Home Solar Systems

Home Solar Systems – Starting From Zero

The solar radiation energy is more than enough to meet the global energetic demands. During a year, the amount of solar energy emitted to the Earth is 10.000 larger than of the energy sufficient to satisfy the needs of the entire global population.

About 37% of the global energetic demands are satisfied by the production of electric energy. If this energy was generated by photovoltaic systems with their modest output power of 100kWh per square meter a year, we would need a surface of 150 x 150 square kilometers to accumulate the solar energy. The biggest part of this absorbing surface could be installed as home solar systems on the roofs and walls of buildings, so there would be no need to create extra space for these systems.

The solar radiation energy is sufficient to produce in average 1,700 kWh of electric energy per year on each square meter. Also, the bigger radiation is at some location, the more energy is generated. From this point of view, the tropical regions are more suitable for home solar systems than the regions with a more moderate climate. The average solar exposal is about 1.000 kWh per square meter while in the Middle East it makes up 1.800 kWh.

The solar light has influenced the architecture designs since the very beginnings of the history of construction. The progressive solar architecture and the methods of urban planning were originally used by the Greeks and the Chinese who used to orientate buildings to the south in order to guarantee themselves the light and warmness, making them the very first builders of home solar systems.
How does the photovoltaic cell work? The industrial development of photovoltaic solar modules comes from the 1950, when it was invented mostly for the purpose of charging satellites in the Earth orbit. Since then, the technology development has reached incredible heights as to the simplicity of usage, power, reliability and the price as well.

The concept of it is actually simple: for some sorts of materials, such as single crystalline silicon, it is characteristic to produce electric energy when exposed to solar emission. In the very module, composed by several inter-connected cells, the voltage is generated as well as the electric energy suitable for charging standard batteries (6, 12 or 24 V). This guarantees the production of electric energy with the necessary voltage and intensity for charging the batteries directly or the production of the direct current for the consumers. The quantity of electric energy is in fact proportional to the home solar system’s module surface and the solar radiation intensity.

Besides the photovoltaic modules, home solar systems may contain the charge controllers, batteries for storing the generated electric energy, invertors for converting the direct current into the alternating, etc.
There are two kinds of home solar systems: “off-grid” – the battery system not connected to the distributive network and “on-grid”, the system adapted to the distribution of electric energy into the network. These home solar systems really pay off and have a long useful life span of the equipment (25-30 years).

There are two ways of installing the photovoltaic modules of the home solar systems, depending on the location where they are to be installed, more precisely, the fixed systems and the trackers.
The fixed systems are a very stable way of installing, mostly used for mounting on roofs and open-air surfaces. It is mainly used for the home solar systems of lower capacity.

The trackers are the most efficient systems of mounting the solar photovoltaic modules. With the help of the right mechanism, this system provides that the module position adapts to the ideal angle towards the Sun during the day. The amount of electric energy obtained this way is about 45% higher than the energy generated by the fixed systems. There are two sorts of trackers, uniaxial and biaxial trackers. These systems are mostly used for bigger projects, i.e. solar power plants.