Alternative Forms of Energy - Solar Powered Water Heater

A solar powered water heater, often known as a solar water heater, is a system which utilizes the sun’s heat to warm water for domestic use in your own home. In contrast to solar photovoltaic panels, heat is not converted directly into electricity.

How Does It Work?

The sun’s heat is harnessed by using a device that is typically installed on the roof of your home. The main types of solar powered water heaters are flat plate collectors or evacuated tubes.

Flat Plate Collectors

A flat-plate collector consists basically of an insulated metal box with a glass or plastic cover (the glazing) and a dark colored absorber plate. The absorber plate absorbes solar radiation, which is transferred to a fluid that flows through the collector in tubes.

Some designs offer the addition of a pump to circulate water throughout the tubes but this may not be always required and is dependent upon the installation environment.

A flat plate collectors is usually installed on the roof but can also be integrated into the roof tiles themselves, or free standing.

Evacuated Tube Collectors

This solar powered water heater solution has a series of glass evacuated tubes. The sun's light penetrates the glass and heats up a copper pipe on the inside. A fluid is contained withing the copper pipe, the heat can then be transferred later from this fluid. The evacuated tube water heater is a completely closed system and the glass tubes are easily added and removed as needed for maintenance.

The main advantage of using evacuated tubes is the greater efficiencies attained. The means you can get hotter water temperatures and/or hot water for longer periods. As much as 90% efficiency can be attained. However, evacuated tube collectors are more expensive than flat plate collectors

The explanation for the large efficiencies using this technique is that the copper and contained fluid within will hardly loses any heat to the outside, even during cold days. This is because of the vacuum between it and the outdoors. Vacuum double-glazing operates on exactly the same principle. Compare this to flat plate collectors which can be subjected to cold weather and strong winds.

Other Facts

Solar powered water heaters are a good starting investment for a domestic setting. They have a high relability than wind turbines and solar photovoltaic arrays, are more efficient, as well as being cheaper to install and maintain.