inverter based refrigerator for smaller inverters.

animatt · February 2014

Wife picked up an inverter based refridgerator. Kind of on the small side and probably more prone to fail but it is already bought. I plugged it into a kill-a-watt meter. First meter inched up to 1watt then after a few seconds it read like 35 watts. From there it slowly increased and leveled at 130ish watts. The most i have see it consume is 142w. Supposedly defrost is 140w as well. Pf on lower consumption was around .6 but at max observed load was right around .7.

I have not read about inverter based refridgerators, but was thinking they do not surge, kind of like the air conditioners. If that is the case i am suprised i have not heard more about them for offgrid use.

Seems like a good match for the morningstar 300w inverter that is more plug and play.

I have only measured with kill-a-watt meter and do not have anything to measure peak. Power consumption behavior is different than the other fridgerators i normally measure. They usually start high then consumption settles down. Obviously i still do not see the peak but based on observations the inverter type refridgerator may help with small inverters.

Thoughts and comments? Also sorry for any typos this is posted from a cell phone.

Sun Dog · February 2014

Re: inverter based refridgerator for smaller inverters.

Interesting, could you pass along the make and model?

animatt · February 2014

Re: inverter based refridgerator for smaller inverters.

Samsung
RT32FARLDWW
270kwh/ year.

My question was more about inverter fridges in general.

Sun Dog · February 2014

Re: inverter based refridgerator for smaller inverters.

Understood, I would like to learn more about these as well. The website I just looked at showed a wind turbine in the picture with the refrigerator

animatt · February 2014

Re: inverter based refridgerator for smaller inverters.

I bought in mexico but have seen inverter refridges before in other places.

Blackcherry04 · February 2014

Re: inverter based refridgerator for smaller inverters.

Best link I could find. Doubt it's imported to the USA .... Road Trip to mexico anyone ?

http://translate.google.com/translate?hl=en&sl=es&u=http://www.samsung.com/mx/consumer/white-goods/refrigerators/top-mount/RT32FARLDWW/EM&prev=/search%3Fq%3DSamsung%2BRT32FARLDWW%26client%3Dfirefox-a%26hs%3DZ0O%26rls%3Dorg.mozilla:en-US:official%26channel%3Drcs

animatt · February 2014

Re: inverter based refridgerator for smaller inverters.

http://www.panasonic.com/my/consumer/kitchen-appliances/refrigerator/inverter-series/nr-by602xs.html

Blackcherry04 · February 2014

Re: inverter based refridgerator for smaller inverters.

animatt wrote: »

http://www.panasonic.com/my/consumer/kitchen-appliances/refrigerator/inverter-series/nr-by602xs.html

The closest place I could find one is "Panasonic Malaysia Online Store "

animatt · February 2014

Re: inverter based refridgerator for smaller inverters.

I know panasonic, lg, and samsung sell inverter refridgerators. I not sure any are available state side. I just assumed they would be available. If they are here in mexico they already made their long trip.

I do not see any documentation about soft starts but that looks like what happens. I am very tempted to get a morningstar inverter and try it out. Also tempted to get a cheap inverter at say autoZone etc. But i am sure they are all msw inverters and i am not going to feed refridgerator that.

Blackcherry04 · February 2014

Re: inverter based refridgerator for smaller inverters.

animatt wrote: »

I know panasonic, lg, and samsung sell inverter refridgerators. I not sure any are available state side. I just assumed they would be available. If they are here in mexico they already made their long trip.

I do not see any documentation about soft starts but that looks like what happens. I am very tempted to get a morningstar inverter and try it out. Also tempted to get a cheap inverter at say autoZone etc. But i am sure they are all msw inverters and i am not going to feed refridgerator that.

They will find there way here sometime as soon as they find there is a market for them. They are a great addition to a big hole in the power savings market, thank 's for the post. I'll be looking for one, the Samsung had a 10 year warranty, that's a plus.

animatt · February 2014

Re: inverter based refridgerator for smaller inverters.

10 year on the compressor. There is a big sticker on the fridge in english (in mexico)that states as much.

not sure what warranty is on the electronics.
My fridge cost about $515 usd. Probably nothing special except the compressor and inverter.

I read the nicer/ bigger fridges have vacuum insulated panels etc. The panasonic econavi line seems nice. Panasonic has another inverter base line that is not econavi as well. There is a thread ( australian) mostly about the panasonics, although not very technical in nature. Thread started in 2012.

Sun Dog · February 2014

Re: inverter based refridgerator for smaller inverters.

Samsung offers 22cuft models with the inverter compressor for the US/Canada markets but I couldn't find anything smaller. Has that same 10 year warranty. I emailed them about the startup surge but no response yet.

animatt · February 2014

Re: inverter based refridgerator for smaller inverters.

I am sure many here would be interested in the answer to that. Please share when you get response.
Be nice to use the 300 watt suresine from morningstar to run a house. The idle consumption of that unit is wonderful. Could do everything for me except microwave and well pump. And i could live with out a microwave. Only would need to use well pump once a week for about 10 minutes.
I have a shurflo 12v pressure pump from a storage tank.

Matthew

DavidOH · February 2014

Re: inverter based refridgerator for smaller inverters.

Interesting indeed. I would want to know that start-up surge. That is something I am working to tame.
Bought a relay and that capacitor to use. http://www.adrive.com/public/GBPFSU/Converting-a-Freezer-to-Start-Up-On-an-Inverter---4pages.pdf
I have a refrigerator so the "conversion" part is irrelevant, but the second part on reducing the surge is.
http://mtbest.net/chest_fridge.html

Sun Dog · February 2014

Re: inverter based refridgerator for smaller inverters.

Nothing yet from Samsung but great links from Ohio Dave, thanks! Have you had any success lowering your surge?

DavidOH · February 2014

Re: inverter based refridgerator for smaller inverters.

Just got the parts in, but the ref has been loaned out. :-) So, no report yet. Got the Watts up on it getting readings for now. I sure hope this works.

Surfpath · February 2014

Re: inverter based refridgerator for smaller inverters.

Just came across this thread and found the discussion useful. The Fridge is probably the 'bottleneck' appliance for most small-system off-gridders who would prefer smaller and more efficient inverters to power their modest loads.

Here is a related article I retrieved from Panasonic on the topic:

http://www.panasonic.com/industrial/includes/pdf/invertercompressors-improvingefficiency.pdf

A couple of excerpts:

Compared to the traditional single speed compressor, the inverter compressor can run at
a number of desired speeds, depending on how the refrigerator is being used by the consumer. This
provides options for quick pull down or freezing, or to run at a very low speed once the cabinet is at a
steady state, thereby significantly reducing energy consumption....
and...
By varying the speed of the inverter compressor, the cooling capacity can be tailored to the cabinet’s
need at that time. For example, if the door is left open for a period of time due to loading of the cabinet,
the compressor can run at a high speed to provide maximum cooling, in some cases possibly more
than what the conventional single speed compressor could deliver. Likewise the compressor can run at gradually
lower speeds as the need for cooling capacity diminishes.
and...
All compressors will cycle on and off based on the temperature level in the cabinet and the cooling
capacity required. An inverter compressor, by running at a low speed, can actually be run for a longer
period of time, but the result would still be reduced energy consumption as the input watts required for
the lower speed operation are much lower.

I wonder if the inverter compressor speed could be manually controlled by the user?

Once maximum cooling periods can be avoided, say by gradually pre-cooling empty fridges before they are filled, or avoiding long cabinet loading times, then constant fridge temps should be possible using less input watts (and thus smaller more efficient inverters).

Makes sense. I believe a lot of folks out there would find this technology useful.

westbranch · February 2014

Re: inverter based refridgerator for smaller inverters.

I'm not so sure I can buy all of that. I can see less 'surge' draw as the motor can be ramped up on startup, but a Watt only has so much energy. Do they have any numbers regarding longer run times with less consumption showing less Watts used or is this just conjecture? or wishful thinking?

animatt · February 2014

Re: inverter based refridgerator for smaller inverters.

Reconstructing a post by ken marsh. New forum i think deleted it:

We have a Sunfrost, purchased about three years ago.
It has two compressors, one for the refrigerator section and one for the freezer section.
The compressors are regular 120 VAC compressors.
It came with two inverters for running on 24 VDC.
We cut the inverters out and run them with the regular inverter at 120 VAC.

I have made several VFD inverter installations with single phase in and three phase out.
They do start at 0 amps.
Current ramps up with motor speed.
There is no starting surge at all.
Typically the VFD with 3P motor will draw about 20% less power than a single phase motor doing the same job.

One caution here, The VFDs do have big capacitors in their input rectifier.
You want to turn the motor on and off with the low voltage control (Voltage supplied by VFD).
You will get a significant surge when cold starting the VFD.
But this only happens once.

animatt · February 2014

Re: inverter based refridgerator for smaller inverters.

Well kind of itching to get a suresine inverter but have to control my spending a bit. Especially if i am not sure new inverter will fit my needs.

But have a purposed test to see if refridgerator actually surges.

Connect an extension to the wall outlet. The extension should have 2 outlets. One for refridgerator another for a light bulb. If refridgerator surges light bulb will shows signs as voltage drop will cause lighting issues.
But what kind of extension would work for up to about 2 amps of power but would make light flicker 5+ amps.

Running a voltage drop calculator would seem i would need.a fair amount of cable. Any ideas

DavidOH · December 2014

Re: inverter based refridgerator for smaller inverters.

DavidOH wrote: »

Interesting indeed. I would want to know that start-up surge. That is something I am working to tame.
Bought a relay and that capacitor to use. http://www.adrive.com/public/GBPFSU/Converting-a-Freezer-to-Start-Up-On-an-Inverter---4pages.pdf
I have a refrigerator so the "conversion" part is irrelevant, but the second part on reducing the surge is.
http://mtbest.net/chest_fridge.html

http://www.adrive.com/public/6P58GP/Converting-a-Freezer-to-Start-Up-On-an-Inverter---4pages.pdf Public file repost.

animatt · December 2014

Re: inverter based refridgerator for smaller inverters.

I did eventually try my refrigerator on a suresine and it did work wonderfully. Started a 1w then slowly ramped up to about 140w if I remember correctly. I did another post on it somewhere.

I was in a Lowe's or home depot in Atlanta this past thanksgiving and. I did see various inverter refrigerators that were large in size.
So there are somewhat friendly offgrid refrigerators in the USA. Efficiency was not terribly different than a normal refrigerator. As insulation is about the same. But not having such large spikes in usage leaves a inverter to be more fully loaded without worrying about tripping it.

DavidOH · December 2014

Re: inverter based refridgerator for smaller inverters.

A got a relay and the capacitor from Arrowhead Electric Company
http://www.carbonbrush.com/

$4.50 30mm 125V motor start capacitor (PMJ30) Packard Motor Start Capacitor 30-36MFD Round 110-125 VAC
$25.00 (19169) Mars II 169 Potential Relay Continuous Coil Voltage-332 Pickup: Minimum-180 Maximum-193 Drop-Out: Maximum-105

Shipping: $7.50 Total $37.00

http://i59.tinypic.com/anh56o.jpg ..... http://i62.tinypic.com/2s8fofq.jpg

Surfpath · December 2014

Re: inverter based refridgerator for smaller inverters.

animatt wrote: »

I did eventually try my refrigerator on a suresine and it did work wonderfully. Started a 1w then slowly ramped up to about 140w if I remember correctly. I did another post on it somewhere.

I was in a Lowe's or home depot in Atlanta this past thanksgiving and. I did see various inverter refrigerators that were large in size.
So there are somewhat friendly offgrid refrigerators in the USA. Efficiency was not terribly different than a normal refrigerator. As insulation is about the same. But not having such large spikes in usage leaves a inverter to be more fully loaded without worrying about tripping it.

Hi,
Here's a video of someone also running an inverter fridge on a 300 watt inverter.

[Aside: however I wondered about the safety of some of what I saw but, hey, it shows that it can be done]

If you could post a similar video showing your kill-a-watt screen as you turn on your fridge that would be neat.

CDN_VT · December 2014

Re: inverter based refridgerator for smaller inverters.

animatt wrote: »

I was in a Lowe's or home depot in Atlanta this past thanksgiving and. I did see various inverter refrigerators that were large in size.
.

Any chance of any part numbers or model #'s OR SKU's for Lowes & HD .
Problem now if you don't have a number , they never made it.

VT

westbranch · December 2014

Re: inverter based refridgerator for smaller inverters.

VT, just compare the .COM sites vs.CA for LG and Samsung, some interesting models there .... but pricey . The inverter types we get are all >$2000

animatt · December 2014

Re: inverter based refridgerator for smaller inverters.

If you could post a similar video showing your kill-a-watt screen as you turn on your fridge that would be neat.

When I did my initial post and testing I did not find those videos. did not see when that video was posted. Anyway I am about 200 miles away from that refrigerator right now.

When I get back over there i will see what I can do. It maybe just a video running from grid power as it is a bit of a pain to setup the inverter.

As to model sku or something similar I do not have a one. I am about 95% sure most were Samsung in brand.

They were more expensive in Usa then here in Mexico though. Although there maybe other factors driving price difference. Different model more insulation etc.

Graham Parkinson · December 2014

Re: inverter based refridgerator for smaller inverters.

Based on quick reading of info in the links on Samsung inverter fridges, they plan to soon make most all of their fridges based on inverter style compressors.

Apparently these do not cycle on and off like the older fridges, rather they keep running all the time and ramp down the rpms to the amount needed to regulate cooling as required.

This makes me wonder if there will be a large penalty, especially for those with larger inverters, from inverters always running at minimum load instead of having the fridge shut down after a run and the inverter going back into search mode?

The increase in always on load losses from the inverter self loads could completely negate the advantages of lower annual power draw from inverter fridges!

animatt · December 2014

Re: inverter based refridgerator for smaller inverters.

I do not see these fridges have dramatically lower energy usage. I see the advantage of eliminating spikes in usage.

You point has some reason to it. But in practice does not hold up to wellBut most refrigerators need power 24x7 and can not be run on search mode anyway. They have timers inside that reset on power outages. When power returns defrost cycle is started. While there are some refrigerator that do not cycle like that, but most need a little bit of electricity to run the brains of the thing anyway. Most have digital thermostats. When Temps varies from set point the thermostat turns on compressor again. But this needs electricity without it could not turn compressor back on.

Refrigerators that do work are those with mechanical thermostat and also have manual defrost cycle. Which is a very limited set of refrigerators.

One thing to note about the inverter refrigerators if using on a small inverter the defrost element must be checkout(size/ wattage). On my small refrigerator it is a small element and works on my sure sine inverter(300w). Not sure if large refrigerators would have higher rated elements.

solar_dave · December 2014

Re: inverter based refridgerator for smaller inverters.

animatt wrote: »

I do not see these fridges have dramatically lower energy usage. I see the advantage of eliminating spikes in usage.

<snip>

I don't know about that, if they are anything like the mini-split AC units they will save power.

animatt · December 2014

Re: inverter based refridgerator for smaller inverters.

I guess I should have worded that a bit differently. Maybe used the word noticeably instead of drastically. air conditioners use how many kwh per day. Easily could have air conditioning loads being 30-50kwh in a house. a 30% decrease in usage would save many kwh. A refrigerator using 1-1.5kwh per day. Saving 30% is not super ground breaking in terms of kwh. It could make the difference on a small 12v system. But a large 48v system would not know the difference.

I could see efficiency in inverter refrigerators probably being used to change refrigerator design just a bit. Maybe less insulation to get more cubic feet refrigerator in a smaller space. Probably keeping efficiency in about the same range but more flexibility in the refrigerator design. probably permit more tightly installed refrigerator (less air space around). Etc.

Higher range would probably benefit from increased efficiency and good insulation levels.

inverter based refrigerator for smaller inverters.

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