Solar Water Heater: Recommendations for Doing It Yourself

A solar water heater is a cost effective solution for reducing your homes energy bill.  Solar water heater systems can be designed for any climate and use the most inexpensive heating source available – sunlight!

The first consideration a “do-it-yourselfer” must make is what type of system they wish to install.  Active solar water heater systems use pumps and controls to keep water circulating and maintain efficiency.  Active solar water heaters are usually more expensive; however, the cost savings in added efficiency makes them more cost effective.

When considering active solar water heater systems there are two basic types available.  Direct circulation systems pump regular water through the collector system and through the home.  These systems are best suited for locations that very rarely experience a freeze.

The second type of active system is an indirect circulation system.  In this type of solar water heater an anti-freeze fluid is circulated through the solar water heater system and then transfers heat through a heat exchanger.  This system is best used in regions with freezing temperatures.

Passive solar water heaters do not use pumps or controls for circulation.  They simply rely on normal flow through the system.  Passive systems are usually cheaper, and require less maintenance making them last much longer, however, they lack the efficiency of active systems and can have a lower cost effectiveness.

There are three basic components for both solar water heater systems: 1) collector plate, 2) storage tank, 3) interconnecting piping.   In active solar water heater systems a fourth component, the circulating pump, will be added.  Indirect circulation systems will also require a heat exchanger.

The collector plate is the heart of the solar water heater system and should be carefully considered.  When considering collectors efficiency is important.  Any collector considered should be adequately engineered and professionally constructed. There are three basic styles of collector plates:

•    Flat-Plate – These are flat insulated boxes that have a dark absorber plate under a glass or plastic cover.

•    Integral collector-storage system – ICS, or batch systems, use tanks or tubes contained inside a collector box to preheat water before supplying it to the conventional backup system.  These collectors are used primarily in mid-freeze climates where outside pipes could be subject to freezing.

•    Evacuated-tube – Contains parallel rows of transparent glass tubes and metal absorber tube attached to a fin. This fin is coated to allow for the absorption of energy while inhibiting heat loss.  These are the most commonly used in residential applications

The other parts of a solar water heater system can be readily found at most local hardware stores.  Interconnecting thermal piping and fittings can be purchased based upon the design of the application.
The storage tank required for a solar water heater is a little different than a tank used for a conventional system.  For solar water heater applications the tank requires additional inputs for water coming from the collector.  Additionally, for better efficiency the tanks are designed with extra insulation to reduce heat loss.
When building a solar water heater it is also important to understand that a secondary system will be required on non-sunny days.  Any system design should be incorporated into a conventional system that provides enough supply when extra demand is required.

Complete “do-it-yourself” designs can be easily located and with most of the materials readily available a solar water heater system is easy, and cost effective to build.