Domestic Compressor Fridge ..?

Discussion in 'Fridges & Ovens' started by scotjimland, Mar 29, 2009.

  1. scotjimland

    scotjimland Funster Life Member

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    I've had an idea to replace the fridge / freezer with a domestic compressor one.. the question I need to answer is would it be feasible to run it off solar power during the summer.. and when travelling between sites, so how big would the solar panels and battery bank need to be .. ?


    I started off by looking at A rated fridge/freezers, which use around 280kw per year .. = about 75watt per day .. ( Information from manufacturers)

    The reasons for considering this option were

    a) Cheaper to buy
    b) Uses no LPG, (a bonus when off ehu)
    c) Easier to source
    d) One less appliance on 110v
    e) One step closer to self sufficiency

    I appreciate that the cost of solar panels need to be factored in but I was intending to get them anyway ..and already have a 1600watt inverter.


    Opinions , good idea/bad idea.. ?

    tia

    Jim
     
  2. Kon tiki

    Kon tiki Read Only Funster

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    I think this was discussed on the self build motorhome forum, one of the problems I believe is that the domestic fridges are possibly more fragile than a purpose built compressor fridge for use in boats & motorhomes. Maybe if you buy a high quality domestic fridge it would be more robust. So while it would work it might fail mechanically.
     
  3. scotjimland

    scotjimland Funster Life Member

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    Hi ED ..
    I never considered this.. was there a consensus of opinion on SBMCC or was it left as an open question .. ?

    I'll also do a search on SBMCC

    Cheers

    Jim
     
  4. Terry

    Terry Funster

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    Hi Jim I cannot see why not if you have a big enough battery bank and the panels can keep them supplied :thumb:At around a quarter of the price of a 3 way I have thought about them my self :thumb: after all they now do 12v compressor fridges but they are even more expensive than 3 way ones :Rofl1:
    They are not on all the time anyway mainly after opening the door :Rofl1::BigGrin: The only thing that stopped me fitting one in this van was the cost of extra battery's and an inverter (that added up to the cost of the 3 way)but if you already have them then I would say go for it :thumb::thumb:
    terry
     
  5. American Dream

    American Dream Read Only Funster

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    I guess the only negative point I would see there is the noise aspect when the compressor is running Jim.

    If you could live with that, I don't see why not.

    I guess it would run ok off the inverter/batteries while travelling.

    What's the start-up peak current draw of the compressor?
     
    Last edited: Mar 29, 2009
  6. scotjimland

    scotjimland Funster Life Member

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    Edit to first post .. should be 750 watt not 75 watt per day :Doh:
     
    Last edited: Mar 29, 2009
  7. scotjimland

    scotjimland Funster Life Member

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    I don't think noise would be an issue, it won't be in the bedroom.. have you heard the noise from an 8yr old and a puppy running about .. :Laughing:

    Should be fine off the inverter travelling, motor size or current isn't given in the specs .. so don't know what the start current would be .. but fairly sure a 1600watt inverter would cope, but worth checking before committing ..

    Cheers

    Jim
     
  8. American Dream

    American Dream Read Only Funster

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    Yes I was invaded by an 8 year old this morning playing her flute,guitar AND recorder :Rofl1:What puppy is it?

    The girls can certainly make a racket.:RollEyes:

    Just thinking about the surge rating of the inverter.Don't want to damage it.
     
  9. scotjimland

    scotjimland Funster Life Member

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    In the avatar .. Mylo .. a Jack Russell , 10 weeks old and a bundle of mischief :RollEyes:
     
  10. Terry

    Terry Funster

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    :Rofl1: Must be somebody on here who can use one of the digital things and get a read out on how much power a fridge will use :BigGrin: both on start up and running :thumb::thumb:
    I researched a couple of years back and cannot see why it will not work,indeed a friend used to make fridges for ice cream vans but I am not sure if they just cooled overnight on H/U then went all day with the cold ice cream in :Rofl1::Rofl1:
    Fill the fridge with cold things :thumb::thumb:
    They cannot use that much power ???:thumb::Rofl1:
    terry
    PS I also remember reading about someone taking the cooling bits from his fridge and making his own box to fit ?
     
  11. scotjimland

    scotjimland Funster Life Member

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    I recall that discussion, think it was Steve from Hereford .. he used to be on the 'dark side' .. runs his own internet store Motorhome, Caravan & Marine equipment lots of useful stuff and information..
     
  12. Wildman

    Wildman Read Only Funster

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    You don't have a large enough roof area to supply 750W per day allowing for max 25% output in the winter, a wind generator might do it, but then you usually are on site with a hookup, why worry, switched off it will keep cold for several hours when travelling anyway. My panels only supplied a hundreth of the rated output in the winter. However I do seem to remember someone on here using 2 x 130W panels and running a 12v compressor fridge, but then they were in Spain.
     
  13. Terry

    Terry Funster

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    Hi Jim it may well have been :Rofl1: long time ago :Rofl1:
    My mate who does all leccy stuff for me is away for a week or too,but he would know the answers or investigate and find them :Rofl1:
    I will ask him if you do not get the answers before he comes home :thumb:
    I am certain we were going down the domestic route but a 100 ltr 3 way came up for 300 so stopped looking at it :thumb::BigGrin::Rofl1:
    I suppose it would all depend on how much you leave the door open as to how much it would have to work :Rofl1::Rofl1: after all in the event of a power cut they say food will be ok for above 24 hrs before starting defrosting. We or should I say me often forget to switch from 12v to gas for a few hours :Rofl1::Rofl1:
    terry
     
  14. scotjimland

    scotjimland Funster Life Member

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    Hi Roger , thanks for your input , it's good to bounce ideas about :Smile:

    I agree it would be difficult to supply enough solar energy all year round .. as you rightly point out we spend a lot of time on ehu in the winter.. I'm thinking for during the summer in Europe where we spend a lot of time on free aires without ehu ..

    I figured 2 x 120 watt panels coupled to a 720ah battery bank would do it during summer .. and have the genny as a back up..

    It's a big investment .. around £2k but a replacement yank 3 way fridge is over £1k and I want solar panels in any case .. it's not a case of IF but when it needs replacing..

    As full timers it's good sense to cut costs .. and it's a 'green' solution.. even in winter on ehu the solar panels will aid even if they cannot support ..

    Jim
     
  15. Terry

    Terry Funster

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    So do you need or WANT solar panels ?:Rofl1:
    Do you run out of power now ?
    720 amp hr battery's bank I would think is ample to keep you going :Rofl1
    Why not try one and see :Rofl1: you may not need to spend on panels :Rofl1:
    You need to know how much power per day as they seem to average 280/300 kwhrs per year which in my mind is less than 1 kw per day :thumb::Doh: if it was only that simple :Rofl1::Rofl1::cry:
    terry
    edit--- come on Roger you should be able to figure this out and put it in simple terms --- where isPaul when I need him
     
    Last edited: Mar 29, 2009
  16. scotjimland

    scotjimland Funster Life Member

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    It would be hard to justify solar panels of that size as a part timer but full time it makes economic sense ..
    Last season in France I used the genny when not on ehu .. it worked out about €9 a week for petrol .. €36 per month. just to charge batteries, not bad but it is also inconvenient having to stay beside the van while it's charging, not to mention the noise , so yes, I want panels .. and payback would be less than two years ..

    Secondly, if you are paying leccy by the unit, as we will soon be doing, anything that can reduce costs is worthwhile looking at .. having the Owl Wireless monitor has opened my eyes to how much we use and the cost to the site..
    I calculated we were using almost £7 a day .. with site fees of only £8 .. the owner was barely breaking even.. but I digress, :Laughing:..
     
  17. Tony Lee

    Tony Lee Read Only Funster

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    It is probably 750 Watt-Hours per day and converting it to RV-speak for a 12V system, this equates to say 70Ah per day.

    This is roughly comparable to the 12/24VDC compressor fridge I have installed in my Oz BigRig. It is a 220 Litre Waeco compressor fridge.

    Domestic fridges are not regarded as being particularly efficient and the RV dc compressor units are said to use less power. However, in Australia there is a range of domestic fridges that have quite spectacular efficiencies and are intended for use when there is no mains power. Those who have done the sums reckon they are a good alternative to a DC compressor fridge and quite a bit cheaper.
    Big advantage of standard domestic units is they are dirt cheap - say $AU600 compared to my RV dc one at around $AU1800

    Certain things to be aware of. Features such as auto defrost and anticondensation heaters need to be disabled. Some inverters will not start mains fridges. Need to factor in losses in the inverter, especially if it needs to be left on all the time.

    Regardless of what sort of compressor fridge you select - even a very small one - you are moving into a whole different world as far as your electrical supply goes. If the sun doesn't shine for a few days, what are you going to do. Need to allow for some pretty abysmal solar panel collection efficiencies in all of UK and most of northern Europe even in summer and there is no getting around it by buying a bit more gas.

    Depends on your lifestyle of course. While you are moving, your engine alternator will supply all you need to keep the fridge running.

    As an indication - I have 640 watts of panels at 24V and 500+Ah of battery and we can normally go 4 or 5 days without sun before things get critical. We also use a lot of power for computers and microwaves and lighting and if it is cold the Webasto heater runs much of the time.
    The only place I have problems is in Tasmania where the weather can be pretty crappy even in Summer and the sun is lower in the sky as well. An atlas will show how the latitude compares to where you want to operate your system
     
  18. scotjimland

    scotjimland Funster Life Member

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  19. scotjimland

    scotjimland Funster Life Member

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    Since this post I've done some calcs using this site How to choose an electrical solar panel system

    AVERAGE (Four hours Sunshine per day)
    In order to supply 1209 WattHours of energy per day, the panels (which we assume receive 4 hours sunshine in the UK), will need to be rated in total at 1209 divided by 4 = 302 Watts

    So 2 x 150w panels should do the job ..

    Cost £799 Each = £1598 + charge controller aprox £ £1750
     
  20. Terry

    Terry Funster

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    Ahh but have you calculated in has to how efficient the panels will be getting 4 hrs ????
    Roger was doing a thread about reading's from panels :thumb: looked like nowhere close to your calculation :Wink::Rofl1::Rofl1::Rofl1::Sad::cry:
    terry
     
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