day or so (354 kw/hrs a year).

WOW!!!!


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## mightybooboo (Feb 10, 2004)

Ive crunched more numbers and Sundanzer is losing bigtime from what Im seeing...


Energy Star freezer,14.8 cf total delivered with taxes = 346.00

TWO 8 cf Sundanzers.16 cf = 2000.00 NOT including hundreds in taxes and shipping
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Round one goes to energy star,at LEAST 1700.00 cheaper.Sundanzer adds 1.2 cf more...pretty expensive for 1 cf!!!
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Energy use.....
Energy Star= 980 watts/day

Sundanzer=740 watts/day T 88F. ambient and real use numbers.These are SUNDANZERS numbers BTW.Oh wait,DOUBLE that,youre using TWO sundanzers remember? so make it 1480 watts/day!
http://www.mrsolar.com/pdf/sundancer/residential_system_sizing.pdf

Caveat= Im not sure where Energy Star will come out at those ambient temps,but I will be finding out in a week or two.
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Round 2,efficiency,Energy Star takes it again
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Design Capability

Energy Star=0 degrees F.
Sundanzer=10 degree F.

I can tell you, and Buddy with Sundanzer will swear to,BIG difference in how your product stores between 0 and 10 degrees F.
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Round 3,Energy Star takes it again!

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Synopisis....

Energy Star is 1700 MINIMUM cheaper,uses LESS power,and freezes better.

Yep,world is changing fast,be sure you are keeping UP TO DATE in the very latest on appliances.


Unknowns.....How energy star does REAL WORLD at 88 F.,I will give real world kill-o-watt numbers soon,and 2 how much in inverter/battery losses,bearing in mind during day when sun is shining that power is going into inverter and not charging batteries. The rest of system mentioned would really have to fall on its face to not at least match Sundanzer in size and energy use,not to mention that extra 1700 dollars in your pocket. 
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BTW,if I fell on my face doing these numbers,please point it out,wouldnt be first time Ive butchered numbers,Im not good at them and Im just a hobbyist,not a pro electrician.


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## artificer (Feb 26, 2007)

mightybooboo said:


> Stay away from RV refrigerators!


Ammonia cycle single stage refrigeration has a COP (coefficient of performance) of only about .5 That means for every btu of cooling, you need 2 btus of heat. Since propane contains a large amount of energy in a handy package, and its fairly cheap for the weekend, thats why you see ammonia refrigerators in RV's.

The normal COP of a compressor refrigeration system is around 3. That means if you use electricity to heat the ammonia fridge, a compressor system will use 1/6 of the energy for the same cooling.

Short answer is: if you have electricty, DO NOT run an RV/ammonia system. Cheap electric units will be more efficient in the long run. (just like you found out)

As for the Sundanzer vs. energy star freezers: before efficiency became important, features and cost ruled the consumer market. Now that everyone is concerned with efficiency, you can find good consumer products out there. When sundanzer started, there wasn't as many options. Yes, 12v operation is nice, but not for 4 times the price. Its still a niche product, and has the niche price to go with it. A well built unit, but still... its more than I want to spend.

Thanks for crunching the numbers.

Michael


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## WisJim (Jan 14, 2004)

In comparing the Sundanzer and a "regular" Energy Star freezer, you also need to figure in the additional cost of the inverter needed to run the Energy Star freezer, and the 10% or more energy lost in inverter inefficiencies.

Over 20 years ago, we replaced our Servel propane refrigerator with a $2000 Sunfrost that runs on 12v DC, primarily due to operating costs, even back then when our PV panels cost almost $20 a watt, and LP was pennies a day to run the Servel.


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## mightybooboo (Feb 10, 2004)

Im not going to figure inverter costs as most everybody off grid already has and uses one with few exceptions.And uses it for much more than an added freezer.

What I will do is get those kilo-watt numbers from it,its going at zero F,and put up honest usage numbers and would like to see real world numbers for sundanzer.

As for Servel propane I was surprised to see my RV refer (dometic) and buddies home refer (Sibir) both use 3900 watt/hrs a day or .27 gallons of propane a day,those things are dinosaur energy hogs of the highest degree.


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## mightybooboo (Feb 10, 2004)

I got the external plug in thermostat from Johnson controls to turn 8 cf freezer into a refrigerator,will do kill-o-watt testing on it too to see if it works out using very little energy like the one noted on internet claims.

Give me a week or two to get the numbers.


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## mightybooboo (Feb 10, 2004)

1st 24 hours of freezer as a refer came in at .204 kw/hrs,or 200 watts for one hour.The 200 watts is used over the total 24 hour period for 200 watts daily.Averages 8.3 watts/hr.Also works out as 73 kw/hrs per year,amazing!!!! Uses 117 watts when running,dont know the surge.

Looks like one 75 watt solar panel would pretty much power it.

At 13 cents/kw thats 2.6 cents a day,wow! Times 30 days that 78 cents a month! Or a whopping $9.36 USD yearly,wow thats cheap!!!!


So Im using twice as much as the celebrated .1 kw/hrs the famous internet guy was using in his.

Still cant complain and this is a very preliminary result with day temps 85 degrees and night temps at 60 last night.Inside temp 36.5 degrees towards the top.

Will do the weekly result when its a week.

This is the Johnsons control unit,65.00 dollars delivered...






The inside of now refrigerator...


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## mightybooboo (Feb 10, 2004)

64 hours in,used 640 watts,10 watts/hr or 240 watt/hrs (.24 kw/hrs) daily.

Just read a thread elsewhere where guy was using .2 kw/hrs a day,so I guess we have our answer.Though mine is very cold at 36.5 degrees.

Its running right now reading 38.4


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## mightybooboo (Feb 10, 2004)

OK,so the chest freezer used as a refer is 200 wh/hrs a day,approximately.

The freezer with temp at 8 degrees F is using about 1500 wh/hrs daily,3 days testing.Freezer is maybe 3/4 packed?

So looks like,preliminary results,that 2000 watt/hrs a day of production should about run these 2 items.


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## mightybooboo (Feb 10, 2004)

No Sundanzer real world results? Anyone?

You got mine,where's yours?

Ive heard Sundanzer the ONLY way to go,maybe we could compare real world and make some conclusions on efficiency,function and costs?

Silence is deafening.

Sure would like to see what 14.8 cf of sundanzer freezer(s) uses,or sunfrost refer for that matter.I put up my numbers.....

:shrug:


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## scatyb (Jan 20, 2009)

sorry MB, I have nothing for you. But I am curious to know what the freezer energy usage is when turned up to 20F. Maybe you'd like to take a stab at measuring that eh? I"m going to be buying two of those small chest freezers from HomeDepot for my house and have found your posts very informative.


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## mightybooboo (Feb 10, 2004)

ScatyB,I will increase temp to 20 degrees and get you some REAL numbers.

Friends sundanzer at around 10 degrees is using about 20 amp hours/day.

He says his Lowes freezer like mine (exact same model) is using *HE THINKS* about 25 amp hours a day.At Zero to minus 5 temps F.
But he isnt certain on those numbers as its added into his household circuit and he is measuring the total daily usage at his place.And since the dealers wont take up the challenge to print THEIR Real WORLD numbers.....its the best I can give you.Unfortunately thats a very poor report on energy usage.

But it speaks volumes to me that Sundanzer sellers are silent on their use here. 


Im not afraid to compare and post real numbers and let the chips fall where they will,instead of making unsubstantiated claims and just telling you Im an expert so 'TRUST ME' and failing to PUBLISH the TRUTH on their products,eh? Times have changed in the last few years in energy efficiency.I want TODAYS comparisons,not outdated ones.

Then again,I dont HAVE AN AGENDA to sell expensive appliances at 5 times the cost either.Only reason I can HONESTLY see for why,or 'I hurt their feelings'......some excuse for sure though.

Hail Energy Star! The working mans efficiency champs.And you can take that to the Bank,literally.Until I hear otherwise and someone can refute that conclusion which AINT HAPPENING,LOL! As we see here all the time,back it up REAL WORLD or it means nothing......

At least as far as I can tell Sundanzer has fallen into just another freezer in the RAPIDLY changing dynamic of appliance efficiency.It certainly isnt 5 times more efficient for 5-6 times the cost.


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## artificer (Feb 26, 2007)

mightybooboo said:


> ...
> And since the dealers wont take up the challenge to print THEIR Real WORLD numbers.....its the best I can give you.Unfortunately thats a very poor report on energy usage.
> 
> But it speaks volumes to me that Sundanzer sellers are silent on their use here.


http://www.sundanzer.com/News_files/HP107.pdf
http://www.sustainablechoice.net/pdf/SunDanzerDCPowered.pdf
http://www.sundanzer.com/Prod_Info_files/SunDanzerProducts.pdf

What more could you want for energy usage?

As for "Real World Numbers," what defines that? They've posted both the no door opening specs, as well as what they consider normal usage. The problem is that its going to vary between people, ambient conditions, and whats in the unit.

I personally prefer our cheap Menards Special chest freezer and inverter. But if I had the money, the Sundanzers are more efficient.



mightybooboo said:


> No Sundanzer real world results? Anyone?
> 
> You got mine,where's yours?


How are you measuring the energy usage? If its using a Kill-a-watt meter, get rid of it and try to get the accumulated energy usage. I don't know of any similar DC energy monitoring devices out there in the sub $25 range. I don't think anyone in this tread has something like it. The silence may not be due to an unwillingness to share their data, but just not worth the effort. They have their freezer/fridge, and know its good. 

If I had one of the sundanzers and wanted to measure the energy usage, I would have to borrow either a data logger or data acquisition system from work. Not everyone has those resources.

Michael


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## Harry Chickpea (Dec 19, 2008)

You pretty much confirmed what I had already discovered via the labels on energystar appliances. There were significant government incentives to create mainstream low energy freezers and refrigerators, and when you get major corporations working on a task like that they have the resources to pull it off. The big issue for off-grid use is the inverter inefficiencies. I suspect the way around that is to use a timer to power a dedicated inverter on about four times a day and have it go off once the load is dropped. An ice bank could hold over the cold in the off periods. If the condenser coils are open on the back, then additional insulation can be added around other areas to give even a tiny bit more efficiency. Mainstream units have to fit within certain physical dimensions, which may be less important in an off-grid situation.

BTW, kill-a-watts do measure accumulated usage. Unless the power factor is way off, they are pretty accurate as well.


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## artificer (Feb 26, 2007)

Harry Chickpea said:


> ...
> The big issue for off-grid use is the inverter inefficiencies. I suspect the way around that is to use a timer to power a dedicated inverter on about four times a day and have it go off once the load is dropped. An ice bank could hold over the cold in the off periods. If the condenser coils are open on the back, then additional insulation can be added around other areas to give even a tiny bit more efficiency. Mainstream units have to fit within certain physical dimensions, which may be less important in an off-grid situation.
> ...


One way to get around inverter standby inefficiencies is to wire the thermostat to the inverter's on/off switch. Instead of the 5-10watts of standby power, it would only use power when the refrigerator needed it. The switch could be in parrallel with the normal power switch. Fridge/freezer turns on the inverter when it needs to, or you manual turn the inverter on/off when you need AC for another load. 



Harry Chickpea said:


> BTW, kill-a-watts do measure accumulated usage. Unless the power factor is way off, they are pretty accurate as well.


I know that. My point was that it really easy to get accumulated power readings for AC power, mainly due to the kill-a-watts. Most people that are concerned about power usage already have one. For DC, however, its a different story. You could wire your battery monitor temporarily up to only the fridge/freezer load, but there goes your power tracking for the duration. Its not a simple unplug cord, plug meter in, plug cord into meter operation.

Michael


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