SWH prototype project part 4 - a bigger tank

See also previous instalments.

A solution to the leaking tank problem:



















We lined the box with some plastic sheeting* and after a few unsuccessful attempts found a way of connecting the tubes in a non-leaking manner using a short length of metal pipe and those metal hose ties you tighten up with a screwdriver. But then it was time to think a little bigger.

(*One of the recurring issues we have here is the question "what is this made of?". Will it melt? Dunno. Will it degrade over time? No idea. Will dangerous chemicals leach into the water? Who can tell? (Don't worry, this is only a temporary solution, and no-one will be drinking the water!) At the bazaar WYSIWYG applies, but that's only any use for those properties measured using the eyes and/or fingertips.)

Also, behold Peter, engineering student from NZ who is over for 6 weeks. In that Christian community small world way, it turns out he knows one of our friends from home...

And now behold one of our workshop buddies, ignoring all health-and-safety notions in true Pakistani style. While this photo doesn't belong here in any kind of thematic sense, it does in a camera-memory-card-chronological sense, and it looked cool. So there.



















So here's baby tank's big brother in situ, constructed in a similar manner (wood frame supporting polystyrene insulation lined with plastic sheeting). This one contains about 59 litres, including the water in the panel and tubes. As you can see, in its current position, the sun disappears behind a tree around 2.30pm, so we've got a bit of repositioning to do.

And here is a pretty rainbow-coloured graph depicting the other day's temperature variations - this tank got up to around 45°C, which is a fair bit lower than the small tank (as you would expect), but actually represents nearly a 3-fold increase in the amount of useful energy harvested. (Lower tank temp means lower heat losses, and this tank has a relatively smaller surface area to lose heat from.)

Towards the end of the day we got round to drilling a hole in the top of the panel so we could measure the panel temperature, hence the blue line appearing at the right hand side.



















To be continued...