Research and Development of DSDE(Double Side Dual Energy) modules based on bifacial is going to finish.
Recently, bifacial PV-panels are gaining popularity, which are able to convert into electricity the light reflected on their back surface from the ground or roof. The use of a specially prepared surface as a white diffuse reflector on the rear of the panel allows you to increase the electric power by 10-30%. However, intense solar irradiation heats the bifacial panel even more intensely than the usual single-sided panel and this gives additional importance to its quality cooling. Using the transparent heat collector, we have created an original 3-D design of a hybrid solar module with two light-reflecting surfaces, which has no world analogues.
We have been developed since the beginning of the 2000s, but glass-made PV-modules required a lot of manual labor and had a significant weight. We have created several samples based on plastic, each time improving the design and method of forming the module. As a result, we developed a prototype quite suitable for industrial production. Received a patent of Ukraine for a utility model № 140944.
We made a lot of experimental tests. These tests have been performed on a bench with monitoring and regulation of the heat and electricity generation ratio. During tests promising results have been obtained, some of them are listed below. On the photo - the results of monitoring the operation of the stand are displayed on Smartphone.
At the pic. 1 you can see the dependence of the amount of electrical energy and maximum electrical power on time, the intensity of solar radiation, coolant temperature and environment. Measurement of electric and thermal power was carried out with the orientation of the DSDE modul to the south.
SR-intensity of solar radiation; blue curve and columns - electric power of the DSDE-module; yellow curve and columns - electric power of the base panel BiSon of similar passport power.
It is obvious that the electrical and thermal energies (W/h) increases. The electric and thermal power at the beginning of measurements increases from morning to noon, and then gradually decreases. However, blue curve down after the astronomical afternoon is not proportional, which is due to the increase in the intensity of the thermal component of solar irradiation, which peaks at 14 hours 30 minutes (GMT +2. Kyiv).
The graph at pic. 3 presents the experimental data of the comparison of the electric power of the DSDE-module and the basic module using sun-tracking system. In this case, we provided heating of the coolant from a temperature of 20 to 23-25 degrees with fluctuations in flow rate from 6.5 to 10 liters per minute, which is ideal for heating the pool. Under these conditions, the DSDE-module produced an electric power upto 16 - 19% more than the basic module, and the value of the allocated thermal power during this time reached 1.4-1.5 kWh.
Figure 3. P1 and P2 electric power is derived from the basic module and DSDE-module, Wh1 and Wh2, respectively, - electrical energy, and SR - solar radiation power.
At pic. 4 shows the current-voltage characteristics of the basic double-sided module BiSon and formed on the basis of the same panel DSDE-mudule, on the front part of which in addition (to the diffusion surface from the rear) is directed radiation of the rotating mirror, which added 52% to total electric power. As a result, the electric power of the DSDE-module was a record 400 watts. The thermal capacity of the DSDE-module also increased and amounted to 2.5 kWh. Such an intensive irradiation mode heats the double-sided panels so significantly that there is a risk of their destruction, while heat dissipation prevents the destruction of the modules against the background of a significant increase in their productivity. This is clearly confirmed by photos taken with a thermal imager.
Options for using hybrid solar modules
At the photo - a stand which includes a heating device with a parabolic concentrator of solar radiation. Since it makes no sense to allow heating to a high temperature of the coolant in the modular structure (because this will lead to a significant drop in the generation of a more valuable type of energy - electricity), we propose to use a heating device located outside the modular structure. An alternative is to heat the water in the tank with an electric heater.
This option is especially attractive in the winter, when under conditions of high insolation and low ambient temperatures, electricity production increases significantly and very little heat is produced. The use of hybrid solar modules in combination with heat pumps is also extremely effective, which is especially useful for heating cottages.