As we reach the end of August and finally have some nice
weather to enjoy in Nova Scotia, it is easy to assume this time of year has the
most solar energy potential. Sunny days
are more frequent and the days are still longer than average.
However, the answer isn’t as obvious as you may think!
While PV energy generation potential is directly
proportionate to solar radiation, solar thermal energy potential also depends
on the starting temperature of the cold water it is heating. Colder starting temperatures allow for more
energy to be transferred as well as the efficiency of that transfer to be more
efficient (due to higher deltaT).
So far in 2011, many of the solar hot water systems
installed by the team at Doctor Solar have harnessed most energy in the month
of March.
While there are many variables that could contribute to this
variance, the most likely cause is the temperature the cold water supply. The amount energy harnessed is calculated by
the difference between temperature of solar pre-heated water and the original
temperature of the cold water supply (the status quo). In March the cold water supply averages close
to 5C, while in August it averages 21C.
