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Standardised approaches and products for the systemic retrofit of residential Buildings, focusing on HEATing and cooling consumptions attenuation.

Periodic Reporting for period 3 - BuildHEAT (Standardised approaches and products for the systemic retrofit of residential Buildings, focusing on HEATing and cooling consumptions attenuation.)

Reporting period: 2018-09-01 to 2020-02-29

Space heating uses are quite uniform all over Europe, amounting to around 140-170 kWh/m2y of final energy consumption, compared to around 25 kWh/m2y needed for DHW preparation. Space cooling consumption is an issue mainly in the southern countries, where it generally ranges between 30 and 50 kWh/m2y. In absolute terms, heating consumption in the residential sector in Europe arrives at around 2300 TWh/y, DHW consumptions reaches 500 TWh/y, while cooling consumption is less than 100 TWh/y. From this picture, it is clear that the construction sector offers unique opportunities to decarbonise the European economy. However, as the replacement rate of the existing stock is very small (1-1.5 % per year), acceleration is needed.
On top of this, the reorganisation of the construction sector poses tremendous challenges due to its extreme fragmentation: more than 50% of the residential buildings are owned by private single owners. Finally, whilst few major industrial players are active on the market, it is largely dominated (more than 95%) by SMEs both on the manufacturers’ and the professionals’ side.
BuildHeat addresses this challenging sector by:
• elaborating systemic packages for the deep rehabilitation of residential buildings
• developing innovative technologies facilitating the implementation of the renovation measures
• developing financial tools enabling large public and private investments
A set of reliable, energy efficient, industrialised retrofit solutions is being made available. BuildHeat integrated solutions allow to reduce the space heating and domestic hot water demand from the actual standards (170-190 kWh/m2y) to around 50 – 70 kWh/m2y, with an investment cost in the range of 50-60% lower than the new built.
Despite the affordability, financing models are needed to facilitate the massive entry to market of the new technologies. BuildHeat aims to leverage large private investments by using European structural funds, thus promoting retrofit actions at quarter level.
The partners collaborated to developing industrialized retrofit solutions.
Solution 1: An innovative, photovoltaic-powered heat pump system with mechanical ventilation and hot water storage for single dwellings
BuildHEAT integrated a dwelling heat pump and mechanical ventilation solution with a small size PV inverter. The integration and control logics developed allow to maximise the utilisation of PV electricity by the heat pump unit, reducing the energy exchange with the grid and shifting electric consumption towards high solar availability periods. This unit is remotely monitored and data is stored in the Cloud, thus enabling the building managers to access them without accessing the dwellings.
Solution 2: An innovative water storage tank, supplying individual dwellings with domestic hot water, space heating and cooling
BuildHeat developed an innovative thermal storage tank to be installed in each dwelling of a multifamily house and aimed to supplying hot water and space heating and cooling. This solution allows distributing a huge thermal storage capacity within the building and to manage it based on the single users’ habits.
In addition to the hydraulic section, the storage tank has been integrated with a mechanical ventilation unit that covers the air exchange needs of the dwelling. The integrated solution arrives prefabricated to the construction site, facilitating and shortening the installation.
The units finally integrate monitoring and control hardware allowing to metering the dwelling energy uses, to monitor comfort conditions and to implement the detailed dwelling energy management.
Solution 3: A multifunctional façade, including insulation and active elements
The solution is a preassembled multifunctional façade system made out of (1) a preassembled metal substructure, which is anchored to the existing façade, (2) a thermal insulation layer integrated in the metal frame and between the frame and the existing façade and (3) cladding panels.
The façade system is engineered to allow hosting eventual pipelines, ducts and cables between the metal frame and the existing façade. In this way, decentral units can be connected to central systems (e.g. a central heat pump, a PV field on the roof) without new shafts being installed.
In addition, the metal frame can host PV panels or solar thermal collectors in place of the cladding elements, allowing to use the new façade as a surface to generate useful energy for the building.
Solution 4: ICT infrastructure to monitor and control the heating and cooling solutions in a smarter way
The BuildHeat ICT infrastructure provides for optimised energy use and storage, which reduces peak loads and ensures indoor comfort. It is scalable to buildings or to district level.
This solution relies on a network of low-intrusive sensors and actuators installed in the dwellings and in the technological equipment. The devices transmit data along cables to an open protocol gateway. From there, the data is sent to the cloud database following a stable and safe protocol. The cloud processes the data by means of control logics, which serve to optimise the energy fluxes in the building.
In addition, interfaces have been developed to share data with different users. On the one hand, a mobile app provides inhabitants with information about their energy use and comfort conditions, suggesting eventual behaviour improvements. On the other hand, a BIM platform has been adapted to read, analyse and display monitored data, making useful information available to ESCOs and building managers.
In addition to the technology development, BuildHeat tackled the financing of the renovation projects:
Firstly, retrofitting in this market is often fragmentary through lack of coordination. Secondly, small-scale projects or investment in new technologies often struggle to attract interest due to their perceived risks or their lack of governance.
BuildHeat proposed a risk mitigation approach by creating a local ecosystem that is attractive for investors.
This approach fosters synergies between contractors, individual customers, private banks, investment funds and public funding and ensures that measures proposed are bankable and attractive to private investors, while being economically sustainable for building owners.
The innovative technologies developed with respect to both HVAC and envelope solutions move towards the massive use of RES and waste heat. This is done thanks to the exploitation of the diffused thermal capacity management approach (through compact thermal storages), and punctual monitoring and control.
The innovation here is linked to the high degree of prefabrication of the devices and sizes adopted. Moreover, the technological developments follow the market trend of assessing low intrusive, scalable and easy to install devices.
In this way, BuildHeat has the potential to streamline deep renovation actions by simplifying the planning and installation processes and to trigger the transformation of the installers sector from low-level jobs to highly skilled professions.
Moreover, most of the innovation potential of the project also resides in the social dimension of its solutions. The deep renovation is structured as a process involving all the stakeholders of the construction chain from the very beginning through the planning and installation phases and all along the lifetime of the building in a continuous commissioning process.
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