Design and evaluation of passive concentrator and reflector systems for bifacial solar panel on a highly cloudy region – A case study in Malaysia

Photovoltaic (PV) systems are the most promising renewable energy source in Malaysia because it is a tropical country receiving a huge amount of solar irradiation every year. However, Malaysia is surrounded by South China Sea and Malacca Straits. The vapour from the sea water with the blow of seasonal winds causes a large amount of clouds passing over the country, hence creating the variation in the direct and diffused sunlight throughout a day. The performance of the concentrators and reflectors for bifacial solar cells under the variation of direct and diffused sunlight has not been studied thoroughly. Therefore, several concentrators and reflectors have been designed, constructed and placed under a specially designed bifacial solar panel. The setup of each concentrator and reflector is as follows; scattering particles (scatterers) sprinkled across the plane mirror under the solar panel, an array of adjustable small plane mirrors placed underneath the solar panel, and long triangular prisms in between solar cells with a plane mirror underneath. Another solar panel is constructed and placed on top of the plane mirror as a reference. Each setup of the concentrators or reflectors is evaluated by measuring the power output of the tested and the reference panels together throughout a day under the sun. Empirical approaches are developed to compensate for uncontrollable factors including solar cell manufacturing mismatch and unequal degradation between the tested and the reference solar panels. A few potentially working static concentrator and reflector systems are identified based on the experimental results. An assessment is carried out to show the economic viability of the proposed setups with respect to that of the mono-crystalline solar cells. •Several passive concentrator and reflector systems for bi-facial solar panel are tested on cloudy area.•An array of adjustable small mirrors is able to increase the energy output of bi-facial solar panel.•Long triangular prisms in between bi-facial solar cells increase the energy output of the solar panel.•Scattering particles under bi-facial solar cells are not able to increase the energy output.•The unit cost of the solar electricity from bifacial solar panel by concentrator and reflector systems is reduced.