Solar Water Heaters

April 15th, 2010 - Posted by RESNET under Solar Energy

Sometimes referred to as solar domestic hot water systems, solar water heaters are the most efficient form of producing hot water for your home.

Similar to Standard Water Heaters – Except for Energy Source

Solar water heaters work much the same as standard heaters, except they use the sun’s energy to heat the water instead of gas or electricity. The interface between the heater and a home is almost identical, and the technology isn’t much more expensive.

There are two types of solar water heating systems:

  • Active – Has a system of pumps and controls.
  • Passive – Has no such system.

Active Water Heating Systems

An active solar water system is the more expensive of the two. This system uses pumps to circulate the water into a home and uses both Direct Circulation (best for climates that do not freeze often) and Indirect Circulation (best for freezing climates) systems.

Passive Water Heating Systems

Passive systems can be more cost effective, and can last longer due to less moving parts, but may not work quite as well, and may require a back-up system in case of a lack of solar energy.

There are two basic passive water heating systems:

  • Integral collector-storage passive systems – Great for climates with hot, sunny days and large daytime and early evening hot water needs.
  • Thermosyphon systems – A bulkier system, but very efficient and reliable.

Solar Collectors
There are also three different types of solar collectors that connect to water storage tanks to heat the water.

  • Flat-plate collector – These are glazed, flat-plate solar collectors, they are usually a dark absorber contained in a weatherproofed boxes.
  • Integral collector-storage systems – Known as ICS or batch systems. This system contains tanks or tubes in a box. The solar collector pre-heats cold water, then flows to a back-up water heater to be used if needed. This system is not ideal for very cold climates, as the tubes may be susceptible to cold weather.
  • Evacuated-tube solar collectors – Used mostly for commercial applications, this is a system of parallel rows of transparent glass tubes.

Which is the Right System for You?

To determine the right solar water heater for you, a solar water heating specialist will start by evaluating the hot water needs of your family and consider the climate you live in and other factors unique to your home. Find a RESNET Qualified ENERGYSMART Contractor specializing in solar water heaters.

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