The Dutch housing project Mannoury, in Amsterdam, is a CO2-neutral building with a mission: to install smart, innovative green roofs that help make cities cooler, more sustainable and liveable. The Urban Photosynthesis project, supported by the Dutch TKI Water Technology Programme, studies if cooling greenery on Mannoury’s blue-green roof improves the productivity of the solar panels.

“We have found that blue-green roofs help in cooling and increase the yield of PV panels,” explains Gijsbert Cirkel of Dutch research institute KWR.

Real estate investor Aedes initiated the development of the Mannoury building in Amsterdam, which is home to the TKI Water Technology project Urban Photosynthesis. The project brings together Aedes, the City of Amsterdam, ECOFYT, Permavoid, Techniplan Advisors, SDR Elektrotechniek, and KWR. They are working on creating a unique apartment block that will enhance biodiversity and habitability and support the energy transition in the city by combining a blue-green roof, local grey-water treatment, and efficient solar panels. The building helps to cool the city and the solar panels reduce the risk of flooding during intense rainfall, recycles treated water from showers in dry periods, and, above all, produces pleasant and healthy living conditions for residents.

Roof with plants and solar panels
Roof with plants and solar panels

Roof of the year

The project has won the 2022 Roof of the Year award in the flat roof category. During the award ceremony last March, the jury explained how it greatly appreciated the combination of different systems and experiments in a single project: “Because the water storage in the cellar, the extra circulation systems for grey water and a heavier roof floor require additional investment. The integration of all the systems for water, energy, greenery, and safety was also a process that was completed successfully in the end. Mannoury is the result of an excellent alliance between the city authority, the project developer, research institutes, the architect, the builder, suppliers, and subcontractors.”

Identical towers: ideal for comparison purposes

Mannoury consists of two identical towers that provide an ideal opportunity for full-scale comparative research. The Urban Photosynthesis project compares the amount of solar energy generated on the blue-green roof with the amount produced on a standard black bitumen roof. It also compares the water-treatment properties of a helophyte filter using natural vegetation that is integrated into the blue-green roof on one roof with those of a biomembrane reactor filter plant in the cellar of the other building. Finally, a completely computer-operated water management system and a combination of natural overflows and gravity are also being tested. The results of this two-year study are expected by the end of 2023.“The initial results are promising. We can clearly see cooler conditions on the blue-green roof. The yield from the PV panels is about 4.5% higher on the irrigated blue-green roof,” says Gijsbert Cirkel of KWR Water Research Institute.

The TKI Water Technology Programme

The TKI Water Technology Programme shares information about financing opportunities and can connect entrepreneurs and innovators to knowledge institutes and other SMEs. The programme targets companies that offer solutions for specific challenges in the agriculture, food, and horticulture sectors, companies operating in the field of energy, and companies working in the field of clean and healthy water.

This case was originally published on the website of Netherlands Water Partnership