Photovoltaic shades in buildings offer energy efficiency and electricity generation, but an international research group says their commercial viability will depend on the control strategies used to optimize performance.
An international research group has conducted a comprehensive review of all designs and control strategies for PV-integrated shading devices (PVSDs), in order to help bring the technology closer to commercial viability.
“Currently, the application of the solar panels to the kinetic shading devices is very limited so that is not possible to come across any instances implemented in the urban buildings, despite some prototypes,” researcher Ayca Kirimtat told pv magazine. “The basic criterion to consider before implementing such a system still is and will be the return of investment rather than sustainable energy development for green life. The implementation cost of conventional panels is very high for many customers and the tailor-made panels for shading devices would be considerably higher. However, given the fundamentals of new product development, the costs should be automatically lowered by the market, as the demand gets higher.”
Kirimtat and her colleagues said that module orientation is crucial in PVSDs, as it strikes a balance between power generation and the use of sunlight to reduce the heating, cooling, and lighting needs of buildings.
The control strategies used to optimize the performance of solar shades were divided into three groups. Hard control techniques use dynamic systems such as energy and daylight simulation models in order to evaluate the thermal behavior of the buildings. Soft control methods utilize mathematical models to predict system behavior analytically. Other techniques involve reinforcement of learning control and multi-agent control, while hybrid methodologies are based on all of these approaches.
The scientists presented a detailed literature matrix to provide an overview of previous studies on different methods for PVSDs in buildings. It was based on PVSD type, control strategy, and building type, with 77 business cases identified and briefly introduced.
The scientists stressed the importance of considering long-term performance monitoring of PVSDs as a crucial aspect for their viability, as well as the issue of replacing the shades.
“To shorten the payback time of the PVSD systems, relevant control methods should be encouraged to be used in the early design process of these systems,” they said. “However, for each PVSD design, the optimal control method could change based on the climatic characteristics, building type, and orientation.”
Kirimtat said the commercial viability of PVSDs may be accelerated by the green energy policies ruled by the governments.
“Simple and less expensive solutions offered by the competitive market players will be beneficial for this niche market to reach some size. Every market, whether niche or not, would eventually reach the maturity, by definition,” she said.
She estimates that it would be possible to see some instances of PV panels operating on the kinetic shading devices in 10 to 15 years.
The scientists presented their findings in “Control of PV integrated shading devices in buildings: A review,” which was recently published in Building and Environment. The research team includes scientists from the University of Hradec Kralove in Czechia, Auburn University in the United States, and the University of Zilina in Slovakia.
“The major goal of this paper is to offer an interdisciplinary and integrated state-of-the-art of PVSD system practices using various control methods and technologies. A systematic literature review was undertaken in order to conceptualize and offer a full knowledge,” the scientists said.