A Chinese research group has developed a portable balloon-integrated photovoltaic system (BIPVS) for low-altitude applications.
“The genesis of our research was a groundbreaking idea about low-altitude PV deployment proposed by Professor Jinyue Yan from the Hong Kong Polytechnic University, who envisioned the integration of photovoltaic technology with kites,” the research's corresponding author, Tingsheng Zhang, told pv magazine. “However, after considering the environmental constraints, particularly the limitations imposed by wind conditions, we engaged in a series of feasibility discussions, which led us to pivot towards the concept of a photovoltaic balloon system.”
The proposed system is intended for emergency power needs in post-disaster reconstruction efforts at low-altitude, where photovoltaic deployment can significantly reduce the occurrence of shading, according to Zhang. It can be utilized during high solar radiation months and be stowed during the rest of the year, thus minimizing the risk of damage during unworkable months.
“Our solution involves filling the balloon with a mixture of helium and air, ensuring that the system can be deployed at low altitudes,” he added. “The design allows for easy assembly and disassembly through the inflation and deflation of the balloon, which is particularly advantageous for regions with harsh winters and frequent snow and ice at mid to high latitudes. The portability of our system also makes it an ideal solution for remote areas.”
The BIPVS consists of a customized balloon, 19%-efficient thin-film cadmium telluride (CdTe) solar cells, an exhaust valve, control and storage modules, fixed ropes, and a cord reel, as well as an upper hemisphere and a lower arc surface. The upper hemisphere is based on transparent material that harvests solar radiation in all directions and has light-concentrating effects due to refraction properties. The lower arc surface reduces the installation area of the thin-film solar cell without affecting effective light harvesting.
The solar cell position below the balloon has the function of protecting the cells themselves from dust, snow, and hail. The exhaust valve is used for active or passive gas discharge to drive the balloon, while reducing high pressure inside caused by exposure to the sun. Control and storage modules are used to manage power conversion and storage of the BIPVS, including charge and discharge of storage devices, system parameter monitoring, and overload protection. The system also features four cables stabilizing its center of gravity and a fixed rope linking it to the control and storage module and the cord reel on the ground.
Through a series of simulations, the group analyzed the performance of the system for five different locations: Vasteras in Sweden; Vancouver in Canada; New York in the United States; and Shanghai and Hong Kong in China. Shadowing was not considered, as the scientists assumed the system to be deployed at low altitude.
“Upon excluding unsuitable months, the case analysis shows that the average monthly power generation of the BIPVSs during the effective working months of a year is as follows: 3.921 GWh, 4.238 GWh, 4.275 GWh, 3.337 GWh, and 3.379 GWh, respectively,” the group explained. “In addition, the life cycle of the BIPVSs results in cumulative power generation figures of 479.492 GWh, 592.18 GWh, 672.105 GWh, 641.155 GWh and 708.334 GWh, accompanied by total profits of 79.614 million USD, 37.007 million USD, 75.146 million USD, 12.946 million USD, 107.369 million USD, respectively. The corresponding return on investment measures 218.6 %, 101.6 %, 206.3 %, 35.5 %, 294.8 %.”
The system was described in the paper “A portable balloon integrated photovoltaic system deployed at low altitude,” which was recently published in Energy. “The proposed balloon-integrated photovoltaic system provides an efficient and feasible solution for PV power generation in mid-to-high latitudes, offering substantial energy, economic, and environmental benefits,” the scientists concluded.
