(Above) Firman Solar panels harnessing the thermal energy of 'diffuse radiation'.
The Sun's energy
Firman Solar panels rely on the Sun's abundant energy. The Sun's energy reaches our planet in forms of radiation; direct sunlight and diffuse radiation.
Direct sunlight can be thought of as the light that you receive directly from the sun; while diffuse radiation is sunlight that has been scattered by the atmosphere.
We receive very little direct sunlight in our climate; this is important to remember because any solar panel that relies on direct sunlight will most likely under perform. Firman Solar panels have been designed to work on not only direct sunlight, but also to perform in light levels experienced on a very cloudy day -harnessing the power in diffuse radiaton.
(Above) Firman Solar panels have been designed with a specially coated surface.
Capturing the Sun
The black surface inside every Firman Solar panel is 'selectively coated' with a special material made from Aluminum Oxide.
It is called selective coating because the surface is coated in a way that some parts receive marginally more coating than others, creating a surface which under a microscope might look like a range of mountains. This enables many surfaces to be presented to the light.
The selective coating specially designed and used in our solar panels enables the molecules to vibrate and create heat in all types of light conditions as well as in below freezing weather conditions.
How the heat is transferred to your home or pool
Once the absorber plate (complete with its selective coating) has captured the heat it is conducted to the heat to a heat pipe, running through the panels. This piping is filled with an edible safe glycol to prevent freezing.
The pipe work (which is highly insulated) forms a closed heating pipe which connects to a coil in your domestic hot water cylinder. If you already own a traditional gas central and water heating system the solar heat circuit will connect to the lower coil in your cylinder and the fossil fuel heating system will connect to the upper coil in the cylinder.
Will it work with my existing cylinder?
You will usually need a new cylinder because solar cylinders are larger than normal cylinders, taking advantage of the ability to store energy in the form of heat fro days when there is little light energy available for the solar panels.
How the system heats your water supply
Finally, in Firman Solar systems there are sensors in the solar panels and in the hot water cylinder. These sensors feed information about the state of the system to a digital controller, which is connected to a specially pumping station.
When the digital controller recognises that there is energy available in the panels and energy is needed in the cylinder it switches on the pump; that pushes the hot Glycol in the panels around the heat circuit and into the cylinder, making the solar coil in the cylinder very hot. The solar coil conducts its heat to the water stored in the cylinder. When the cylinder reaches a pre set temperature level the controller switches off the pump and the system returns to rest.
The heat circuit is connected to a pressure vessel to enable the glycol to expand and contract without damaging the system. Some small amount of electricity is used to drive the pump; in typical installations the electrical energy used for the pump and the controller will be less than 1½ % of the energy produced by the solar panels.
| And finally, how not to design a solar water heating system |
It is sometimes thought by a layman that solar collectors are designed to collect as much light as possible and convert it to heat. This is actually not the case. When designing domestic water systems, solar engineers know that there is no point in overheating the system because the hot water usage and storage capacity is finite and the way in which people use hot water and the times at which they use also have to be taken into account.
If you make the collectors too hot they will have a very short life time and overheating will cause problems.
At Firman Solar, we use employ a specially designed and manufactured selective coating, which is designed not to get too hot. There are other coatings that we could use, at lower costs, which get hotter but we have to bear in mind that we are not making collectors to create more heat than can be used usefully.
With Firman Solar heating systems you can safely go on holiday during the hottest times of the year knowing that your system will not overheat and will be safe. Advanced technology is behind our glazing and absorber surface and heat circuit design; affording the consumer excellent solar thermal efficiency without the expense of overheating or creating a short performance life.
