Web log of tank temperature

[Paulh_Boats]

Yet another web-tastic data log can be found here:

http://www.millibee.com/logtemp/tank.htm

I've used an old laptop (24-26 watts) with a 1-Wire USB adaptor and a sensor temporarily glue-gunned to the retro-coil boss.

A neat little program LogTemp does all the work and FTPs graphs and XML data to my website, about every 20 mins. On the website is a HTML page that loads the latest graphs - I've added a bit of theory about Newton's Law of Cooling as Ivan was once interested in analysing a temperature graph.

The critical point is of course how much the temperature falls overnight, but quantifying the data is the rigorous approach.

cheers
Paul

[Ivan]

Nice graphs. Intrieged by the long linear heat loss. Doesn't look like someone using water (would expect variation), but doesn't look like exponential decay - which is what we'd expect. Any ideas?

[Paulh_Boats]

Great work Sherlock. There is a simple explanation - I disconnected the laptop to work on the insulation.

When I reconnected it LogTemp drew a straight line from the last temp to the new temp!

I also drained the tank. It was touching the back wall and during the summer I noticed the other side of the wall was warm. So I nudged it forwards and jammed 20mm of polystyrene (recycled) between the tank and wall.... then filled it with cold water and later reconnected the laptop.

LogTemp is a great program, easy to use if you have a low energy laptop spare.


BTW From 9.30 am Sunday the solar panel kicked in, working very well and over 300 Watts from the 480 Wpeak PV.


-Paul

[Ivan]

That had me really confused! A simple explanation, after all.