Saturday, August 1, 2009

Got it working!

Well, after some pause to get the right pump and to have the weather align, the first solar panel now is working - although, as expected, it doesn't actually have the oomph yet to really impact the pool's temperature.

Here are a few stats from today's run of about 5 hours:
  • Average pool temperature ran around 22°C - the impact of the cell was negligible.
  • The internal temperature of the box itself was around 35°C while the unit was running.
  • The outlet temperature was around 24°C showing that heat was, in fact, transferring to the water.
  • When I turned it off for an hour or so and then started it up, the water temp was 60°C - which shows it can develop some pretty good heating!

I did have to buy a new pump since my old one was just too small. This one is a nice little 1/4 HP submersible pump that has the benefit of running very quietly. I'm not 100% sure it will be able to pump through three units, but I at least think it will be able to handle two.

This shows the general arrangement. The pump is in the pool and the cell is propped up pointing south. This is just temporary until I prove out the design, then it's up to the roof of the garage.

Another shot from the front:

When I get it a bit more proved in, I'll try running my Arduino monitoring system then have the monitoring system actually turn the pump on and off.

The key thing I learned from the run today is that the cell needs to have the air purged out of it before it will run, so I need to hook it to the hose to flush the air and then quickly get the pump hooked up to it. In future, I may have to build an Arduino and solenoid valve based solution to handle the start-up purging automatically.


  1. The collector would be more efficient if instead of the serpentine flow path, a "parallel" flowpath was used. You'd have to buy a bunch of Tee fittings then though.

  2. Interesting! I would have assumed that the longer the water spent traversing the tubes, the better so I figured the longer the tube the better. That being said, the results haven't been great.

    I'm coming to the end of this seasons experiments, but maybe I will try one next year along those lines. These could be rebuilt to that design with some work.