Solar Panel Placement--Help Needed!

Mike T., Swampeast MO

Just got back from talking to the Director of Facilities Maintenance with the University. He's new (not the one I talked to before) and LIKES SOLAR and is, in fact, working to do some solar projects on campus!!!!

He sees NO problem with me building a small structure (essentially like a bus stop shelter) on their property. Also no problem with me designing and building as it's not intended to hold out the weather. All I'll have to do now is verify with the city that I can build as close to the sidewalk as I want.

Given the difficulties with the other mounting locations should I choose this?

Any other suggestions?

Mike T., Swampeast MO

Really need some advice gentlemen. Paper's fine and dandy for a "new" idea, but I still have an "old" problem. REALLY rough to locate solar panels!

This is the front of the house. It faces about 6° east of due south. 37° N latitude; 40° roof angle.

Photo displayed shows possible location for 2-2 sq. meter panels. Not particularly easy to access. As you can see there will also be some shading of the W panel during the morning (now) and of the E panel during the afternoon. Took this pic at about 7:30 a.m. today Dec 16th. Sunny with sun nearly as low in the sky as ever happens. Fortunately the higher sun angle when the trees have leaves puts the roof in full sun most of the time except early morning when a massive elm to the East keeps it shaded. Tree so tall you can't even make out branches in the photo--they'd be over to the right and above (but not overhanging) the house.

Dormer roof is hipped just like the main roof. A 3-meter panel would sort of fit on the front face of the dormer roof, but it would obviously overhang and the upper corners. Not very attractive and won't work with "standard" mounting and access would still be difficult.

Three-meter panel would also sort of fit above the dormer but there's only about 30" of roof before it hits the ridge--so the panel would be sticking up over the ridge by about 4 feet. Might not be too bad if I could devise a way to mount, but access would still be far less than ideal because the top would be so far above the roof on the back side--would be at or above my head level from a toe board. In a way though this is the best access as there's a valley leading down to the 2nd floor balcony at the rear. Best however for collection as it would almost always be in complete sun. It would also be virtually invisible from the sidewalk.

Vacant area at left side of picture is owned by University. You can see their facilities maintenance complex below. Note that the camera is virtually at the level of the roof but I was standing on ground level with my front yard--that will give you an idea of the slope in the lot--about 25' drop over 180' and quite evenly sloped.

I have verbal permission that I might be allowed to "do something" on the lot, but still problems. To keep my house from shading the collector for hours each day it would have to be in the very front portion of the lot--either that or be installed on a virtual tower. Lots of students and a number of party houses around so there's NO WAY I'd ground mount anywhere near the sidewalk. Have thought of building a fairly small shelter and mounting panels on the roof. Since property is state-owned I'd probably have to employ a certified engineer, union labor, etc., etc., etc. Something "simple" would probably wind up cost MANY thousands... Would also have to run the piping underground--fortunately the boiler room is on that side of the house at the front.

Any suggestions (no matter how outlandish) GREATLY appreciated!

jp_2

OH BOY!!!!!

a verbal OK from an "employee" to build a permanent structure on university property? permits,fees,inspections.......

Mike T., Swampeast MO

Employee yes, but the actual director of facilities maintenance, construction, etc. He's the one with the authority to approve so when he says "yes", I don't see much problem. I just have to give him a drawing, plot plan and fill out a form for "volunteer" labor on what we both consider a "landscaping" project. He told me there are "some plans" to expand their parking area into this lot, but not using this portion as the elevation difference is too great.

Previous man in his position wasn't as warm to the idea, but this guy LIKES SOLAR!

Just got back from city hall where I talked with P&Z and inspections. No permit required, no fees, no inspections because it's University owned. Not even a setback requirement. I can build very close to the sidewalk. Perfect--not only for solar collection but for use as a pedestrian shelter. True win-win-win situation for all involved.

Solarstar

Mike.. Do these trees shade that roof in the spring and summer.. Don't worry about the winter????? Also 40 degrees is perfect and so is your 6 deg to the east. But Trees grow ...Paul

Mike T., Swampeast MO

> Mike.. Do these trees shade that roof in the

> spring and summer.. Don't worry about the

> winter????? Also 40 degrees is perfect and so is

> your 6 deg to the east. But Trees grow ...Paul



Yes, some roof shading from those front trees when the leaves are out--mainly mid-spring and mid-autumn. Above the dormer however the trees would have to be considerably taller to block the sun. They're a variety of Bradford Pear and some storm will take care of them before they get too tall...

The now completely viable alternative to roof mounting is at the front of that lot to the left. 12' x 7' or so "pedestrian shelter" open on three sides with panels on the "flat" roof that actually slopes slightly to the one solid wall at the back.

Mike T., Swampeast MO

Yes, some roof shading from those front trees when the leaves are out--mainly mid-spring and mid-autumn. Above the dormer however the trees would have to be considerably taller to block the sun. They're a variety of Bradford Pear and some storm will take care of them before they get too tall... With selective pruning I've been keeping them about their current size for a few years however.

The now completely viable alternative to roof mounting is at the front of that lot to the left. 12' x 7' or so "pedestrian shelter" open on three sides with panels on the "flat" roof that actually slopes slightly to the one solid wall at the back.

Wide true boulevard (divided street) in front of the house. The area where I'd build the structure is ideal with regards to shading. Just a few small shadows from VERY high branches around noon-time in the dead of winter. Otherwise completely in the sun.

Solarstar

Mike: Go with the Any mount that is nearer to the ground..Period. Roof mounts are a pain.. Don,t get too hung up on shadow /heat loss on hot water panels since at 37 deg lat. you will be ok. I'm at 45 deg.. PV's hate tree branches, solar thermal will tolerate them as a small loss.More to follow .Paul

Mike T., Swampeast MO

"Nearer the ground" was my thinking as well. Panels will be evacuated tube. No PV currently planned.

ALH_4

shelter

Something like this?

Who assumes liability for the structure? It seems pretty benign, but there could be at least one hot pipe running down the outside. No doubt, the university would want to formally approve any plans before construction begins. What about maintenance of the structure? Would there be any ADA issues? It sure seems safer and simpler to keep it on your property if at all possible.

Mike T., Swampeast MO

Aerial View

Black outline is my property. Red dot shows boiler location. Red rectangle shows where'd I'd locate the shelter with roof-mounted solar panel(s).

Conveniently, the photo appears to have been taken in mid-winter fairly late in the afternoon. Judging from the things I see, I'm almost positive it was taken last winter. No--it's MUCH newer because I see the fountain in the front yard between the houses. It was installed this spring and leaves were definitely on the trees. From the length of those shadows this photo is probably just a few weeks old.

Am I missing any obvious problem with the location?

Larry Weingarten

The only other...

... location I see is wall mounting, like overhangs. It can work nicely with four foot wide panels. The shelter roof does have lots of plusses though. If you do roof mounting, good standing room, particularly at the foot of the panels is useful.

Yours, Larry

Mike T., Swampeast MO

Yes, very similar but mainly wood and a bit more detailed to look reasonly in place in an old neighborhood. Can run the piping inside the back wall before it enters the ground--no way for anyone to get burned or hurt anything unless they get on the roof.

It's on the one level area of the lot so nowhere to fall. Will use an on-grade slab so anyone could access. No electricity and already well-lit by a street light in the island that divides the street.

Maintenance (including mowing the immediate area) my responsibility and already part of the deal. I already mow there frequently anyway.

Must agree that I'd prefer it on my property but other than the roof there is no possibility anywhere--even in the area between the two houses. Too many trees, too much shading from the houses themselves and too great a slope to the rear.

Mike T., Swampeast MO

Thanks Larry. I was looking at the front wall as well but just can't bear to mount panels on the front facade of a 100+ year-old house.

Solarstar

Are Vacc tubes going to be safe near the road close to ground.?? Kid throwing rocks at the glass!!Esthetics/clean design? Damage to any exposed piping?? What is pumping distance Vs. a closer roof or as suggested wall mount maybe off to the side of your second floor..Having them on there property wouldn't sit well with me, especially Vac tubes! Paul

Solarstar

Mike what is your sun Data. (hours per day avg.for the year and winter /versus summer. . what is Swampeast MO near? Paul

Mike T., Swampeast MO

Have the sun data here somewhere plus some good insolation measurements from a nearby agricultural reporting station.

Am in Cape Girardeau, MO. SE part of state. 100 miles S of St. Louis on the Mississippi.

Mike T., Swampeast MO

Yea, the vandalism thing certainly occurred to me as well--that's why ground mounting is out. Kids will be kids but surely it would take some pretty serious effort to harm them 9' - 10' up.

Wouldn't mounting off a wall (west side the only feasible) greatly reduce the amount of time in the sun due to shading by the house?

Pumping distance from shelter mount about 60' - 70' with an elevation difference of about 15'.

For roof mounting (two panels one on either side of front dormer), pumping distance about the same due to higher elevation difference and less direct route. Mounting off W side wall would be very short.

In my mind's eye the aesthetics of panels on the shelter roof would be most pleasing of any of these possibilities.

Solarstar

Results Solar for St. Loius
Solar
Radiation
Month (kWh/m2/day
1 3.60
2 4.22
3 5.09
4 5.40
5 5.67
6 5.83
7 5.86
8 5.50
9 5.33
10 4.83
11 3.53
12 3.01


Year Avg 4.83

Of Course you ar looking at 2 sq. m of Vacc tubes times the 3514 btu. X about 80 % eff. .

Example for March. 2 x 5.09 =10.18

10.18x 3514 btu = 35772 btu x .8=
28618 btu average per day for that month. Also heres the data in excel.

Paul

Mike T., Swampeast MO

Thank you VERY MUCH Paul! Will definitely help.

I've run sizing numbers over a year ago and found that 3 ideally located square meters of evacuated tubes were just about right. What you provided seems to confirm.

4 square meters would be a better for winter but would likely waste heat during mid-summer. This will be the one AND ONLY good thing about the big hydronic towel warmer connected to my DHW recirculation system.

My ideal panel sizing goal is 100% solar space heating for 6 hours during a sunny day with high temp around 40°F even on the winter solstice. Somewhat cooler days will still see a solar contribution to space heating provided overall heat loss drops below about 25mbh once during the day and my logs show such to be a VERY common occurrance--it essentially has to be completely cloudy or quite cold by our standards for such not to happen.

When the solar can't be used for space heating it goes to DHW. I sincerely believe that the system will be most efficient when driving space heating--these big old standing iron rads and TRVs are again proving their worth!

1solarguy

awning

Have you considered configuring the tubes into an awning over the front first floor windows? It would shade the windows in the summer and let the sun in during the winter.
It would be worth your while to have someone do a site analysis with a solar pathfinder. Those branches look problematic.