Is it necessary to run a refrigerator 24/7.....

K4KMG
K4KMG Solar Expert Posts: 50 ✭✭
....or can it be shut off at night? For how long? On a timer? (full size fridge)
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Comments

  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    Lots of opinions, but basically, yes.

    They don't actually "run" continuously, but run like your air conditioner. A thermostat keeps food in a safe range of temperatures. Cycling times vary with the ambient temperatures of the environment the fridge is in....
    ... the warmer the environment the more they run..

    Freezer conversions, run less since they have more insulation and loose their "cool", slower. Often you buy a thermostat for they that you select the safe range of temperatures, a feature rare in standard fridges.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • K4KMG
    K4KMG Solar Expert Posts: 50 ✭✭
    Thanks. Yes, I'm aware of the freezer conversions. Did quite a few back in the days I was brewing my own beer.
    I'm currently in somewhat of a difficult situation. Had to move rather quickly to my off grid camp. RV fridge is not doing the job. I do have a full size regular fridge available, but my current solar setup is insufficient to add a fridge running 24/7. It will probably take me a month or two to upgrade the solar. In the meantime.........
  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    Vero Beach?

    Might just get a cooler an large blocks of ice (single large blocks of ice, 15lbs or what ever they sell) they will last several days in a good cooler. Likely your cheapest alternative, unless you have an ice cream addiction.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • K4KMG
    K4KMG Solar Expert Posts: 50 ✭✭
    Photowhit wrote: »
    Vero Beach?

    Might just get a cooler an large blocks of ice (single large blocks of ice, 15lbs or what ever they sell) they will last several days in a good cooler. Likely your cheapest alternative, unless you have an ice cream addiction.

    Actually 60 miles W of Vero. (k4kmg.com) This is probably a permanent situation. Yes, ice will get me through till solar is upgraded, but a real PITA!

    Maybe I'll just go get the fridge and see what happens. (140 mi rd trip)
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Consider that bacteria numbers can double every 20 minutes when some foods are allowed to reach room temperature, and also grow somewhat slower if allowed to be above 40F or below 140F, you should consider your health. Is a possible and preventable serious illness or worse, worth the risk to you?
  • K4KMG
    K4KMG Solar Expert Posts: 50 ✭✭
    Consider that bacteria numbers can double every 20 minutes when some foods are allowed to reach room temperature, and also grow somewhat slower if allowed to be above 40F or below 140F, you should consider your health. Is a possible and preventable serious illness or worse, worth the risk to you?

    Thanks. Decided to just leave well enough alone and upgrade solar sys to better handle the addition of my refrigerator.
  • lkruper
    lkruper Solar Expert Posts: 115 ✭✭
    K4KMG wrote: »
    ....or can it be shut off at night? For how long? On a timer? (full size fridge)

    I had the same question for a different reason. I have a generator for emergency backup but would like a battery backup with a small inverter to keep light and electronics on at night and not run the generator all night. My thought process is that the power can go out for maintenance all day and the fridge/freezer stays cold so long as it is not opened frequently. But I do not know if repeating that every day would make a difference. I think 12 hours is enough to bring the temps back down but I have not tested it.
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Some fridges now use an electronic timer for the Defrost Cycle, and when the power is restored, it starts a defrost before it resumes cooling.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Unfortunately the bacteria in food do not respond to the average temperature. They make the most of the highest temperature they see to replicate like mad.
    As long as the highest temperature reached is still low enough for food safety (~38F???) and you do not try to go below 32F on the cold end, you can make on/off cycling work (with the caveat mentioned by Mike about the defrost cycle.)
    Instead of cycling the power on and off you could have two thermostats mounted in the fridge and switch between them based on the time of day. Leaning in the Rube Goldberg direction, but IMHO workable.
    That way you could be sure that excessive door opening or other abnormal use patterns did not let the temp get too high during the setback period.
    SMA SB 3000, old BP panels.
  • K4KMG
    K4KMG Solar Expert Posts: 50 ✭✭
    Thanks all but I've decided not to screw around. Rack for 4 more panels, (picking up panels tomorrow), is about done and ordered a Morningstar Tristar 60 from NAWS. Batteries as soon as cc gets here. Luckily I have a Trojan dealer right down the street from me.
  • lkruper
    lkruper Solar Expert Posts: 115 ✭✭
    inetdog said:
    Unfortunately the bacteria in food do not respond to the average temperature. They make the most of the highest temperature they see to replicate like mad.
    As long as the highest temperature reached is still low enough for food safety (~38F???) and you do not try to go below 32F on the cold end, you can make on/off cycling work (with the caveat mentioned by Mike about the defrost cycle.)
    Instead of cycling the power on and off you could have two thermostats mounted in the fridge and switch between them based on the time of day. Leaning in the Rube Goldberg direction, but IMHO workable.
    That way you could be sure that excessive door opening or other abnormal use patterns did not let the temp get too high during the setback period.
    That's a good point (the average temperature).    What I had in mind was to power during the day with the generator and  switch to a small battery bank at night to keep electronics on.    Since it is at night, I don't plan on opening it.    Also, in my case this would only happen if utility power failed and was not restored within one day, not a case of an ongoing practice.  
  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭

    I was messing with my 2013 Kenmore full size normal fridge today, putting it on inverter/battery power and then intentionally left it unplugged for 3 hours. I put the flir on the inside contents after it had been off for 3 hours. The walls of the fridge were showing 40'F, the non reflective contents were showing between 33'F and 34'F.

    In the freezer the ice was just starting to get a little wet.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • lkruper
    lkruper Solar Expert Posts: 115 ✭✭
    oil pan 4 said:

    I was messing with my 2013 Kenmore full size normal fridge today, putting it on inverter/battery power and then intentionally left it unplugged for 3 hours. I put the flir on the inside contents after it had been off for 3 hours. The walls of the fridge were showing 40'F, the non reflective contents were showing between 33'F and 34'F.

    In the freezer the ice was just starting to get a little wet.


    I just got a Frigidaire model that is supposed to work in an unheated garage or basement and had it installed in an unheated area.   To work in cold weather they suggest setting the freezer to as low as possible.  I think mine reads about 5 degrees.   I wonder if starting out at a colder temperature would extend the time it can be unpowered.
  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
    lkruper said:
    oil pan 4 said:

    I was messing with my 2013 Kenmore full size normal fridge today, putting it on inverter/battery power and then intentionally left it unplugged for 3 hours. I put the flir on the inside contents after it had been off for 3 hours. The walls of the fridge were showing 40'F, the non reflective contents were showing between 33'F and 34'F.

    In the freezer the ice was just starting to get a little wet.


    I just got a Frigidaire model that is supposed to work in an unheated garage or basement and had it installed in an unheated area.   To work in cold weather they suggest setting the freezer to as low as possible.  I think mine reads about 5 degrees.   I wonder if starting out at a colder temperature would extend the time it can be unpowered.

    When ever there was a bad line of thunder storms moving through or when I lived on the east coast and there was an incoming tropical storm or hurricane my parents would always turn the fridge down to its lowest settings. If the power went out, the fridge would be colder when the power went out. Making it take that much longer for the food to reach the food temperature danger zone.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • hooperv
    hooperv Registered Users Posts: 1
    I'm new here I hope I do this right.
     Okey so I planned to run a mini fridge in my van. It has a proper separate freezer.
     I was thinking of running it off of the solar during the day while freezing a bunch of 16 oz bottles of water. Then shutting it off at night after moving all the frozen bottles of water to the fridge section and placing them in and around any food. In effect using it like a cooler. The door would be closed all night.
     Any thoughts from anyone?
  • bill von novak
    bill von novak Solar Expert Posts: 891 ✭✭✭✭
    K4KMG said:
    ....or can it be shut off at night? For how long? On a timer? (full size fridge)
    Sure.  I can shut down the fridge in my garage for 4 hours at a time with no ill effects.  There are refrigerators out there (often called DC vaccine refrigerators) that contain eutetic salts, so as long as they run about 4 hours a day they stay cold all the time. 
  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
    edited September 2015 #18
     
    hooperv said:
    I'm new here I hope I do this right.
     Okey so I planned to run a mini fridge in my van. It has a proper separate freezer.
     I was thinking of running it off of the solar during the day while freezing a bunch of 16 oz bottles of water. Then shutting it off at night after moving all the frozen bottles of water to the fridge section and placing them in and around any food. In effect using it like a cooler. The door would be closed all night.
     Any thoughts from anyone?

    I think the frozen bottles of water would last afew days before all the ice was gone.

    Search "Insulin refrigerator" on the old evilbay to see examples.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • lkruper
    lkruper Solar Expert Posts: 115 ✭✭
    hooperv said:
    I'm new here I hope I do this right.
     Okey so I planned to run a mini fridge in my van. It has a proper separate freezer.
     I was thinking of running it off of the solar during the day while freezing a bunch of 16 oz bottles of water. Then shutting it off at night after moving all the frozen bottles of water to the fridge section and placing them in and around any food. In effect using it like a cooler. The door would be closed all night.
     Any thoughts from anyone?

    When you say "off the solar", do you mean to run without a battery bank?   There are AC/DC fridges like Engel, ARB, and others than can run directly from a battery without an inverter, but I don't think even they will run directly from solar panels.   A conventional AC mini-fridge (eg dorm style) fridge will also need to be able to handle a surge when the compressor starts up.

    Also, if you are driving the van for any length of time, you will be able to power the fridge from your alternator and get a whole lot more power that way than from solar panels.





  • peakbagger
    peakbagger Solar Expert Posts: 341 ✭✭✭
    There reusable freezer packs that contain a liquid that freezes at a lower temperature that will extend the period of time a freezer can be unplugged. I think Sundanzer offered an solar refrigerator that was lined with these freezer packs to compensate for periods of low light.
  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
     

    Here is one guy that turned his fridge off for 6 hours at night.

    http://ecorenovator.org/forum/appliances-gadgets/1448-test-results-power-savings-timer-fridge.html


    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • cupcake
    cupcake Solar Expert Posts: 254 ✭✭✭
    look into inverter-compressor fridges.. times are changing and the DC motor is gonna run appliances now...

    mah washer is a DC invertery motor type... DC motor ceiling fans are alreay here, and DC fridges are here and more are coming...
    this means no more surge... a variable speed.. and more efficency...

    again, research DC INVERTER MOTORS ...


    ~1.5Kw PV in parallel
    Morningstar MPPT-60 controllers (2) in parallel
    3 Trojan tr-1275's in parallel 450ah total
    Samlex 2,000 watt 12-volt inverter hardwired


  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    cupcake said:

    mah washer is a DC invertery motor type... DC motor ceiling fans are alreay here, and DC fridges are here and more are coming...
    this means no more surge... a variable speed.. and more efficency...

    again, research DC INVERTER MOTORS ...
    At least in the case of the washer, it also means that it can use a direct drive motor with lots of poles around the circumference, eliminating the need for a multispeed gearbox and belts.
    SMA SB 3000, old BP panels.
  • zoneblue
    zoneblue Solar Expert Posts: 1,220 ✭✭✭✭
    They also now makeoff the shelf RV slash marine fridges that have built in salt packs. When the fridge detects its running on engine/solar it super cools the packs, then when the voltage drops, it turns the compressor way down.
    It oughtnt be hard to do something like that with an arduino or something if yoru the DIY type.
    1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,
    http://zoneblue.org/cms/page.php?view=off-grid-solar


  • 2twisty
    2twisty Solar Expert Posts: 199 ✭✭✭
    I have my regular fridge on a timer.. Off at 11PM and on again at 6AM.  NO troubles at all.

    Make sure you have enough thermal mass in the fridge.  I put a few gallons of water in the top to act as a thermal battery. 

    I also have a chest freezer that I turn off at 10 and back on again at 8.  The stuff at the top of the freezer can get a little soft, so as long as you put stuff on the top that can handle some minor thawing and refreezing, there's no real problem there, either.  Saves me enormous amounts of power this way.
  • Trickle Charge
    Trickle Charge Solar Expert Posts: 28
    I had to buy a new fridge when I went off-grid.  Ended up getting a Whirlpool that was EEE Tier 3 rated with a top freezer.  Top freezers use 20% less power for some reason.  It uses approx. 1.8 kWh/day. 
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
      Top freezers use 20% less power for some reason.
    Better insulation and better air sealing have something to do with it.
    SMA SB 3000, old BP panels.
  • K4KMG
    K4KMG Solar Expert Posts: 50 ✭✭
    2twisty said:
    I have my regular fridge on a timer.. Off at 11PM and on again at 6AM.  NO troubles at all.

    Perfect. Just what I needed to know. Thanks

  • Trickle Charge
    Trickle Charge Solar Expert Posts: 28
    K4KMG said:
    2twisty said:
    I have my regular fridge on a timer.. Off at 11PM and on again at 6AM.  NO troubles at all.

    Perfect. Just what I needed to know. Thanks

    Isn't it just going to use up as much or more power during the day to make up for the temp loss overnight?  My freezer works harder when I put stuff in it as opposed to when it just maintains a temp.
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    edited October 2015 #30
    I had to buy a new fridge when I went off-grid.  Ended up getting a Whirlpool that was EEE Tier 3 rated with a top freezer.  Top freezers use 20% less power for some reason.  It uses approx. 1.8 kWh/day. 
    We got this model in May,  GE Model GTE18GMHDRES 319 kWh Canada/ 358kWh US  and it uses about 60-75% of the 319kWh per year in the summer 75% = ~ 240KwH/YR / 365 =~ 656 W/day
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    summertime, my freezer in the garage runs 24/7, but in winter, I put it on a timer, and shut it off 2am - 9am, to save the batteries a bit.  Last year we had 4 or 5 cloudy weeks in a row, lots of generator run time.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,