Solar system design for home radon fan remediation system (off-grid)

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  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    #32

    > If you stubbed your toe once a day for 50 days - or 50 times in 1 day, which do you think would do more damage?

    I think your analogy is absolutely silly and has no relation to radiation dose.

    I am available for custom hardware/firmware development

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  • Rezolution
    Rezolution Registered Users Posts: 19 ✭✭
    #33
    https://forum.solar-electric.com/discussion/comment/395515#Comment_395515

    Fair enough. I'll refrain from commenting further off-topic remarks as I see that you do post helpful and useful information in other people's threads.

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  • Rezolution
    Rezolution Registered Users Posts: 19 ✭✭
    #34

    I guess this story has a happy ending. I wound up installing an APC smart-ups 2200 with (4) 100Ah AGM batteries (4.8KWh). It turns out the fan draws around 57 Watts. With the current setup, the fan will run for almost 2 full days. I have the option to add another row of 4 batteries, but I haven't decided if I want to or not.

    If anyone is curious, this is what the final setup looks like.

    UPS for radon fan.jpg


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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #35

    The UPS solution sounds good to me.

    Personally, I'd add a small inverter type generator (eg honda 2000i) before more batteries.

    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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  • Rezolution
    Rezolution Registered Users Posts: 19 ✭✭
    #36

    There was an error rendering this rich post.

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,623 admin
    #37

    OK, Looks like this "Radon" thread has been fixed... The last post is still corrupt, but we can continue from here.

    -Bill "moderator" B.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Horsefly
    Horsefly Registered Users Posts: 476 ✭✭✭✭
    edited March 2019 #38

    I know it isn't ideal, but have you thought about running the radon fan mostly during the day? We run ours from 9am to about 5pm. Running during the mostly daylight hours would dramatically reduce the impact on a solar power system.

    Off-grid cabin: 6 x Canadian Solar CSK-280M PV panels, Schneider XW-MPPT60-150 Charge Controller, Schneider CSW4024 Inverter/Charger, Schneider SCP, 8S (25.6V), 230Ah Eve LiFePO4 battery in a custom insulated and heated case.
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  • Rezolution
    Rezolution Registered Users Posts: 19 ✭✭
    #39
    https://forum.solar-electric.com/discussion/comment/395673#Comment_395673

    I have a 9KW generator now that interfaces directly with my house panel. I just purchased the Champion 2000W inverter generator as well. I wound up getting it for $399 from Home Depot. I made up a plug so the generator will interface directly with my 50A manual interlock breaker that feeds power to anywhere in the house, both sides of the breaker panel but 120V only (no 240V since there would be phase issues). I can run the 9KW generator as needed during the day and the 2KW generator all night. It's VERY QUIET. I was able to run the radon fan, the UPS for the radon fan (so it charges), and the refrigerator with the generator in 'eco mode' and the generator doesn't even throttle up. It's a great setup and I'm very happy to get 8 to 10 hours per gallon of gasoline.

    It's not a "long term" solution in the event of SHTF, but it's enough to get us through most outages that could occur.

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  • Rezolution
    Rezolution Registered Users Posts: 19 ✭✭
    #40


    https://forum.solar-electric.com/discussion/comment/395991#Comment_395991

    I'm not sure what the trade off would be running it for 1/3 of each day and having it off 2/3 of the day. After about 12 hours of it being off, the house would go up to about 50 pC/L. once that happens, it takes about 3 to 5 days of running the fan 100% of the time to get the house back down to "under 1 pC/L". I doubt I'd be able to keep the levels ok if I only ran it for a little bit each day.

    The other nice thing is that I just found a Radon meter that runs for 2 years on (3) AAA batteries. Now I don't have to plug the radon meter into the UPS and I'll always be able to tell what the radon level is in the house. As long as I have a decent stock of Energizer Lithium AAA, I'll always be able to tell what the radon levels are :)

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,623 admin
    #41

    It sounds like you have a good start there... I agree that a genset+fuel is probably a less expensive solution vs trying to do batteries+solar...

    If you have family that cannot setup and run the genset without your help (away traveling, unplanned family stuff, etc.), the UPS for short term operation (a couple of days) should buy you enough time to hopefully get power back, or at least fire up the genset.

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Rezolution
    Rezolution Registered Users Posts: 19 ✭✭
    #42
    https://forum.solar-electric.com/discussion/comment/396571#Comment_396571

    Bill,

    Thanks for taking the time to answer all of my questions. At some point in the future, I'll probably wind up installing a "whole house" solar system with battery backup. Solar wasn't worth the cost for 'just' the radon fan but I think I can justify the cost of doing the whole house. I was able to get a decent short term solution in place and I'm ok with that.

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  • JRHill
    JRHill Registered Users Posts: 361 ✭✭✭✭
    #43
    This thread has been quiet for a while. I just came across it after a G search. Most of our off grid system came from NAW&S - love y'all. Anyway, back to the subject: I'm curious how the ventilation was resolved - maybe I missed it.

    Background, several years back I did a Radon test in the crawl space. New construction roughly 26x34 footprint, off-grid. It was after several winters and the crawl space vents were closed off for the season (we heat with wood but pull the air from outside). Go figure, the Radon reading was high. Our geo says at radon is moderate in 2 - 4. We were over that.

    I have pondered pulling the air for the wood burner from the crawl space but it will create a vacuum from all over the house. I could create leakage in the crawl space but that sucks. Pantry is down there and cold main floor = echh.

    So how did this end up?
    Off Grid. Two systems: 1) 2925w panels, OB VFXR3648, FM80, FNDC, Victron BMV-712, Mate3s, 240 xformer, four SimpliPHI 3.8; 2) 780w, Morningstar 30a, Grundfos switch, controller and AC/DC pump, 8 T105. Honda EU7000is w/AGS. Champion 3100. HF 4550, Miller Bobcat.
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  • JRHill
    JRHill Registered Users Posts: 361 ✭✭✭✭
    #44
    jonr said:

    > If you stubbed your toe once a day for 50 days - or 50 times in 1 day, which do you think would do more damage?

    I think your analogy is absolutely silly and has no relation to radiation dose.

    So rarely does someone state a true fact.
    Off Grid. Two systems: 1) 2925w panels, OB VFXR3648, FM80, FNDC, Victron BMV-712, Mate3s, 240 xformer, four SimpliPHI 3.8; 2) 780w, Morningstar 30a, Grundfos switch, controller and AC/DC pump, 8 T105. Honda EU7000is w/AGS. Champion 3100. HF 4550, Miller Bobcat.
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