Roberta Pernetti and Marco Castagna present urban planning processes in the city of Bolzano and their monitoring research
City of Bolzano had a severe problem of lack of housing, thus in 2000 the Municipality of Bolzano decided to start an important urban operation, acquiring a large port of land in the South-West of the city and managing directly the whole process aimed at:
- Ensuring quality and efficiency of the urban processes;
- Enhancing environmental performance of the buildings;
- Implementing a model settlement with high quality of life and valorisation of the suburbia.
The result of this operation is the Casanova district, which provides accommodation to about 3,000 people in 950 apartments grouped in eight building castles. The owners of the buildings are the local Institute for Social housing of South Tyrol (IPES) and a series of local cooperatives, a mechanism based on the association of a group of people that pool resources to build their housing.
The Municipality of Bolzano was strongly committed to adopt the best practice with regard to newest technologies and quality of life in the planning of a new urban quarter. This choice has allowed the Municipality to define and set specific and ambitious standards with special attention to the social services and sustainable transport for the inhabitants. In this regard, the Municipality established a new train station on the railway connecting Bolzano to Merano, ensuring the connection with the city centre in a few minutes.
The approach used in the design included measures at different levels: the urban planning concept, the energy concept and the architectural competitions for individual lots.
General view of Casanova quarter (source: Google maps)
The urban concept
An interdisciplinary team coordinated by Fritz Van Dongen from Amsterdam developed the design concept. The team planned the construction of eight so-called “castles”, which consist of 3-4 buildings built around a common green space. The urban concept gave substantial freedom to the designers in terms of architectural and technological solutions of individual castle projects.
During the first six months of the urban design, the team organized six workshops in Bolzano with the direct involvement of the political and technical representatives of the Municipality of Bolzano, representatives of utilities, IPES, cooperatives and the board of the district.
One of the eight castles of the Casanova district (photo credits: EURAC)
The energy concept
The energy concept considered three main objectives: reduction of the heating energy needs, minimizing the use of traditional energy sources and increasing use of renewable energy sources.
To achieve these goals, the concept set a district heating system with heat recovery from an incinerator and guidelines on energy requirements for individual lots.
The Municipality set the energy requirement for heating energy use between 30 and 50 kWh/m² per year, depending on the heated space of the buildings. This target was ambitious in comparison to the minimum building performance set by the national energy policies (Law n.10/1991) that require a maximum value of 90 kWh/m2 per year for heating energy demand.
Therefore, all buildings were planned to include high levels of insulation, some buildings were equipped with ventilation systems with heat recovery and, in order to optimize the passive gains, the designers coordinated and optimised the height of the buildings in the Casanova district in relation to their position in order to reduce the shadowing effects.
Each building was planned to cover part of its energy needs through renewable energy sources, i.e. solar and geothermal energy. Solar energy has been implemented with solar thermal collectors for domestic hot water production and grid connected photovoltaic systems for electricity production. Some buildings were deigned to cover a part of their heat demand with geothermal heat pumps and by direct airflow through a geothermal pre-heater.
The Ministry of Environment, Land and Sea included Casanova district within the campaign “Sustainable Energy Europe (SEE)” promoted in Italy. The City, the Province and the district itself are considered as good example at the national level of implementation of energy efficiency and use of renewable sources to reduce CO2 emissions.
Casanova district (photo credits: EURAC)
Monitoring by EURAC
As a concrete action within the active partnership with the Italian Ministry of Environment, in the context of the implementation of the SEE campaign, EURAC was in charge to carry out the monitoring of the Casanova district. The entire monitoring campaign aimed to evaluate the actual energy performance in comparison with the design values (predicted), and to analyse the level of comfort (air quality, temperature and humidity) in a set of sample apartments. In addition, EURAC distributed specific questionnaires to the users in order to evaluate their energy saving awareness and the perceived level of comfort. The results of the monitoring campaign will be the basis to develop an educational campaign for the users in order to foster positive behavioural changes. In general, the results of the monitoring campaign highlighted an important rebound effect of the users that, on the one hand, adopted critical behaviours in the use of non-traditional technologies (e.g. mechanical ventilation, heat recovery and massive heating system) and, on the other hand, required higher comfort levels contributing to worse the energy performances of the building operation. A preliminary round of trainings started within the ASP project CABEE (Capitalizing Alpine Building Evaluation Experience), that promoted the educational campaign “An efficient building needs you!”. The participation was quite active and, in parallel to the seminars, EURAC distributed a short guide on how to use energy in an efficient manner in the buildings in different seasons while ensuring high indoor comfort level. Electricity saving advice was provided as well.
The guidelines for energy efficiency and energy saving in Casanova district (in Italian) (source: EURAC research)