Solar hot water - 30°C

This morning it was 8 °C outside in the world when I started the test. The maximum temperature for the day was 9.8 °C.

Air temp in the collector was 18°C

Air temperature within the poly pipe collector was around 23 °C
And the temperature within the water tank was around 9 °C

The water tank has developed a very slight leak so the water wasn't circulating until I topped it up, thus the temperature difference. Once flowing you can actually see it flow. You see it as heat haze emited from the inlet hose and as a current swirling little bits of gunk that I failed to clean out of the hoses.

An hour and a half later and it reached 30°C inside the water tank, and 33°C within the collector.

As far as I know, my water didn't get any hotter than 30°C, but It stayed at that temperature, and still is at that temperature, even though the day became overcast and colder.

I took the temperature at the bottom of the storage tank as well and found it to be only 1°C less than at the top. This might mean I need a bigger storage tank to allow the heat to rise to the top. The flow might be enough to be stirring the water and mixing it too much. If it was a deeper tank, or the flow was less I might be seeing higher temperatures. Slowing the flow would be as easy as adding a tap. I'm not sure that I'll bother on this small test system. I think I have made the correct number of errors to allow myself to move on to the bigger version, and actually do something with the collected heat. 30°C is still 9 degrees short of my target but I think with a better made, and larger unit, 39°C should be achievable on a day like today.