north facing array

[J.P.M.]

J.P.M. Thanks for your wisdom and patients with my newbie questions. I will indeed learn PVwatts first (learn to walk before I run) and move into SAM. As a computer guy the program itself intrigued me but I definitely need to learn the terminology.

All that said, I still am not quite sure, are you a proponent of solar or not? It seems your not buy with your knowledge I thought you might be more for it then against it.

Anyway, you keep teaching and I'll keep learning. I will know more then the sales reps for these companies.

I am the biggest fan of solar energy I know.

Since you ask, I'll PM you with the gory details in abstract form. I don't care to put my business in the street.

Regards,

J.P.M.

[shocknocka]

The short answer is yes. Something of what you describe but more involved is part and parcel of solar design with respect to resource assessment and performance estimation.

I'm not trying to be rude, but if you do what you say you do, I'm a bit surprised you'd ask that question. I'd respectfully suggest that if you want to keep your job, you not tell your boss you asked.

Hey J.P.M.
Not much direction in that response my friend. I definitely do what i say i do, haha. Quite a bit. Sometimes 6 surveys in a day. I have also spent a lot of time on pv watts looking for subtle differences in production given small changes in azimuth. As I stated before, if you know of a field formula that i could use to quickly calculate a difference in estimated production without having to resort to pvwatts or sam, i would appreciate it. I am here to learn as well.

Thanks
Shock

P.S. I have asked my boss this question. Still here.

[njguy]

From 4:00-6:00 I make about 12-15% of my total output. I won't expect to lose all of that production but it might derate your system by 6-10%.

When you go through the process they will do a site survey estimate shading from trees and give you better production estimates.

That is a help. Thank you. I figured as much. It is generally the hottest time of day so I would think the sun is strong then. I do not want to lose 10 percent of my production. That seems like you're leaving the window open with the ac on.

On another note, I look forward to seeing that PM J.P.M. Thanks again.

[J.P.M.]

[QUOTE=shocknocka;117745]Hey J.P.M.
Not much direction in that response my friend. I definitely do what i say i do, haha. Quite a bit. Sometimes 6 surveys in a day. I have also spent a lot of time on pv watts looking for subtle differences in production given small changes in azimuth. As I stated before, if you know of a field formula that i could use to quickly calculate a difference in estimated production without having to resort to pvwatts or sam, i would appreciate it. I am here to learn as well.

Thanks
Shock

Most vendors around here use laptops and canned software. An accurate number for what your looking for may be best done w/ a spreadsheet of about 75 col. and 8760+ rows w/ TMY3 data and formulas.

[J.P.M.]

That is a help. Thank you. I figured as much. It is generally the hottest time of day so I would think the sun is strong then. I do not want to lose 10 percent of my production. That seems like you're leaving the window open with the ac on.

On another note, I look forward to seeing that PM J.P.M. Thanks again.

PM sent. Also, FWIW, panel efficiency is somewhat inversely proportional to panel temp. Increasing ambient temp. generally increases panel temp. thus reducing panel efficiency. However, depending on array azimuth and elevation (tilt), the array may see less solar energy at that time, decreasing its output but also reducing the array temp. It's not complicated but it is a bit involved. Other things come into play as well. PVWatts usually does a fair job of a 1st order estimate. Use the hourly option for unobstructed output on a "clear" day when the offending shade is incident on the array and reduce that hourly output by, say, 75-80% for a SWAG. This is not an exact science.

[silversaver]

I am new to the business. I have only been working in solar for a few years. I am here to learn and to pick the brains of professionals who are more experienced and knowledgeable than myself. Do you have an answer to my question? I could really use a field formula that i can use when talking to our salesmen and customers about why certain facing arrays will not be as beneficial to them. I don't always have access to PV watts.
Thanks

If you have been business for few years, then you should have already know about PVWatt and SAM.

This will also offers you measuring solar position.

http://www.esrl.noaa.gov/gmd/grad/solcalc/