SUSTAINABILITY

The definition of "Sustainable Construction" is a living concept and varies in different scenarios based on peoples’ needs. Taken as the starting point, the definition above has been reinterpreted and expanded based on different approaches and priorities from country to country. In a study led by the International Council for Research and Innovation in Building and Construction (CIB) and carried out with the collaboration of experts from countries around the world, different definitions were given.

Evolution path

In the 1970s, awareness of sustainability emerged, amidst oil crises. At that time, people began to realize the necessity and urgency of energy conservation, which is to utilize energy in an efficient way and find alternatives to contemporary sources of energy. Additionally, shortages of other natural resources at that time, such as water, also raised public attention to the importance of sustainability and conservation. In the late 1960s, the construction industry began to explore ecological approaches to construction, aiming to seek harmony with nature.

The concept of sustainable construction was born out of sustainable development discourse.

Green jobs involved in the sector:

▪ Energy auditor

▪ Environmental certifying technician

▪ Energy certifying technician

▪ Green Building technician - architectural

▪ Green Building designer

What are NZEBs and what are the advantages of a “nearly” zero energy building

The acronym NZEB stands for Nearly Zero Energy Building, that is a building with high energy efficiency, whose operation requires a very minimal amount of energy. In fact, buildings are still responsible for a high energy expenditure and a large amount of emissions and this is why energy saving, in the construction sector, is considered one of the primary objectives for sustainable development of the sector.

This means redeveloping existing buildings and constructing new, highly efficient ones. The main consumption of buildings, domestic and beyond, is attributable to heating, cooling, the production of domestic hot water, electricity for lighting and electronic devices and mechanical ventilation.

Therefore, planners and technicians, by resorting to technological and design solutions, must ensure that those consumptions are reduced so much that they are almost zero, and then satisfy the remaining demand through energy produced from renewable sources. Thanks to efficient redevelopment, it is also possible to transform a home from energy-consuming to class A or even NZEB.

An NZEB building is built according to the principles of sustainable and bioclimatic design, integrated into the context, correctly oriented, able to make the most of natural resources such as the sun and wind, well insulated, powered by renewable energy and equipped with technologically advanced systems.

The heat must be captured as much as possible in winter and stopped in summer, it is important to ensure a good level of natural ventilation and passive cooling and to ensure that dispersions are minimal.

It is clear that the almost zero energy house must consider the seasons: in winter it will have to make the most of the sun's heat, maximize accumulation and ensure thermal insulation. To ensure a cool climate in summer, it is necessary to shield the building well, study the best performing thermal insulation technique and shading systems.

Once this is done, the energy that remains necessary for the operation of the building can be supplied from renewable sources. It is clear, therefore, that an NZEB building in a very hot climate will be different than one built in a cold climate. All, in any case, with the aim of reducing the energy needs of the building. Saving energy also means reducing emissions due to energy production and the consumption of resources. Finally, it should not be forgotten that an NZEB is also characterized by very low operating costs, thus offering high comfort and reduced costs. The term NZEB was first used in the EPBD (Energy Performance Building Directions) package of European Directives published eight years ago. Member states subsequently had to commit to the introduction of national regulations that would promote the construction of energy efficient buildings.

Regulations and obligations for new buildings: NZEB mandatory from January

The concept of NZEB, as well as the obligation of buildings of this type, is contained in the European Directive 2010/31/EU, also called EPBD. Within this text, reference is made to the time limits within which all new public and private buildings must be nearly zero-energy buildings, starting with the public and then with the private sector. In addition, the directive also required each country to draw up specific development plans to encourage the increase of new NZEBs, setting objectives and any useful incentives, taking into account local traditions and specificities.

As regards Italy, specifically, the process began in 2005, when Legislative Decree 192/2005 introduced the topic of energy efficiency. This decree was modified by the D.L. 63/2013, which later became law with Law 90/2013. Precisely this law supplemented the requirements of the EPBD and also introduced the issue of energy production from renewable sources on site. To encourage the growth in the number of NZEB buildings, an "Action Plan aimed at increasing the number of nearly zero energy buildings", called PANZEB, was also thought of, designed to give a precise definition of nearly zero energy buildings, on also based on specific numerical indicators of energy consumption, but also to highlight any financial policies and measures aimed at promoting their development. Finally, for a more complete approach to the issue, the Ministerial Decree of 26 June 2015 “Application of methodologies for calculating energy performance and defining the prescriptions and minimum requirements of buildings” came into force. The decree defines the characteristics that a building must comply with, the minimum performance requirements, to be a nearly zero energy building. With January 1, 2021, the NZEB obligation was introduced in our country for all new buildings or for interventions that involve demolition and subsequent reconstruction, for public buildings the deadline was set at December 31, 2018. This obligation in some regions has been anticipated: in Lombardy and Emilia Romagna, for example, all new buildings have been NZEBs from 2016 and 2019 respectively. At a regulatory level, the matter is governed by the new Legislative Decree 48/2020, which transposed the Directive European 844, known as EPBD III. Parallel to the European and national work for drafting legislation, there have been local commitments that have introduced standards and protocols with the utmost attention to energy efficiency. Italian examples are that of CasaClima and the PassivHaus certification. The legislation, both European and Italian, although increasingly complete, still does not fully deal with the issue of existing buildings which, moreover, are the majority throughout Europe. This very topic, in fact, should be crucial for the transformation of the building stock into an increasingly efficient system, especially since the ways in which to intervene on the existing are often more complex and the problems more numerous. A step was taken with the European Directive 2018/44, which also provided incentives for the renovation of public and private buildings, as long as it leads to high improvements in energy performance. What are the characteristics of an NZEB

There is no real one-size-fits-all rule for the construction of a nearly zero-energy building, but rather some principles to be respected in order to develop a project that is as efficient as possible. According to the legislation, an NZEB has little or no energy needs in both winter and summer, thanks to good thermal performance (low transmittance and high thermal inertia) and makes extensive use of renewable sources and efficient plant technologies. The parameters and reference indices for calculating the performance of a NZEB are contained in the Ministerial Decree of 26 June 2015, which contains values ​​and definitions of the global average heat exchange coefficient (H'T), the summer equivalent solar area for useful surface unit (Asol, est / Asup useful), the thermal performance index for heating and cooling (EPH, nd and EPC, nd) and, finally, the global energy performance index of the building ( EPgl, tot). We then introduce the comparison of the calculated values ​​of these last three performance indices (EP indices) of the real building, with those of a reference building, with respect to which they must be lower. The reference tables for the parameters and characteristics to be respected are contained in Appendix A of the decree. The change of pace can be seen by observing the main innovations introduced, such as the request to calculate the energy consumed by the building during all seasons, while previously we focused only on winter needs.

From January, therefore, all new buildings built on the Italian territory must comply with these indications, with the aim of ensuring an increasingly sustainable development for the sector.

Source: infobuildenergia