CITyFiED Site Laguna de Duero
Laguna de Duero is one of the municipalities surrounding the metropolitan area of the city of Valladolid, the administrative capital of the Castile and Leon region. Throughout the centuries, what was distinctive about the area was its natural lake, which dried out during the 1970s. This turn of events determined the future of the city in a significant way. Laguna de Duero went through a period of growth and expansion, including the creation of the Torrelago district, which is the focus of the CITyFiED project activities.
The Torrelago district was built in two phases, each one involving a district heating network and the following numbers of buildings and dwellings:
- Phase I: 12 buildings of 12 floors, with 4 apartments per floor, for a total of 576 dwellings with an average area of 100 m2 per dwelling. These buildings were constructed in 1977.
- Phase II: 19 buildings of 12 floors, with 4 apartments per floor, for a total of 912 dwellings with an average area of 100 m2 per dwelling. Eleven buildings were constructed in 1979; the remaining eight were constructed in 1981.
Nowadays, this metropolitan area is established under the spatial planning directive of Valladolid and its surroundings, as all municipalities in the region have similar urban characteristics and mobility problems. A total of 416,000 residents live across a total area of about 1,000 km2.
The overall gross floor area of 140 000 m² that has been refurbished in the Laguna de Duero demo site affects more than 4000 residents. The annual final energy saving estimate is 6598 MWh with respect to thermal energy savings (reduction of 38,65%) and 137.2 MWh/yr regarding electric energy savings associated with the district heating (reduction of 63.64%). The total CO2 emission savings estimate amounts to 212 tonnes per year.
In a truly cooperative approach, CITyFiED representatives carried out a workshop with the residents about the visualisation side of the district’s renovation. Participants had the opportunity to address various technological and non-technological solutions designed to cut energy consumption, and the effects that these could have on residents. The approach seeks to take account of user perspectives, and places residents at the heart of the decision-making process. For long-term success in green energy, projects like CITyFiED need residents to fully buy into the planned retrofitting and development. Such an approach raises awareness of energy challenges and increases the prospect of replicability through citizen engagement.
It is clear that investing to improve energy efficiency has profound environmental impacts. The CITyFiED demonstration site in Laguna de Duero is showing the economic and societal benefits as well, with 50 unemployed Laguna residents due to receive training and work on the renovation implementation of the building facades. More than 400 résumés reached CITyFiED partner 3IA, the company responsible for placing the new Torrelago building facades, when 50 new positions were advertised. Previously unemployed residents have been prioritised in the recruitment and the new hires will receive an extensive training programme, lasting around 2 weeks, to ensure a high-quality delivery of tasks on the facades and to prepare a talent base for future implementations in the project.
*Information regarding the technical and financial performance will be available at a later stage.
The key energy-efficiency measures implemented in the demonstration site are:
Energy efficiency in buildings
The analysis of the thermal envelope of the buildings of Torrelago highlighted the existence of significant thermal losses, thus it was necessary an energy efficient retrofitting of the building envelopes of the 31 buildings of the district to achieve high-energy performance and better internal comfort in the dwellings.
The building retrofitting reduced the energy demand of the district by implementing an Exterior Thermal Insulation Composite System (ETICS). The solution consisted of the installation of 8 cm-thick panels of expanded polystyrene (EPS) on the exterior side of the existing façade.
The original façade, with a width of 25.5 cm and a U-value of 1.36 W/m2K, was retrofitted with a new resulting wall of 35 cm and a U-value=0.34 W/m2K. The adopted solution is even more energy-efficient than the requirements of the Spanish Technical Building Code (U-value ≤ 0.66 W/m2K) ensuring a significant reduction of the energy demand
Energy systems integration
The old district heating system was composed of two independent networks supplied by gas-fired boilers. One district heating network provided thermal energy for 12 buildings (Phase I) and the other district heating network provided thermal energy to the other 19 buildings of the district (Phase II).
A full renovation of the existing district heating was carried out and a new centralized power biomass plant generation and an efficient distribution system were installed. In order to increase the overall performance of the energy system, a set of measures were implemented:
- The installation of a new biomass thermal plant with a thermal output of 3.5 MW (three new high efficiency biomass boilers)
- The construction of a new buried building to locate the biomass boiler room and the biomass silo
- The existing independent networks were merged into a new distribution system
- The installation of new heat exchange substations at building level for the buildings of Phase I; Phase II counted already with heat exchanger substations.
The partial substitution of the gas boilers with new biomass boiler aims to cover the 80% of the energy consumption with renewable resources. Some of the gas boilers are maintained in a second boiler room as a reserve for use at peak and potential failures or outages biomass periods.
A micro cogeneration system (thermal output of 71,6 kW and electric output of 33 kW) was installed in order to contribute to increase the ratio of energy supplied by renewable resources in the district. The energy supplied by the micro cogeneration system should have covered partially the energy consumed by the thermal and electric installations. Actually, the micro cogeneration system is installed but it is not working due to a number of administrative barriers.
The implementation of a set of energy conservation measures was planned together with a new integrated energy management system in order to monitor and check constantly the performance of the whole system, from the generation system to the dwelling level. The control system of the facilities allows to optimize the performance of the district through the monitoring of real-time data and adjust the operation of the system according to the needs.
DEMS (District Energy Management System)
An advanced control system was developed for the management of district heating system, using a communication architecture distributed in star topology. Control panels were implemented and information at generation and distribution level from the district heating is gathered.
BEMS (building Energy Management System)
The BEMS monitors the energy flows in each of the buildings in the Torrelago district. All the information related to the exchange substations for the management of heating and domestic hot water (DHW) in each building is collected.
HEMS (Home Energy Management System)
Smart meters, thermostats, cut-off valves and other devices have been installed at dwelling level. This system allows to know the energy consumption and the behaviour of each dwelling. In addition, it provides the opportunity to get the involvement of the residents. The residents can manage the comfort temperature at their homes and be aware of their thermal and electrical energy consumption. The new system provides residents with useful information to make decisions towards a more efficient use of the energy.
Monitoring platform and visualisation tools
The information supplied by KPIs enables to validate the energy performance of the district. Furthermore, the visualisation tools are a valuable instrument for different stakeholders, e.g. promote awareness about energy consumption within the residents, provide useful information to the energy company or to the responsible of the maintenance.