It Actually Works!!

so..  I finally got the solar collector mounted on the roof and plumbed into the heat exchanger...  after several days of contemplation and a midnight epiphany, I managed to drain all the air from the system and got it heating water...  It's been working for a week now...  a solid week of thunderstorms and cloudy afternoon skies.  Today is the first day of actual full sun all morning..  at just after solar noon the temperature in the panel is 135 degrees.  I have a thermistor on both the solar panel and the bottom of the hot water tank so I am able to collect temperature data to evaluate how well the system is working..  here is what I've decided...  It doesn't heat water fast enough to be able to disconnect the lower element in the hot water tank.  I turned the thermostat on the lower element up to about 115 degrees.  The bare minimum temperature that must be maintained in order to fill the bathtub with hot water.  I feel certain at this point that two things must happen..  a second panel must be added to the roof to bring the temperature up there up a notch or two and there must be another "hot water tank" added in the basement.  I feel there needs to be a first storage tank..  with an integrated heat exchanger that solely heats water from the temperature it is when it enters the house to as warm as the solar panel can get it...  the water warmed from the first tank then feeds the second tank which will be returned to its default configuration.  Basically, this strategy will return the system to having all the hot water it initially did and also an additional 50 gallons of hot(warm) water in reserve.  The electric hot water tank should never be called on to heat water from 60 degrees up to full operating temperature... 

BTW, my theory about the paint protecting the mdf adequately is busted...  fortunately the sides were laminated with plywood as well, I will have to construct new sides and back for this panel when I build the second one, but I should be able to exact the repairs without taking the panel off the roof. I think I have enough material to build the second with a minimum of expenditure.  Speaking of which..  you're wondering how much this has cost me right??  About $800...  I think I can finish up with the second panel and adding another tank (I already have a slightly used gas water tank that I intend to convert) and keep the final total right around $1000..  How long will it take to save the money back out of our electric bill?  Probably three years....