Question about solar hot water heating

>Sure. Whats known as a "breadbox" batch
>solar water heater can go inline
>on the cold water side before
>your conventional water heater. A word
>of caution though, there has to
>be freeze protection if the region
>you reside in has freezing temperatures
>in the winter months. This would
>true of any solar water heater
>unless it incorporated a double wall
>heat exchanger and a solution that
>does not freeze such as silicon
>oil or antifreeze. As for sizing,
>that would depend on just how
>much you want to produce in
>a day. If you just want
>to heat a pool or, potable
>water or, if you want to
>heat your home or, just reduce
>the fuel or electric bill. Check
>out - kingsolar.com they have schematics
>of sample systems with explanations as
>well as prices.

Thank you for your reply.  Having just done a quick glance, would I need a heat exchanger if I built an open-loop system?  Also, looking at the models at kingsolar.com, they show a two tank setup but I don't have to do that right?

As for size, it would be for 2 people with occasionally 2 more.  I would like to use it to heat the water used (i.e. showers) in the house.