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Post by tommyFL on Jul 7, 2021 23:57:42 GMT -5
Is it possible to convert AU sites with this method? 36.21° S, 981 m AMSL on an exposed hilltop:  Using the mean monthly number for each day of the month (approximate, but very close), it comes out to 2544 hours annually. That doesn't take elevation into account, however. I haven't found a definitive answer, but it seems like the radiation increases about 10-15% per 1000 m or so above sea level. So perhaps a number like 2200 hours is more realistic. |
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Post by tommyFL on Jul 8, 2021 2:20:19 GMT -5
Here is a Excel template I made that calculates monthly averages for sunshine hours and percent of possible sunshine. This one takes elevation into account, with a 8% increase in radiation per 1000 m (there isn't a lot of info out there so this could be way off). climateatlas.org/SunshineHoursCalculator.xlsx |
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Post by knot on Jul 8, 2021 3:27:09 GMT -5
First result - using R.L. Snyder's template and deducting 10%  Tommy's estimate of 2,200 hrs (annual) was spot-on. I'll try his own template afterwards. |
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Post by Ethereal on Jul 10, 2021 8:33:48 GMT -5
Can you calculate solar radiation of non-US cities? There is a website (forgot its name) that has a world map with a solar radiation layer. Non-US cities (aside canada) actually measure sunshine hours though. I mean those that lack an instrument that measure sunshine hours. Perhaps you can convert their solar radiation figure to sunshine hours amount? Refer to Adaminaby post above. |
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Post by Ethereal on Jul 10, 2021 8:38:10 GMT -5
Is it possible to convert AU sites with this method? 36.21° S, 981 m AMSL on an exposed hilltop: Using the mean monthly number for each day of the month (approximate, but very close), it comes out to 2544 hours annually. That doesn't take elevation into account, however. I haven't found a definitive answer, but it seems like the radiation increases about 10-15% per 1000 m or so above sea level. So perhaps a number like 2200 hours is more realistic. Can you do Penrith's?  |
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Post by Babu on Jul 10, 2021 11:58:09 GMT -5
Honestly, I feel like Solargis.imaps direct radiation map is a lot more reliable for comparing sunshine hours between places than this scuffed method...
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Post by tommyFL on Jul 10, 2021 12:47:45 GMT -5
Can you do Penrith's?  |
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Post by knot on Jul 10, 2021 17:38:19 GMT -5
Honestly, I feel like Solargis.imaps direct radiation map is a lot more reliable for comparing sunshine hours between places than this scuffed method... Can you link it then? |
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Post by Babu on Jul 10, 2021 17:56:52 GMT -5
Honestly, I feel like Solargis.imaps direct radiation map is a lot more reliable for comparing sunshine hours between places than this scuffed method... Can you link it then? |
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Post by knot on Jul 10, 2021 18:20:34 GMT -5
Looks like nonsense to me - doesn't even have monthly figures. |
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Post by Babu on Jul 11, 2021 2:53:11 GMT -5
Looks like nonsense to me - doesn't even have monthly figures. Exactly |
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Post by Ethereal on Jul 11, 2021 23:41:00 GMT -5
Can you do Penrith's? Hm, seems much lower than expected. Sydney CBD is around 2600 hours in these normals. I doubt Penrith is 200 hrs less sunnier and I would assume that our winters would be sunnier than the CBD because offshore winter rain/clouds don't reach further inland. I don't know...  |
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Post by knot on Jul 11, 2021 23:44:20 GMT -5
Hm, seems much lower than expected. Sydney CBD is around 2600 hours in these normals. I doubt Penrith is 200 hrs less sunnier and I would assume that our winters would be sunnier than the CBD because offshore winter rain/clouds don't reach further inland. I don't know... No it's pretty accurate, especially in winter. Penrith being closer to the escarpment would definitely increase winter cloud cover, particularly that from Northwest Cloudbands; coastal Sydney is further in the lee. Then there is the fact that Penrith gets a lot more fog than coastal Sydney. As for the lower summer sunshine, Penrith gets a lot more storm buildup and tends to catch the bulk of those N/NNE'ly inland trough events (the ones that spill Warragamba Dam). |
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Post by tommyFL on Jul 12, 2021 0:18:57 GMT -5
Ethereal knot I checked Sydney airport. 2639 hrs of measured sun vs 2546 hrs calculated from the mean daily solar exposure. So perhaps a 3-4% error. Correcting for this error brings the Penrith number up to 2508 hrs.
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Post by Steelernation on Jul 12, 2021 16:51:48 GMT -5
This one takes elevation into account, with a 8% increase in radiation per 1000 m (there isn't a lot of info out there so this could be way off). That elevation value seems way off. For example Flagstaff had 3565 hours last year, which seems very accurate for their driest year. Now using you’re new spreadsheet taking elevation into account, they only had only 2787. That’s just not reality and would put their average like 2400-2500 which is obviously way too low. |
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Post by tommyFL on Jul 12, 2021 16:58:32 GMT -5
This one takes elevation into account, with a 8% increase in radiation per 1000 m (there isn't a lot of info out there so this could be way off). That elevation value seems way off. For example Flagstaff had 3565 hours last year, which seems very accurate for their driest year. Now using you’re new spreadsheet taking elevation into account, they only had only 2787. That’s just not reality and would put their average like 2400-2500 which is obviously way too low. Yeah, it's a guess based on just one study done on some mountain in Switzerland. In reality, it probably varies widely by cloud cover/time of year/latitude etc. So it's safe to say the calculator will not be very accurate for high elevations. |
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Post by Ethereal on Jul 12, 2021 19:49:43 GMT -5
Ethereal knot I checked Sydney airport. 2639 hrs of measured sun vs 2546 hrs calculated from the mean daily solar exposure. So perhaps a 3-4% error. Correcting for this error brings the Penrith number up to 2508 hrs. Now that's far more accurate!  I actually could tell that it was off by 100 hours or so. There's no way the Sydney region receives sunshine hours less than the 2500 mark. |
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Post by Ethereal on Jul 12, 2021 19:55:20 GMT -5
Hm, seems much lower than expected. Sydney CBD is around 2600 hours in these normals. I doubt Penrith is 200 hrs less sunnier and I would assume that our winters would be sunnier than the CBD because offshore winter rain/clouds don't reach further inland. I don't know... No it's pretty accurate, especially in winter. Penrith being closer to the escarpment would definitely increase winter cloud cover, particularly that from Northwest Cloudbands; coastal Sydney is further in the lee. Then there is the fact that Penrith gets a lot more fog than coastal Sydney. As for the lower summer sunshine, Penrith gets a lot more storm buildup and tends to catch the bulk of those N/NNE'ly inland trough events (the ones that spill Warragamba Dam). This is true and I have noticed it as well with Penrith (more fog in winter and more summer storm buildup, which "clouds" things up). But I would've assumed that Sydney CBD would get more coastal cloud cover? This may be an anecdote, but I've noticed (winter) days where there the skies are partly cloudy here and virtually overcast in the CBD. Oh, and not to mention, how the CBD is around 250mm wetter than us in the west.... |
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Post by longaotian on Jul 12, 2021 20:33:54 GMT -5
No it's pretty accurate, especially in winter. Penrith being closer to the escarpment would definitely increase winter cloud cover, particularly that from Northwest Cloudbands; coastal Sydney is further in the lee. Then there is the fact that Penrith gets a lot more fog than coastal Sydney. As for the lower summer sunshine, Penrith gets a lot more storm buildup and tends to catch the bulk of those N/NNE'ly inland trough events (the ones that spill Warragamba Dam). This is true and I have noticed it as well with Penrith (more fog in winter and more summer storm buildup, which "clouds" things up). But I would've assumed that Sydney CBD would get more coastal cloud cover? This may be an anecdote, but I've noticed (winter) days where there the skies are partly cloudy here and virtually overcast in the CBD. Oh, and not to mention, how the CBD is around 250mm wetter than us in the west.... I've actually noticed the opposite during my time in Sydney. Many times particularly during July and August which is the sunniest time of year in Sydney, it is clear weather in the CBD/coast, with more cloud cover heading towards the Blue Mountains. |
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Post by Babu on Jul 13, 2021 2:30:45 GMT -5
That elevation value seems way off. For example Flagstaff had 3565 hours last year, which seems very accurate for their driest year. Now using you’re new spreadsheet taking elevation into account, they only had only 2787. That’s just not reality and would put their average like 2400-2500 which is obviously way too low. Yeah, it's a guess based on just one study done on some mountain in Switzerland. In reality, it probably varies widely by cloud cover/time of year/latitude etc. So it's safe to say the calculator will not be very accurate for high elevations. This only works for solar panels laying flat on the ground anyway doesn't it? Most solar panels don't do that, and since you don't know the angle and direction of any of these solar panels, your calculated figures are just gibberish that happens to sound reasonable in some cases. |
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