DESIGN FOR ENERGY EFFICIENCY

1.1. DESCRIPTION In order to limit the consumption of energy sources, particularly fossil fuels, it is advisable to design new buildings, or to intervene in the redevelopment of existing buildings, operating from the perspective of energy efficiency: a design of this type envisages obtaining an envelope capable of minimising dispersion, always respecting the regulatory limits in force, and of exploiting free contributions and passive mechanisms; at the same time, the systems are designed to have high efficiencies, without wasting energy when not necessary and limiting losses due to malfunctions. 1.2. RELEVANCE FOR CIRCULAR BUILDINGS The design for energy efficiency is based on the principles of the circular economy Reduce and Rethink: in fact, the building is planned to minimise the demand for thermal energy, both thanks to choices concerning the configuration of the building, such as its orientation, and the materials that are chosen to store thermal energy and exploit free inputs. The correct behaviour of the building's user is also part of the reduce perspective: this must be suitably educated for energy saving and can be helped by home automation systems that guarantee maximum efficiency and, at the same time, thermo-hygrometric wellbeing inside the building. A reduction in energy consumption makes it possible to reduce the use of energy sources, nowadays mainly covered by fossil fuels, and consequently the emissions into the atmosphere, decreasing the environmental impact. In addition, the use of heat recovery and controlled mechanical ventilation systems allow for the recycling and reuse of heat once produced. 1.3. INNOVATION ASPECTS As energy efficiency regulations are constantly evolving, and performance requirements are becoming more and more binding, innovation in the approach must lie in adopting solutions in advance: in the case of new buildings, it is not enough to simply comply with regulatory constraints, such as for envelope transmittances, but to aim for the best possible environmental performance, despite the necessary investment. In the case of existing buildings, interventions must be timely, as any delay in energy upgrading entails an impact that cannot be compensated for later. As far as technological innovations are concerned, manufacturers must engage in the development of new materials and new plant technologies that improve the energy performance of buildings, while those who choose building components must consider the contribution they can make. Suppliers of plant components must innovate in the integration of sensors and probes to monitor the efficiency of the systems: in this way they can intervene and extend their useful life as much as possible.

2.1. PRACTICAL APPLICATIONS - Use of materials with reduced embodied energy (including reused materials) - Adequate wall insulation, with overall transmittances of opaque closures lower than those required by regulations - Windows and doors with at least double chamber and thermal break frames and shading systems - Building orientation and configuration to minimise dispersion (e.g. compact configurations) - Attention also to passive heating solutions (e.g. materials with high thermal inertia) - Installation of probes and detectors of internal conditions for the automatic control of systems, also with the contribution of home automation, and careful maintenance - Optimisation of construction and demolition processes, especially in terms of means - Installation of state-of-the-art generators and heat recovery units - Identification and meticulous elimination of thermal bridges - Thermodynamic modelling of the building, preferably on an hourly basis

3.1. BENEFITS - Reduced building running costs - Better control over indoor comfort for the user - Reduction of CO2 emissions and environmental impacts in general - Possibility of achieving zero energy buildings (NZEB or ZEB buildings) by adopting such solutions in combination with the introduction of renewable energy sources and on-site production - Ability to constantly monitor consumption through the use of sensors and plant control bodies - Opportunity to replace old, inefficient plants, very often burning fossil fuels, with new, less impactful and higher performance plants 3.2. COMPLEXITIES - High costs of the latest generators and the most thermally efficient materials - Higher impact of insulation materials compared to others and numerous difficulties in their recycling and/or reuse - Continuous evolution of building energy performance regulations, resulting in the need to go beyond the required limits and thus the risk that new interventions will be necessary in the short future - Need for elaboration, accompanying redevelopment projects, of solutions for the management of waste arising from the decommissioning of, for example, old windows and doors - Indication in reference frameworks of design optimisation criteria limited to the operational phase of the building only