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Resource- and Cost-effective integration of renewables in existing high-rise buildings

Final Report Summary - COST-EFFECTIVE (Resource and cost-effective integration of renewables in existing high-rise buildings)

Recent studies by Fraunhofer ISE reliably prove that electricity and heat supply systems for Germany based completely on renewable energy sources would cause lower macroeconomic costs than the current energy system relying mainly on nuclear and fossil fuels. The total costs for the construction, operation and maintenance and financing of a German electricity and heating supply system based on 100 % renewable energy sources would thus be lower than the costs which are incurred today (comprising construction, operation and maintenance, fuel costs and financing) to supply electricity and heat. This scenario was calculated using current global market prices, and does not take any projected price increase for fossil fuels into account, although this can be anticipated.

In the study, it is assumed that the required photovoltaic (PV) and solar thermal systems can be installed exclusively on roofs and building façades, i.e. that building envelopes offer a sufficiently large potential surface area. It is of course rational to use the available roof surfaces of a building first, as they usually receive more solar radiation than the façades. Particularly for taller buildings, however, the roof area is often relatively small compared to the entire building envelope. Furthermore, the roof area of high-rise buildings is often completely occupied by equipment for technical building, services, such as cooling towers, chillers and similar installations. In these cases, it is also sensible to use the façades for PV and solar thermal purposes. Recognition of these facts, combined with the national and European goal of carbon dioxide (CO2) neutrality for the building stock by 2050, means that a strong increase can be expected in the number of solar energy components mounted on buildings or integrated into the building envelope. Such building integrated facade components have to be customised so that they meet the individual requirements of the building under consideration (sizes, wind load, safety barrier function). Such customised components will be manufactured in most cases by local manufacturers on demand. This means that such locally produced innovative components are a big chance for European manufacturers on the European market.

Within this project we have achieved the following:

1. Developed a set of five of new façade components and systems:

- a glazing integrated transparent solar thermal collector;
­ air-heating vacuum tube collectors for façade application;
­ an angle-selective transmittance building integrated photovoltaic (BIPV) component;
­ a façade integrated natural ventilation system with heat recovery;
­ a solar assisted decentralised heat pump system using unglazed solar thermal collectors with plaster covering.

2. Developed integrated (techno-economic) concepts consisting of technical concepts and corresponding business models for the most important categories of existing high-rise buildings in Europe (EU-25): This includes also the identification of the most important categories of existing high-rise buildings.

3. Demonstrated the practical feasibility in two pilot buildings in Spain and Slovenia: The Slovenian pilot building has been added to the project within the within the project lifetime in order to be able to demonstrate more of the new technologies.

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