A solar air heater or a solar space cooling system can save huge amounts of energy

Find out how they work...

Heating
A solar air heater system can work in a similar way to water heating systems. There are two solar air heater types for buildings; active and passive. Although passive systems are cheaper, they can not fully support a building, and that is why a combination of both is usually prefered.

• Passive
• Direct Gain
We allow the sunlight pass through the windows and hit the absorbing materials. At night, these materials will release the thermal energy and heat the house.


• Indirect Gain
The materials that hold the heat are between the room and the sun (usually the walls).


• Isolated Gain
A collector at the exterior of the building harvests the solar thermal power. Then, heat is transfered to the storage medium which is in a different, isolated place.
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• Active
Attaching electric fans and pumps on an isolated passive system makes it active.

These systems are more efficient when a controller is used. These devices control the air (or liquid) flow from the solar air heater collector to the storage. If the collector's temperature is lower than the storage's, then the flow will stop.

An auxiliary conventional heater supports the system in such occasions.

Cooling
It is really odd to use something extremely hot as sun is, to cool a place. Fortunately, it happens, and it also reduces electricity costs in a remarkable way.

• Passive cooling

It is achieved in two steps:
• Prevent heat transfer
Shading, proper window positioning and proper roof design are significantly effective.


• Remove heat from the building
For hot humid climates TACS are mostly used, whereas cooling towers & solar chimneys and ventilation techniques are prefered in mild climates.


• Active Cooling - Thermally Activated Cooling Systems (TACS)
These systems use the sun to provide 30% to 60% of a building's cooling requirements. Usually, they are supported by an alternative fuel source such as natural gas.

TACS are divided in tow categories:
• Absorption coolers
• Desiccant coolers


Generally, TACS are not prefered because they are too expensive to install and they need large solar fields to collect sun's energy.

Read more on the impact of water on the environment at water-kingdom.com

Ventilation
Passive solar ventilation concept is very simple. It just works as a greenhouse does. It uses the ability of hot air to go up, to insert or remove air from the building.

Using a solar chimney, a solar wall or a solar room we create air updraft to produce ventilation.

In winter, hot air is driven into the house to heat it.
In the summer, ventilation can be used to cool a room.



P.S. Solar thermal power is one of the most effective forms of solar energy because we can use it as it is. Why should we invest on passive solar heating, cooling and ventilation? Because using sun's renewable energy, they offset zero carbon dioxide helping to save the environment. Solar heating, cooling and ventilation are the mostly used technologies for residential solar energy use.

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