Most people, when they think of going solar, don't think of the hot water system as the first thing to invest in. Rather, they feel that the should try to power up their entire homes. A solar hot water heater is considered, though, but most accounts, the ideal stepping-off point for anyone who's new to the technology.
A solar hot water heater tends to be far more efficient at using up the solar power that comes its way than a regular solar power system.
Now you might think that there's just one kind of solar hot water heater out there today. But that's really not true. There are in fact, thousands of kinds that have been designed over the past 20 years or so. Today, there are basically five kinds that you could choose from. And they come with some pretty high-tech sounding names too. There is the thermo-siphon heater, the open-loop direct heater, the pressurized glycol heater and the batch heater. There are many things that you need to consider before you decide on one of these.
Let's say that you live in a small household with two or three members and you live in a place where it doesn't get too cold in the winter. In this case, you will probably go with a solar batch heater. In fact, if most of the water used in your home happens at the end of the day, this would be an excellent choice.
What if you were to live in a place that was very cold say in the New England region? Well, the closed loop drain back system or the pressurized glycol system, is considered the perfect choice for such a place.
Let's take a look at how these systems work.
The solar batch heater is about the oldest solar technology around. It's pretty simple you put an insulated tank of water with a solar collector attached, up on the roof, and out in the sun. Whatever water heats up, it rises to the top, while cold water remains at the bottom. When anyone needs warm water the house, it is suctioned off the top of the tank. There are no electrical components in this, and it's pretty cheap thing.
The closed loop drainback system is an active set up. it consists of a solar collector out in the sun, and a closed loop of distilled water that passes through the collector, collects heat, and then passes to the hot water heat exchanger farther down. It works very well, and it's quite efficient.