Solar-plus-storage for LED lighting in commercial buildings

Scientists from India’s Techno India Salt Lake (TISL) research institute have looked at how standalone photovoltaics linked to lithium-ion battery storage could be used for LED lighting in commercial buildings. They aim to develop a way to use solar power for LED illumination systems in order to reduce electricity costs.

“The scope of the work is to design an effective solar photovoltaic system which would meet the complete energy demand of a proposed business complex without consuming conventional energy supply,” they said.

In “Design of LED lighting system using solar powered PV cells for a proposed business complex,” which was recently published in Scientific Report, the researchers said that commercial PV projects for LED lighting should follow nine steps. They include the identification of a location, the determination of a grid connection point, and the pre-construction documentation and negotiations. The scientists also noted the importance of building infrastructure such as roads and fences, purchasing equipment and logistics, installing mounting structures, building transformer substations, setting up grid connections, and installing monitoring systems.

The academics assumed that the PV system would be built with 6,097 solar modules, with power outputs of 150 W and a total capacity of 914.4 kW. They also assumed the array’s tilt angle to be 49.3 degrees. The PV array design would have 41 stings and 24 modules in series.

In addition, they included an adjustable lithium-ion battery with 512 cells, with 16 connected in series and 32 connected in parallel. For the commercial building complex, the scientists assumed annual electricity demand of 190,830.7 kWh.

“The battery is to be operated at standard room temperature at 24 C in a fixed air-conditioned room,” they said.

The scientists concluded that the standalone energy system would provide complete energy independence for the building. The solar array’s transposition factor could reach a value of 0.98 in the proposed system configuration, they noted.

The modeling also showed that the system’s solar fraction and performance ratio achieved values of 0.740 and 0.569, respectively. The latter measures the quality of a solar plant, independent of location, and the former defines the percentage of the total thermal load satisfied by solar energy. 

“The cost estimation shows that the acquisition and installation cost of PV systems is economically feasible for a typical business complex,” the research team said. ” It is very much possible to use them in individual buildings to attain complete energy independence in the future.”