The following graphs summarize the outputs of 33 different
annual simulation runs, on varying roof pitches and orientations.
One of the interesting results of graphs is the Western bias. This is caused by 2 factors,
- True South (i.e. Solar South) is 6° to the West of Magnetic South
- There are many days
when morning cloud and haze are "burned" off by 10 or 11 O'Clock, so when averaged over the whole
year, afternoon solar output is a little higher than the morning output.
- 2 x Wimex 30 tube panels (5.6 sq meters)
- DHW Tank - 300L - TSOL Default
- Daily hot water usage - 210 Litres at 43°C
- Incoming water temperature - 8°C February, 12° August
- 16 meters of 15mm internal pipework, insulation 15mm Wall 0.045W/mK
- 1 meter of 15mm external pipework, insulation 15mm Wall 0.045W/mK
- Results in kWh
Simulator outputs Month by Month
Winter output is significantly higher on steeper roof angles, and only marginally lower in the winter.
Despite the massive differences between summer and winter energy levels,
a significant correction can be made by the angling of the panel so that
equivalent winter shadow lengths are as long as possible. The solar panel
is then receiving all the energy in the shadow area.
The graphs below show the expected monthly outputs of a Wimex 60 tube system.
Outputs with different cylinder sizes
A 30° roof angle is very common in the UK and Ireland
and was chosen to give the most relevant results.
Likewise to compare like with like, the daily consumption was fixed at 250 litres of
45°C water per day. Changing the water consumption both in volume and profile
can lead to large changes in system output which overwhelm other system parameters.