Do you really need to spend 8K dollars to run a 600Watt fridge?

ericlpericlp Registered Users Posts: 11 ✭✭
http://partsonsale.com/sundanzer.html

Is this claim BS? If you went down to sears and got a REAL refrigerator with a built in ice maker. That uses around 400kWh a year.

I don't know about you but if I had to spend 8K just to run a refrigerator it's be hooking my house up to the mains and would never think about going off grid.

Comments

  • KeithWHareKeithWHare Solar Expert Posts: 140 ✭✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?
    ericlp wrote: »
    http://partsonsale.com/sundanzer.html

    Is this claim BS? If you went down to sears and got a REAL refrigerator with a built in ice maker. That uses around 400kWh a year.

    I don't know about you but if I had to spend 8K just to run a refrigerator it's be hooking my house up to the mains and would never think about going off grid.

    Actually, the numbers for solar components to power a conventional refrigerator look a bit low. A sine wave inverter is better for motors and that will be more like $2000 - $3000 than $800.

    Keith
  • KamalaKamala Solar Expert Posts: 452 ✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    I don't know about the claims, but when they list a BZ240 charge controller as one of their components, I walk away. Cheap crap.
  • BB.BB. Super Moderators, Administrators Posts: 29,359 admin
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    We can do some back of the envelop estimates.

    Using PV Watts, 400 kW per year, Youngstown Ohio, 0.52 system efficiency (off grid / battery / inverter, fixed array, start with 1kW array (nice round number):
    "Station Identification"
    "City:","Youngstown"
    "State:","Ohio"
    "Lat (deg N):", 41.27
    "Long (deg W):", 80.67
    "Elev (m): ", 361
    "PV System Specifications"
    "DC Rating:"," 1.0 kW"
    "DC to AC Derate Factor:"," 0.520"
    "AC Rating:"," 0.5 kW"
    "Array Type: Fixed Tilt"
    "Array Tilt:"," 41.3"
    "Array Azimuth:","180.0"

    "Energy Specifications"
    "Cost of Electricity:"," 8.5 cents/kWh"

    "Results"
    "Month", "Solar Radiation (kWh/m^2/day)", "AC Energy (kWh)", "Energy Value ($)"
    1, 2.17, 34, 2.89
    2, 3.05, 44, 3.74
    3, 4.12, 65, 5.53
    4, 4.61, 68, 5.78
    5, 4.95, 72, 6.12
    6, 5.20, 72, 6.12
    7, 5.21, 73, 6.21
    8, 5.21, 74, 6.29
    9, 4.21, 58, 4.93
    10, 3.84, 58, 4.93
    11, 2.24, 32, 2.72
    12, 1.93, 29, 2.46
    "Year", 3.90, 680, 57.80
    Say you want "solar only" 9 months of the year (use generator for for winter/poor sun conditions)... That gives us 44 kWH per month per 1,000 watts of panels.
    • 400 kWH per year / 12 months = 33.33 kWH per month for fridge
    • 33.33 kWH per month fridge * 1/44 kWH per month per 1kW of panels = = 0.758kW = 758 watts of solar panels
    So, their solar panel estimate is pretty close--Although, the price is around $5 per watt vs ~$3 a watt or so...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • KeithWHareKeithWHare Solar Expert Posts: 140 ✭✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?
    ericlp wrote: »
    http://partsonsale.com/sundanzer.html

    I don't know about you but if I had to spend 8K just to run a refrigerator it's be hooking my house up to the mains and would never think about going off grid.

    Now that we've kicked around the accuracy of the estimate of 8k to run a refrigerator, lets look at the other part of you comment.

    If you want cheap reliable power, in many parts of the world the power grid is the place to get it. The mitigating factors are:
    • Some places have incentives (tax, power buybacks, etc.) that make solar power more reasonable
    • Some places do not have access to a reliable power grid
    • Some people are willing to spend money to be less reliant on the power grid
    • Some people like the technical challenges

    In any case, conserving power is cheaper than generating it.

    If your real question is, "Don't you have to be nuts to do solar instead of the power grid?", the answer is "No, but it helps."

    Keith
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    From the "ask the man who owns one" department:

    I run an electric refrigerator off-grid. Yes, the system cost about $8,000 - Canadian. (Self installed.)
    A couple of notes:

    First, it is a sixteen cubic foot refrigerator, twice as big as theirs and it cost half as much. It also has a freezer and auto-defrost. It does not use "600 Watts" of electric - not even in defrost mode. The worst problem is the start-up current; you need a large inverter (1 kW+) to handle that momentary 'blip'.

    Second, the $8,000 system also runs the computer/satellite/telephone set-up, the lights, the water & sewage pump, the microwave ... Strictly speaking, just to run the 'frige would have been a lot less equipment and money.

    Third, I'll agree with Kamala; if they pick a BZ charge controller we'll take that as proof they don't know what they're talking about. :p

    What it comes down to with refrigeration is: application. How and what on you spend the money depends on your intended use. If it's part-time, weekends away then the best value might be propane rather than electric. More time in the remote and you need more storage space; the electric becomes more practical (especially if used for other purposes as well). Is there a place 12V refrigeration? Of course. But it is foolish to say one system that's so completely different in size/price is better than another in the same application. Can't compare apples to rutabagas and all that.
  • icarusicarus Solar Expert Posts: 5,156 ✭✭✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    I think the OP is missing a critical part of the equation. That is, why would one wish to go off the grid if one has grid power available? Grid tie PV solar comes at about 1/2 the cost per installed watt, with about twice the efficiency, leaving a system that is ~ 4 times more bang for the buck.

    An 8000 system might buy about 1.5 kw of grid tie PV, which might yield ~ 4 kwh/day perhaps, on average. (Run and grid tie PV Watts Calc)

    The point here, is any battery based Pv system is by it's very nature, very expensive to buy and maintain, ergo the kwh cost of the power is also very expensive! If you goal is to save money, do conservation. If your goal is to be "green" go grid tie. If your goal is to play around and learn about PV, build a small battery based system to see what you can do with it.

    Tony
  • zeuspaulzeuspaul Solar Expert Posts: 59 ✭✭✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    My emergency backup solar system design has evolved into an off grid solar system that powers a chest freezer. There is enough surplus to run the 25 watt fire pump block heater and run the 6 watt circulation pump for the fire water supply. The self installed cost is about $6500 ($4500 after tax credit).

    The power in my area is becoming less reliable. We have two 12 hour outages planned for maintenance. Also we have been informed that the power will be shut off when it is dry and wind speeds reach 50+/- mph. This is likely once or twice per fire season an is likely to last for one to three days.

    For the twelve hour outages the freezer will supply stored energy in the form of ice to be moved to a cooler for basic refrigeration needs.

    For the longer outages in addition to the ice for the cooler the system will provide power for limited use of the computer and TV.

    For the true emergency the system will power an air purifier in a fire shelter. The worst case scenario is a wake up in the middle of the night and a run to the fire shelter. No time to start a generator.

    The first 1000 installed PV watts is the most expensive. If I want to expand the system the second 1000 watts would be about $1500 less because I wouldn't need another inverter and less wiring.

    $8000 (after tax credit) would be 2000 watts off grid PV installed (my labor)which would run my freezer, block heater, circulation pump and in addition I could now run my computer full time. An added benefit would be more power in low light conditions during a grid outage.

    Zeuspaul
  • icarusicarus Solar Expert Posts: 5,156 ✭✭✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    Doesn't this sort of beg the question,, if you are desiring a back up system to the grid, isn't ~$6000 to power the freezer a bit steep? The same $6k in gird tie, might put out ~1200 watts day in and day out. That plus a Honda Eu generator for the outage times might make better sense. Just a thought. (your fire shelter issues not withstanding, as it sounds like you are in a fairly unique situation)

    Tony
  • BB.BB. Super Moderators, Administrators Posts: 29,359 admin
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    Lets let the thread rest a bit... The OP has not been back for a day or so (October 31st, 2010 21:18 PDT last login).

    See where Ericlp wants take this thread (philosophical or technical).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • zeuspaulzeuspaul Solar Expert Posts: 59 ✭✭✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    oops:D I started this post a while back and did not see BB's note before posting: (edit)
    if you are desiring a back up system to the grid, isn't ~$6000 to power the freezer a bit steep?

    Agreed, however it is $4500 after the credit but even that is steep if all you want is to power a freezer.

    In my case I need an instant fail safe system. Wildfire is a real threat. I don't trust a small engine generator to work when I need it.

    There are other ways. I could set up a UPS system with just batteries, an inverter a charger and a better generator for guessing about $3000. However there would be no tax credit.

    $4500 for a solar charged UPS system compared to $3000 for a grid charged UPS system. (not exactly UPS as there is no automatic switching)

    The freezer draws about 1000 watt hours per day and the block heater, water pump, inverter add another 1000 watt hours per day. At 30 cents a killowatt hour that is $2190 over ten years assuming no increase in the cost of electricity.

    Now the comparison is $4500 initial solar cost minus $2190 electric savings = $2310 compared to $3000 for a grid charged UPS.
    The same $6k in gird tie, might put out ~1200 watts day in and day out. That plus a Honda Eu generator for the outage times might make better sense.

    Grid tie doesn't do anything in an emergency when the grid is down. I only started looking at alternatives to the grid after the utility informed me that they would be shutting down the grid in a fire emergency. I would rely on a small engine generator for back up but not for emergency backup. I considered a 7kw Kuboto diesel generator for $5000.

    Considering tax credits and electricity savings $2500 for solar emergency backup doesn't seem unreasonable to me and it is a lot more fun than the alternatives.

    Zeuspaul
  • ericlpericlp Registered Users Posts: 11 ✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    Sorry... I just thought it looked a bit much to run a refrigerator. I do want to run a refrigerator and I plan to move to Hawaii next year.

    I was thinking of buying 5 Sharp 240W PV monocrystalline panels.

    I want a full size fridge with an ice maker no more the 400kWh per year. Run a TV, Computer, Washer Machine, 12v water pump. Ceiling Fan, Lights (led), Satellite Receiver, modem, skill saw, battery chargers for rechargeable drill, Alarm Clock, charger for cell phone, a blender ... Maybe a microwave tho I can probably do with out one.

    Don't need AC, Water Heater will be Passive solar, and any cooking devices will be run off propane like BBQ, burner for making tea / coffee and or cooking.

    Would it be enough or should I invest in more panels? I plan to operate washer at peak sun light hours only. Probably ceiling fan and running things like saws and tools will more then likely only run when it's sunny outside. The rest of the stuff will only be on when in USE, when not they will be switched off.

    As for charger / inverter yeah, it should be over 1kWatts since, A fridge for about 1 second when the compressor kicks on draws about 13Amps. A skill saw or table saw/ router can draw some amps as well but like I said I'll use them in the day time so... should be too much of a hit.

    Tho, what if your using a skill saw and the fridge comes on at the same time?

    Then you got to think about batteries I am not shipping those to Hawaii but we do have a wall mart and a costco. Can I buy some deep cell gel batteries?

    So...... Power lines is not an option since the lot I am buying only has phone line no power yet.

    Thanks!
  • icarusicarus Solar Expert Posts: 5,156 ✭✭✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    Ericlp,

    Slow down a bit. You are running the risk of the greatest pitfall in RE, that is the "Ready, Fire, Aim!" syndrome.

    Before you buy, or build anything, sit down, and do real, and real time load calculations factoring in all your likely uses. Build in some fudge factor for loads that will inevitably grow with time. Once you have your load calcs, you can then begin to size components, working backwards from Invereters, to batteries, to charge controllers to PV.

    Just for the record, an off grid Pv system net numbers might look something like this. Take the name plate rating of the PV, divide that number in 1/2 to account for all system loses (PV/wiring/charge controller/battery chemistry/inverter etc) then take that number and multiply it by 4. That represents the AVERAGE number of hours of good sun one can expect on a 12 month basis. Some areas might get a few more, but not too many on an annual basis. For example, you might have ~12 hours of daylight in Hawaii on average, but how much haze is in the air early or late, how many hours of puffy cloud, how much over cast etc?

    So your proposed 1,250 watt system might look like this

    1250/2=625*4=2500 wh/day, or 2.5 kwh/day. There will certainly be days when you might get more, but there will most certainly be days when you get less. One often overlooked efficiency number with off grid PV systems is the amount of power that is lost (not generated) when the batteries come close to full and the charge controller drops currents back. This is one reason I like to use the 50%*4 rule more than a more conventional PV watts that gives a more best case, but not real situation for off grid.

    So knowing that you can reliably generate ~2.5 kwh/day gives you a starting point in knowing if that will fit your loads.
    want a full size fridge with an ice maker no more the 400kWh per year. Run a TV, Computer, Washer Machine, 12v water pump. Ceiling Fan, Lights (led), Satellite Receiver, modem, skill saw, battery chargers for rechargeable drill, Alarm Clock, charger for cell phone, a blender ... Maybe a microwave tho I can probably do with out one.

    Don't need AC, Water Heater will be Passive solar, and any cooking devices will be run off propane like BBQ, burner for making tea / coffee and or cooking.

    I have a pretty good hunch that you are going to have way more loads than capacity. A couple of guestimates:

    Fridge .5kwh/day, computer .3 kwh, pump .1, ceiling fan 35 watts 24/7= .8 Sat receiver 4 hours .2 kwh, TV 4 hours= .4 for a total of just that stuff ~2.3 kwh charge the drills, charge the phone and you will be way over. It is very common for people to over estimate the amount of solar power they can harvest, at the same time underestimating the loads they actually use.

    Just for the record, we have ~400 watts of PV, we routinely use ~.6-.8 kwh/day. We can go three days without using a generator. On a really good day we can generate ~ 1.5 kwhs (more in the summer) but I use the 50%*4 rule for the whole year and it works out just fine.

    Good luck,

    Tony
  • techntrektechntrek Solar Expert Posts: 1,372 ✭✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?
    zeuspaul wrote: »
    Grid tie doesn't do anything in an emergency when the grid is down.

    With the recently-announced high-voltage charge controllers, it can. Expensive as heck, but they'll take the 400-500 volts from a grid-tie system and charge your batteries when the grid is down.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
  • ericlpericlp Registered Users Posts: 11 ✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    yeah I'm noob for solar esp, DC and batteries. Plus Hawaii is totally separated from the other 50 states and makes shipping heavy items like batteries expensive. I think hawaii is a good climate to harvest the suns power since it doesn't freeze and pretty much it's nice hot sunny days for the most part. There are times when it can rain for a few days straight and that would have to just ultra conserve mode or fire up a generator to keep the batteries charged up.

    Tho, this should probably be on a topic for itself. But what really got me going on refrigerators was this. I really like the idea but... It would be nice if someone in the USA made a KIT for these. I was thinking of someone did make a kit and you just buy an energy star freezer chest to link the kit up with then you'd be good to go. Tho, I'm not sure about an ice maker but I suppose I could figure out a way to do it.

    Anyway here is the link... I'm sure you guys have seen this but just in case you haven't.... This dude is running his refrigerator on .1kwh a day.

    http://ecorenovator.org/diy-superefficient-fridge-1-kwh-day/

    I'm not sure how do you convert .1kwh to watts used in a day? Would it be 100 watts a day?

    so, 3kWh a month? (avg) *12 = 36 kWh a year?

    That's pretty damn good....
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    It's a chest freezer with a thermostat wired in so it runs at fridge temperature instead of freezer temp. Very efficient.

    Also, since it's a top lid, all the cold air doesn't fall out when you open it.

    Solar panels put out less power the hotter they get - so in Hawaii when it gets hot and humid, you can expect a significant drop in your solar power output.
  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    Sure its possible to use a chest freezer as a fridge but its such a pain to do so.. Itried it soon gave up and it drove my wife mad. its hard to lean into it to get things out"she is only 5'4" .THre seems no simple way to put things on top of the things at the bottom then easily get the things out from underneath. It nearly impossible to use all the interior space the simple way you can with a refrigerator.

    It not that expensive to run a refrigerator off solar and batteries or that difficult..
    Well its not with refrigerators made up to about 2 years ago but I have been told the new ones work "differently" to the older ones,, but dont know what the differences are as im not a fridge mechanic
  • ericlpericlp Registered Users Posts: 11 ✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    It's a chest freezer with a thermostat wired in so it runs at fridge temperature instead of freezer temp. Very efficient.

    Also, since it's a top lid, all the cold air doesn't fall out when you open it.

    So you read the article I take it? Freezers have thicker walls with more insulation R value then a standard fridge. Glad you enjoyed ... Hope you learned something from it.

    Solar panels put out less power the hotter they get - so in Hawaii when it gets hot and humid, you can expect a significant drop in your solar power output.


    How hot do you think it might get in Hawaii? Have you been there? Are you some sort of solar hawaiian panel expert? LOL

    But that's ok my passive panels will LOVE it.
  • ericlpericlp Registered Users Posts: 11 ✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?
    john p wrote: »
    Sure its possible to use a chest freezer as a fridge but its such a pain to do so.. Itried it soon gave up and it drove my wife mad. its hard to lean into it to get things out"she is only 5'4" .THre seems no simple way to put things on top of the things at the bottom then easily get the things out from underneath. It nearly impossible to use all the interior space the simple way you can with a refrigerator.

    It not that expensive to run a refrigerator off solar and batteries or that difficult..
    Well its not with refrigerators made up to about 2 years ago but I have been told the new ones work "differently" to the older ones,, but dont know what the differences are as im not a fridge mechanic


    Yeah, I'm sure it would take a little getting use too. But I'm 6'1 and I'm also single no wife to worry about except for me. My thinking was a FREEZER chest with 16 CF sure beats the snot out of a tiny SOLAR fridge ...

    Another thing you do realize what .1kwh is don't you? You can't get a fridge this size a normal stand up one to go below 400kWh

    Uh, 36 vs 400kWh. I know there are trade offs for everything but. I'm willing to make a go of it.

    So, can you share what freezer you had and how you wired it up and what kinda readings were you getting from it?

    Pics? Wiring Diagram?

    Thanks ...
  • BB.BB. Super Moderators, Administrators Posts: 29,359 admin
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    There is an old thread here about converting a chest freezer to a chest refrigerator.

    You can go to Graingers or Master/Carr, etc. and get an adjustable AC thermostat and set it to ~34F and plug the freezer into the thermostat.

    Since AC inverters tend to waste a lot of power idling, you may end up having to look at an inverter that has "search mode", or a DC inhibit line, or using a large DC relay to control the inverter.

    From the thread--It sounds like closer to 250-350 Watt*Hours per day.

    You can add a fan (runs when compressor is on) to mix the cold air a bit. And add some gutter material on the walls to capture the condensation and direct it to a drain (vs) just puddling on the floor of the freezer.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    EriclpIm a bit confused about this. can you explain??Another thing you do realize what .1kwh is don't you? You can't get a fridge this size a normal stand up one to go below 400kWh

    Uh, 36 vs 400kWh.


    I had and still have Whirlpool chest feeezer 20cft and and a 16cft Whirlpool fridge
    The chest freezer uses about 960 kwh per year the fridge uses about 450kwh per year.


    Freezers have thicker walls with more insulation R value then a standard fridge

    This is not true for my fridge and freezer in fact the fridge wall thickness is slightly more than the chest freezers

    So, can you share what freezer you had and how you wired it up and what kinda readings were you getting from it?It is just a standard chest freezer? only reading was 960kwh per year
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?
    ericlp wrote: »
    It's a chest freezer with a thermostat wired in so it runs at fridge temperature instead of freezer temp. Very efficient.

    Also, since it's a top lid, all the cold air doesn't fall out when you open it.

    So you read the article I take it? Freezers have thicker walls with more insulation R value then a standard fridge. Glad you enjoyed ... Hope you learned something from it.

    It's old news actually. But I'm always interested to see if anyone came up with a new angle on an old trick.
    Solar panels put out less power the hotter they get - so in Hawaii when it gets hot and humid, you can expect a significant drop in your solar power output.


    How hot do you think it might get in Hawaii? Have you been there? Are you some sort of solar hawaiian panel expert? LOL

    But that's ok my passive panels will LOVE it.

    Hot enough. The PV modules are dark, and they are pointed at the sun - they will get hot. From what I understand, most usually end up putting out around 80% of their rated capacity under normal conditions, though they have been known to put out more than their rated capacity when it's very cold out. You gonna get much snow at your location?
  • icarusicarus Solar Expert Posts: 5,156 ✭✭✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    80% is a pretty good bench mark figure. I would bet in Hawaii you are going to get less on average.

    As for chest freezers to use as fridges. While they are very efficient, they are a pain to use, as in order to use the volume, you have to stack stuff on top of other stuff, the net result is you have to always be taking stuff out to get to other stuff, negating some of the advantage.

    I'm sure there are those that have felt that headache worth it,,, but not me!

    Tony.

    Edit: sorry, didn't realize most of this had already been said,

    T
  • KamalaKamala Solar Expert Posts: 452 ✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    With my vertical fridge I still have to leave the door open long enough to move the stuff in front to get at the "good" stuff in back. Sometimes, I have to put a lot of stuff on the kitchen counter, setting it aside, to remove a special container.

    I guess I save energy by not working against gravity. :p

    K
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    maybe you need a frig lazy susan.;)
  • KamalaKamala Solar Expert Posts: 452 ✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    In a "top loader" the lazy susan would become something like a Ferris wheel, maybe.

    You still lose the corners.

    K
  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: Do you really need to spend 8K dollars to run a 600Watt fridge?

    So your 20cft freezer becomes a 10cft fridge,, just great.. I really think unless you willing to put up with huge inconvienence using a chest freezer as a fridge is not practical . Nobody can ever show how to make full or even 3/4 of the freezer usable. And by usable I mean make any item easy to get in or out for all members of a family, mum ,dad and the kids big and small.:cool:

    Something else never mentioned if you now use a chest freezer as a fridge instead of your "old fridge" where do you keep your items you need to keep frozen??? in the frezer half of the "old fridge" ?? or in another chest freezer???Seems self defeating to me:confused:
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