SWH project part 16 - up and running

It's going! I'll be leaving behind a short list of outstanding finishing touches, and a couple of suggestions for future improvements, but in the meantime it's working: preheating the water for the laundry so the geyser doesn't have to work so hard, and thus saves fuel.

Solar Water Heater opening ceremony.  The first overcast day in ages, but was
actually just as warm and twice as humid.  Sweaty.

Some of my main helpers.

Re-fitting the heat exchangers (see here for why)

Lid back on after much intricate wielding of the hacksaw.

The brazing chap from Lahore was back doing some other work in the hospital,
so I got him to attend to a minor leak.

One last piece of colourful frazzled copper.

Snug as a bug in a rug about to chug a mug of... hot chocolate?  Glug!

SolarBot doing his thing.

Modest temperatures on a cloudy morning.  In the middle of a clear day the
panels hit 80°C, and the tank gets to 65-70°C.

Again, on a clear day the output beats 50°C.  This could be improved by
lengthening the heat exchanger coils, or by moving to a pressurised tank
with no heat exchanger.  The latter is almost certainly worth doing.  When
someone gets round to it...

Finished system.  For a given value of "finished".

Tank insulated and roofed.  Among the final touches I'm
leaving for the workshop guys to do at some point is to stop
the rainwater collecting on the platform and soaking into the
bottom couple of inches of insulation.  Preferably before the
monsoon starts in earnest.

Thermal expansion coupled with cycles of thunderstorms
followed by hot clear days has done for these strips we used
to hold down the glazing.  They'll replace them with some-
thing better and redo the seals...

(This one's an extreme example - the other nine seem to be fine!)

...which should hopefully stop this happening.  They'll also put some metal
sheeting along the top edge of the panels.

SWH project part 12 - welding*

*or in actual fact, brazing.  But everyone here seemed to call it welding...

This has been a busy week, which may or may not have had anything to do with Mr P's out-of-the-blue announcement the other week that "I think we should have it up and running by the 15th". Perhaps a little over-optimistic given that that's tomorrow, but nice to have some sudden ambition introduced to the proceedings.

So the panels have been fitted into the frames, and their tubes welded together and leak tested. Pipes to connect the system with the laundry have been purchased, along with glass wool sheets to insulate them with. Polyurethane foam sheets for the backs of the panels have been ordered, produced and delivered. My temperature monitoring system is pretty much complete, and semi-installed (more on that another day).

A good week's work.

Fitting the panels required a spot of saw-wielding.

First three in place - some dropped in beautifully; others had to be beaten into
submission with planes, saws, hammers and a little brute force.

Even before paint and glazing are applied the panels are around 50-60°C, and
visibly bending.  This week it has been high 30s outside, and in the sunniest spot
on the compound, in front of what is essentially a 7ft x 40ft mirror, it's HOT.

A couple of chaps came up from Lahore to do our welding.  After they'd been
connected together some of the panels required re-beating-into-submission.

Lugging those oxygen cylinders across the orchard is no joke...

The pretty colours of tortured metal.

Finally all welded together and in place.  Time for a leak test, which in typical
Pakistani style involves about 5 hoses shoved into each others ends, and a guy
holding it on to the tap at the other end.

A leak!  But actually in one of the previous welds from when the panels were
fabricated.  Still, 1 out of 164 ain't bad.

Take that pesky leak!

SWH project part 11 - panel beating

Or perhaps more accurately, squeezing, sticking and nut-and-bolting.

A quick catch-up to where we are now - tried to post this 2 weeks ago, but a combination of temperamental internet and holidays prevented that.  So...

Frames are up.

Our sheets of aluminium had grooves pressed into them by a guy with a
hydraulic press.  This should enable the fins to be made in one shiny piece...

...or at least it would have, had the guys at the metalwork
yard, on finding that they didn't have a die the right size,
not gone ahead and done it anyway with the smallest one
they had...

...meaning that we had to improvise a method of squeezing the fins so that
they fit tightly around the copper tubes for good thermal transfer...

...which in turn meant slicing up our nice big shiny multiple-grooved sheets
(or at least paying a guy in the bazaar with some big scissors to do it for us)...

...and slicing up our left-over sheets to fill in the gaps...

...thus giving us double the number of nuts and bolts to do
up.  Sigh.  And just to further illustrate the way things work(!)
here, we were well into our third panel (with around 286 nuts/
bolts per panel) before my boss casually mentioned "I've got
an electric screwdriver here - do you want to use it?

Panel 1 of 10.  Two of us managed six between us before
we went on holiday, by which time the guy I was working
with had learned enough to carry on and finish them by the
time we arrived back yesterday.  Twice the amount of work,
and not as aesthetically pleasing, but after 2 or 3 thousand
nuts, bolts and washers and a dozen or so tubes of silicone:
Job Done.

For Gavin

An innocuous little box of screws, complete with manufacturers label:



So imagine my surprise and delight at discovering this inside:

That's Pakistani Reuse & Recycle at its finest...

SWH project part 9 - framing up

The project continues forward in bounds and thuds, much like a sack race where the competitors have labyrinthitis.  If the momentum is not kept up then the workshop guys get diverted back onto their other work (fair enough I suppose!), so it's taken a little while to get things moving again since our little break.  So I've had a fairly quiet couple of weeks working on my temperature monitoring electronics - more on that another day.

Still, this week we've started making some progress again, with I and one of the guys making a start at getting the frames put in position.  A decent trench has been dug for the pipes between the array and the laundry - and will probably remain open for a least a couple of weeks until we get our pipes and pipe insulation sorted out.

The frames are covered in several coats of nasty brown oily stuff which apparently stops the termites getting interested in our wood, and also keeps the rain out.  The downside is that you get covered in nasty brown oily stuff while working on them.  Which begs the question "why didn't we wait until it was assembled before coating them?".  No idea - they were already being painted when I came into work one morning.

We've had a couple of teething problems to work round, of the "how-do-I-screw-this-screw-in-now-that-I've-placed-things-in-such-a-way-that-I-can't-get-at-it-with-my-screwdriver" nature, along with the more expected little-bits-of-drill/saw/file-work to make things fit together properly, but on the whole I'm quite pleased that it's coming together more or less as I'd expected.

I'm not really sure what this little concrete step is for...

A little old man with a huge beard was hired in to dig this trench for the pipes.

The first cross-piece about to be fixed in.  Note our safe and healthy
collection of home-made extension leads in the foreground.

We managed to get the nearest 3 lined up rather beautifully (though I say so
myself); the ones on the far side might require a little judicious application
of power-tools to get them quite right.  There needs to be a gentle slope up
towards the middle to prevent bubble traps. 

SWH project extra - visual progress report 2

The first set of legs go in.

7 feet of doubled-up 2" angle iron is not light.  Getting them lined up is a bit of a
nightmare - adjusting it in one degree of freedom also moves it in the other five
(forward/back, left/right, up/down, plus rotation around 3 axes = 6 Ds of F).

Back legs in place.  Nobody sneeze!

6 completed frames.

Front legs in place and both sets concreted in.

Rain over the last couple of weeks prevented much progress
while we were away, but yesterday and today have seen most
of the trenches filled in.

SWH project extra - visual progress report

Frame 1-and-a-bit out of 10.

Anyone need to stick together any Synthetic Muslims?
(I suspect it's the equivalent of "guaranteed to not be made of pigs".)

We'll make the frames into portable section like this,
then assemble out at the site, like a big lego set.

First rough layer of concrete.

SWH project part 7 - the real thing

Notice the exciting lack of the word 'prototype' in this post's title.

Yesterday we started digging. I say 'we' - I actually mean one or two of the workshop guys. It's not that I don't want to help dig; it's mainly that they won't let me. I would actually quite like to help dig, but I have a suspicion that they take my suggestions of helping out as a kind of mild insult to their ability to get the job done. I wonder how they would take it if I just grab a spade from somewhere and join in. I digress.

But it would be faster if I joined in. Just saying.

Anyway, we started digging foundations for our forthcoming batch of solar panels. Having dubbed the prototype a success, for the last few weeks I've been working on the design of the bigger system, which should provide around 1000 litres of hot water to the laundry.

It might end up looking something a little like this:
















The design work is very much an iterative process, as I keep having to alter the design to accommodate that material that is only available in this size, always assuming of course that you actually know what you've bought. But we seem to now be at a point of more-or-less being able to start building. I expect that as we build we'll get through a couple more design iterations.

Here is one of my friends not letting me dig:



















They've also been cutting blocks of wood into planks to build the frames of the panels. The planer leaves something of a mess:



















Drilling holes for bolts in the angle-iron leg. The 1/2" drill doesn't want to go through 1/4" steel. As usual, safety gear is optional - even if you could find some:



















And welding parts of the legs together. At least he's wearing his sunglasses: