A smart retrofitting kit aims for Near Zero Energy Buildings
About 40 % of energy consumption in Europe comes from buildings, of which 95 % are from stock built prior to 1980, due to their energy inefficiency. Renovating buildings, to make them more energy efficient, is only undertaken for about 1 % of building stock per year. This means that many buildings will need to be retrofitted. This is especially true for non-residential buildings – particularly public buildings - where energy consumption is 40 % above residential buildings (measured as kWh/m2y). The A2PBEER project, funded by the EU, set out to develop a retrofitting methodology for public buildings, concentrated at the district level, using both pre-existing, as well as newly developed techniques. The team created three kit concepts which demonstrated solutions in three actual district, and three virtual, sites. These evaluated energy performance, before and after retrofitting. Developing the ‘kit’ concept The project methodology to design an energy efficiency ‘kit’ for buildings, was developed principally with public building managers and owners in mind as they grapple with the high energy consumption, and so high maintenance costs, of their buildings. As well as representing an audience for the research, these people also can represent good advocates, as Mr Eneritz Barreiro Sanchez the project coordinator further explains, “Public bodies fulfil several leadership, pioneering and incentivising roles. They can promote the introduction of green building solutions and also act as regulators and standards developers, introducing and tightening sustainability requirements.” The research was conducted along four clear stages: design, simulations, validation in real environments and finally demonstration in operational environments. The project developed a number of innovative technological solutions, two of the principal ones being the ‘high performance retrofitting envelope’, along with ‘smart lighting’. The ‘high performance retrofitting envelope’ had three key components. Firstly, a ventilated façade which integrated a 3 cm insulation layer. The additional thermal resistance of the solution, combined with the existing facade, achieved U values (the measurement of a material’s insulation effectiveness) of around 0.2 W/m2K, which meets most of the standards required by European countries, from north to south. Secondly, the solution included a stud mounted internal facade with a vacuum insulated panel (VIP). Finally, a smart retrofitting window was also introduced that can switch thermal properties in response to changing outdoor conditions. By maximising solar gains in winter and minimising them in summer, a balance between heating and cooling is reached across the year. The smart lighting component of the project included lighting which integrated low consuming LED technology and natural lighting that is captured on the roof and brought to the building via slim cable fibre optics. As Mr Barreiro Sanchez recalls, “The challenge here was to extend the coverage of the fibre optic cables from 20 metres to 100, without losing the quality of the transmitted natural lighting, so that it could be deployed in any area of a building.” Towards the EU’s ambition for Near Zero Energy Buildings Importantly, the project also sought to develop synergies at a district level. For example, A2PBEER’s provided heating and cooling to connected buildings through a single thermal distribution network. Mr Barreiro Sanchez enthuses, “This network concept will probably allow the transformation of existing district buildings into the realm of high energy performance nearly zero-energy buildings, taking advantage of descentralised renewable energy systems in a smart, complementary and managed way.” All A2PBEER’s solutions underwent analysis using simulations and then were implemented in three demo buildings, representing different climatic conditions (continental, oceanic and Mediterranean). Additionally, at the end of the project the team performed an analysis of the replicability of the methodology in social housing, with some solutions demonstrated to be applicable in a French social housing district. Ultimately, the technical solutions of the kit concept are intended to be versatile enough to be adapted to the requirements of all building types. As Mr Barreiro Sanchez summarises, “To improve the lives of citizens, some solutions will require further technical development. In other cases, it is the market strategy which will make the solution widely available.”
Keywords
A2PBEER, energy efficiency, buildings, retrofitting, renovation, maintenance, green, sustainability, renewable, smart, climate targets
