Why use double glass solar panels in solar vegetable greenhouses?

- Feb 09, 2019-

Double-glass solar modules are used in many fields because of their own advantages, such as vegetable greenhouses, but many users only know the benefits of double-glass PV modules for vegetable greenhouses during installation. Here is a brief introduction to solar greenhouses why want to use double glass components?

 agriculture solar hybrid system application

1. Because it is a greenhouse, the influence of temperature on solar panels cannot be ignored.


*Effect of temperature on mono crystalline solar panels


The open circuit voltage of the single solar cell decreases with the increase of temperature. The voltage temperature coefficient is (2.0~2.2) nrw/°C. That is, the temperature of the open circuit of the single solar cell is reduced by 2.0~2, 2mv for every 1°C increase in temperature; The short-circuit current of the cell increases with the increase of temperature; the peak power of the solar cell decreases with the increase of temperature (directly affects the efficiency). That is, the peak power of the solar cell increases every 1 °C.


The loss rate is about 0.35--0.45%. For example: working at 20 (the silicon solar cell, its output power is 20% higher than the work at 70 ° C)


*The effect of temperature on solar modules


A single solar module is usually composed of 36 solar cells connected in series. According to the results measured in the area in Xining, the solar module back surface temperature can reach 70 ° C in summer. At this time, the solar cell operating junction temperature can reach 100. °C (rated number calibration is under 25 conditions), the open circuit voltage of this component will be reduced by about 2.3 × (100-25) × 36 = 6210mv) compared with the rated value, and the peak power loss rate is about 0.4% X (1)-25)=310%.


It can be seen that when the silicon solar panel works at a high temperature, the open circuit voltage drops sharply with the increase of temperature, and at the same time, the charging work point is seriously deviated. It is easy to make the system insufficiently charged and deteriorate; silicon solar panel the output power is also greatly reduced with the increase of temperature, so that the solar module can not fully exert its maximum performance.


2. Using light-transmissive thin film cell + ordinary glass, one is considering cost performance, the second is direct and indirect direct sunlight 3:5% is only theoretical data, asking how much sunlight is coming out, but not every day the same case, most of them are not like this.