4 ms·
5kW of panels don't produce 5kW in winter, that's the issue I guess.
by CorrectHorseBat 5y ago
5kW of panels don't produce 5kW in winter, that's the issue I guess.
- Epa095 5y agoWhat does the 5kWh of energy turn in to, of not heat?
- jacquesm 5y agoCorrect, they will produce more. Solar panels produce the most power on cold winter days. The 'rated power' is for 20 degrees ambient at full (90 degrees, no cloud) incidence at sea level.
- notahacker 5y agoIn practice it's kWh you care about, and you get significantly fewer hours of sun in winter. No cloud days are rare in some regions in winter too.
- jacquesm 5y agoSure, but the time factor wasn't present in the above comment, it was just instantaneous power.
- CorrectHorseBat 5y agoIt was about how that could heat (or not heat) a cabin, time is definitely a factor in that.
- jacquesm 5y ago"5kW of panels don't produce 5kW in winter" -> there is no 'time' factor in there. What you could say is that solar panels in the winter do not produce the same amount of power in an average day as they do in the summer due to the shorter day and the bigger chance of occlusion as well as the longer path the suns rays have to travel through the atmosphere.
- CorrectHorseBat 5y agoThat really depends on how far north you live. Where I live a good winter day's production is ~10% of a good summer day's. (Also depends on the orientation, but it's never even close, let alone more)
- jacquesm 5y agoThat's total production over a day.
- angularbot77 5y agoProblem is, the sun doesen't necessarily rise above the horizon for weeks in northern countries
- jacquesm 5y agoYes, in locations like that you will have to use some other solution for those periods. Maybe wind power. Battery storage will not last long enough unless you have an absolutely massive setup that would not be cost effective the rest of the year. I had 48KWh worth of storage, 2500 W worth of wind and another 5000 W worth of solar. This was in Northern Ontario. Until we added the windmill we fairly regularly needed the generator, after we added the windmill the generator just sat there gathering dust.
- mattst88 5y agoCould you say something about the analysis you did to decide that wind was going to be useful for you? I'm interested but I don't really don't have a good sense for how cost effective a wind turbine is or how to evaluate a site.
- jacquesm 5y agoThe Canadian meteorology department puts out pretty useful stats, and I dropped in on a couple of people in the neighborhood that had windmills up to see what kind of windspeeds they were seeing and how long on average their machines stood still. This was a major factor in designing the machine the way I did, variable pitch is a lot more work but a machine like that will start up far earlier than a fixed pitch machine. It also had its effect on that stator, which I made with the laminates at a slant over 1/3rd magnet width, which reduced cogging to nearly nothing. This is a huge factor in starting up a direct drive machine.