Passive solar seems to work much better before Dec 21st than after.

softdown
softdown Solar Expert Posts: 3,925 ✭✭✭✭
edited February 2023 in Off Grid Solar & Battery Systems #1
The sun must be significantly "lower" on Nov. 21st than Jan. 21st. The passive solar sunroom is no longer getting real warm. Funny I never noticed this phenomenon before. It is no longer receiving a highly useful amount of warming sun. 

I should check and report back. *Did a little checking and failed to find verification for the above. Nevertheless I'll leave the post and see if any useful input develops. 
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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  • BB.
    BB. Super Moderators, Administrators Posts: 33,634 admin
    #2
    Maybe look at your location for average temperatures and amount of sun... Just a random look at the high plains seems to indicate that November is 14F warmer than February...

    And looking at solar insulation for Greely:
    http://www.solarelectricityhandbook.com/solar-irradiance.html

    For a vertical panel (aka windows on side of house):

    Greeley
    Average Solar Insolation figures

    Measured in kWh/m2/day onto a vertical surface:

    JanFebMarAprMayJun
    3.85
         		3.98
         		3.94
         		3.26
         		2.81
         		2.62
     
    JulAugSepOctNovDec
    2.73
         		3.08
         		3.80
         		4.40
         		4.10
         		4.01
     
    October and November, on average, are going to have more hours of sun through south facing windows than February on... Not that the differences between Nov and Jan are that much... Variations in weather (year over year) probably are at least as much (10%+ variations?).

    -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
    ^^^Nice explanation Bill. 

    Plus my ~3" thick foam door has been compromised by dogs growing and charging about. It feels like every time I fix one thing another issue develops. 
    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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  • BB.
    BB. Super Moderators, Administrators Posts: 33,634 admin
    #4
    I was really surprised how many hours of sun per day middle of Colorado gets from south facing/vertical windows/solar panels... Around 4 hours per day fall and almost that into winter.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,113 ✭✭✭✭✭
    #5
    The first day of winter indicates it will be winter for the next 3 months. Consequently colder than the days leading up up winter. 
    Other side of the coin, First day of summer you'd think it should be gradually getting warmer up to the longest day of the year and gradually getting less warm from June 21st on. It doesn't work out that way.
    Nothing scientific here, just my ramblings. Okay gotta go now. lol

    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 ✭✭✭✭
    #6
    My observation was based on how many vertical inches of sunlight were getting past the 39" overhang and heating the room. I have complained about excessive heat from the sunroom in October as I recall. Heat caused by vertical inches of sunlight getting past the 39" overhang. 

    Guess I should use a tape measure and write things down though that would not change anything. 
    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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