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Chest refrigerator article

Discussion in 'Home Power and Microgeneration' started by [email protected], Jul 20, 2005.

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  1. Guest

    Here is an article I came across on a home made chest
    fridge. Note that I said fridge and not freezer

    see link

    http://tinyurl.com/cay4t

    To me this idea has merit

    What's everyone else think?

    Anyone actually using such a device on daily basis?
     
  2. Guest

    To me this idea has merit
    well I thought it was a good idea

    It pointed out to me that the basic shape of an upright
    fridge is flawed cause all the cold air falls out of
    unit when door opened

    A chest design is more like a "bucket". Keeps that
    cold air contained even when top is open
     
  3. samc

    samc Guest

    I agree . this is simply the best energy saving idear I have recently
    herd of . our fridge frezer (80/20 split) uses in 24h 1.95kwh (15-27degc
    amb) . my very next project . thanks Tom Chalko .
    samc
     
  4. Guest

    I agree . this is simply the best energy saving idear I have recently
    So what will you do?

    Build a chest fridge or buy one?
     
  5. Sorry to piggyback; the original post isn't available on my news
    server.

    FYI Backwoods Solar Electric has been advocating this concept and
    selling an external thermostat to do it with for years.

    http://backwoodssolar.com/Catalogpages2/refriger2.htm

    Item R-4E047, just under the Crossley freezer.

    -=s
     
  6. Guest

    I wonder who makes it.

    Tom Chalko says the 2 AAA batteries onwould last "several months."
    They might last longer (the shelf life date of Duracell AAA's for
    sale today is 2011) if they were trickle-charged... 3 months is about
    2000 hours, and the AAA low-current capacity is about 1 Ah, so they
    might last till 2011 if trickle-charged at 1 mA via a simple charge pump
    with a 0.047 uF cap in series with a 3.6 V zener diode to ground...

    Like this:

    0.047 uF
    -------||---------------
    | |
    240 VAC - 3.6 V --- 3 V
    50 Hz ^ -
    | |
    ------------------------

    1 mA = 50C2x240 makes C = 0.04 x 10^-6.

    The zener vs plain diode would avoid harming the load
    if the battery is removed with the power on.

    Nick
     
  7. wmbjk

    wmbjk Guest

    Wow, nice project, and well done web site.

    I'm not keen on the chest-fridge idea though. Access to the full
    capacity is going to be awkward, and extra time spent rummaging is
    going to waste some of the benefits of the chest configuration.

    If I understand his reasoning, he's saying that the top door is the
    primary advantage. He also says it only took 2 minutes of run time to
    cool it from room temp to 6C. Disregarding any possible extra leakage
    of a vertical gasket over a horizontal one, it would seem that the
    maximum the horizontal door configuration can save is say, 10 openings
    per day at 2 minutes run-time each. In reality, the savings are likely
    much less. But lets call it 20 openings at an extra runtime of 1
    minute each, perhaps 155 Whrs per day total for a more practical
    vertical configuration, versus 100 for the horizontal layout. About
    $80 in PV to avoid the stooping, rummaging, and enable the practical
    use of shelves. Or perhaps quite a bit more for either arrangement in
    a more typical application.

    I notice at the Backwoods site that they're still marketing fridges by
    using non-standard energy ratings, and claiming that by top-mounting
    the compressor, "no heat goes back into the box". Yet a top-mounted
    compressor doesn't seem to be needed at Mt. Best... I wish vendors
    would stick to publishing the Energy Star ratings instead, in order to
    make comparisons fairer.

    Wayne
     
  8. Guest

    Freezers also have more insulation than fridges. Dr. Chalko says he got
    started on this when he noticed that some chest freezers used less energy
    than some fridges, despite the larger temperature difference.
    That may be a large disregarding.
    Compared to a vertical door...
    Why did you get 155 Wh/day?

    Nick
     
  9. Guest

    Mine is a White-Rodgers type 1609-102 style P1, remote bulb, set-
    point and differential both adjustable.


    Tom Willmon
    near Mountainair, (mid) New Mexico, USA

    Net-Tamer V 1.12.0 - Registered
     
  10. wmbjk

    wmbjk Guest

    Yes, but some fridges have much more insulation than others. I doubt
    that one needs to live with the disadvantages of converting a chest
    freezer to a fridge to get the advantages of better insulation. The
    Vestfrost 255 is normally rated at 610Whrs per day
    www.solarshop.com.au/fridges%20page.htm, which is about the same per
    cubic foot as a fairly standard $800, 22 cu.ft., front opening,
    self-defrosting fridge-freezer.
    Why do you say that? Most gaskets seem to make a pretty good seal, and
    are about the same size on both arrangements. The temp difference
    across either gasket should be similar as well. And we're only talking
    about the sides and bottom of the gasket after all, the top is the
    same for both configurations. ;-)
    Because the two minutes run-time he noted was to take the empty box
    from room temperature to 6C. In normal ops, a fridge is only partly
    empty, and opening a front door doesn't drop the empty portion to room
    temperature.
    He wrote 90 seconds run-time per hour - 36 minutes and 100Whrs per
    day. I imagined the same box tilted on its end, and added a generous
    20 minutes runtime to cover one minute extra for each of 20 openings
    of the now vertical door. If 36 minutes run-time uses 100Whrs per day,
    then 56 minutes needs 155Whrs per day. But if we knew that at Mt. Best
    the fridge is only opened 10 times per day for example, then the
    difference might be even less.

    I'm thinking that at Mt. Best, the low energy consumption of the chest
    fridge might have more to do with the small size, coolish room
    temperatures, and minimal door openings per day, than with the unit's
    configuration. According to this http://tinyurl.com/bp4mu door
    openings (and hence door configuration I would think) only account for
    10% of energy consumption, while an extra 10 degrees F can account for
    40%.

    Anyway, this is getting into a lot of supposing. It would be
    interesting to see a side-by-side comparison of the two
    configurations, with consumption figures quoted for the same
    conditions the Energy Star system uses. A worthwhile project for Home
    Power Magazine or ESSN.

    Wayne
     
  11. Guest

    Anyway, this is getting into a lot of supposing. It would be
    Agreed
     
  12. Guest

    I'm not keen on the chest-fridge idea though. Access to the full
    Couldn't good design help with access in a chest fridge
    tho?
     
  13. wmbjk

    wmbjk Guest

    Air-ride elevating shelves perhaps?
    Articulated parallelogram racks on the underside of the lid?
    Drawers that slide open to the front? ;-)

    Wayne
     
  14. Guest

    Air-ride elevating shelves perhaps?
    Well... something like the above. <G>

    Just seems to me that with some clever engineering it
    could be just as easy to get stuff in and out of a
    chest design as an upright fridge.

    It seems so obvious to me that the chest design has got
    be so much more efficient at keeping that could "in"
    the unit than an upright that access has to be designed
    around it. Rather than efficiency being designed around
    access
     
  15. I don't know about efficiency but drawer fridges/freezers
    seem to be getting popular these days. Why go with a chest
    or upright when you can get one built in under the counter?

    Anthony
     
  16. Dave

    Dave Guest

  17. Guest

    Shelves on rollers that slide left and right as you look at the fridge
    with the lid up might halve the capacity...

    Maybe we need a winch on the ceiling that hauls all the shelves
    up to eye level :)

    Nick
     
  18. Pete C

    Pete C Guest

    How about adding a thin perspex flap across each shelf to keep cold
    air in? They could be bottom hinged with a light magnetic catch or a
    sprung hinge.

    Shouldn't be too tricky to do a mock up with cardboard and measure the
    difference in power consumption.

    cheers,
    Pete.
     
  19. wmbjk

    wmbjk Guest

    I can't think of any practical way to do it, at least not any way that
    would be as good as a front door and shelves. The article mentioned
    removing basket loads of groceries altogether, which would provide
    easier access to the bottom tier(s). But having the door completely
    open, and exposing some of the contents fully to room temperature seem
    like things that might eat away at any efficiency advantage of the
    chest configuration.
    It shouldn't be too hard to test for any efficiency advantage.

    Perhaps a simple test box, built with variable refrigeration component
    mounting, so that the same box could be run in a top-door and a
    front-door configuration. Test both configurations with door closed,
    and with a number of door openings per day. Perhaps test with top and
    bottom compressor mounting as well.

    I'd prefer that someone else did the work, and that I get to comment
    on their methods. <G> But if somebody loaned the refrigeration unit
    (this one should do http://www.novakool.com/remoprnt.pdf), then I'd
    supply the materials for the box and build it. Until the end of
    August, I might even be able to provide an Energy Star compliant 90F
    room. ;-) Testing methodology by the group (within reason).

    Wayne
     
  20. Guest

    Why go with a chest
    Didn't know such a thing existed.

    Do you have a link to one?

    These are fridges that are mounted under cabinet,
    right?
     
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