open loop solar water heating in SF bay area
I'm considering a solar water heating system for my home in Oakland, CA. I'd like to do the install myself, and I'm pretty handy with plumbing tasks, so I don't think that should be a problem.
I do want to get the design nailed down though before I begin. Right now I'm considering an open loop system (where the potable water is circulating through the solar collectors). For freeze protection I will use a drip valve and/or recirculation.
My question is, will that provide enough freeze protection for the climate here? Usually during the winter we get a handful of nights with frosty windshields, but no temps below 32 F. Last winter was an exception, and we got a few nights down to 29 F during the cold snap in January that damaged the citrus crop in southern California.