An international research group has analyzed the visual impact of PV facades integrating crop cultivation among architects, PV specialists and farming experts. Their research showed that there is broad acceptance for this kind of project, and has also defined a series of recommendations on how to design similar installations.
An international research team including scientists from Cuba’s Technological University of Havana and the National University of Singapore have investigated the potential of integrating PV facades with vertical farming in high-density cities.
According to their findings, presented in the study “Architectural quality of the productive façades integrating photovoltaic and vertical farming systems: Survey among experts in Singapore,” published in the journal Frontiers of Architectural Research, there is a broad acceptance for projects combining crops cultivation and solar power generation, which the researchers defined “productive facades (PF),” despite concerns for their architectural integration.
Web survey
The researchers conducted an anonymous 10-minute multiple-choice web survey in English with 15 questions. They also provided different pictures of four variants of the PFs, with the respondents asked to rate the architectural quality on a five-point scale, from 1–very poor to 5–very good.
The questions regarded topics such as the visual impact of PV modules and crops, preferences regarding the arrangement of PV modules, and ease of operation for owners and workers, among others. Around 80% of the 97 respondents were architects, with the remaining percentage represented by engineers, PV specialists, PF experts, horticulturalists, solar facade experts, consultants and professionals of different kinds.
Lower acceptance from architects
According to the survey, architects and designers gave low ratings to all four of the designs presented and tended the design of the PV installation as poor. Meanwhile, respondents with experience in horticulture, farming or PV facades showed stronger acceptance of building integrated PFs. “All groups of experts agree that PFs have the most positive effect on the exterior facade design and have accordingly graded them with higher marks than the designs without PV and VF systems,” the paper notes.
Concerns were also expressed by almost all respondents on the logistics of crop cultivation and its irrigation system in the presence of electronic devices such as the vertical solar modules. “Several comments recommended exploring more creative designs,” the researchers stressed.
The lowest mark – 2.84 – was obtained by the PF with only PV modules visible from the inside, while the highest – 3.90 – was scored by the PF in which only plants were visible.
Tips for developers
The study also provides a series of recommendations for the improvement of PF prototypes. “It should be noted that the selection of elements for practical application cannot be made based on a single isolated PF element, but the entire building should be considered, especially the aesthetic elements of the building envelope such as: composition, proportion, rhythm, transparency, scale, colors and materials,” the scientists specified.
As for the solar technology, the researchers recommended the installation of the PV systems on north and south façades, with the preferable location being at ceiling level.
Tilt angles of less than 20 degrees are suggested as a better aesthetic solution, which would also avoid reflection to neighboring buildings. “However, a well-designed integration of the PV modules with the planter of the above storey provides additional advantages – it improves the quality of indoor daylight and obstructs the view from inside to a lesser degree,” the also affirmed.
The research group also said copper indium gallium selenide (CIGS) panels are preferred to common crystalline silicon modules, due to their more homogeneous structure.
Source: pv magazine
