Solar Air Heaters
Economical solar air heaters could not be built previously because air is a thermal insulator and does not accept heat easily. We overcame these difficulties and succeeded to design and manufacture a new generation of solar air heaters that can deliver hotter air but are very inexpensive. Therefore, the heat they deliver is competitive with the fossil fuels heat.
During their warranty period they make savings on fossil fuels which are at least two times larger than their cost, so they are guaranteed to be profitable for the users. Depending on the design of the solar collector, the installation characteristics and the current solar and atmospheric conditions, our collectors can efficiently produce air of up to 1100C, despite not using solar radiation concentrators.
A proper design is necessary to ensure that the solar collector will perform optimally and will deliver economical heat.
The heart of the solar collector is the solar radiation absorber, that transforms light into heat. It is essential that the material the absorber is made of absorbs as much of the incoming light as possible and reflects and emmits as little as possible. It also has to transform as much of the absorbed energy into heat and as little as possible in destructive energy that can ultimately destroy the absorber.
We have developed a few types of solar radiation absorbers, each suitable for a certain application. Some absorbers will last indefinitelly in time, some others will last more than 10 years, despite being made out of plastic materials. We have specially treated polymers that can withstand even the harsh Australian conditions for many years; this is essential for the performance in time of the solar collector, as they impart to it a long service life.
Our new solar air heaters succeed in paying themselves back and making a profit during their warranty period. They can be used in all climates. Obviously, their payback time will depend on the amount of energy they can deliver, which in turn depends on the amount of solar radiation they receive. For this reason, a careful design has to be made so that the solar collector will be economical in those conditions.
Our solar air heaters comprise of: the solar collector, the thermally insulated conduits and the distribution means. If complex coordination is needed between the flow of heated admission air and the industrial process, an additional control device will be part of said distribution means. Because all of the above parts are included in the price of the solar air heater, the overall cost of heat can be assessed.
The solar collector is made out of parts that have to be assembled on-location. We have developed a standard set of modules that can be easily installed on different support surfaces or directly onto the ground.
The cooling function
On clear summer nights, a solar collector has its black surface exposed to the very cold night sky. As the solar radiation absorber is designed to very well exchange heat through radiation, it will be cooled by the night sky in a similar way it is warmed by the light of the day: through direct exchange of radiation. As a result, the air that passes through the solar collector will be also cooled, and when admitted in the house it will relieve the well-known summer night discomfort. However, this cooling effect is smaller than the heating effect that can be obtained during the day. We also have a model of solar air heater that cools a building during summer days and heats it during winter days.
We use this advantage of our solar collectors (patent pending) to extend their use through the warmer months. The diagram below shows the year-round usefulness of our solar air heaters in a temperate climate:
See also: installation of solar air heaters