Environmental assessment to support ecodesign: from products to systems - A method proposal for heating systems and application to a case study

摘要

Different policy instruments at the macro and micro level coexist with the goal of reducing the energy consumption of the building sector. At the macro level, the Roadmap to a Resource Efficient Europe (EC, 2011c) and the Energy Efficiency Directive (EC, 2012a) highlight the importance of the building sector, which accounts for 40% of the total energy consumption in the European Union (EC, 2011a). Greater energy efficiency in new and existing buildings is crucial in order to reach the goal of the European Commission’s energy roadmap for reducing the GHG emissions by 80-95% by 2050 compared to 1990 (EC, 2011b). The implementation of the Energy Performance of Buildings Directive (EPBD) 2002/91/EC (EC, 2010b) promotes the energy efficiency in the heating, cooling, lighting and operating appliances and the use of renewable energy in buildings. In particular, Heating, Ventilation and Air Conditioning (HVAC) systems account for 50% of the total energy consumption of buildings (Pérez-Lombard, L., et al., 2008). In 2012, half of the EU’s energy consumption (546 Mtoe) facilitated heating and cooling, and much of this was wasted through insufficient insulation or inefficient equipment in buildings, among others (EC, 2016a). At the micro level, product policies such as Ecodesign and Energy Labelling Directives, EU GPP and EU Ecolabel have the common goal of making the EU market more sustainable. Indeed, they have been very successful in improving the energy efficiency of building products, especially those involved in HVAC systems such as water and space heaters, coolers or air circulators. However, even greater saving potentials could be achieved when the focus is done at the system level rather than at regulating products alone. The issue is that here are huge methodological challenges regarding the definition of systems, the scope and boundaries of a system, the modelling of components that make up a system and its interactions, and the measurement of the energy flows within the system. Policy makers have already recognised the limitations of considering isolated products instead of product systems, and have proposed to move these product policies from components to packages or groups of products (e.g Regulation 811/2013).This report provides guidance towards bringing closer micro and macro scale policies at the building sector. The objective of the work presented in this report is to explore the methodological aspects of environmental assessments of systems at the design step, in order to get higher environmental benefits.The procedure followed to develop the work of the present report began at analysing the system approach and environmental aspects at different product policies (Ecodesign and Energy Labelling Directives, EU GPP and EU Ecolabel) and the scientific literature (only on HVAC systems). As a result of this analysis and the comparison of both sources, some gaps were identified and general requirements were identified for a method supporting the design of good performing heating systems.Product policies usually apply the extended product approach to include additional products, part of the system, that influence the overall performance of a group of products (packages). However, the system approach, i.e. including all the components is not widely applied, as it should be. Product policies focus on environmental performances during the use phase, including energy efficiency, although other aspects can also be considered (e.g. air emissions, sound levels or other technical requirements). On the other hand, the scientific literature uses the system approach and holistic environmental assessment such as LCA. Then, the report proposes a simplified method and a calculation tool, to support the design process of good heating systems in residential buildings, based on the choice of the performance of its components. In the method, product performance figures provided by European sellers according to EU product policies are used when they are available. When product policy data is not available, designers are free to decide on which other tool to use to calculate the missing data. The method allows designers to study the improvement potential and combination of products’ performance levels and to achieve energy-saving targets at system level. The method provides two new aspects that are not yet covered by the literature: 1-it allows the assessment of heating systems grounded on well-known and proven labelling schemes such as EU product policies, which are available at the early design stage and implemented by all manufacturers, and 2-it supports design activities at system level, providing informed decision-making on multiple design solutions based on different configurations of products with performance levels currently available on the market. The method is also tested on a specific case study, simulating the re-design of two heating systems (a solar sanitary hot water system and space heating system) in a dwelling located in North Italy. The case study shows how the method can be applied using data of product policies when available, other tools and/or making assumptions. It also shows the quantitative results on the improvement potential of relevant components and on the combination of components with different performance levels. In addition, the package concept is applied to the case study. Despite the current limitations of the EU package concept (e.g. missing components and climate conditions, rough calculation, etc.), similar conclusions can be drawn from the EU package concept than from the method proposed, which shows the validity of the former. On the other hand, the method proposed is more complete, accurate and flexible and can therefore better support design activities.The method represents a step forward on how to address better the system approach in environmental assessments and how this could be applied to ecodesign of product’s systems. The report demonstrates that the method contributes at improving the task of building designers and regulators to easier achieve common and equivalent energy efficiency objectives.