Solar water heaters are the most cost effective way of using solar energy. They use simple and reliable technology to capture the sun's heat for domestic hot water or heating. Depending on the type of fuel used in a household's current water heater, solar domestic hot water can typically save between 50% and 70% of a household's annual hot water costs.
How solar water heaters work
Solar collectors: either flat plate collectors or vacuum tubes, depending on your heating needs.
Glycol: a solution of food-grade propylene glycol and water. The solution is non-toxic and prevents the system from freezing to -40°C.
Heat exchange module: a box containing the pump, heat exchanger, pressure reducing valve and automated system control.
Solar storage tank: a standard 60 gallon electric water tank, except that due to its insulated design it is heated by the sun and not electrically.
Conventional Tank: Any type of water heater you currently use. This will provide backup heat when the sun doesn't have enough heat.
1. The solar collector gets its heat from the sun.
2. The glycol being pumped into the system is heated as it passes through the collector.
3. The glycol continues to circulate into the heat exchange module located in the basement and transfers the heat it has absorbed from the solar collectors to this module.
4. The heat exchange module feeds the heat into the solar storage tank.
5. Now, instead of drawing cold water into a conventional hot water tank, it is filled with solar hot water.
How long will a solar water heater last?
The standard lifespan of a system is 25 years; however, a properly maintained system can easily exceed this.