If you plan to design and install a grid tie solar PV system for your home, you will want to know how much electricity the system can produce each year. Now we will take the roof of 60m2 as an example to make this calculation.
Relatively speaking, if the effective area of each family roof is 60 square meters, it will be rather enough. Then, what maximum capacity of solar panels can be installed for the 60 m2 roof? How much electricity of solar panels can be generated every day?
At present, the household solar power system generally adopts the monocrystalline silicon solar panel and polycrystalline silicon solar panel. Its specification is generalized as 36V 280W, and the single piece of solar panel generally has an area of 1.8 m2. The solar panels are connected into different group in series and parallel. In installation, the appropriate inclining angle, and the correct lighting direction should be selected. In addition, each group of solar panels should be staggered with a certain distance, thus avoiding the mutual stacking and sheltering in sunshine illumination. In the meanwhile, the solar panel array should be reserved with passage for the cleaning and maintenance convenience. Therefore, for the roof of 60m2, it is suggested to appropriately arrange 20 pieces of solar panels. The capacity is 5.6kW and the total area of the PV modules is 36 m2.
How much energy do the solar panel generate every day? This is mainly determined by factors such as the photoelectric conversion efficiency of the solar panel, the sunshine time, and the mounting angle.
The photoelectric conversion efficiency of the solar panel refers to the ratio of the maximum output power of the solar panel to the solar power that is irradiated on the panel under standard test conditions. Generally, the photoelectric conversion efficiency of polysilicon cell module and monocrystalline silicon cell module is not less than 15.5% and 16% respectively.
Therefore, under standard sunshine conditions (1000W/m2), the actual power of the solar panel array is: 5.6kW/0.16=3.5kW. If the solar effective power generation time is calculated according to the optimal 6 hours (10:00-16:00), the power of 21kWh can be generated per day. If it is calculated by 240 days in the whole year (20 days of effective solar power generation per month), the total PV power generation is 5040kWh.
Of course, the above calculation is based on the ideal conditions. The actual energy generated by a solar power system is affected by many factors, including the selection, installation and maintenance of the solar kits like bracket, solar inverter and so on, other than the temperature, weather, and other conditions.
The bracket for the solar panels is an important component of the solar power system. The bearing capacity of the roof structure is the main factor affecting the installation of the PV system. If it is unable to meet the specification requirement, the house must be reinforced to ensure the safety and reliability. In addition, before fixing the bracket, attention must be paid to the maintenance of the roof coating and waterproofing and other measures. At the same time, the coverings around the house, such as large trees and nearby buildings, will directly affect the effective time and power generation efficiency of the solar modules to receive solar radiation.
The home solar power system is connected to the public power grid with two different grid-tie schemes of single phase 110V/120V/220V/230V/240V AC or three-phase 380V/400V/415V/440V/460V/480V AC. If it is connected to the single-phase power grid, the optimal on-grid inverters are usually 1kW, 3kW, 5kW, etc. If it is access to three-phase power grid, the optimal grid-tie inverters are generally chosen above 10kW.