Buolus - Building physics design of urban surfaces for sustainable quality of urban living and environments

Graph project goal BUOLUS
© Fraunhofer IBP
The BUOLUS project aims to improve climate resilience and ensure the sustainable development of municipal structures.

Municipalities are faced with the challenge of adapting to climate change. On the one hand, they have to choose effective and sustainable measures, and on the other hand, they have to take into account the interests of residents and act under cost pressure. Improving urban climate resilience alone is not enough to bring about this change successfully, especially when it comes to small and medium-sized municipalities. It is much more a matter of responding to the challenge of climate-resilient urban design with environmentally and financially compatible measures, while at the same time serving growing demands for a better quality of life in cities. This is the integral approach that the BUOLUS project is taking to identify sustainable solutions for a climate-resilient city.

Project phase II

Project goals BUOLUS II

Solargründach Fahrradparkhaus Rosenheim
© Fraunhofer IBP
Solar green roof on the bicycle parking garage in Rosenheim.
To collect data, volunteer surveys are being conducted in Rosenheim.
© Fraunhofer IBP
To collect data, volunteer surveys are being conducted at the Salzstadel reality lab in Rosenheim.
3D model of the city Rosenheim
© Fraunhofer IBP
Screenshot of the 3D model of the city of Rosenheim developed in the project, which is now being optimized.

The implementation and stabilization measures in this second project phase will be carried out on three different levels: Building, district and city. The main objective is to facilitate the transfer of theoretical results from the first funding phase into practical implementation and, at the same time, to develop and document implementation procedures and concepts. The implemented measures can also be studied metrologically, and their actual effect evaluated as well as iteratively adapted. The effects of these innovative approaches can also be reproduced using simulation and validation tools so that they can be extended and adapted to meet specific requirements.

BUOLUS takes a sustainable approach in addressing these aims to improve climate resilience and develop municipal structures. In this context, sustainable means taking into account financial constraints, ecological demands and user acceptance in equal measure.

 

Project focus:

  • Greening: Evaluating the use of greened roofs and façades to reduce heat islands and to improve air quality, retention, biodiversity and quality of life.

  • Cleaning: Development of concepts to prevent pollution and clean the interior of public buildings as well as outdoor spaces.

  • Urban development: Assessment of measures to improve the quality of life in inner city areas.

  • Data management: Use of existing data as a basis for selecting measures and making decisions.

  • Rainwater harvesting and heat island prevention: Assessment of measures to improve the urban climate by using rainwater to cool surfaces.

  • Management: Sustainability analyses based on sustainable development goals (SDG).

Result based on an example

Innenansicht des Sitzelements am Salzstadel
© Fraunhofer IBP
View of the interior of multifunctional, modular seating element at the Salzstadel square in Rosenheim. It has an awning and a rear wall, which offers a certain amount of acoustic protection and is partly greened.
Außenansicht des Sitzelements am Salzstadel
© Fraunhofer IBP
View of the exterior of the partially-greened multifunctional, modular seating element at the Salzstadel square in Rosenheim.
Akustikmessung Sitzelement am Salzstadel
© Fraunhofer IBP
Acoustic measurements on the multifunctional, modular seating element at the Salzstadel square in Rosenheim in April 2024.

Multifunctional, modular seating element

How can the quality of time spent in a city square be improved quickly, temporarily and cost-effectively so that users enjoy spending time there?

With this in mind, a multifunctional, modular seating element was erected on the Salzstadel city square in Rosenheim at the beginning of November 2023 in collaboration with the City of Rosenheim. The design of the seating element is based on results from prior user surveys carried out in 2021 and 2022, which revealed that there are three main factors impairing users’ enjoyment of spending time in the Salzstadel square. These include background noise in the square caused by road traffic, summer heat intensified by too little shade and the lack of greenery in the square. For this reason, the multifunctional seating element which was developed pursues an integral approach. It has a rear wall, which offers a certain amount of acoustic protection and is partly covered with greenery. There is also an option to install a low-emissivity coated awning on the element in summer. The acoustically-effective rear wall consists of a soundproofing element with a sound-absorbing, perforated inner side. It is intended to help improve the acoustics in the square, particularly in the seating area, and to reduce the noise generated by passing traffic. The low-e coating of the awning utilizes the natural properties of bare metal and strongly reflects radiation in the long-wave range (heat radiation). As a result, a large proportion of the solar radiation is reflected back into the surroundings, making it feel “cooler” under the low-e coated awning than under a conventional one. The rear wall of the seating element has been planted in different ways. These include, among other things, ground-based façade greening with both deciduous and evergreen plants. In addition, planters containing bee-friendly, and, to some extent, edible plants are also placed between the individual seating areas.

The seating element is made up of a total of eight separate modules, allowing it to be arranged to suit requirements. Thanks to this modular design, the seating element can therefore also be erected in other places and adapted to the needs of the users.

Within the scope of the project, the seating element is now being further investigated. In April 2024, for example, measurements of the seating element were made to objectively verify the acoustic effect of the back wall. Results showed that it is up to 15.1 dB(A) louder in the seating area without the seating element. This proved that the acoustically effective rear wall has a positive effect on the perceived noise level. In addition, the maintenance and management costs of the plants used are currently being investigated in collaboration with the University of Stuttgart, and a new user survey is being conducted to assess the acceptance of the seating element.

Project sponsors and funding bodies