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: 33,688 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: 33,688 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: 429 ✭✭✭✭
    #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: 429 ✭✭✭✭
    #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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  • Tristantatcher
    Tristantatcher Registered Users, Users Awaiting Email Confirmation Posts: 1 ✭
    #45
    Consider going with a 300W inverter instead of a 1000W or 2000W—smaller inverters are more efficient for low-power loads like your radon fan.
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  • Ralph Day
    Ralph Day Solar Expert Posts: 1,033 ✭✭✭✭
    #46
    I use a 12v computer fan drawing air out of my sump pit.  My readings went from over 600 bq/cubic meter down to  18.  Tested under same conditions one year later.  The pit is sealed, the fan exhausts outside 24/7.  
    I only hope that almost 40 years of exposure isn't fatal eventually.  My plan to live forever is going well so far 
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  • omaharadonpros
    omaharadonpros Registered Users, Users Awaiting Email Confirmation Posts: 1 ✭
    #47
    Consider using a smaller, more efficient inverter—large ones can waste power when running small loads like your fan. Also, slightly oversize your solar panel setup to make up for winter and cloudy days.
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  • Ralph Day
    Ralph Day Solar Expert Posts: 1,033 ✭✭✭✭
    #48
    My 12 volts comes from a 48 to 12 volt converter.  Several 12 volt loads, this way I'm not parasitizing off just 2 batteries.
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  • rochesterradon
    rochesterradon Registered Users, Users Awaiting Email Confirmation Posts: 1 ✭
    #49
    Looks like a solid plan. Just be sure to slightly oversize the system to handle cloudy days and winter. Good luck!
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,991 ✭✭✭✭✭✭
    #50
    Ralph Day said:
    I use a 12v computer fan drawing air out of my sump pit.  My readings went from over 600 bq/cubic meter down to  18.  Tested under same conditions one year later.  The pit is sealed, the fan exhausts outside 24/7.  
    I only hope that almost 40 years of exposure isn't fatal eventually.  My plan to live forever is going well so far 
    Hi Ralph,

    What meter did you use? I see alot on amazon and a client needs one. Thx !  --Dave
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • JRHill
    JRHill Registered Users Posts: 429 ✭✭✭✭
    #51
    I purchased an "Airthings" unit from Home Despot model Corentium Home. It gives a long term average and also short term averages of 1 day and 7 days in pCi/L. It wasn't cheap. Been using it for over a year now. Mounted 42" above the floor in a traffic area where there is air movement. AA battery lasts forever.

    As for crawl space ventilation I still close off the vents in the cold weather (2" pink foam) . I cut a 4" hole to accept an elbow, in-line (12 watt 120vac) fan to the floor to a T in the low spot as Radon is heavy and stays low. THERE IS NO AIR INLET. I have 10' of tubes going out from the T. The set up works great. When running in the winter the exhaust does create a negative pressure in the house which is really tight. The results are that it DOES suck A LITTLE heat out of the house and brings in cold, outside air. Good. Too tight of a house is not so good. So we feed a bit more wood to the woodburner. So what?

    The inline fan is on a cheap timer for two hours on and two hours off throughout the winter. 12 watts is silly to even contemplate. The crawl space is sealed so it does pull from the living area into the crawl space. Again, ya need fresh air coming into the living spaces.

    I open the crawl space vents in the summer and unplug the fan. At this moment the reading is below 0.5. This was our solution and it was cheap and maintenance free. Just one of the seasonal things to be done when I adjust for the season.

    For the record we don't spend too much time below 42" above the floor. But radon would affect our security system (three Catahoula hounds). We don't want to breathe it and don't want the dogs doing it either. So you do what is important to you. Again, we pull outside air for the woodburner so the negative pressure is a non issue.

    All in all I could get run over by a truck tomorrow so what about that radon? But My wife and the dogs will breath better air. And there is nothing better than the clean forest air.

    @Dave Angelini , it was a really simple modification. It also sucks excess humidity out of the house instead of it running down the windows. That was a welcome advantage I didn't expect.


    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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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,991 ✭✭✭✭✭✭
    #52
    Thanks JR !   The radon one on left.    right?


    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,991 ✭✭✭✭✭✭
    edited June 4 #53
    Having trouble visualizing your T and  10' of tubes going out from the T. My wife is not home now and she is the visual person here...
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • JRHill
    JRHill Registered Users Posts: 429 ✭✭✭✭
    #54
    Picture is worth a thousand words:

    Simple as simple can be. It's worked really well for us

    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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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,991 ✭✭✭✭✭✭
    #55
    The red 1 below is in the crawl space with the fan/valve venting crawl space outside in winter?

    In summer you open the vents around the house crawl space and your readings are good enough?

    Thank-you !


    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • JRHill
    JRHill Registered Users Posts: 429 ✭✭✭✭
    #56
    Dave Angelini said:
    Thanks JR !   The radon one on left.    right?


    Correct.
    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: 429 ✭✭✭✭
    edited June 4 #57
    Dave Angelini said:
    The red 1 below is in the crawl space with the fan/valve venting crawl space outside in winter?

    In summer you open the vents around the house crawl space and your readings are good enough?




    Yes, in the crawl space vented outside in the winter. 2 hrs on and two hours off. 

    In the summer, yes, I unplug the fan because the foam covers are down and the vents open. Our threshold is 2.0 to 3.0 on the meter. In the summer its <0.5.

    Be healthy, esp if its so easy. I still don't know about the radon thing.... I ingest enough other toxins that I can say I tried to minimize risks. Bwahh-hahh. I'm still kickin'. The 4" tin and the fan was cheap.

    https://www.amazon.com/dp/B0BW5Z19B1?ref=ppx_yo2ov_dt_b_fed_asin_title

    https://www.amazon.com/dp/B0CLLLKZ5W?ref=ppx_yo2ov_dt_b_fed_asin_title

    The rest was from HD. Can't hear the fan unless ya go into the crawl space.
    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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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,991 ✭✭✭✭✭✭
    #58
    Thank-you !   Will pass this on but I think they have high readings all year with the crawl space vents always open.  Almost Happy hour!  I am buying😉
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • JRHill
    JRHill Registered Users Posts: 429 ✭✭✭✭
    edited 12:23AM #59
    Until they get a monitor they don't really know. I have very little faith in the mail in tests. I have less faith in a company who is going to do radon testing because they are ultimately tied to folk who radon remediation. What do you think the test will reveal?

    Before we built I had a guy come to give me a quote for solar. He kept saying how much he would save us on our power bill. I kept telling him that we would be off grid so how could he save me money on our power bill? We went around a few times and he got mad at me because he was the specialist. I kept waiting for him to correlate it to generator run time but no, it was all about the power bill we'd never have. So I did my own system, thank the Lord for sending that guy to meet me.
    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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