The Sharing Cities project provides a living example of how working public service buildings can improve energy performance while still preserving their architectural character.
Historic Lisbon City Hall has completed a pioneering energy retrofit which has lead to energy savings of more than a third (36 per cent).
The retrofit has been carried out under the EU Horizon 2020 Sharing Cities programme, which uses open source solutions to improve the sustainability of cities and wellbeing of citizens.
Considered one of the most significant heritage buildings in Portugal, Lisbon’s City Hall stands on the east side of the Praça do Municipio square. Completed in 1880, based on plans by architect Domingos Parente da Silva, the building is home to the Municipal Chamber of Lisbon, the mayor, and more than 100 municipal staff.
It was among the five highest energy-consuming buildings owned by the municipality and plans were put in place to undertake a full energy rehabilitation of the building in 2016. The project aimed to provide a living example of how working public service buildings can improve their energy performance while preserving the architectural character and original features of traditional town halls.
As the only heritage building in Portugal to have undergone deep energy efficiency retrofit measures, the completion of this project signifies an important milestone in the Sharing Cities programme, and a major boost for the 2020 European Green Capital’s climate adaptation strategy.
“The intervention provides a viable technical and business model, from which data insights will be extracted to drive our future energy policies”
“Heritage buildings are commonly perceived as difficult to rehabilitate. Thanks to Sharing Cities, the deep energy retrofit of the Lisbon City Hall sets a world class example of what can be achieved through collaboration,” said David Cunha, senior adviser for information technology and digital transformation for Lisbon’s Municipality.
He continued: “The intervention on one of the capital’s most iconic public buildings provides a viable technical and business model, from which data insights will be extracted to drive our future energy policies.”
Sharing Cities points out that non-residential buildings, including public buildings, are around 40 per cent more energy intensive than residential buildings. Across the EU, this represents an average energy consumption of about 200 and 300 kWh per m², compared to an average of 180kWh per m² in residential buildings.
The latest data gathered from monitoring the building’s energy performance already shows energy savings of 36 per cent, demonstrating the significant savings that can be realised from retrofitting public building stock and using renewable energy sources for greater efficiency.
The retrofit interventions were defined in line with regulations for protected heritage, comfort levels, energy reduction and environmental impact targets. In light of these challenges, Sharing Cities said continuous dialogue between the municipality, national bodies and local partners was vital to the project’s successful execution.
Using existing plans, a 3D model of the building was created to establish the building’s baseline characteristics such as building materials, occupancy and usage patterns, lighting systems, temperatures and equipment power usage (including heating and cooling systems). The 3D model, together with dynamic energy and weather simulation software helped to determine the most suitable approach and package of retrofit solutions.
The set of interventions included the replacement of the HVAC system, the substitution of all existing lamps to LED, as well as the installation of a photovoltaic (PV) system for local power generation. The only intervention to the building envelope was the special restoration of the existing windows, the condition of which had significantly deteriorated due to age and exposure to atmospheric elements.
Central to the retrofit programme was the use of innovative sustainable technologies. A sustainable energy management system (SEMS) was installed to monitor the loads from the PVs, HVAC, water heaters and other smaller equipment.
‘The significant energy savings realised in Lisbon’s City Hall using tried and tested solutions represent a high replication potential for other cities facing similar sustainability challenges, especially in historic buildings”
Developed by Sharing Cities, SEMS is an advanced modular system that centralises information and control of local energy systems and devices and optimises the energy network to achieve savings and environmental improvements.
The interventions achieved the following building energy performance savings:
‘The significant energy savings realised in Lisbon’s City Hall using tried-and-tested solutions represent a high replication potential for other cities facing similar sustainability challenges, especially in historic buildings,” said Nathan Pierce, programme director for Sharing Cities and head of Smart London Team at Greater London Authority.
He added: “We are proud to have been part of the journey with Lisbon from the start, sharing resources and expertise to what we hope will serve as a model of best practice across Europe.”
Monitoring systems will provide continued impact assessment of the retrofit interventions, focusing not only on energy consumption, but also on perceived levels of comfort by the municipal staff and the energy management activities of the building.
The full project team included: Câmara Municipal de Lisboa (building owner and promoter); Lisboa E-Nova (energy consultants); EDP Distribuição (SEMS); and Instituto Superior Técnico (energy modelling and monitoring).
Sharing Cities is part of the European Innovation Partnership on Smart Cities and Communities (EIP-SCC01). The project draws on €24m in funding from the European Union’s Horizon 2020 research and innovation programme.
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