Permits 'n Parts

Permits

Yay! I got my plumbing permit yesterday at the SF Department of Building (1600 Mission Street) for $164. I had no idea how much it would cost me and this price seems very reasonable.

Dave the Inspector was not interested in the system schematic that I created. He said their biggest concerns are: (1) how the panels are affixed to the roof, (2) placement and strapping of the solar storage tank, (3) that I'm real careful about not allowing water from the sytem backfeeding into the potable supply. He recommended that I refer to the California Plumbing Code for any code questions that I will have. Unfortunately for this project, I'm much more familiar with the electrical code (NEC) and how to find things in it than for plumbing, so I might have to bring on a consulting plumbing. We'll see...

Parts!

Yesterday, the first small bits of my system arrived via UPS. The parts on hand from pinky to thumb are: a pressure relief valve, gate valve, flowmeter, 3/4" full port ball valve, and a tempering valve. Additionally I received a swing check valve (plumber's diode) to keep water moving in one direction. Getting the the first few parts makes this project seem more real than any Dia diagram or SketchUp model can. woO! The big component (panels, storage tank) will be coming up on a separate non-UPS truck in the next week or so. It's time to make space in the garage...

Parts Ordered!

I put in the order today for the components of my solar system with
Solartrope of Orange County, CA. At this point I'm not sure that
this system requires an expansion tank like I have on the schematic.
I have asked SunEarth in an email whether or not it is and hope to
hear back soon. Ideally the air headspace in the drainback tank
is all the expansion space I'll need. This would be better because
I wouldn't have to buy yet another component, a large one at that,
and the rubber diaphragms in expansion tanks eventually wear out.
One less thing to go wrong is certainly a good thing.

The quotes I got from both Solartrope and another company both
specified a painted SunEarth collector (Mdl. EP-32). For ~$100 per
collector I opted for the black chromed ones. They're a bit more
efficient. Also, when the pump on the system turns off because the
solar storage tank is up to temperature, then the collectors should
drain, leaving that paint cooking at 300+ F (150+ C) in full sunlight.
Double, double toil and trouble, sunlight burn and black paint
bubble!

Parts List:

SunEarth 80 HE-1 80 Gallon Tank with Internal Heat Exchanger.
SunEarth EC-32 Collector, Black Chromed, 4x8, 1" Header.
STECA 0301U Steca Controller with display, freeze protection and 2 sensors.
Mixing Valve (075NL-S) 3/4" Mixing Valve, Sweat Connections
Grundfos UP15-100F
Grundfos CF075 Flange, cast iron 3/4"
Winters Hot Water Thermometer
3/4" Brass Swing Check Valve
Pressure relief valve (150 PSI) 3/4"
Blue White 0-10 GPM Flow Meter
3/4" Ball Valve - Full Port 2
3/4" Male, Threaded Drain Valve
SunEarth 5 Gallon Drainback Tank
SunEarth RexRack 2... 3 RexRack Front Feet
SunEarth RexRack Rear Telescoping Legs (58-97")
27 #12 3/4" Self-Drill SS Steel Screws
8 3/8" SS Strut Nut Assembly w/Clips
5/8" BA SolarStrut

My good friend Dominic is allowing all this gear to be sent to his
place of business nearby here in the city so that I can avoid
expensive crating charges. If you have access to a proper
shipping/receiving area that can accomodate large trucks and has a
forklift, you can save a couple hundred dollars!

Parts should be here within two weeks. woO!

Next, I'll submit a bunch of docs (schematic, rack specs, and
SketchUp 2D view of panel location) to the SF Bldg. Dept. May all
that go smoothly...

System Schematic

Just finished the first seventh pass of my system schematic using Dia. My friend Devan suggested using this solar template. The only object I had to make myself is the symbol for the pressure relief valve. My schematic is based on the OG-300 certified SunEarth system schematic that's listed on the SRCC (Solar Rating and Certification Corporation) website. I wanted something easier to read than the SRCC diagram. I need to get this schematic `proofread' and do some final cleanup and then submit it to the SF Department of Building Inspection which I hope to happen this week.

Solmetric SunEye Solar Site Survey Sussed

I completed a solar site survey today on my roof in the two most promising spots - to the left of our skylight (see green dot in house view) and to the right of our skylight near the two sewar vents. The spot I like the most is to the left of our skylight (green dot on house top view), but it could be mighty ugly to have 8' panels tilted up here at 49 degrees from the front of the house.

Annual `solar access' according to the reports is 99%, which isn't a huge surprise, but woOO(!) nonetheless.

The big yellow band is where the Sun is in the sky at different times of the year. Yeah, I know it's hard to read b/c blogger.com scale's it down a bit. But anyway, on the left, 06:00 is sunrise and 18:00 is sunset near the summer solstice path. In the fish-eye image, there is only a little shading in the late afternoon. You can see that in the yellow highlighted band where the green-ish images appear near the horizon. You can see how the chimney is the biggest `threat' to my solar resource just beneath the blue December solar path line.

The Solmetric exports an HTML report that gives tons more info that just these images. Providing this report to the State is one of the requirements of getting the California Solar Initiative (CSI) rebate. One less thing to do!

SunEyes and Shading.

I went down to the PG&E (our local utility) Pacific Energy Center to borrow a Solmetric SunEye from their tool lending library. They currently have this GPS-enabled model. I've used their non-GPS device and look forward to the simplicity of using this one. I hope to make it up on the roof this weekend to take readings in promising areas of the roof.

My SketchUp model now sports shadows. Below you can see the shading at noon on winter solstice (Dec. 22).

Our chimney is 74" (187 cm) tall! It casts an unfortunately long shadow =( At this point I'm thinking that the two panels can be squeezed between the skylight (circle in square bit) and the west edge of the roof, but this will make them quite visible from the front, especially since I'm planning on tilting them up at 49 degrees. The good thing about this location is that it keeps the pipe runs short and leaves a good deal of unshaded space on the roof should we ever want to install a photovoltaic system. Another possible location for them is in front of the two sewer vents.

In other news, thanks to Bob and Adam at SunEarth I got a detailed mechanical drawing of the collector that I would like to get (SunEarth EC-32). From that, I created a SketchUp model of the collector so that I can start laying them out on the roof of my house model. woO!

SF Permits and Inspections

I spoke with `Steve' today in the division of Electrical and Plumbing at the SF Department of Building Inspection. He said that I need to come down to 1660 Mission Street, 3rd Floor

with plans for this system.   At this point I'll only need to show
them a sketch of where on the roof the panels are going to be placed.
Also, I need to calculate the total weight of the water-filled panels
with the rack and give some idea of the "bolt pattern" I plan to use.
When they determine that I am worthy and my plans aren't loco, they'l
issue me a Homeowner's Plumbing Permit.

At this point, I don't need to show the plumbing.  When they come to
inspect the system down the road, they will want to see how it is all
plumbed.

The House in Question

Here's a Google satellite view of our house.

The light beige part is flat, the darker pitched bit above that is the older part of the house.  Currently I'm planning to put the panels to the left of the skylight facing due South.  There's no shading there, but still I'm planning to get a Solmetric SunEye from the PG&E PEC tools lending library at the end of the week (free!) to do a proper shading analysis of the site.

I've gotten reasonably handy with Google Sketchup, so I've created a no-frills model of my house in 3d to get a better idea of how to lay out this system:

Yeah, I know there's a door to nowhere =)  It leads out onto a deck that I might eventually include in this model.  I had hoped to simulate shading in this model, but it looks like I'd need to get the Pro version of SketchUp and that's not in my budget.  So, next steps are:

1. Solar site survey.
2. Settle on a Bill of Materials for this project.
3. Submit system plans to the city.

I'm getting sage advice and help from an engineer friend of mine who suggested the city might have concerns about wind loading on the panels given the pitch that I want (~50 degrees), so #3 needs to be done soon.

First Steps

My budding family uses a good deal of hot water - dirty clothes, baby baths, and now a dishwasher.  We can easily drain our 30 gallon hot water heater a couple times a day.  We heat that water with natural gas that is actually pretty `cheap' in the Modern Economics sense, but expensive for our species.

I've been a long-time solar hacker, dragging homebrew tracking photovoltaic systems to Burning Man, building small grid-untied DC LED night lighting systems for the homes I've been in, and volunteering with GRID Alternatives installing solar electric system on low-income housing here in San Francisco.  Along the way, I picked up my NABCEP Entry Level certification for Solar, making me (foolishly?) confident enough to decide to self-install a solar thermal system =)

Happily here in California we currently have what look to be excellent rebates for solar hot water. You can read about that here.  My calculation of the state rebate for the system I want to install is a generous $1875.  Further helping tamp down the bill is the 30% Federal tax credit for solar thermal.  I hope to have a total system cost for under $3000 when all is said and done.  Stay tuned...