March 2009 Temperatures

[martin W]

Well I just installed the 30 tube (47mm) array with a 172 litre themal store (see me in the pics area).

Last 3 days seems to give around a 22C degree even increase in temp (themral store so bottom and top are pretty much the same). Store just under 60°c today (started at 12°C on wednesday morning so its a long slog to get it up to temp). I work out as an average 4.5KWh of energy put into the water on each day before major draw of of 2x showers. This obviously does not include the heat looses due to cylinder is in the attic (5 degree loss last night!).


HTH

[sjaglin]

I only have 20 thermomax tubes, (...)

Nearly 5 kWh a day from 20 tubes seems almost too good to be true. The result could be scewed a lot if the temp distribution in the tank didn't reflect the simplistic averaging. Any change for more sensors along the height of the tank? Even just one in the centre would help. Ask Wyleu how to add a couple of hundreds ;-)

Anybody else with actual figures of how much a 20tube / 170l setup can gain (in March)?

Klaus

Ummm, I am not sure really, when I was preparing my project I used Solarmaster to modelise what could probably be produced (see this link). As per results in the table, for March I should expect about 90kWh which is almost 3 kWh a day.

I think we can all admit that the weather is rather good at the moment so nearly 5kWh for an excellent day would average out for a day where it doesn't do much.

Maybe it comes also from our way of life, we use the hot water in the evening or in the morning before 10-11 then the tank stays undisturbed until 6-7 PM, leaving a nice stratification take place.

Indeed I would like to put a simple low cost extra sensor in the middle of the tank, any suggestion?

Stef

[Ivan]

Yet another day with the entire tank exceeding 70C. This time, up to 72C.

[dhaslam]

My system is showing about 10Kwh each day  this  week, from 60 tubes, but I think the actual output is about 14 KWh because the whole 250 litre cylinder is heated from about 10C to 60C each day.    In the late afternoon the full cylinder was heating  by 4C per hour but the system was showing 1Kw or less.   I am getting one error in readings. The bottom sensor shows a higher reading  when the pump is running and falls back when it stops.   I think this is because the sensor pocket is directly over the return pipe from the coil.   Worst days this month were 3 Kwh but the system is showing about 50Kh total for each of the last four weeks so with adjustment that is about  9.5KWh per day average or about two thirds of requirements.

[Ivan]

My cylinder hit 78C at the bottom today. We've had a few bad days here, with little sunshine - yesterday evening we'd only managed 48C, so I was thinking we might need to heat the cylinder via boiler....which we haven't needed to do since the first week of March, but with a day's good sunshine the temperature has shot up.

[langstroth2]

Really good 35C increase today.

Ave temp at 9am 18.6C
Ave temp at 4.30pm 53.5C

It clouded over around 3PM.