So, how does one build this “miracle” of solar heating: the simple and cheap “batch” heater? It turns out there are plenty of plans out there. For starters, a simple “solar shower,” in which water in an inner tube or bucket is heated for personal use, is one of the simplest forms. But for a system you can use on your home:
Mother Earth News offers plans and tips. They also share the “Six Commandments” of Passive solar hot water heaters (on which they elaborate in the article):
- Locate your heater for maximum solar exposure
- Make the collector and storage tank(s) as efficient as you can
- Ensure your system will retain heat
- Size your heater appropriately
- Make an efficient, freeze-resistant connection to the backup system
- Build your system to last
From these tips, it’s obvious that the passive solar heater won’t replace fossil fuels. Most cheap systems are preheaters. Every degree you warm up the incoming water is a degree the conventional hot water doesn’t have to heat. The goal here for the most part is reduction, not elimination.
Want another take on the concept? Check out ByExample.com, which shares the experience of creating and installing a batch heater. BuildItSolar.com offers a number of plans, including one made from a stock tank (see photo above), which also uses a mirror to increase solar exposure.
