Challenge / Goal
Under the GrowSmarter project, GNF(Gas Natural Fenosa) has implemented energy refurbishment of almost 12,500 m2 of tertiary buildings including a hotel, a sports centre and an education centre.The aim is to validate the technical and economic feasibility of adding renewable energy generation to a tertiary building in the form of building integrated photovoltaics (BIPVs) for self-consumption. It is estimated that this solution will reduce combined energy consumption of the refurbished buildings by almost 2GWh/year.
Due to differences in the occupancy and use profiles between each building, each of the three typologies of buildings needs an individual solution for refurbishment. This use case focused on the refurbishment of Educative center Escola Sert. This is a protected building catalogued as historical heritage. Therefore the intervention has been designed and executed respecting the composition and aesthetic of the original building while improving its energy performance and comfort.
Different measures have been implemented for the energy refurbishment of the building.
1. Façade insulation, roof insulation:
- In winter; external Thermal Insulation Composite Systems (ETICS) reduce heating demand and improve internal comfort
- In summer, external insulation reduces the heating of the façade due to solar irradiation while preventing heat dispersion from inside to the exterior. It is also iimportant to use natural ventilation and to avoid direct sunlight using solar protection systems.
- External insulation reduces cold bridges in comparison to internal insulation.
2. Change of windows:
- Improves thermal insulation (lower U than the existing windows) and reduces solar transmission to the inside
- Overcomes the cold bridge of the window itself by installing a window with a thermal break
- Reduces infiltration, thanks to a high quality installation and higher air permeability class (UNE EN 12207)
- Improves acoustic comfort
1. Replacement of existing lighting with LEDs:
- LED technology improves the efficiency of lighting systems as less power is required to meet the same lighting requirements compared to other existing technologies.
- This solution is also an improvement in terms of its life cycle costs, as it has a longer life expectancy than other comparable technologies leading to lower maintenance costs. Replacements are rarer, leading to lower production-related energy consumption.
2. BEMS (Building Energy Management System) installation:
- Monitoring of energy consumptions (electricity, gas, water..) and possibility to export monitoring reports to Excel
- Clear display of consumption for each system and zone
- Help controlling consumption and to take decisions for the optimisation of the working calendar of different systems, in order to improve both the control system and thermal comfort.
Implemented renewable energy solutions:
1. Implementation of a 19.5 kWp façade-integrated PV plant for self-consumption.
- This solution is proposed after analysing a building’s orientation and shadows. It provides added value to the project as the roof of many buildings serves other purposes (HVAC equipment, services for building users, etc) and is therefore not able to host photovoltaic panels. This change serves to test a new solution with higher replication potential.
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