REMOURBAN is a large-scale demonstration project, whose objective is to accelerate urban transformation towards the concept of smart city taking into account all aspects of sustainability. The demonstration addresses a holistic intervention in Valladolid (Spain), well balanced in terms of actions on energy, mobility and ICT, which is monitored and properly evaluated. The interventions of the mobility sector focus on improving the sustainability of urban mobility, safety and the reduction of atmospheric and acoustic pollution. Energy sector interventions focus on achieving low energy and low carbon emission districts, and ICT sector actions focus on the integration of urban infrastructures to take advantage of their isolated performance. The demonstration in Valladolid aims to reduce 50% of the energy consumed and 80% of CO2 emissions, actively involves more than 5,700 citizens.
The building renovation actions are focused on the FASA neighbourhood built during the 60s and composed of 19 blocks of 5 floors, a tower of 14 and a building containing the thermal power plant that supplies heating to the 398 homes that they make up the neighbourhood. These buildings presented serious deficiencies in terms of thermal insulation with consequent lack of comfort for the occupants and poor energy efficiency.
The heating system consisted of a district network supplied by two fossil fuel boilers (natural gas and heating) and was divided into three different circuits that provide heating to the 398 homes, while domestic hot water (DHW) was produced individually in each house with different technologies depending on the source of energy in each particular case: natural gas, butane and electricity. The objective of the project is to convert the neighbourhood into a Near Zero Energy District through cost-effective strategies based on the following actions:
Passive interventions - envelope insulation: by means of this intervention, the buildings could be isolated avoiding in addition the typical thermal bridges (slabs and pillars) when the internal insulation is installed. All the facades of the buildings in contact with the houses have been isolated with the ETICS system. The system consists of a 60 mm EPS insulation plate fixed to the brick wall by means of adhesives and mechanical fixings; after this, a first layer of mortar, a fiberglass mesh and a second layer of mortar is applied. The last step is to apply a finish that provides the aesthetic appearance chosen. Concerning the roofs, in the FASA district there are two types of solutions, one for the sloping roofs of the blocks and another for the flat roof of the tower. In the case of the blocks, the interventions consist, first of all, in an intensive cleaning of the space between the last concrete slab and the sloping roof, since it has been used constantly by the birds to live there. Once the slabs were completely clean, the polyurethane foam was sterilized until it reached a thickness of at least 60 mm. The density of the foam must be less than 36 kg / m3 to reach the level of planned thermal insulation. Finally, all the accesses that are used to ventilate this space were closed with a metal mesh to prevent the entry of birds. In the case of the tower, the intervention consisted of installing on the existing asphalt waterproof layer a geotextile layer, 80mm of mineral wool with asphalt finish on the top and a second asphalt layer on the insulating panels.
Active interventions - photovoltaic solar installation integrated in facade and biomass heat network : The enormous potential of solar energy in Spain is wasted due to the lack of awareness and the high cost of building integrated solutions. REMOURBAN tries to encourage investment in the BIPV solution by demonstrating its effectiveness, in this way, a ventilated facade has been installed on the south facade of the tower with photovoltaic glass cladding panels. On the south facade of this tower, there are two large areas that stand out from the rest of the south façade, which are the sunniest spaces in terms of kWh / year. In these areas, a photovoltaic ventilated façade with sufficient surface area was installed to reach 27.4 kW of power and an annual output of 24,400 kWh.
Finally, the district heating has been renovated, installing two new biomass boilers, a biomass silo, an inertia tank, a hydraulic separator, two collectors, three pumping stations and optimising the network. The new biomass silo feeds the two new boilers, where thermal energy is produced together with the old gas boiler. To ensure an adequate inlet temperature of the water to the biomass boilers, an intermediate storage tank was installed. The network, distributing the hot water from the boiler room to the buildings, has been integrated with new insulated pipes, for domestic hot water supply, and the thermal losses reduced thanks to the lower water temperatures (85°C vs the initial 120°C). Finally, to improve efficiency and energy comfort, a system has been installed to control the heating work hours to ensure comfort with minimum consumption. To fulfil that purpose, thermostatic valves were installed in each radiator. These valves allow to control the temperature in any room of the house at any time. Therefore, the heated areas are those in which a user is located, avoiding energy losses in unoccupied areas.
By intervening in existing buildings and systems, it is expected to achieve a 33% reduction in the consumption of thermal energy for heating. Another 5% savings is expected thanks to the innovative comfort controllers and urban heating management. In terms of electricity consumption, it is planned to obtain additional savings of 25%. Finally, 87.57% of the reduction of CO2 emissions is due to the installation of biomass boilers both for district heating and for the new centralized system of ACS. In total, a reduction of 954.36 tons of CO2 per year is expected (808.09 kg CO2 per year per citizen).