More Tile -- and More Solar

Today started out with the usual, trying to find the right supplies for another strange issue.  One would THINK, that you could walk into a roofing supply company (that means that ALL they sell is roofing supplies) and ask for a flashing to go over a 3/4 inch copper pipe.  One's conversation may go something like this...

One - "Good Morning"

Guy sitting at desk of roofing supply company -- ...............silence

One - "Would you have a roof flashing for a 3/4 inch pipe

Guy -- Yes ...  for a 2 inch pipe, right

One -- No, 3/4 inch copper, it's for a water pipe through the roof

Guy -- "those are normally a 2 inch vent pipe

One -- No, I'm putting up a solar collector. (explanation... yada yada)

Guy -- I can probably order something like that

One -- ah, how long would it take to get here

Guy -- probably a couple of weeks...

What!! You've got to be kidding me.  This pretty much describes the normal expectations of people when it comes to the building trades.  I can get on eBay and within two days have just about anything I want.  BUT, if you don't know exactly what you want in advance, it would be nice to be able to actually buy something like this.  The kicker is that he can order it, wait 2 weeks, another trip into town to pick it up, and then it costs twice as much as the internet. 

I guess I'll be paying shipping, then...  eh??

Roof progress, it's beautiful!  And it's the only finished surface on the whole place except for the garage floor.

The other day I showed you the frame supports for the solar collector.  I painted them, and then had to go up on the roof and lay them out and attach them.  This was accomplished by determining the location, then drilling a hole through the roof so my wife could figure out where I was from below, then, while she held a 2x6 in position, I put 4 giant lag screws through everything to sandwich the roof deck between the board and the flange.  Also put roofing sealant everywhere to keep things watertight. 

Today, the roofers came back, and in additon to a million other things, they installed the roof tile around all the brackets and flashed everything with giant sheets of lead.  I wasn't there, but it looks like they pound the lead over another tile to copy it's shape, and then place it similar to a tile over any holes they have cut.  Pretty cool system, actually.  The lead is not cheap...

Another thing the tile guys did was show me how to walk on the tile roof.  The other day I broke a tile getting up there, which is obviously a bummer.   Anyway, you walk on the peaks of the tile, with your foot spanning the valley, so your weight is distributed over two tiles.   AND, you have to walk on the bottom edge of the tile, because that is the spot on the tile that connects directly to the next tile below it, and thus distributes your weight to the roof deck rather than making a tile bridge, which breaks the tile. 

So, I had so much confidence with my training that I hand carried the collector frame right up into position. 

What you MAY notice is that the copper connectors do not GO anywhere...  That is because I had some holes drilled into the roof deck where the copper pipe comes out from the attic, but the roofers saw those holes and promptly fixed them....  So, one more thing to ask them to redo.  It's easy to make the hole, but it bumms me out to have the guys rework stuff. 

BUT, if the roofing supply company would have had the dang pipe flashing... We wouldn't have this problem....

The other thing that had to be figured out was how to get the sensor wires from the thermistor down through the tile and roof deck.  After some thought, I decided I would just drill a hole in the frame pipe, and another through the deck directly under the pipe flange (through the mount), and push the wire straight down...  Which I did... Should have taken a picture... It was cool.

OH, to enable me to HAVE this thermistor, I had to buy the entire Solar Pumping Station... Why??  because, of course, nobody keeps a thermistor like this in stock.  They can order it, though, which goes from the plumbing supply store, to the distributor, back to the factory, and then has to repeat the return trip...  Since I eventually needed the pump station I just bit my lip...

Here is a picture of the Taco Solar Pumping Station...

Na, that's the cat infestation....  There is an idea...  Use cats as a packing material...  How about this...

I also learned to solder (or sweat) copper pipe.  There are many things that need to be sweat fitted together. 

Here is an example of my soldering, this is the left end of the solar collector.  This is where the collector sensor also goes.  The 3/4 inch threaded hole is for the "air elimination valve" will go.  The male pipe end will act to hold the water heater pipe connection (my choice for connection) which will connect to the roof penetrations...

The leg bones connected to the thigh bone...
The thigh bones connected to the hip bone...

etc...

Goodnight...

Ok, that's it for now...  We will soon talk plumbing again...  Goodnight...

Solar Hot Water Collector

Evacuated tube, that is...  There are two basic kinds of solar hot water heaters out there (besides your typical garden hose in the sun), a flat panel collector, where you have a circuit of copper tubing running inside an insulated flat chamber, and evacuated tube.  The whole tube is not in a vacuum, but actually the outer shell of the tube is a double walled tube, and between those walls is an evacuated tube.  In the middle, there is a fin mechanismn that picks up the heat (trapped by the vacuum and the fact the glass is thermally opaque, so it can't effeciently radiate its heat back through the glass).  The fins transfer the heat to the copper tube in the middle, which contains a little bit of a working medium, which boils and evaporates, becomes superheated, and then transfers the heat to the top of the tube, where the copper tube is exposed to the insulated manifold header, where the water runs across, picks up the heat, and takes it back to the storage tank. 

No, I didn't invent this thing... I just bought it, and I think it's really cool.

There is, of course, a raging debate over which type of panel is better, but bottom line, the flat panel is normally cheaper, and the tubes are more...not for me, though, because I don't buy anything the normal way.  In our climate, we could have easily used either, but we chose the tubes for these reasons...

1.  Cool factor (yup, vanity)

2.  Higher operating output

3.  Much higher temperature output (not more heat, but more "temperature voltage")

4.  Higher resistance to hail

5.  Modular... Broken tube, change it out.

6.  Easier installation (perhaps)

7 Higher resistance to freeze

8.  Availability

I could go on...

Anyway, 30 tubes in all, have the potential to produce about 38,000 BTU/Day, or the same as 11.3 kWh per day, which at our utility rate of about 12 cents/kWh that translates to about 41 dollars per month...average.  Payback in my opinion is instant, especially if we ever had to sell the house.  There are other advantages, with tricky accounting, and I would never go into those here ;-)  Suffice it to say I have a 1.2 million pound heat storage device ;-)

OK, so here is a little experiment, moring haze, with no load on the panel, so the pipe can't get rid of it's heat, hooked up a thermistor to my non contact temp gun.  The big number, 67F, is the temperature of the grass, and the little temperature is the heat pipe, 200F and climbing fast.

Then off to check out the progress on the tile.  Most of which is now laid in the "fields", mainly they have to do the ridges and then tidy up around plumbing and flashed walls, neither of which is going to happen anytime soon, as I need to line those guys up...

You can click on these, which make them big, for much better color...  It rained in the night a little bit, which washed away a lot of the tile dust, so the color was even better than before without all the "dusty rose" powder color on things.

Starting the Master Bath tile, which was about the last thing to go.

Then, off to my regular warehouse hardware store for something to build a frame to hold the solar collector.  Of course, with a normal house, and a normal person, you could have just mounted the thing on a 5/12 pitch and about averaged out the use between summer and winter at this latitude, and on a shingle roof you wouldn't have to do much for flashing other than a little silicone...  But, we are on a tile roof, so the collector doesn't sit on the tile, it sits on the deck below, and has to be suspended up above the tile.  So here is my solution...  1/2 inch pipe fittings.  I have also decided I want to optimize the panel only for the winter season... Why??  Because the rest of the year I am trying to maximize the use of the desuperheater (which makes the GSHP run more effeciently).  To make a short story long, the solar panel with run us a chance of overheating things in the summer, because between the desuperheater, the solar collector, and low demand for hot water, we could easily cook the water past the boiling point (at atmospheric pressure, anyway, which of course we have in excess of 50 PSI which significantly raises the boiling point)...  regardless, by optimizing the panel at a higher angle in winter, there is less angle of incidence in summer, and the panel can't produce as much heat as it otherwise would in the summer....hopefully causing us to not have a boiling event which causes the pressure relief valve to let go.  In addition, it gives me more effeciency (though with less sun) in the winter, when I need the heat more.  Additionally, in the middle seasons, I am also closer to optimum when there is less chance of the desuperheater being in operaiton... Bored YET???

This is a closer look at the header, which is an extruded aluminum piece that holds the copper manifold and accepts the evacuated tubes, as shown...  They just sit in there, nothing magic.

Nifty little plastic widgets at the bottom pop onto the rail, and then allow you to tighten and push up on the tubes, holding them in position on the collector.

Another view down the row of 30 holes... 

Any why the upside down and backwards h shape?   Because I wanted the frame to have some resistance to the shear effect of having the collector being fairly heavy, and the pipe brackets being fairly small.  This makes the thing much harder to "twist" and makes it a lot stronger.  I honestly don't think you will see any of this from the ground, which is all under the collector tubes, but, I painted them anyway... brown.

So, my strategy for installation...  Tomorrow I am hoping to get the vertical supports actually mounted to the roof deck (the only place not tiled in) and then they can actualy drill holes in the appropriate place for the tile to slide over the pipes.  Then, I will have them tile the field under the collector completely, but leave a perimeter at the sides and bottom.  The copper lines coming through the roof have to wait for a special piece of flashing I ordered (later in the week), but after than happens, I can pierce the roof with the copper and then solder on all the fittings, as well as run the wire to the thermistor (temperature sensor for the controller).  I can then mount the collector frame and header.  If you mount the tubes dry, repeated heat cycles aren't good for their health...