OffGridInTheCity
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- Dec 15, 2018
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Thank you for the thoughtful response.
The problem I'm having right now is 9 days in a row (so far) of total dense clouds / fog / drizzle. Never happened before. There just isn't any sun to work with at all.
But its a good idea, I'll add it to my list for serious research.
Are there any other practical ways to convert excess PV to 9month storage for re-conversion to electricity? For example...
I did the math on lifting mechanical weights (such as my 2,500gal water tanks) to 10ft in air and then running generation as it came back to the ground but it comes out to like a few hundred watts for 10tons! I need several hundred kwh.
Spinning up flywheels is similarly impractical at useful scale for DIY and actually dangerous if the disk explodes.
Yes, I'm with you on Solar electric panel vs Solar water panel.I live off grid and grew up living off grid. We heat with wood which sounds like not an ideal option for you. We do have solar hot water panels but they do basically nothing in the winter because the days are too short to bring the water up to temp(northern MN). I have also noticed that partly cloudy days the solar hot water does nothing but the solar still brings in a decent amount. Based on all that I have decided that for my uses extra solar PV and an efficient heat pump water heater would be the way to go.
In a way - the butt end of our house is 2 stories directly in the sun which has a huge affect in summer.As to thoughts on ways to improve your situation. Something I am sure you have heard before and have probably looked into is just to reduce the need which with heating being dominant for you and you say you have mild winter conditions more insolation and maximizing southern window solar exposure could get that huge heating load a little lower. Insulation, Insolation, Insolation Are you aware of the Passive House Standards? It takes a lot to go the whole way with that but when done properly even really cold MN winters can stay warm with very minimal added(beyond the natural window gains) heating.
The problem I'm having right now is 9 days in a row (so far) of total dense clouds / fog / drizzle. Never happened before. There just isn't any sun to work with at all.
But its a good idea, I'll add it to my list for serious research.
Interesting. When I add the extra panels I'll have excess PV in spring/summer that will go to waste - maybe 1500kwh. I've watched youtubes on 'toy' hydrogen generators etc. Do you have any leads / youtubes or something practical at a larger scale? Wouldn't 500kwh of potential power require a lot? For example, it takes 200gal of propane to get near 500kwh of generator output. Seems like significant hydrogen storage would be a huge danger / big no-no / I'd be a menace to the neighborhood!As another thought that I have considered for myself but my load is low enough it hasn't made sense yet is hydrogen as energy storage(different type of battery). I imagine you have significant excess energy during the summer months so the idea is you electrolyze that extra solar energy into Hydrogen which can be stored in propane type tanks and with minimal modification fun propane appliances. Then you use that Hydrogen in the winter to heat ether directly with combustion or a fuel cell to produce electricity for your heat pump. The upfront investment hasn't made sense for me but with your high load it might be more efficient/cost effective for saving that summer energy for winter when you need it.
Or how most folks do it is to use the utility grid as the "battery" with net metering selling the summer power back to the grid and then buying in the winter
Are there any other practical ways to convert excess PV to 9month storage for re-conversion to electricity? For example...
I did the math on lifting mechanical weights (such as my 2,500gal water tanks) to 10ft in air and then running generation as it came back to the ground but it comes out to like a few hundred watts for 10tons! I need several hundred kwh.
Spinning up flywheels is similarly impractical at useful scale for DIY and actually dangerous if the disk explodes.
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