Selçuk Yerci, Chairman of the Board of Directors of Middle East Technical University Solar Energy Application and Research Center (ODTÜ GÜNAM), stated to the AA correspondent that rooftop solar energy applications can be used as an indirect tool against the urban heat island.
Yerci said that the panels provide shading on roofs and facades, reducing the heating of buildings and the need for air conditioning, and that producing electricity during the hours when air conditioning demand is highest in the summer months provides an advantage for the grid.
Stating that the effect of solar panels on urban temperature does not depend only on how hot the panel gets, Yerci explained that the characteristics of the roof on which the panel is mounted and the shading created by the panel should also be taken into account.
Yerci pointed out that the panels can be 20-30 degrees hotter than the outside air temperature under the sun, and stated that this heat can be transferred to the environment, but on dark-colored roofs, the panels can create a different effect by shading the surface, and that leaving enough ventilation space between the roof and the panel is critical for efficiency.
Stating that panel temperature is also a determinant of electricity production efficiency, Yerci said, "In crystal silicon panels, every 1 degree increase in panel temperature reduces electricity production by approximately 0.3-0.5 percent." made his assessment.
"The aim should not be to cover all roofs with solar panels"
Pointing out that heat waves with climate change will increase the need for cooling, Yerci said, "In a hot climate like Antalya, the cooling load of a typical office building may increase by approximately 45 percent in 2050 and 88 percent in 2080." he said.
Stating that it is an important advantage that this demand increases in hot and sunny periods when solar energy is most abundant, Yerci said that solar energy is an important tool in meeting the increasing cooling need.
Yerci emphasized that photovoltaic panels can be used in suitable areas, and high-reflective cool roofs and green roofs can be used in other areas, and said, "The aim should not be to cover all roofs with solar panels." he said.
Stating that designing green roofs with panels can support the performance of both systems, Yerci noted that public, commercial and industrial buildings with large roof areas can be prioritized.
Yerci stated that solar energy can also be integrated with shading elements on the facades and that this approach can be carried to the neighborhood scale, adding, "It is possible to transform an entire neighborhood into a system that produces and shares energy." he said.
Pointing out that this transformation should be considered not only in terms of energy production, but also in terms of the safety of existing buildings and long-term planning of cities, Yerci said that building safety should not be ignored in rooftop SPP applications, especially due to the earthquake risk in Türkiye.
Yerci stated that it is not right to install photovoltaic systems in old, damaged or inadequate buildings just because their roofs are suitable for solar energy production, and said, "In structurally risky buildings, the priority should be not energy production, but the strengthening or renewal of the building. We should consider cool and green roofs, afforestation, shading and solar energy systems as parts of the same climate strategy, not as alternatives to each other." made his assessment.
While cool roofs used to cool cities use special coatings and materials that reflect sunlight, the roof heats up less and reduces the cooling need of the building, green roofs are covered with plants and soil layers, strengthening the thermal insulation of the roof and contributing to the retention of rainwater.
