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    • CommentAuthorWoo
    • CommentTimeSep 18th 2017
     
    House runs off 3kW of wind power, via a battery and inverter-charger, plus backup generator.

    Now starting to look at connecting stuff to this shiny system (currently only have sockets and LED lights). The major criteria for the fridge are :
    - as low as possible starting/peak load
    - as high as possible energy efficiency

    However:
    Are there any particular considerations for a fridge in a room with UFH?
    Are "tower" fridge-freezers more efficient than a separate fridge and chest freezer?
    What else should I be thinking about?
    • CommentAuthorBeau
    • CommentTimeSep 18th 2017 edited
     
    Last time we looked into fridges Liebherr were the most energy efficient according to sustit.net and it's what we bought but dont know what the start loads are like. We didn't put any UFH pipes in the floor where the fridge sits. We went for a chest freezer as we need a large freezing area and it just seems logical to not have an upright where all the cold air floods out every time the doors open.
    • CommentAuthortony
    • CommentTimeSep 18th 2017
     
    How about a cold press, larder or cool store as an alternative to a fridge? Even an Ice House.

    I would have the heat pipes bit outside during the summer and indoors during the winter and vica versa for the Fridge/freezer.

    Minimise requirement must be the starting point.
    •  
      CommentAuthorSteamyTea
    • CommentTimeSep 18th 2017 edited
     
    Posted By: tonyI would have the heat pipes bit outside during the summer
    What, in 30°C air temperatures?

    I have a small fridge, cost 110 quid from Currys and pulls about 500W when it starts up for about a second.
    Then pulls around 80W.
    I don't know much about fridge pump sizing and how it relates to the volume of the fridge, but you could take a power meter into a shop and ask them to plug it in and watch the readings.
    • CommentAuthorWoo
    • CommentTimeSep 19th 2017
     
    Not sure I understand what you mean, Tony, about the "heat pipes bit". It's early :)

    The intention is to have a larder with a cold shelf if possible in the kitchen, so I'm talking about a small fridge only. There's only two of us an we don't need anything bigger.

    We're in Orkney so summer is a relative term... since we had the house we've just kept any fresh goods in the unheated back room and that's been OK - however with increasing insulation and draft-proofing that's not really a practical option any more. Plus now we have electricity.

    I saw the Liebherr fridges on the internet and they look pretty good. There's a Zanussi coming out on top on sustit.net at the moment, without a freezer compartment. We have a dog who's fed raw so a chest freezer is pretty much compulsory, so will probably go for that.

    Good idea re. testing them in a shop. I was just going to go round all the neighbours...
    • CommentAuthortony
    • CommentTimeSep 19th 2017
     
    How about a gas fridge?
    • CommentAuthorWoo
    • CommentTimeSep 19th 2017
     
    Thought briefly about it (I work in places where a gas or more often a kerosene fridge is the only option) but rejected it on cost, space, efficiency and fire risk grounds... Anyway the system calculations were done with a fridge in mind so the capacity is there.
    • CommentAuthorBeau
    • CommentTimeSep 19th 2017 edited
     
    Posted By: Woo

    I saw the Liebherr fridges on the internet and they look pretty good. There's a Zanussi coming out on top on sustit.net at the moment, without a freezer compartment. We have a dog who's fed raw so a chest freezer is pretty much compulsory, so will probably go for that.



    Happy to plug ours into an energy meter to see what it uses in real world testing if that would help. Got a Liebherr chest freezer coming in the next few days so could get some real world numbers for that as well.
    • CommentAuthorWoo
    • CommentTimeSep 19th 2017
     
    Beau, that would be super helpful. Thank you.
    • CommentAuthorBeau
    • CommentTimeSep 19th 2017
     
    Posted By: WooBeau, that would be super helpful. Thank you.


    OK meter is on starting at 13.00 on the 19th
    •  
      CommentAuthorSteamyTea
    • CommentTimeSep 19th 2017 edited
     
    Posted By: BeauOK meter is on starting at 13.00 on the 19th
    Make a reading of the peak start up load and the running load. Accumulated kWh is not that much use if the off grid system cannot handle it.

    Quick look at some old night time data and this is what my fridge does.
    Peak is 745W during 1 6 second sampling period.
      Fridge Power.jpg
    • CommentAuthorBeau
    • CommentTimeSep 19th 2017 edited
     
    Posted By: SteamyTea
    Posted By: BeauOK meter is on starting at 13.00 on the 19th
    Make a reading of the peak start up load and the running load. Accumulated kWh is not that much use if the off grid system cannot handle it.

      http:///newforum/extensions/InlineImages/image.php?AttachmentID=6833" alt="Fridge Power.jpg" >


    Not sure my plug in gizmo will do that but will check.
    •  
      CommentAuthorSteamyTea
    • CommentTimeSep 19th 2017
     
    Keep it on the instantaneous reading i.e. watts or kW, then turn the fridge on (or up a bit, which is really down).
    Keep an eye on the meter and see what the figures say as it kicks in and after running for a few seconds. Only got to do it a few times to get an idea.
    • CommentAuthorWoo
    • CommentTimeSep 20th 2017
     
    Wow, you guys are great. The system can handle the startup load for our wood pellet boiler and the vacuum pellet-feed system, so I don't imagine it would have a problem managing 800W for a few seconds. Still, best to minimise where possible.
    Looking forward to seeing the results for the Liebherr...
    • CommentAuthorMHicks
    • CommentTimeSep 20th 2017
     
    I've got a Leibherr TP 1720 fridge on an off-grid system. We had it running on a 350W Victron inverter for a long time which was usually fine, it tripped it occasionally if the 120W electric blanket was also on!

    I've watched the meter when it starts and the peak load is between 300 and 350W.
    • CommentAuthorWoo
    • CommentTimeSep 20th 2017
     
    MHicks, brilliant. Exactly the kind of information that's super-useful. Are you off-grid by choice or by necessity?

    We're a long way away from having the kitchen finished (but at least we've evolved from old doors laid across breezeblocks :bigsmile:) but I think one of the undercounter Liebherr fridges plus a chest freezer could be just the ticket. Have to think more about size, probably.

    Might get a cheap 2nd-hand freezer to see us through Christmas (the unheated back room will be fine in winter as a fridge) and look at making some investments in the new year.

    We hope to add a couple of kW of solar PV to the house setup next year, too...
    •  
      CommentAuthorSteamyTea
    • CommentTimeSep 21st 2017
     
    Just had this in my news feed:
    http://www.bbc.co.uk/news/business-41336234
    Seems Which wants us to stop buying half the fridges on the market.
    •  
      CommentAuthordjh
    • CommentTimeSep 21st 2017
     
    Posted By: SteamyTeaJust had this in my news feed:
    http://www.bbc.co.uk/news/business-41336234
    Seems Which wants us to stop buying half the fridges on the market.

    The story says Which are backing up a recommendation by the London Fire Brigade so I'd tend to trust them rather than a manufacturers organization. Besides, they say:

    "all the models made by Beko, Bosch, Grundig, LG, Miele, Samsung and Siemens were fully protected"

    and that seems like a fairly good selection of brands to choose from. Of relevance to this thread, in the full list that is linked to, all the Liebherr models listed are OK as well. Perhaps there are others.
    • CommentAuthorgravelld
    • CommentTimeSep 22nd 2017
     
    Liebherr make great fridges. My wine fridge (storage, not serving) is a Liebherr, just whispers away.
    • CommentAuthorMHicks
    • CommentTimeSep 22nd 2017
     
    Posted By: WooMHicks, brilliant. Exactly the kind of information that's super-useful. Are you off-grid by choice or by necessity?


    No prob.

    Our plot is half a mile away from the nearest pole, connection was going to be well in excess of £20k (that was quoted 9 years ago). We moved here after a few very much off-grid years on a boat, it didn't seem like a big deal to stay off grid and offered independance, an interesting challenge and less mail.
    • CommentAuthoralexc
    • CommentTimeSep 22nd 2017
     
    Perhaps not useful but,
    We have a one year old Liebheer, parents in law the equivalent Bosch:Its amazing how long things stay fresh in them. I grew up with a real larder. I think with these modern devices with the stay fresh areas tech has caught up with old fashioned knowho. Just costs 40 euros a year.
    I you look at the triple star chest freezers they say they can go for 55 hours plus without power. So off grid freezer must be possible now. But the open the door fridge, even these the triple A ++ turn on after the door is opened too much.
    • CommentAuthorgoodevans
    • CommentTimeSep 22nd 2017
     
    For an off grid system like this it seems like a small battery/monster capacitor with a suitable inverter/charger would help get over the peaks from motor starts such as fridges - capacity is not the issue in your case just peek load for a few seconds so capacitor storage may be ideal to get the short term high discharge and inevitable high cycle count. I have no idea if such a system exists tho.
    • CommentAuthorBeau
    • CommentTimeSep 23rd 2017 edited
     
    Posted By: Beau
    Posted By: WooBeau, that would be super helpful. Thank you.


    OK meter is on starting at 13.00 on the 19th


    13.00 on the 23rd. 486 watts total used. Start load as best as I can see is 272 watts. Standby is just 0.2 watt

    The freezer has arrived and settled down with it's new load so will put the meter on that next. Started at 14.00 on the 23rd
    •  
      CommentAuthorSteamyTea
    • CommentTimeSep 23rd 2017 edited
     
    Posted By: Beau486 watts total used
    Should that be Wh?
    • CommentAuthorBeau
    • CommentTimeSep 23rd 2017 edited
     
    <blockquote><cite>Posted By: SteamyTea</cite><blockquote><cite>Posted By: Beau</cite>486 watts total used</blockquote>Should that be Wh?</blockquote>

    Oh I dont know Nick. I never remember the terminology but it's a less than the spec says. http://www.appliancecity.co.uk/liebherr/fridges-and-freezers/tp1760/product-16275//?gclid=CjwKCAjwjJjOBRBVEiwAfvnvBJ3EDgzNHI1uhhu23ZFuGASbNYQLBfX0N3vOSon49an1VX4B3pphwBoCpq8QAvD_BwE which has it as 64 kWh and looks like it uses 44.35 kWh for us but only two of us here so maybe opened more often with a large family.
    •  
      CommentAuthorSteamyTea
    • CommentTimeSep 23rd 2017
     
    Right
    Think of it as how fast your car goes, say an average of 30 MPH, and then how long your journey is, say 2 hours.
    You have travelled 60 miles.

    So 64 kWh/year, divided by 8760 hours (in a year) is a mean of 7.3 W.
    Or
    64 kWh/year divided by 365.25 days = 175 Wh/day

    So you started reading at 13:00 on the 19th and finished at 13:00 on the 23rd.
    It used 846 Wh, so divide by 4 days, 211.5 Wh/day, slightly worse than the quoted figures.
    • CommentAuthormarktime
    • CommentTimeSep 23rd 2017
     
    Oops! Nick. 486/4 = 121.5 Wh/day so Beau is being prudent when using the fridge.
    •  
      CommentAuthorSteamyTea
    • CommentTimeSep 23rd 2017
     
    Yes sorry, forgot which figures I was referring too.
    Purely as an aside, the usage will change depending on the internal temperature of both the house and the fridge.
    • CommentAuthorBeau
    • CommentTimeSep 27th 2017
     
    Posted By: Beau

    The freezer has arrived and settled down with it's new load so will put the meter on that next. Started at 14.00 on the 23rd


    At 18.00 on the 27th the freezer is reading 1.163 kWh. I make that 0.28 kWh a day
    • CommentAuthorWoo
    • CommentTimeOct 2nd 2017
     
    Thanks guys. All good stuff for future fridge purposes. Our inverter has good capacity for handling peak loads - it's just the combination of peak loads that needs to be managed :smile:
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