Sunday, May 27, 2012

Roof and Solar Install

The active period continues and just last week we completed our solar installation immediately after the roof install.  The photo shows the Schuco racking in place and the first day of panel installation is nearly over.  The racking took one day to install, with the 45 250W poly panels an additional two days.  Roof pitch is 8/12 - walkable, but not that comfortable.

Schuco rails are heavy duty.  We received our rails from our supplier DTE Solar's old stock.  This was fortunate since the rails were a full 20' long.  The new products out there are apparently available in standard 10' lengths only.  Longer lengths are special order.  I was glad we were able to get these longer lengths.  The L brackets, which are attached to the roof throuth the shingles and into the rafters with 1/4" x 3.5" stainless lag screws are mounted along each rail, 4' OC.  Pre-drilled mounting, with a special flashing that tucks under the shingles and sealant is applied under the brackets as well.  This is a long and messy job - the mounting of all these brackets.  It is also very permanent.  Once in place, it becomes an issue to repair the roof under these feet.  And all the traffic on the roof in warm weather has really worn down the shingles.  Especially near the scaffold.  However, we are expecting the shingles will last a long time due to their being protected a great deal by the panels.

Note:  We originally intended to go with a standing seam metal roof.  Price for our Vicwest Tradition 100 22ga painted steel roof was $7.50/SF (this is a very thick sheet metal gauge for steel roofs), compared with $2.30/SF for the shingles (including full Ice and water on the south side and ridge vent).  Major difference in cost, but we were totally willing.  It would have been an excellent looking roof, but also extremely long lasting, recyclable, good for rainwater collection (no much concern of the tar from shingles), and waterproof.  In addition, the solar panels would have been mounted directly to the steel seams with S-5! clamp mounts, giving a very sleek and low-profile integrated panel install.  Unfortunately, the timing didn't work out and we had to meet our microFIT deadline, so we went with a shingle roof (not to mention we are elated at the cost savings).

HOWEVER:  One thing to keep in mind:  The metal roof with the S-5! mounting would have been a very versatile roof/solar system, because the S-5! clamps can mount anywhere along the seams, and there are no penetrations through the roof.  The rail system is quite a downgrade (although significantly more expensive than the S-5!) in my view because once those rails are in place, they are not moving.  Whatever the future brings, it must go on those rails.  And one thing I'd like to see in the future is that we increase the number of panels on the roof - no chance with those rails - with the S-5!, it would have been simpler, I think.  I do foresee that people will want solar PV even beyond the microFIT limits.  I certainly do - the cost is so reasonable right now, and I feel it can be made even cheaper by not using the inverters - for example solar PV water heating can do fine with DC - no need for AC.

The panels are on a portrait layout, 3 rows of 15 panels for a total of 45.  6 Rails, 2 for each row of panels.  The rails have a splicing hardware which is basically a bar that slides into the rail grooves and screws in place.  Note, with the metal roof and S-5! clamps, it would have been a landscape layout. We have two 5kW 'Power One' inverters for a total output of 10kW.  The array is rated at 250x45 panels for total of 11,250W.  One is allowed to install up to 12kW for a 10kW system capacity.  We could add 3 panels to the system - perhaps on the garage in back?  Each inverter takes 2 channels of DC input.  We have therefore divided the array into 4 blocks - 3 with 11 panels and one with 12 panels.  This uneven-ness is no problem for the inverters to handle (without any loss of energy to speak of).

What is annoying to me is the system architecture mandated by the MicroFIT program.  It centres around this Anti-Islanding feature.  Simply, the system is not configured (and cannot be configured, I'm told) to provide the homeowner directly with power, bypassing the grid.  In other words, the array serves the grid only, and the inverters shut off automatically if they detect no grid.  This means they cannot be used to provide the household with power.  Personally I hate this - it means there is no redundancy benefit for the owner.  When the grid is down (during a blackout), so is our own generation system.  This serves to protect hydro workers from being exposed to electricity while they repair the grid.  Investigation is needed to see if there is a safe and legitimate way around this.

Saturday, May 12, 2012

Ext Frames, Roof, and Solar Installation

We've had a very active recent month.  There was a tour from the recent Passive House training held in Toronto.
We've received gifts-in-kind from Terrell Wong at Stone's Throw, 3C Carpentry (Carlo Terzi), Jimenez Carpentry, and friendly support from neighbours.  Of course, Fourth Pig Workers Co-Op have provided excellent carpentry services throughout.  We've also had strong support from our metal roofer Heritage Tinsmiths, who waived a significant cancellation fee when we ran into some timing and other issues.
And we've had another volunteer added to our list of observers and helpers.
PV Master and DTE Solar have been excellent as well. - Plugs for you all!

Our solar PV installation is shaping up.  One of the issues was the load side electrical service which must be in place first.  We really wanted to avoid an ugly overhead service to the building (where birds sit and poop on cars), and the balcony on the south-w corner made it even worse (electrical lines must stay well clear of openable windows and balconies).  It also results in these plastic conduits running all over your side facade.  We'd been working with Toronto Hydro since quite a long time ago to get an underground service to the building - but costs and timing were major issues.  They request $1000 to make a drawing, plus $6000 to $12,000 for the actual work, and 3 months lead time.  Like everyone else, we ended up having no time or money for this, so we placed our own hydro pole at the corner of our property and made our own underground service to our own pole.  From there it is a short 15' overhead run to the city's pole.  One of the design considerations with utility rooms is the following:  On a corner house in the city, you often will have additional choice as to which side of the property the service comes from, as in our case.  With the new smart meters, the electric company is less concerned with mounting the meters close to the front of the house - although it is still preferred.  Mid-span connections are also possible - so there was ample choice for us.  I found out it is even possible to have the main service attached to our detached garage - and have the house fed from the garage rather than vice versa.  However, getting the service to the electrical panel was tricky because we wanted the electrical/utility room on the north side (back of the house), since it is a room without windows - this location was the furthest from the possible meter locations.  During the concrete wall stage, we placed a 2" conduit in the ground around the building  from the electrical room to the anticipated meter location - a run of about 50'.  Later, we dug up the ends of this conduit and routed it into/onto the building exactly where the meter and panels would be.  Connection costs to the city for electricity are minimal (currently the standard price for a permanent connection is $850).  We paid $1500 for the pole installed, and another $1300 to run the service to the pole, including trenching, conduit, wire, weatherhead, etc.)  While I'm not thrilled to see another pole in the neighbourhood, I do hope that one day, I can work with hydro to extend our underground service right up to their pole and do away with ours.

Hydro Pole Installation:  You need to hire a company with this special truck designed for installing hydro poles.  In our case, York Power and Lighting.  Note the pole length.  This was a standard pole of 30'.  We needed only about 17.5' out of the ground, so we chopped off 7.5'.  burial depth is 5' for this small pole.  4' is ok as well, but I elected for 5'.  This was a good thing because the trench up to it stayed open overnight in quite windy weather - I was glad the pole didn't fall down.  Minimum height is 16', per Toronto Hydro specs.  
Lifting up the tall exterior frames.  This is 2x8, 16" OC with two rows of blocking and diagonal strapping on the backside.  Not quite meeting the tall wall specs in the code, but OK, since it will be thoroughly braced to the 2nd floor assembly when we get the scaffolding up.  Lifting it was a piece of cake with a chain fall/lever hoist anchored to a large beam in the cathedral ceiling assy.  With the other walls, there was a lack of large beams to anchor to, so we connected to the 1/2" anchor bolts in the concrete wall on the far side of the building.
Note the tilted blocking.  This is 2x10 blocking material in a 2x8 stud frame.  Tiled to ease the installation of the cellulose later on. I would have liked it if we thought of this earlier - the tall walls around the stair could have benefitted from this idea.  You can see the temporary frame we set up on the ground to build the next wall.  That was the longest wall we built and lifted in one piece - approx. 2000lbs, and 38' x 20'tall.  Two hoists were employed.  Worked fine.

Tall walls and rafter beams in place.

South side rafters going in.  These double 2x6 rafters turned out to be a fair bit of labour.  The building is overbuilt in some areas, but I'm happy about not skimping on the frame and concrete.  We do plan to economize in other areas - but not in these.  With our overbuilt frame, I feel confident our structure will do better in this time of climate change - who knows how much snow will fall next winter, or how heavy future solar equipment may become?  The historical design snow load in North York is about 1.2kPa, but only 30km to the north, it increases dramatically.  The rafters are placed at 16 1/16" on centre, and carefully laid out so the pattern is centered on the building.  This was to accept the standing seam metal roof (another story), and so that the standing seams would line up exactly with the 3" thick rafters.  Thus, the seam pattern on the roof would also be centred on the building.  Don from Heritage Tinsmith told us the standing seam panels end up being a little over 16" on centre.  All this will allow the solar panel installation to be very strong and secure.  It will be easy to keep the 5/8" T&G roof plywood in line with the rafters - we'll just provide a 3/8" gap between panels to compensate.  The fact we are using 3" thick rafters means it will be easy to install the plywood regardless.
Lots of rain in recent days, making the whole place a mud-bath - mainly because of all the grading and trenching going on.  Tip:  trenching in winter can be cleaner due to less rain.  The problem is the mud is carried right through the building at this stage since we are working on the roof.  Note the black sealant we've applied to the attic floor seams.  It is Bakor Aquabloc.  Very effective, but messy for the first day since it is water soluble until cured - and it rained just an hour after we trowelled it on.  The black stuff flowed and got deposited as a residue in other parts of the building.
Sewer and water service also connected and you can see the new bit of fence we had to put up once the hedges were mowed down during the installation.  This was OK, however, because we planned it that way.....there will be a short walk through the hedge in this area, to the east entrance.  The sewer service is a single 6" PVC pipe with 6" clean-out.  The pipe is reduced to 4" before it goes into our building through the 4" pipe we installed during the footing pour.  We should have installed a sleeve for the water service as well, because they had to dig under the footing to place that in any case.  You would think they could have used something like a 2" earth auger to drill through the earth - but they dug it - messier.  The city's contractor did this work - they charge about $7500 to do a sewer connection, and about $3000 for a water service.  We elected to re-use our existing 3/4" water service, but still had to pay some $400 so they could inspect it.  The sewer pipe is simply left open for all the sewer gases to enter the building - we've since plugged it.  Wondering if we can get rid of our portable toilet soon, which costs about $175/mo in winter, and a bit less in summer.