Solar hot water systems absorb solar energy and use it to heat water for household use. An increasing number of homeowners across Australia are installing these water heaters in their homes because they want to take advantage of the free supply of sunshine. There are various kinds of solar water heaters available on the market today. Before selecting one to cater for your needs, you should first have a general idea of what the various options are.
Active systems
Active systems rely on a pump to move water through the system. They are available as direct circulation systems and indirect circulation systems.
Direct systems pump water from storage to the collectors where it absorbs the sun's heat. The hot water is then used directly, stored in a tank, or pumped to a tankless water heater. These systems are ideal for use in climates where it does not freeze often. In cold climates, freeze protection is required. This can be provided by draining down the collectors or by recirculating heated water from the storage tank.
Indirect systems, also known as closed-loop systems, heats water by pumping a non-freezing, heat-transfer liquid through the solar collectors and then the heat exchangers. These systems are widely used in climates with freezing temperatures.
Passive systems
Unlike active systems, passive solar water heaters require no pumps. Instead, they depend on natural convection to circulate water through the system. Passive systems are available as thermosiphon systems and integral collector-storage systems.
In thermosiphon systems, the heated water rises from solar collectors to the storage tank when cooler water sinks. The storage tank is positioned at a higher level so that the collector can be installed below it. This allows the hot water to rise by natural convection. In thermosiphon systems, fluid circulation and heat transfer, increases with a rise in the intensity of solar heat. Therefore, these systems work efficiently in areas with hot climates.
In integral collector-storage systems, the solar collector is the hot water storage system, as the name suggests. Unheated water moves progressively through the collector, where the sun's energy heats it up. When hot water is demanded, it is supplied from the top and cold water moves into the bottom to replace the drawn water. These systems are ideal for use work in climates where temperatures seldom fall below freezing. They also suitable for homes that enjoy significant daylight and after-sundown hot water needs.
Contact a company like Solar Repairs to learn more.
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