Integrating Solar

Pete & Sun

I do mostly PV installs, but have a client that would like to mitigate her propane bill by using solar thermal. She currently has a Munchkin boiler that heats the fluid for her floor loops and indirectly heats an 80 gallon Superstor storage tank for her hot water needs. I did a number of solar hot water systems back in the 80's, but not so much since then.

I am proposing a 6-8 panel system with 300 gallons of storage. I am thinking of using antifreeze in the solar loop and storage tank and feed directly to the boiler from the solar storage tank. The water in the Superstor tank would be preheated somewhat by passing through a heat exchanger in the solar storage tank. Does this make sense?

Also, the solar array would be ground-mounted below the level of the storage tank. I'm wondering about thermosiphoning vs active pump system.

hot_rod

The dhw load

is an easy one to start with. In most areas of the country a two panel system can supply 50% solar fraction or more.

Heating is a bit more complicated. Determine the heat distribution, low temperature radiant is the best match for solar
.
Then look up solar radiation available at your location.
Consider RET Screen or F-Chart for a solar calculation.

then determine what incentives are available and figure some costs. Most solar design programs have economic modules to show ROI, etc.

Here is a simple "get you in the ball park" calculator, free at

www.valentin.de/calculation/thermal/start/en

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