LP Fridge for Off Grid Application

chevensteinchevenstein Solar Expert Posts: 100 ✭✭
It's time for me to buy a fridge for my almost complete off grid house and I was thinking that an LP unit would be my best bet. Unfortunately, I know little about the topic (a little about RV fridges and only Internet research about bigger ones). Due to the female factor the fridge has to be vertical (no converted chest freezer) and has to be pretty big.

Suggestions and advice? Is the Diamond 19cu. ft. model any good?

Thanks in advance!
«13

Comments

  • BB.BB. Super Moderators, Administrators Posts: 31,090 admin
    Re: LP Fridge for Off Grid Application

    Have you ruled out a solar PV powered Energy Star Fridge? If you will be using the fridge 9 months or more out of the year, the money saved using a standard electric refrigerator (and no propane charges) should work out to be less expensive.

    Here is thread talking propane fridges. Another thread here. And over here.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarusicarus Solar Expert Posts: 5,400 ✭✭✭✭
    Re: LP Fridge for Off Grid Application

    The question becomes murkier depending on how you are going to use the house. Full time, part time seasonally, weekends?

    The net dollar/energy use numbers come clearer when we know what your use is likely to be.

    In general, the more the fridge is used the more you should steer away from LP and towards a hi-ef compressor fridge.

    Tony
  • farmgirlfarmgirl Registered Users Posts: 5
    Re: LP Fridge for Off Grid Application

    I am very new at this off grid living myself. but I did do some research on refridgerators to figure out the best option for my own circumstances. I have some milk cows and need a reasonable sized refridgerator for keeping milk cool all the time. so I didnt want to get a refridgerator that was too small or a chest style refridgerator. I looked at the Summit and Conserv lines and the Sun Frost (which was ulltimately the most energy efficient, but too much investment upfront). I found an 18cu ft frigidaire that was energy star rated at 383 kwh/year to be my best option. Propane would have been the other option, but I figured if I was going to invest in a solar system I wanted to be able to utilize renewable energy in running my refridgerator, which is my biggest load.
    I have measured my refridgerators energy use with a kill awatt meter and it is using about 1 kwh of energy a day.
    like I said I am very new at all of this, but I did do some research on refridgeationa and thats what I came up with.
  • BB.BB. Super Moderators, Administrators Posts: 31,090 admin
    Re: LP Fridge for Off Grid Application

    If you are putting in "fresh milk" every day--the fridge's power usage will go up as you need to cool the new additions every day.

    Regarding your power needs... Do you need off grid because of local conditions (too far from power lines, too expensive to run lines) or do you "want to go green"?

    In general, if you have utility power, a Grid Tied system would be much better, both in cost and in reducing energy usage.

    Of course, there is the issue that some (many small?) utilities and co-ops' will not accept Grid Tied / Net Meter solar power...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • farmgirlfarmgirl Registered Users Posts: 5
    Re: LP Fridge for Off Grid Application

    fresh milk does not go directly in my refridgerator. I hydro-cool it in ice water right away and then put it into the refridgerator. the energy usage seems to be consistant at approx. 1 kwh a day.
  • icarusicarus Solar Expert Posts: 5,400 ✭✭✭✭
    Re: LP Fridge for Off Grid Application

    The energy use is probably greater if you are using ice water, even though you are cooling the milk faster. (That may be important,, I have no clue) It takes more energy to phase change water into ice (and back into water) than it does to cool plain water. So if you are having to make ice, to cool the milk, you might be better off just cooling the milk. If you have free ice from an ice house then it might make sense. Might you be able to cool the milk with tap/well water that is ~50f and then put it into a fridge. This would cool the milk fairly quickly with no additional energy input.

    Tony

    More on LP fridges later.
  • hillbillyhillbilly Solar Expert Posts: 334 ✭✭
    Re: LP Fridge for Off Grid Application

    Regarding LP refrigerators: I have found that there is a huge range in terms of reliability and efficiency. Having lived with a handful of them over the years (unfortunately don't remember any of the early types), some were a constant pain and hassle, while our current one has been remarkably dependable and very efficient. It's a Sibir of some sort that was salvaged from an old travel trailer, and I believe that it may be more than 30 years old now (?). I have a great fondness for tools and appliances that are reliable, long lasting, and effective and this little fridge just may top my list of all time favorite "things that work". The big issue is that it's not... well... big, I believe it's about 8.5 cu ft. And as I said in the beginning, I've found that not all LP refrigerators work this well. I'm kind of waiting to see how much longer this one will hold out, in some ways I would love an excuse to upgrade to a larger refrigerator (which would be a 110V AC powered Energy Star rated unit), but in many ways I am rooting for the "little guy" to just keep on going... cool and quiet.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: LP Fridge for Off Grid Application

    It's been a long time since I was in the dairy but ...

    Yep; you have to cool the milk quickly. Get it below 40F within an hour or some such, in order to keep the bacteria growth minimal. Hydro-cooling was SOP for dairy farms until the invention of refrigerated bulk tanks.

    As for gas vs. electric refrigerators in general, we had propane when we were at the cabin occasionally and it was fine. As we increased our time there, the propane usage became a major issue so we switched to electric. This required significant investment in solar electric upgrade, but that was useful for other purposes as well. The 'frige cost was well below a propane unit, especially if you consider the cost/capacity ratio.

    Over-all, electric refrigeration is the better deal 'every day' use and propane for 'occasional' use.
  • icarusicarus Solar Expert Posts: 5,400 ✭✭✭✭
    Re: LP Fridge for Off Grid Application

    Here is my take,, at least take one. A I suggested earlier and Ccoot seconded, the more you use a fridge the more a conventional makes sense.

    You can however skew the numbers in favour of an LP if you do a few things. The first is, install a evaporator fan and a condenser fan that are triggered to come on when the condenser coils get warm. This will increase the efficiency considerably. (Cost about $20 for the T-stat, and some junk fans from computers. I run 24vdc off of 12 vdc so they are almost silent.

    Next, add ~2" of styrofoam board on the sides, top of the cabinet. (You can also do the door. You can make it look pretty good if you plan carefully. This will also increase the efficiency and reduce the run time.

    Next, I am a great fan of Dometics. Over the years we have used Servel/dometic fridges, some of which are over 50 years old, and they still run fine. The modern Dometics require 12vdc for the control boards regardless of if they are burning LP or running on 120vac or 12vdc. Because they are electronically controlled, they turn off and on as needed instead of going to low (pilot) flame and as a consequence they burn less gas over time. That said, the electronics can be a bit delicate, but spare control boards are under $100, and the aftermarket boards are very reliable. I keep a spare around just is case.

    I have used other brands including Consuls, Sibiers, and a sister brand to Consul that I can't remember. I have also installed a couple of big full sized units (prospector or pioneer or some darn thing. These were horrible since the cooling units were for smaller fridges and they could never get/or stay cold unless we covered them with blankets!) The Consuls work fine, and the Sibiers were quite good units. I don't know if they are still available.

    Given a choice, for some basic part time, I would by a Dometic Americana series. The largest is still smaller than a conventional fridge, so we often run two at a time during the time of year we are island bound.

    Lp fridges are more expensive than good conventional, and way more expensive than cheap conventionals. You can cut the price by buying GOOD used. The biggest single issue is if they have been run out of level, the cooling unit can be damaged easily. You can buy fridges with damaged cooling units for nothing or next to nothing, and then buy a cooling unit to replace it. They are not too hard to replace. You can also buy used fridges for next to nothing from RV wrecking yards. There are a couple of places that sell rebuilt fridges for about 1/3 the price of new. If you can find a reputable rebuilder/reseller it might make sense. I have bought several over the years with good success.

    So the long and short is, if you are starting from the ground up, and you are going to use it full time, then start with a good energy start conventional and size the solar system accordingly. If you already have a building and system, get a good LP and work to make it more efficient.

    Tony
  • chevensteinchevenstein Solar Expert Posts: 100 ✭✭
    Re: LP Fridge for Off Grid Application

    Wow, what great responses. Thank you all!

    The intended use is full time; this is a full time year round residence where grid power is not cost effective to bring on site. My biggest worry with the large LP fridge is that it will not be able to keep cool effectively and longevity and fuel consumption.

    On the other hand, the idea of expanding the array/adding batteries/running the backup genset more frequently just on account of the fridge bugs the heck out of me. ~1KW HR per day for a good AC electric model still seems like a lot of power to come up with to keep my beer and her foodstuffs cold, is this with the auto-defroster enabled?

    Finally, if we go with this Diamond model, does anyone have experience with them as a company and that product, specifically? (If it was me alone believe me - there'd be a salvaged RV fridge in the kitchen!)
  • chevensteinchevenstein Solar Expert Posts: 100 ✭✭
    Re: LP Fridge for Off Grid Application

    PS - I should add some details of the house's electrical system, the location is upstate NY:

    * 8X Kyocera 135 watt panels
    * 4X Kyocera 130 watt panels (not installed, yet, due to issues with mounts)
    *Magnum 4448 48V 4.4KVA inverter/charger/transfer switch/box of awesomeness (thank you, NAWS!)
    *8X T-105 clone batteries (I plan on replacing these with L-16s when I've successfully used the system long enough to convince myself that I won't wreck a good set of expensive batteries)
    * 7KW LP generator (cheap junk 3600 RPM model, it was on the property when we bought it)
    * Xantrex 40A charge controller plus lots of breakers, fuses, disconnects, and many feet of painstakingly cut, threaded, bent and buried RMC conduit.

    Oh, and my favorite:
    * Two 6" dia. mounting poles, drilled 7' into solid bedrock

    The above system was designed to make at least a few KWH or power every day that the sun shines and to be able to go a day or three on battery (depending on whether we're using the central heating system or not and whether we're talking about the training batteries or the planned L16s). This is more than adequate for us sans-fridge, but adding that 1KWHr/day sink into the picture seems like it will push us deeper into the batteries during sub-optimal weather (which we get a lot of!).
  • BB.BB. Super Moderators, Administrators Posts: 31,090 admin
    Re: LP Fridge for Off Grid Application

    Assuming you are near Chicago, have 1,600 watts of solar panels, fixed mounts, 0.52 derating, using PV Watts website:
    "Station Identification"
    "City:","Chicago"
    "State:","Illinois"
    "Lat (deg N):", 41.78
    "Long (deg W):", 87.75
    "Elev (m): ", 190
    "PV System Specifications"
    "DC Rating:"," 1.6 kW"
    "DC to AC Derate Factor:"," 0.520"
    "AC Rating:"," 0.8 kW"
    "Array Type: Fixed Tilt"
    "Array Tilt:"," 42.0"
    "Array Azimuth:","180.0"

    "Energy Specifications"
    "Cost of Electricity:"," 8.4 cents/kWh"

    "Results"
    "Month", "Solar Radiation (kWh/m^2/day)", "AC Energy (kWh)", "Energy Value ($)"
    1, 3.04, 79, 6.64
    2, 3.78, 89, 7.48
    3, 4.34, 111, 9.32
    4, 5.11, 120, 10.08
    5, 5.68, 131, 11.00
    6, 5.66, 124, 10.42
    7, 5.92, 131, 11.00
    8, 5.22, 117, 9.83
    9, 4.94, 109, 9.16
    10, 4.26, 103, 8.65
    11, 2.83, 67, 5.63
    12, 2.27, 57, 4.79
    "Year", 4.42, 1239, 104.08

    If you assume a minimum of 103 kWhrs per month (3.4 kWhrs per day) for 8 months of the year... That means for 4 months of the year you need to make up:

    (4*103)-(67+57+79+89)=120 kWhrs to make up during an average 4 month winter

    That averages out to a deficit of ~1kWhr per day (about that of the fridge).

    120 kWH * 1/5kWH per gallon of gas * 1/0.80 eff charger = 30 gallons of gasoline

    So, if you have a fairly efficient genset, it would cost you somewhere 30-60 gallons of gasoline per 4 months of winter. Which works about to be $90-$180 per season of gasoline ($3.00 per gallon).... Or somewhere around ~$1.00 per day (120 day season)...

    Depending on the size of your battery bank, T-105 ~225 AH at 6 volts:

    8x 225 AH * 6 volts = 10,800 kWH...

    Running an average deficit of 1kWH per day would require you to run the genset around every 3 days to bring the bank back up from 70% to 100% state of charge...

    Anyway, some really rough numbers and one way to look at a solar system that cannot make the numbers 12 months out of the year.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: LP Fridge for Off Grid Application

    Geography lesson for Bill: Upstate NY is not terribly near Chicago. Although it's closer than Vancouver. :p
    (Hey - I grew up in the Genesee Valley so I know!)

    Chevenstein* - I run a 16 cu. ft. 'frige off my set-up with only 700 Watts of panels. Yes it needs more panels and bigger/better batteries. But your panel set-up should be quite adequate for refrigeration, providing all the power isn't being used elsewhere, but the battery bank is on the small side. Should be about enough panel for those L16's. :D

    *I'm guessing your handle is some reference to a modified Chevy truck.:p
  • BB.BB. Super Moderators, Administrators Posts: 31,090 admin
    Re: LP Fridge for Off Grid Application

    Sorry, I took a look at his IP address--I did not search/remember earlier from the thread... Same thing, done for Messana New York:
    "Station Identification"
    "City:","Massena"
    "State:","New_York"
    "Lat (deg N):", 44.93
    "Long (deg W):", 74.85
    "Elev (m): ", 63
    "PV System Specifications"
    "DC Rating:"," 1.6 kW"
    "DC to AC Derate Factor:"," 0.520"
    "AC Rating:"," 0.8 kW"
    "Array Type: Fixed Tilt"
    "Array Tilt:"," 44.9"
    "Array Azimuth:","180.0"

    "Energy Specifications"
    "Cost of Electricity:","14.5 cents/kWh"

    "Results"
    "Month", "Solar Radiation (kWh/m^2/day)", "AC Energy (kWh)", "Energy Value ($)"
    1, 3.13, 85, 12.33
    2, 4.28, 103, 14.94
    3, 4.97, 129, 18.71
    4, 5.12, 122, 17.69
    5, 5.02, 118, 17.11
    6, 5.55, 122, 17.69
    7, 5.55, 125, 18.12
    8, 5.23, 117, 16.96
    9, 4.44, 100, 14.50
    10, 3.67, 89, 12.91
    11, 2.44, 57, 8.27
    12, 2.32, 60, 8.70
    "Year", 4.31, 1225, 177.62

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: LP Fridge for Off Grid Application

    Bill, I'm just picking on you because you so rarely make mistakes and I do it often! :p

    I think when I'm at the cabin my IP address says I'm in Alberta, not BC. :D
  • BB.BB. Super Moderators, Administrators Posts: 31,090 admin
    Re: LP Fridge for Off Grid Application

    There is another thread around here where lots of people think I am wrong...

    Anyway, open source work, open source mistakes, open source corrections. ;)

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarusicarus Solar Expert Posts: 5,400 ✭✭✭✭
    Re: LP Fridge for Off Grid Application

    I won't even tell you the mistake I made this week,,, took me 4 days to do something that should have and then did take 30 seconds>

    Meanwhile back to the topic, here is pretty good link to one of the best Absorption fridge sites that I know of. TJ really knows his stuff: http://rvmobile.com/wb/default.asp?action=10&boardid=2&fid=2

    the dometic americana 2652 is a well proven design:http://www.dometic.com/enus/Americas/USA/RV-Products/refrigerators/Refrigerator-Product-Display/?productdataid=74407

    Mine uses 1500 BTUs/Hour. (There are ~79000 BTUs in a gallon of LP). So on a 24 hour day one would burn a maximum of 36k BTUs/day, or about 1/2 a gallon. Now a normal fridge might run ~50% of the time, making that ~18k or 1/4 gallon. Anecdotally, my tend to run about 35% in the summer, 20% or less in the winter, leaving somewhere between 7200 and 12,600BTUs translating to between 10% and 15% of a gallon.

    So at $3/gallon (just a guess/subject to change,,,,lol) a single 2652 might cost you ~$.30-.50 per day to run. Adding enough Pv to power .5-1kwh/day might cost what? Say 500 watts of PV @ $3= $1500, bigger inverter say another $500, additional batteries another $500, so it might cost ~$2500 to add Pv.

    The compressor fridge might be as much as $1000 cheaper than an NEW dometic, and would be bigger, so the net difference might be ~$1000.

    As for the ability of an LP fridge keeping cold. A well vented fridge will freeze ice cream solid as a brick, and keep the box ~35f with no trouble. The biggest problem people have is poor venting over the condenser, hence the fan recommendation, and people over fill them because they are small. You need some air movement to keep the box evenly cold, (hence the fan recommendation).

    So the choice is yours,, as I suggest, if you are going to be full time AND there for a while, consider a GOOD compressor fridge, but do your research. There is not a lot of good to be said about some of the "solar" fridges like sun frost if memory serves.

    Tony
  • Dave AngeliniDave Angelini Solar Expert Posts: 5,509 ✭✭✭✭✭
    Re: LP Fridge for Off Grid Application
    Wow, what great responses. Thank you all!

    The intended use is full time; this is a full time year round residence where grid power is not cost effective to bring on site. My biggest worry with the large LP fridge is that it will not be able to keep cool effectively and longevity and fuel consumption.

    On the other hand, the idea of expanding the array/adding batteries/running the backup genset more frequently just on account of the fridge bugs the heck out of me. ~1KW HR per day for a good AC electric model still seems like a lot of power to come up with to keep my beer and her foodstuffs cold, is this with the auto-defroster enabled?

    Finally, if we go with this Diamond model, does anyone have experience with them as a company and that product, specifically? (If it was me alone believe me - there'd be a salvaged RV fridge in the kitchen!)

    They are great units. I have 3 customers with the Crytal Cold Diamonds. Your wife will not leave you with this choice! To go electric I use 2KW solar minimum in sunny california for my customers. They have pretty normal energy lives!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • chevensteinchevenstein Solar Expert Posts: 100 ✭✭
    Re: LP Fridge for Off Grid Application
    They are great units. I have 3 customers with the Crytal Cold Diamonds. Your wife will not leave you with this choice! To go electric I use 2KW solar minimum in sunny california for my customers. They have pretty normal energy lives!

    Well, that pushes me back in the LP direction. I'd have to totally re-factor my system to go above 2KW and that's not in the cards any time soon.

    Thanks a lot!
  • TooltimeTooltime Solar Expert Posts: 45 ✭✭
    Re: LP Fridge for Off Grid Application
    icarus wrote: »
    Here is my take,, at least take one. A I suggested earlier and Ccoot seconded, the more you use a fridge the more a conventional makes sense.

    You can however skew the numbers in favour of an LP if you do a few things. The first is, install a evaporator fan and a condenser fan that are triggered to come on when the condenser coils get warm. This will increase the efficiency considerably. (Cost about $20 for the T-stat, and some junk fans from computers. I run 24vdc off of 12 vdc so they are almost silent.

    Next, add ~2" of styrofoam board on the sides, top of the cabinet. (You can also do the door. You can make it look pretty good if you plan carefully. This will also increase the efficiency and reduce the run time.

    Next, I am a great fan of Dometics. Over the years we have used Servel/dometic fridges, some of which are over 50 years old, and they still run fine. The modern Dometics require 12vdc for the control boards regardless of if they are burning LP or running on 120vac or 12vdc. Because they are electronically controlled, they turn off and on as needed instead of going to low (pilot) flame and as a consequence they burn less gas over time. That said, the electronics can be a bit delicate, but spare control boards are under $100, and the aftermarket boards are very reliable. I keep a spare around just is case.

    I have used other brands including Consuls, Sibiers, and a sister brand to Consul that I can't remember. I have also installed a couple of big full sized units (prospector or pioneer or some darn thing. These were horrible since the cooling units were for smaller fridges and they could never get/or stay cold unless we covered them with blankets!) The Consuls work fine, and the Sibiers were quite good units. I don't know if they are still available.

    Given a choice, for some basic part time, I would by a Dometic Americana series. The largest is still smaller than a conventional fridge, so we often run two at a time during the time of year we are island bound.

    Lp fridges are more expensive than good conventional, and way more expensive than cheap conventionals. You can cut the price by buying GOOD used. The biggest single issue is if they have been run out of level, the cooling unit can be damaged easily. You can buy fridges with damaged cooling units for nothing or next to nothing, and then buy a cooling unit to replace it. They are not too hard to replace. You can also buy used fridges for next to nothing from RV wrecking yards. There are a couple of places that sell rebuilt fridges for about 1/3 the price of new. If you can find a reputable rebuilder/reseller it might make sense. I have bought several over the years with good success.

    So the long and short is, if you are starting from the ground up, and you are going to use it full time, then start with a good energy start conventional and size the solar system accordingly. If you already have a building and system, get a good LP and work to make it more efficient.

    Tony

    Quick question, I want to use my RV Norcold in my off the grid home. My concern is the ventilation while on LP. It looks your above post, you have a lot experience in this area.

    Thanks,
    Tom
  • Coach DadCoach Dad Solar Expert Posts: 154 ✭✭
    Re: LP Fridge for Off Grid Application

    Good quesiton regarding ventilation....
    I've used a Diamond 10 cubic foot LP refrigerator in my off grid cabin for about 6 years without any issues.
    That being said.... I just finished insulating and sealing up the cabin and I'm moving to an electric unit due to CO2 concerns.
    You have to understand that the refrigerator is burning LP ALL THE TIME, and there is no chimney. I've never heard of anyone having an issue with CO2, but I have to believe there is a chance if your house is well sealed up.
    I've always had a CO2 detector near the refrigerator but now that things are sealed up I don't want to take a chance of CO2 poisoning.

    Beside the CO2 concern, the ONLY negative thing that I’ve noticed with my Diamond is that it is much harder to light in the winter than the other 3 seasons. It lights first or second click in warm weather but it could take several minutes to light when the cabin is below freezing inside. I don’t heat the cabin when I’m not there. So the cabin is cold inside with I arrive in the winter. If you live that year round, lighting it won’t be an issue, but the CO2 might be.

    Of course the other thing is that you have to lay down on the ground to light it (or verify that it is lit). Not always pleasent when I track mud in on the floor and then lay down on it.:blush:
  • mike95490mike95490 Solar Expert Posts: 9,047 ✭✭✭✭✭
    Re: LP Fridge for Off Grid Application
    Coach Dad wrote: »
    .....It lights first or second click in warm weather but it could take several minutes to light when the cabin is below freezing inside. .......
    ????? Uh, lighting the fridge when it's below freezing ????
    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 ,

  • Coach DadCoach Dad Solar Expert Posts: 154 ✭✭
    Re: LP Fridge for Off Grid Application
    mike95490 wrote: »
    ????? Uh, lighting the fridge when it's below freezing ????

    Yes,,,, lighting the fridge when it is below freezing inside the cabin.
    The cabin is typically only used on weekends.

    The cabin is heated with a wood stove and I don't heat it when I'm not there. During the winter if I go there for a weekend... When I get there, it is below freezing in the cabin. I light the wood stove (first) to start warming things up, I then light the refrigerator and fill it with food and beer.

    While I'm lighting the refrigerator it is still cold in the cabin... and it always takes a long time to light when it is cold.
  • BB.BB. Super Moderators, Administrators Posts: 31,090 admin
    Re: LP Fridge for Off Grid Application

    LP (and kerosene) refrigerators are certainly a source of possible CO poisoning. I believe that if the burners are properly adjusted, the CO output is low. However, the burners do get dirty (and kerosene burners need servicing) and the CO output can go way up.

    As you seal up the cabin (and homes) to save energy (heating/cooling), the issue with CO and low oxygen levels goes up.

    I would suggest a battery powered (or backup) CO (carbon-monoxide) detector--They are cheap, and in California they are now required in homes with gas appliances.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarusicarus Solar Expert Posts: 5,400 ✭✭✭✭
    Re: LP Fridge for Off Grid Application

    Tool,

    There are TWO ventilation issues withq LP fridge. The first is venting the combustion gases. This is a pretty simple matter of installing a simple flex pipe vent out through the wall or roof. This should slide over the top of the fridge flue with a larger diameter "draft hood" so that a natural draft won't pull out the flame. It is also important to test the draw on the flue to make sure it draws in all conditions. Sometimes, in very cold conditions, the air in the flue is so dense that the flue gas can't force it's way out, so be careful.

    Perhaps a more important ventilation issue. To is keeping air flowing over the condenser fins to allow the unit to properly cool. A LP fridge works as a closed loop, and in essence the faster the condenser can dissipate heat, the faster the fridge will cool, and the shorter the run time. So a good ventilation strategy is to provide coo air intakes at the floor level, either through the floor or through an outside wall. This provides combustion air,a s well as a cool air feed for the condenser. If you can't provide a low intake, make sure you proved as much air, behind the fridge, especially low.

    The next aspect ais to provide a way for the warm air to escape, ideally with natural convection. I usually construct a baffle on the back/top of the fridge to create a chimney effect, so the warm air is essentially forced out by convection, drawing cool ir from the bottom. A very simple idea to increase efficincy at little cost (energy/dollars) is to install a small computer fan on the condenser, thermostatically controlled, such that when the condenser is hot, the fan draws air through it, sending it out the top. A 24 vdc fan run on 12 dc is very quiet, and cheap to buy at the computer wreckers.

    In cold climates, simply exhaust this air into the room as it helps heat the house. In warmer climes a wall vent up high on the wall, above the condenser will force the hot air out. It is a simple matter to design these to close in the winter if need be.

    The other trick I do is, install a small fan on the evaporator fins, controlled by the same t-stat that controls the condenser fan. This allows air to circulate over the evap fins, taking the "cold" off them faster. The big trick with a LP fridge is to keep it semi full, but not too full! You need air to circulate, but also need thermal mass to help keep it cold. I will put 1 gallon water jugs in a partial fridge if I need mass.

    One final note, adding a layer of foam board or Thermax to the sides, top and door of the fridge (you can design that into the enclosure) and that will Reduce run time considerably.

    Hope this helps,

    Tony

    PS. Part o f the reason it may be hard to light in the winter is two fold. (guessing!) one is lower manifold pressure avaialbe due to cold temps at the tank. Depending on how cold it is tank pressure can drop enough so that no gas can get out at all -45f or so! As a tip, light the fridge before you light any high BTU draw burners like ovens, heaters or water heaters. That said, I do lift a stove burner to quickly purge the line between the tank and the appliance if the tank has been off for a while.

    The second reason it may be hard to light is the flue has to "push out" all the cold air in the flue in order to work. Until the fridge can purge this air, it may down draft and put the flame out.

    Finally, I would NOT install a LP frige in a newish building ( read relatively tight!) without providing a flue vented to the outside. It is so simple to do, and the margin of safety is so much greater. In the I'd days, LP fridges in cabins that were essentially screened porches were fine, but nowadays the danger is too great. People die every year at fishing resorts in our area by not having proper vents. Failing that, it'll a good CO monitoring system.

    One more final note to Mike etc, Remember while it maye -40 outside it isn't very useful to keep food. Thee is no middle ground, 60 inside is too wrm to keep food, but -40 outside is ay to cold. As an aside, when we come home from town we put veggies in the cooler in the winter to keep them warm! Cooler, wrapped in a tarp, and home fast at -20.


    T
  • Coach DadCoach Dad Solar Expert Posts: 154 ✭✭
    Re: LP Fridge for Off Grid Application
    icarus wrote: »
    Tool,
    PS. Part o f the reason it may be hard to light in the winter is two fold. (guessing!) one is lower manifold pressure avaialbe due to cold temps at the tank. Depending on how cold it is tank pressure can drop enough so that no gas can get out at all -45f or so! As a tip, light the fridge before you light any high BTU draw burners like ovens, heaters or water heaters. That said, I do lift a stove burner to quickly purge the line between the tank and the appliance if the tank has been off for a while.

    The second reason it may be hard to light is the flue has to "push out" all the cold air in the flue in order to work. Until the fridge can purge this air, it may down draft and put the flame out.

    Finally, I would NOT install a LP frige in a newish building ( read relatively tight!) without providing a flue vented to the outside. It is so simple to do, and the margin of safety is so much greater. In the I'd days, LP fridges in cabins that were essentially screened porches were fine, but nowadays the danger is too great. People die every year at fishing resorts in our area by not having proper vents. Failing that, it'll a good CO monitoring system.

    One more final note to Mike etc, Remember while it maye -40 outside it isn't very useful to keep food. Thee is no middle ground, 60 inside is too wrm to keep food, but -40 outside is ay to cold. As an aside, when we come home from town we put veggies in the cooler in the winter to keep them warm! Cooler, wrapped in a tarp, and home fast at -20.

    Great information Tony...
    Regarding the P.S. info...
    I would say that this hits the nail on the head...
    "The second reason it may be hard to light is the flue has to "push out" all the cold air in the flue in order to work. Until the fridge can purge this air, it may down draft and put the flame out."
    This is exactly what happens.

    You can get a combo CO2/Smoke detector for about $20.00 at Home Depot.

    Yeah... you need to put the food in the fridg because eventually the wood stove heats the cabin up to a nice toasty level. You don't want to go outside every time you need foor or a beer.8)
  • icarusicarus Solar Expert Posts: 5,400 ✭✭✭✭
    Re: LP Fridge for Off Grid Application

    When we come home after several weeks or months away in the winter, things are frozen solid, and frozen to the floor. It takes many days for the canned goods to thaw. I constantly have to wipe the floor as the cans and bottles sweat and drip on the floor.

    Tony
  • TooltimeTooltime Solar Expert Posts: 45 ✭✭
    Re: LP Fridge for Off Grid Application

    Thank you for your reply. This house is 1800 SF. Plenty drafty. The refrigerator is auto ig-night and the house is always warm. I am thinking that having the fridge on is no more then having a burner on on the stove. I do have a O2 monitor plugged in the kitchen.
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: LP Fridge for Off Grid Application
    Tooltime wrote: »
    Thank you for your reply. This house is 1800 SF. Plenty drafty. The refrigerator is auto ig-night and the house is always warm. I am thinking that having the fridge on is no more then having a burner on on the stove. I do have a O2 monitor plugged in the kitchen.
    A CO (carbon monoxide) monitor might be more useful.
    SMA SB 3000, old BP panels.
  • icarusicarus Solar Expert Posts: 5,400 ✭✭✭✭
    Re: LP Fridge for Off Grid Application

    A large LP fridge will burn ~1500 BTUs/hour. Probably not a big deal to vent to the house, but I would avoid it if I could. That said, the real issue is if the flame is not burning properly, potentially putting out too much CO. Like I said, I would vent it if I could reasonably come up with a way to do so.

    A number of the newer model LP fridges (at least those sold in Canada have either a sealed combustion system, bringing combustion air in on pipe, flue gas o it the other. Alternatively, they have a CO monitor that shuts off the fridge if levels get too high.

    The other reason to vent is that it takes that heat out, away from the the condenser. Just letting it vent naturally, brings that heat right on to the condenser, requiring more air to cool the coils.

    Tony
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