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In the current context of joint efforts towards the decarbonisation of buildings, integrating occupants' comfort and health with latest technological advancements for energy efficiency is at the center of the latest development of research, policies and professional practice. Radiant systems are encountering great success since the low-thickness systems can also be used in renovation projects for both heating and cooling, while guaranteeing optimal comfort. However, dehumidification is often required for optimal radiant cooling operation with no condensation risks, and the great potential of mechanical ventilation systems to optimally address the needs for dehumidification, air renewal, health and energy efficiency appears to be far from its full exploitation in the post-COVID-19 era. The present paper aims at providing a quantification of the energy and financial impacts of the implementation of a controlled mechanical ventilation system (CMV) coupled to a radiant system in a typical residential case study building in Italy. The results show that the sole CMV may decrease primary energy demand and energy costs by more than 30% and contribute to an increase in the smart readiness of the building by 8%, but further incentive policies must be developed to cover the still high investment and maintenance cost. [ABSTRACT FROM AUTHOR]

• Novel layout to be easily adopted by existing residential districts. • The novel layout can reduce the primary energy consumption of the residential district. • A primary energy saving index of 38 % and payback period of 2.2 years is achieved. • Power to heat strategy increases the district self-consumed electricity by 15%. • The power to heat strategy is able to further exploit the excess renewable electricity. This paper aims at reducing both electricity and space heating demands of residential districts. It specifically investigates the emerging paradigm, based on renewable energy communities, for existing residential districts. In particular, a novel renewable energy community layout is analyzed. This layout integrates a district heating network and the power to heat control strategy. The proposed system is designed to prevent any major refurbishment inside the apartments, using the existing high temperature space heating system. This arrangement is compared with more conventional renewable energy community layouts. Detailed dynamic models for both the residential district and the proposed layouts are developed using the TRNSYS software. Results show that renewable energy community is an extremely profitable paradigm for promoting the use of renewables at residential buildings scale. Moreover, the layout integrating energy community, district heating network, and Power-to-Heat strategy achieves the best results with a payback period of 2.2 years and a primary energy saving of 38 %. [ABSTRACT FROM AUTHOR]

Energy retrofitting of residential buildings is considered a challenge to be tackled not only at building level, but also at urban scale, to give a stronger impulse for a concrete transition towards climate neutrality. This paper presents an easy-to-use analysis method based on the elaboration and scaling-up of data collected through the energy performance certificates (EPCs) to identify different urban energy zones distinguished by their energy performance index. This method is therefore conceived for better informing urban planning decisions, thus boosting more effective energy-sensitive urban planning strategies and eventually to foresee dedicated financial instruments to act in the more energy demanding areas of the city, establishing priorities for integrated strategies. This analytical method has been applied and tested in one municipality in the Emilia-Romagna region, Italy, where the recent urban planning law is pushing municipalities towards the development of urban planning strategies oriented to drastically improve the energy efficiency of the existing building stock. Results show that only a small number of areas manage to reach a good performance with fairly low levels of energy performance index, with the most critical situation found in the most central areas of the capital and in the hamlets. • Easy-to-use method for assessing energy performance of residential building at urban scale is proposed • Method based on data easily available for local authorities, like energy performance certificates (EPCs) and urban morphology • The method supports urban planners in municipalities in taking more targeted decisions for improving energy efficiency • The main output of the method is the definition of an energy performance index (EPI) for different urban contexts • EPI allows to wisely balance economic incentives, identifying areas where multi-purpose interventions are recommended [ABSTRACT FROM AUTHOR]

• The energy performances of solar-assisted HP for DHW for DHW are studied. • Configuration of HP equipped with PV and PVT panels are investigated. • Solar systems sized to serve small aggregates are studied. • The energy consumption is mainly influenced by the required DHW demand per day. • PVT thermal contribution slightly influences the system performances. The paper investigates the energy performances of several configurations of solar-assisted heat pumps equipped with photovoltaic (PV) and photovoltaic-thermal (PVT) panels as well as solar thermal collectors for domestic hot water production. The systems are sized to serve small aggregates of users assumed as micro energy communities in low housing density context in the South of Italy. Electricity storages are also considered to smooth the interaction with the electric grid. Several indices are defined and calculated to guide toward a correct sizing, to check users' satisfaction and to assess primary energy savings. The results show how the energy consumption from the analysed systems is mainly influenced by the amount and structure of domestic hot water demand per day. Also, according to the chosen plant layouts, it is shown that thermal contribution of PVT slightly influences the system performances. Better results in terms of less non-renewable primary energy consumption are recorded for the PV-based plant. Solar thermal collectors, even if sized for high solar fractions, do not properly support the daily heat pump operation, especially in winter, and present a certain electricity consumption for auxiliaries which results to be penalizing. Additional calculations were performed for the case of energy communities in a context with higher uses of non-renewable energy for electricity generation. Finally, opportunities to support demand-response actions for grid electricity management were investigated. [ABSTRACT FROM AUTHOR]

The present paper illustrates the Italian pilot action of the EASEE project (Envelope Approach to improve Sustainability and Energy Efficiency in existing multi-storey multi owner residential buildings), focusing on the analysis of energy refurbishment trends of the Lombardy region residential building stock. More than 60% of the existing building stock in Lombardy region has been built before the 70 s and it is among the main responsible causes of final energy absorption and corresponding CO 2 emissions with a mean primary energy index for heating of about 202.0 kWh/m 2 y. The promotion of renovation measures for such buildings, also through innovative solutions, is becoming increasingly important for both containing the greenhouse gas emissions and supporting the growth of the construction sector. To this topic, the work presents the energy renovation of a residential building in the Province of Milan through the application of innovative prefabricated composite panels that integrate both thermal insulation and exterior finishing with textile reinforced mortar. In detail, the paper describes, on one hand, the main design strategies following the preliminary analysis and, on the other hand, the whole installation process; besides, the performance of the retrofitted envelope is documented by the results of the monitoring campaign. [ABSTRACT FROM AUTHOR]

Abstract As a large part of primary energy consumption in different countries is related to the residential sector, a reduction in energy consumption at the " household-scale " may determine a significant reduction in the carbon emission at the " country-scale ". Hence, the precise knowledge of the relationships between the household characteristics and the energy consumption/expenditure may serve as basis for policymakers when planning investments aiming to reduce the primary energy consumption in the residential sector. This paper contributes to the existing discussion, focusing on the Italian case study, by analyzing the relationships between the residential energy expenditure and the building factors, socio-demographic variables and appliances. In particular, the impact that the different household characteristics have on per–capita family energy expenditures has been examined commented and compared with the previous literature. The analysis is performed by coupling (a) the ordinary least squares method, to determine the relationship between the variables, (b) the variance inflation factor, to check for multicollinearity issues, and (c) the least absolute shrinkage and selection operator, to select suitable variables. Subsequently, a segmentation of the Italian households has been proposed, by using a segmentation-tree approach and the outcomes of the previous analysis. Highlights • The relationships between the energy expenditure and the household characteristics have been analyzed. • Building, socio-demographic and appliances variables are likewise significant predictors. • A segmentation of the Italian households is proposed, by using a segmentation-tree approach. [ABSTRACT FROM AUTHOR]

The application of retrofit actions to existing building stocks can improve the energy performance of the residential sector. In this context, particular attention should be given to historical buildings, which represent a large part of the Italian building stock. To improve the energy performance of them, adequate retrofit actions must be applied. Many studies and regulations have focused on identifying the best refurbishment measures. However, the selection of these measures is difficult due to restrictive regulations, which are dictated by the Ministry of Cultural Heritage and Activities, high retrofit costs, and variable climate zones. Thus, energy renovations in Italian buildings are not simple, and it is very difficult to find generic solutions that can be applied to buildings across the entire territory. In this paper, the authors investigated the most common retrofit solutions used in Italy, focusing in particular on the energy performance of historical building envelopes. First, energy performance analyses were conducted for two typical base cases in four different Italian cities using TRNSYS software, and some common retrofit measures were analysed. In some cases, the results showed Primary Energy saving of 44.6% (sample A) and 56.7% (sample B). Furthermore, these were used to identify different energy and economic impacts associated with the same refurbishment measures in different climatic contexts, highlighting the non-existence of a generic solution suitable for all regions or countries. [ABSTRACT FROM AUTHOR]

• Electricity and electrification is a viable solution for the energy transition. • Electricity triangle assures a consistent framework for the energy transition. • Multifaceted benefits: energetic, environmental and socio-economic. • Conceptualization of a set of metrics for impact assessment. • A real case study (Italy) considering its evolution up to 2050. Greenhouse gases along with pollution generated by the present energy paradigm widely based on fossil fuels are providing large impacts in terms of climate change and the health of human and biological systems at large. A shift in the energy paradigm, from fossil fuels to renewable energy, is urgently needed for nature and society. This is what we refer to as the energy transition. An old commodity – electricity – can play a new key role in the energy transition. That can happen through what we call the electricity triangle involving electricity generation from Renewable Energy Sources, exploitation of electricity as the main energy vector, and electrification of the final energy uses in all sectors. The possible deployment of the electricity triangle must be carefully assessed in all its possible implications, from technological, economic, societal and environmental perspectives. In this paper, we conceptualize the electricity triangle as a viable approach to the energy transition, and we propose a set of holistic metrics to assess its possible impacts. We apply the electricity triangle framework to the case of Italy based on sectorial studies on RES generation and electrification in building, industry and transport sectors. Our results indicate that Italy in 2050 has the potential to achieve 85.6% penetration of RES in its electricity supply, while 41%, 53% and 42% of the energy consumptions in transport, residential, and industry sectors will be electrified. Ultimately, this would lead to a 68% reduction in CO 2 emissions compared to current levels. [ABSTRACT FROM AUTHOR]