"Cooling" with button fans.

softdown
softdown Solar Expert Posts: 3,925 ✭✭✭✭
in Off Grid Solar & Battery Systems #1
A lot of off gridders are in a position that favors strong energy conservation. Often meaning less air conditioning and heating with wider temperature fluctuations.

During the summer I have got by with a 4" button fan about 98% of the time. With this dry air I am ok as long as the indoor temp is below 80F. 

Dug out a 3" button fan and thought I would reduce energy usage by ~ 50%. Wired it up and was pleased that the net effect was at least as good. Feeling proud I compared the stated watt consumption of the two fans:
4" fan - 9.5 watts  Must turn at a much lower velocity. Or a more efficient motor/German engineering? Or false advertising?
3" fan - 10.5 watts

The 3" fan is slightly louder and safer because there is less room to stick a finger in. Think I'll use it instead. I know the big room fan uses significant energy. Larger room fans often use at least 100-300 watts in my "experience".

They don't "technically cool" but they get the job done. 
First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,641 admin
    #2
    You need to look at the data sheets... More or less a small diameter fan with high airflow is going to be less efficient than a large fan turning slowly with similar airflow.

    Small high RPM fans tend to be noisy too--And may have shorter bearing life.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #3
    BB. said:
    You need to look at the data sheets... More or less a small diameter fan with high airflow is going to be less efficient than a large fan turning slowly with similar airflow.

    Small high RPM fans tend to be noisy too--And may have shorter bearing life.

    -Bill
    I used to install button fans on reef tanks to push out the heat created by VHO lighting. They all had the same manufacturer so the 3" fans had about 1/2 the output of the 4" fans. I had a box around here if they have not been stolen. Would be interesting to see the wattage.

    Your logic is sound but overlooks that the higher air speed, created by higher rpms , may be more pleasant than the higher CFM rating of a larger fan at lower rpms. Noise can also be good with three dogs. The odds of one of them being noisy are pretty good.

     
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #4
    Update:
    They are often called muffin fans. Here is a very quiet unit that consumes 4 watts at 60Hz (USA): https://www.amazon.com/AC-Infinity-Cooling-Ventilation-Projects/dp/B009OXTWZI/ref=sr_1_4?keywords=140mm+fan+120+volt+low+speed&qid=1565810796&s=gateway&sr=8-4#customerReviews
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • NANOcontrol
    NANOcontrol Registered Users Posts: 276 ✭✭✭
    #5
    I use DC computer fans for sleeping. Three in a simple box work well. Where I am it cools down a lot at night.  I use a simple FET and capacitor and it shuts down about an hour and a half after I go to bed.  Otherwise I would wake up from the chill in the middle of the night.
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #6
    NANOcontrol said:
    I use DC computer fans for sleeping. Three in a simple box work well. Where I am it cools down a lot at night.  I use a simple FET and capacitor and it shuts down about an hour and a half after I go to bed.  Otherwise I would wake up from the chill in the middle of the night.
    I live in kind of a big bunker. No windows on a 400' bedroom. Many walls that are ~ foot thick. Light is provided by tubular ceiling lights that work very well when the sun is shining. 

    Windows are nice but weak in the security area. When in Denver I consider how easy it would be to whack somebody with a cracked open window. Why they shoot people instead is a curiousity. Perhaps to send a message. Talk about epic thread drift - my specialty. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • mountainman
    mountainman Registered Users Posts: 439 ✭✭
    edited August 2019 #7
    That 1225 muffin 51 cfm 8 watts looks interesting.  Don't know the cfm but  I use a  14" dc 12 volt fantastic breeze 3 years old.  runs all night 6 months out the year. 13 watts on low. I am really impressed with the amount of air it moves. Too much air on high for a camper bedroom. Not the quietest. And kinda pricey.
    2kw array 6 345 q cells  make sky blue 60 cc
     6 230ah GC @36 volts 
    18 amp accusense charger. 3650 champion 
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  • Thom
    Thom Solar Expert Posts: 196 ✭✭✭
    #8
    We use ryobi 18v fan for sleeping . Living room 120v dc ceiling fan. Inverter is off at night
    Off grid since 1984. 430w of panel, 300w suresine , 4 gc batteries 12v system, Rogue mpt3024 charge controller , air breeze windmill, Mikita 2400w generator . Added 2@ 100w panel with a midnight brat 
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  • wellbuilt
    wellbuilt Solar Expert Posts: 763 ✭✭✭✭
    #9
    I like the 10” o2 fans they use 10 watts on low and 13 watts on high . My 68” ceiling fan uses 20 watts on low and 100 watts on high . It stays 67o in the house all summer so my fans are needed to move heat . The other morning it was 47o out side , I’m going to have to start burning again soon
    Out back  flex power one  with out back 3648 inverter fm80 charge controler  flex net  mate 16 gc215 battery’s 4425 Watts solar .
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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,113 ✭✭✭✭✭
    #10
    Are those the "o2 Cool" fans that run on 8 D cell batteries or 120Ac to 12 Vdc wall wart?

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #11
    littleharbor2 said:
    Are those the "o2 Cool" fans that run on 8 D cell batteries or 120Ac to 12 Vdc wall wart?
    The newer model is now 9 volt, and may use even less wattage, but no longer 12v... :( The wall wart outputs  9Vdc .7 amps. Perhaps they still make the camping base model? The one's without the fold out base also take batteries.

    I've got one running now and have used them for 10+ years now. The ones I keep running nearly 24/7 in the summer/6 months and sporadically other times last 2-3 years. Not simple to clean out, about 9-12 screws to open and clean blades.
    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.
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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,113 ✭✭✭✭✭
    #12
    I had mine, in the 5th wheel set up with a 12 volt cigarette lighter plug power source. How would a 9 volt model work in this scenario? Is there an optional power cord for them?  Mine are all about 10 years old as well.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #13
    I'm using a little buck converter to run 9v load off 12vdc bank:
    https://www.amazon.ca/Converter-Voltage-Regulator-Efficiency-Lanpu/dp/B07CS69HT4/ref=mp_s_a_1_3?keywords=buck+converter&qid=1565963916&s=gateway&sprefix=buck+&sr=8-3
    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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  • Wheelman55
    Wheelman55 Registered Users Posts: 246 ✭✭✭
    #14
    I’ve had good luck using a Caframo Ultimate. It uses less than 0.5 amps at 12v.

    https://www.amazon.com/gp/product/B0016013JK/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1&psc=1

    Caframo has quite a few models. Some made in Canada. Check out the new Sirocco II Elite with brushless motor. 

    https://www.caframolifestylesolutions.com/support/
    Off-Grid in Terlingua, TX
    5,000 watt array - 14 CS 370 watt modules. HZLA horizontal tracker. Schneider: XW6048NA+, Mini PDP, MPPT 80-600, SCP. 390ah LiFeP04 battery bank - 3 Discover AES 42-48-6650 48 volt 130ah LiFePO4 batteries
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  • wellbuilt
    wellbuilt Solar Expert Posts: 763 ✭✭✭✭
    #15
    LH , yes that is  similar to what I have  . 
     Mine are 6/7 years old now and run a lot . 
     I think i used one with battery’s for a complet season with one set of battery’s . 
    Out back  flex power one  with out back 3648 inverter fm80 charge controler  flex net  mate 16 gc215 battery’s 4425 Watts solar .
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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,113 ✭✭✭✭✭
    #16
    Yep, 8 D cells hold a fair amount of power. They also work as ballast to keep the fan from toppling over. I had one at home for my wife. It ran off of a wall wart and I substituted Ziplock sand bags for battery ballast.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #17
    littleharbor2 said:
    Yep, 8 D cells hold a fair amount of power. They also work as ballast to keep the fan from toppling over. I had one at home for my wife. It ran off of a wall wart and I substituted Ziplock sand bags for battery ballast.
    You keep saying wall wart - and I never heard of this wart. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #18
    Wall wart (noun) - a protuberance extending from an AC outlet, typically converting higher voltage AC current to lower voltage DC current for DC loads like laptops or LED lighting.  Can be a "vampire load", sucking power even while doing nothing useful.  Some don't play well with MSW AC power.  Some just don't play well.
    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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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #19
    Is it worth $18 to save ~ 5 watts and have a slightly quieter fan with less volume? Probably so - when you want less volume and noise. As for 5 watts? I probably have a few "vampire loads" bigger than that. I've got too much stuff to sweat all the little bitty details.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,113 ✭✭✭✭✭
    #20
    softdown said:
    littleharbor2 said:
    Yep, 8 D cells hold a fair amount of power. They also work as ballast to keep the fan from toppling over. I had one at home for my wife. It ran off of a wall wart and I substituted Ziplock sand bags for battery ballast.
    You keep saying wall wart - and I never heard of this wart. 
    All those little black cubes that plug into the typical outlet and connect to all the devices we use these days. Generally they convert AC to DC and are of varying low voltage output. 1.5 volts Vdc 4.5 Vdc, 12 Vdc, etc.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #21
    Estragon said:
    Wall wart (noun) - a protuberance extending from an AC outlet, typically converting higher voltage AC current to lower voltage DC current for DC loads like laptops or LED lighting.  Can be a "vampire load", sucking power even while doing nothing useful.  Some don't play well with MSW AC power.  Some just don't play well.
    It's  been  true I the past, but most are 'smart'  these days and  don't draw any noticeable current.  In fact it was running one  of these O2cool fans off a cheap WalMart Battery charger adapter when I realized it would be warm  even  without the fan on. I switched it out for the onethat came with the fan  and  no more warm warts...
    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.
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #22
    I don't see an advantage to using a 12 volt fan when a voltage converter is required. Though saying you have wall warts is sure to stymie a few.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,113 ✭✭✭✭✭
    edited August 2019 #23
    The O2 cool is a D cell battery powered fan that has a 12 volt optional power in port. How you get power to it is up to the user. Cigarette  lighter port, wall wart , squirrel running in a ferris wheel, pedal powered generator, etc. :D

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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