Sunday, November 13, 2016

Two months of Solar Hot Water monitoring

October's Performance

With October done we now have a second month of data from the Solar Domestic Hot Water monitoring project.   In September we had relatively good performance with 41% of the water heating needs supplied by the solar panel.  October on the other had great sun for about a week mid-month, but then was much cloudier, shorter days and substantively lower performance.  Here is both September and October's graphs so you can compare the two months:

Again, a few observations:
  1. Total energy used this month for hot water heating was up 79 kWh to 356 kWh of energy put into the heating of hot water.  Of this only 15%, or 52 kWh was solar supplied.  The higher energy use this month could possibly be explained because the basement is heated off of the hot water system.  I did observe that the basement's infloor heating system was running periodically to supply heat to the basement. 
  2. The amount of solar heat collected this month was again lower than modelled (52 kWh vs. 80 kWh modelled).  Also, as a percentage, the solar fraction as only 15% which was slightly lower than predicted at 16%.  
  3. The total amount of energy actually delivered as hot water was about the same as last month: 131 kWh.  September was 127 kWh, so it looks like hot water usage was consistent with last month. 

There Goes the Sun

Below is a picture of the solar collector and the sun at about noon on November 6th.  As you can see the sun isn't really clearing the trees much.  The sun now goes behind the escarpment downtown shortly after 3pm.  You can see the solar panel itself mounted on the veranda roof (behind the power pole.) So from this point forward, it doesn't like the system will be collecting any heat until February.