Energy efficient refrigerators on solar power?

Photowhit · April 2015

cupcake wrote: »

Sustainability is a matter of line and load. If a system has a low load and a high line it will be sustainable.

So you think that he will be able to continually run a 30 watt per hour load on 90 watts panel rating of harbor freight panels on any batteries? continuously? I took batteries out of the equation. and you are harping on the batteries. I said they system is unsustainable, I repeated it. ....removed.....?

cupcake wrote: »

So don't claim what is sustainable or not before considering the weather in that region. People in northern Alaska can do wonders with that midnight sun for instance...

I'd be glad to see your numbers, I showed you mine, I was generous and claimed the harbor freight panels could produce 70 watts, not very likely, I gave 10 hours of charging at 75% with a fixed array (that's pretty much max anywhere) and still what ever battery your pushing the energy into you would consume more energy with a 30 watt + inverter 24/7 load...

cupcake · April 2015

Photowhit wrote: »

So you think that he will be able to continually run a 30 watt per hour load on 90 watts panel rating of harbor freight panels on any batteries? continuously? I took batteries out of the equation. and you are harping on the batteries. I said they system is unsustainable,......[removed]....?

I'd be glad to see your numbers, I showed you mine, I was generous and claimed the harbor freight panels could produce 70 watts, not very likely, I gave 10 hours of charging at 75% with a fixed array (that's pretty much max anywhere) and still what ever battery your pushing the energy into you would consume more energy with a 30 watt + inverter 24/7 load...

Goodbye for now... this forum gets wierd if I hang out on here too long........

Im out...

--CC

South Africa · April 2015

I have this one: http://www.hisense.co.za/allrefrigerators/index.asp?appCat=2
154kwh per year, runs beautifully on a 1600va inverter that powers other loads also.

softdown · April 2015

Disconnected the gel bank yesterday afternoon trying to isolate the problem. Early morning voltage readings:
8D bank: 12.1 volts
Gel bank: 12.9 volts
Off grid refrigerators should probably be around 300 KwH or lower if possible. Pretty big battery drain overnight. Won't be able to use the fridge this winter. But I don't need a fridge during the winter.

BB...I asked the voltage max charge to be 14.2 x 4 based on your recommendation. So.....56.8 volts. Installer said "Lets go lower." I think we settled on 56.2 volts. I am wondering if this is substantially hampering the recharge rate of the batteries.

softdown · April 2015

That link takes one to a page showing a variety of units.

South Africa wrote: »

I have this one: http://www.hisense.co.za/allrefrigerators/index.asp?appCat=2
154kwh per year, runs beautifully on a 1600va inverter that powers other loads also.

softdown · April 2015

They give a Tier 1 rating to a 19 cubic foot fridge that uses 590 KwH/year. Not impressed. 590 were good numbers....a dozen years ago.

http://library.cee1.org/sites/default/files/library/9349/2015_April_CEE_ResidentialRefrigerator.pdf

westbranch wrote: »

not sure I saw this rating table listed http://library.cee1.org/content/qual...-refrigerators

BB. · April 2015

It is all about getting current into the batteries. GEL and AGM have lower internal resistance (in general), so lower charging voltages can be OK and helpful (keep the batteries from gassing).

When you drop the voltage that low on the GEL, what is your charging current like?

In general, GEL (at least in the US) are very sensitive to high charging current (and, I presume, high charging voltages where the GEL gets permanent gas bubbles). And if you use C/20 (5%) charging current, you may run out of hours of sun before you can recharge a significantly discharged battery bank (take a few days to recharge fully).

I am not a battery engineer--Reading the manuals and talking with the mfg's engineers/support people is the place to start.

Do you have two different types (GEL, flooded cell or AGM) banks in parallel on the same charge controller?

The 8D bank is significantly discharged. The GEL bank is pretty near fully charged (I am guessing).

-Bill

softdown · April 2015

Yes....the 8D flooded bank is parallel with the Gel bank. Clearly less than ideal but only have one CC. Having a few days experience with 48 volt systems, I'm not quite ready for multiple CCs.

Perhaps I have no real choice.

For now, maybe I should disconnect the Gel bank and up the charging voltage to ~ 61-62 volts? With two more 8Ds, I can build a second bank. Next weeks project.

I have already hit a lot of bumps in the solar road. My installer said I did a "perfect job" on my end. So I could have done worse. He only spent four hours here. I did everything I could myself.

I don't think it is hardly possible for one person to know everything about solar installations. Too many subjects rolled into one. Solar seems to have a shining future. So I invested in a very good deal on 4/0 welding cable.

BB. · April 2015

That is probably almost impossible to pull off successfully--GEL+Flooded Cell strings in parallel.

You can get a DC current clamp meter (like this one from Sears) and measure the current flow into each parallel string.

But short of putting in series switches (to switch in/out the different strings) or some sort of large diodes to give you a "voltage drop" for the GEL string during charging--I don't see any good way of doing this.

-Bill

softdown · April 2015

I could maybe handle the large diodes if I knew where to get them. Seems that would be easier than another charge controller for the Gels.

Edit: It appears that standard voltage reducing diodes deal with standard voltages: 48 to 36 volts, 24 to 12 volts, 12 volts to 6 volts etc.

Don't have the best feeling about a neophyte like me finding and installing diodes that will drop the voltage by ~ six volts.

Edit: It would seem that a separate charge controller for the gels is the real solution. Maybe dedicate six panels to the gels. Twelve panels to the 8Ds?

BB. · April 2015

www.digikey.com is a large supplier... But, I would be very hesitant to recommend that you use diodes for voltage drops to charge your GELs (not a trivial piece of engineering work)... Of course, you then have the issue that the GEL battery is isolated from your loads--And then you would need a switch or relay to bypass the diodes for operation (if you are paralleling the Flooded + GEL batteries to drive one load).

-Bill

softdown · April 2015

So.....a second charge controller dedicated to the gels then? I went into my controller and boosted charging voltage to 57.4....the recommended voltage for charging AGMs and Gels according to Outback.

You know....being hit with a major problem after a couple days is kind of hard on the psyche. Getting it all operational was like giving birth. It is downright complicated to the average guy.

Somewhat cloudy weather and a new fridge serve as complications. Sometimes I think it is sunny....then I will think it is cloudy.

Clearly it takes over a week to gain competence with a new 48 volt system.....haha.

BB. · April 2015

Can you run this as two separate banks (two inverter, two seperate loads, etc.?). That would be the right way to do it.

Otherwise, I would try to sell one bank (ideally, the GEL bank) and either get a second bank or just run on the one bank if you can keep it above 50% state of charge most of the time.

Mixing battery types--Almost impossible to do it "right" and "cost effectively". They are just too different (where fractions of a volt matter).

-Bill

softdown · April 2015

Ouch....
Selling the gels would be tough for a couple reasons. Sparsely populated mountain valley. Very hard to sell stuff in a market this small with distances this great. Gels are now three years old though their self discharge rate is almost non-existent. Probably at least $300 batteries (that was my quote for similar gels) that I doubt that I would get $75/each for. Who wants telecommunication tower batteries? They are deep cycle. The giant question is about appropriate charging rates.

The gels were bought from a solar supplier who quit carrying them because he found they were not good solar batteries. Imagine that. I am not the original buyer by the way.

So yea...getting a charge controller and using my old MSW inverter for fridge (biggest load by far) does seem to make sense. After I gulped a dozen times...

Photowhit · April 2015

Might look at replacing your system batteries while the tax credit is available, that should lighten the burden somewhat, hate to have you run a patched up system until 2017 only to miss out.

...but I always try to use batteries until they are pretty much dead, or I would have had much more A/C for 3 summers, living on the remaining life of my golf cart batteries.

westbranch · April 2015

South Africa wrote: »

I have this one: http://www.hisense.co.za/allrefrigerators/index.asp?appCat=2
154kwh per year, runs beautifully on a 1600va inverter that powers other loads also.

Which model? I see they are available locally in Canada..

animatt · April 2015

I know thread is drifting to battery talk. But on original topic. People may want to look into inverter based refrigerators. I have one by pure accident(wife purchased). I have used it with a suresine inverter(300w) it does not have any surge. it is a soft start thing. It is only the smaller side. something like 13cf. i am sure a 200w inverter could power the refrigerator. getting rid of surges is something i think has some real benefits.

westbranch · April 2015

animatt wrote: »

I have one by pure accident(wife purchased). I have used it with a suresine inverter(300w)

Which model? Enquiring minds would like to know8)

animatt · April 2015

I am currently roughly 200 miles from it. I have posted here before about it(HERE) . A little bit. I think I even included a model number. I will look back in my other posts.
It did not have a terribly high PF around .7 if I remember correctly. but at about 130w peak does not make much of a difference.
i am in mexico . but only costs about $500 usd at the time of purchase. currently it would be less due to differences in exchange rates. I have the smaller size. around 13cf. here they range up to about 22cf if i remember correctly. I seen them in various stores here including home depot.

Last thanksgiving I was in atlanta and did see some larger units in LOWES . I do not think it is terribly more efficient. but it does not have any surge which is nice. first wakes up electronics. then shortly after power consumption starts to climb slowly. if i remember correctly climbs to about 130w on my model. then slowly drifts back down.

I would imagine it would be similiar controls for most inverter refrigerators but that would have to be verified. I have seen inverter refridgerators in LG, SAMSUNG and I Believe panasonic but not sure.
Anyway will update here later.

animatt · April 2015

http://forum.solar-electric.com/forum/solar-electric-power-wind-power-balance-of-system/off-grid-solar-battery-systems/23373-suresine-running-unmodified-refridgerator-inverter

westbranch · April 2015

Thanks, I could only get a Google hit for the the latest models.
Ya the North Am. regular inverter fridge type is pretty big and top of the line up here, SWMBO is 'on it' as she wants refrigeration before the real heat starts... last weekend was gorgeous for 3000 ft up, 23*C in the shade and warm breezes, very early this year.

ADD: could not find your exact model

softdown · April 2015

Was worried that SOC was dropping every day and went down to 57% this morning. One sunny day and everything is happy again with SOC currently sitting at 99%. Panels do little to nothing in cloudy weather. Whoo...what a relief. I truly was concerned.

So lets find the ideal solar refrigerators now? Started to examine inverter models and that has died for a bit.

softdown · April 2015

How many years did you squeeze out of your GC batteries? Due to the ease of killing batteries, I am not yet convinced that higher quality solar batteries are a better buy.

Photowhit wrote: »

Might look at replacing your system batteries while the tax credit is available, that should lighten the burden somewhat, hate to have you run a patched up system until 2017 only to miss out.

...but I always try to use batteries until they are pretty much dead, or I would have had much more A/C for 3 summers, living on the remaining life of my golf cart batteries.

softdown · April 2015

Has someone found a fridge greater than ~15 cu ft that uses less than 300 KwH for less than $800 or so? I have been finding very small "solar" refrigerators for well over $1000 so far.

BB. · April 2015

You can go through the Energy Star Website and search:

https://www.energystar.gov/productfinder/product/certified-residential-refrigerators/results?scrollTo=570&search_text=&sort_by=annual_energy_use_kwh_yr&sort_direction=asc&capacity_total_volume_ft3_filter=15+-+17.9&height_in_isopen=&width_in_isopen=&brand_name_isopen=&markets_filter=United+States&page_number=0&lastpage=0

It appears that the lowest US ~16 cuft fridge/freezer is rated for ~344 kWH per year (GE model). There are some refrigerator only models that use ~286 kWH per year (don't know anything about the brand).

-Bill

Dave Angelini · April 2015

BB. wrote: »

You can go through the Energy Star Website and search:

https://www.energystar.gov/productfinder/product/certified-residential-refrigerators/results?scrollTo=570&search_text=&sort_by=annual_energy_use_kwh_yr&sort_direction=asc&capacity_total_volume_ft3_filter=15+-+17.9&height_in_isopen=&width_in_isopen=&brand_name_isopen=&markets_filter=United+States&page_number=0&lastpage=0

It appears that the lowest US ~16 cuft fridge/freezer is rated for ~344 kWH per year (GE model). There are some refrigerator only models that use ~286 kWH per year (don't know anything about the brand).

-Bill

I find it easier to just go to Home Depot or Lowes and search Tier 3 Refrigerators. I find several that are 20 cubic feet range and 350 KWH per year. When you get a model, then just search it for price. Most are around $800.

jonr · April 2015

I'm still looking for a cost effective refrigerator/freezer that can run during the day and then mostly coast for 16 hours by using ice. Such a storage feature would be more important than actual kWH/day draw (panels are cheap, batteries are expensive).

westbranch · April 2015

why not automate the internal temp settings, colder during the day and warmer at night, with the freezer full so the cold mass is maxed out.... might work for you...??

BB. · April 2015

Problem with "coasting" is that you get freezer burn and wilted vegetables, etc...

From my point of view, you want temperatures in a refrigerated environment to be pretty stable. Otherwise, you end up with running "cold" evaporators against "warm" foods. This essentially becomes a freeze drying process. The 'warm food" gives up water vapor to the very cold evaporator coils--Drying out your food.

There are cold plate type refrigeration systems used in sail boats and such... [h=3]Sea Freeze of America - Marine Refrigeration - Cold Plates[/h] I sort of like the idea of using a cold plate type system with water (or other material) as the storage medium.... As long as their is liquid water and ice mixed together, the cooling temperature remains at 32F/0C -- But, since I have never used/experimented with such a system, I do not know if it is really practical or not. Here is one medical fridge that uses a Phase Change Material for cooling:

http://www.sundanzer.com/product_category/medical/

For long term freezing of food, we did have a thread that attempted to answer that question:

http://forum.solar-electric.com/forum/solar-electric-power-wind-power-balance-of-system/energy-use-conservation/302-question-best-freezer-temperature?t=273&pp=10

If you can keep the freezer at 0F or less, you should be OK. If you allow the freezer to "warm up" above 0F, you probably will have loss of food quality.

-Bill

Photowhit · April 2015

softdown wrote: »

How many years did you squeeze out of your GC batteries? Due to the ease of killing batteries, I am not yet convinced that higher quality solar batteries are a better buy.

I think you haven't yet had my speech about golf cart, forklift and solar batteries. Batteries may vary in design, but they don't know what they are hooked up to... We call golf cart batteries that because they are most commonly used as golf cart batteries, same fork lift and floor scrubber (L-16 interestingly L-16's were often called boat batteries where I was in Florida as they were used in commercial fishing boats)

The reason the 'golf cart' batteries are a good value is that they are mass produced, same for fork lift batteries. The batteries don't know what they are hooked up to! The metallurgy is pretty much the same. Car batteries will normally be Lead Calcium, they have excellent long term storage, but poor cycling characteristics, Deep cycle batteries tend to be Lead Antimony, which has much better cycling characteristics.

Solar is catching up, I was surprised recently when someone was suggesting that the HUP1 was the best value in solar batteries, I checked there website for the first time in 3-4years and found that I don't think they have increased their prices in the 10 years or so they have been producing them, and they are getting to be a pretty good deal. The HUP1 is pretty much a 12 volt modular forklift battery for solar. I don't know(or think) the plates are much different from standard forklift batteries, but I think the design has more electrolyte above the plates and perhaps more area below the plates as well. Forklift batteries tend to be maintained daily or at least weekly, while it's normal for solar batteries only to be maintained monthly...

Here's a pretty good paper on batteries, it's amazing that the design varies so much between US and Europe!

My golf cart batteries, the last set I used to completion, I purchased 4 and had them hooked up in series and parallel in a 12 volt system for the first year, I was moving and knew I would switch to a 24volt system, I was living very minimally fans, lights, computer time, a little tv and mp3 music player, and a vcr some. with fans in the summer time, I was pretty much fine on a 2 golf cart battery 12 volt system.

After a year, I moved increasing the array to @1000 watts and used the same 4 batteries, now in series for 24 volts, I used them with a window air conditioner only at night, unless I was away the previous night and the batteries topped out(reached float) early. I ran the A/C 4-5 hours a night in my well insulated cabin, that first summer The batteries had a higher duty cycle, likely 60-70% at least the first couple hours. Likely brought the batteries down to 60% SOC nightly for 8-12 weeks and maybe as low as 40-50% some nights, but our heat comes with sun so I cycled them like that and they worked well through out the summer, In the fall I added a small fridge and 350 watts of panels. I was working within a mile of home and had a fridge there. the next summer I shut off the fridge and was able to run the a/c some during the afternoon directly from the array so likely used less energy(lower duty cycle since the cabin was cooled down). Again in the fall I added another 350 watts, about max for the 4 GC's on a PWM charge controller. I ran the fridge through out the summer the next 2 years.

So 5 years, torturing the batteries during the 4 summers. Please note that the hard cycling isn't as hard on the battery when they don't sit at a low state of charge. I don't know for sure, but suspect one long winter period of no sun for 7-10 days running the battery bank down to 30-40% SOC might be harder than a whole summer of cycling nightly being charged back quickly, though the higher temps of the battery will also shorten the battery life. My batteries have always lived outside.

On the temperature note, CaribouCoot has been able to get 8-9 years or more, out of standard GC batteries, in the wilds of western Canada. I suspect part of the reason is they is they live 6 months out of the year in very cold temps.

Many people here would and have suggested golf cart batteries for your first set. I would unless you will need more capacity than a single string and in most cases 2 strings of these batteries.

On an additional note.iced that the Sam's club GC batteries are now rated at 208 amps hours, I think the set I was referring to was rated at 215 ah.

Energy efficient refrigerators on solar power?

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