Search

The Renovation Wave for Europe highlighted the role of the public building stock for which Directive 2012/27/EU has set an annual renewal rate of 3%, which should rise to reach the goal of decarbonization by 2050. In this paper, the energy retrofit of an educational building—at the academic level—in Southern Italy was investigated. The aim was to evaluate the incentive share, which could accelerate the energy efficiency process, to achieve a cost-effective nZEB. The results show that the highest incentive rate is required for interventions on the opaque building envelope, which are also those that allow the least energy savings. An incentive rate of about 45% for the energy efficiency of the transparent envelope is necessary to reduce the payback time by about 7 years. The efficiency of the plants and the installation of a PV system are energetically and economically convenient even without forms of economic incentive. Finally, if the building is brought to high energy standards—a primary energy saving of 46% and energy class A3—an incentive rate of 40% is required to repay the intervention in about 10 years. [ABSTRACT FROM AUTHOR]

The 2023 revision of the Energy Performance of Building Directive underlines the need to consider the whole life cycle emissions for buildings. The decarbonization targets could not be achieved if reduction of energy demand in the operational phase is accompanied by a high energy resource use in the whole life. This paper proposes a novel investigation of an energy renovation project, involving both building envelope components and space heating system. The adopted method is based on the life cycle assessment, in the variant cradle-to-gate with options, to analyze and compare the design data achieved through an analysis of product (embodied) and use (operational) stages. Different solutions for energy improvement of the building performance are identified, and the scenario with the lowest embodied energy was found to be more energy efficient globally. The most effective scenario, with energy and CO 2 savings of 39% and 40% is characterized by a weight of embodied energy and emissions of 6.5% and 6.9%, respectively. Given the rise of the weight of the embodied energy in the whole life cycle of future buildings, the life cycle assessment will become crucial for sustainable design and in the transition to an energy-efficiency built environment. [Display omitted] • The impact of life cycle analysis in the process of energy efficiency is investigated. • The "cradle-to-gate" with options approach is implemented. • The efficiency of walls and windows involves the greater use of energy resources. • The most energy-efficient scenarios from an operational and non-operational point of view are different. • The scenario identified in the analysis of A1-A4 phases allows a higher total energy saving. [ABSTRACT FROM AUTHOR]

[Display omitted] • Urban overheating phenomenon in Berlin during summer months. • Climate change effect on outdoor microclimatic conditions in Berlin. • Present, past, and future districts are investigated in different climatic conditions. • Air temperature, surface temperature, and PET are compared between scenarios. • Surface temperature near new buildings can increase until 7 °C from 2022 to 2035. The urban overheating phenomenon is becoming significant in cities, causing extreme weather conditions that negatively affect citizen comfort and health, and increase building energy consumption. This research, in line with the objective of reducing overheating in city centers, investigates a Berlin district, in Germany, which has undertaken consistent urban evolutions during the last few years. The area falls into the Mitte, Tiergarten, and Moabit quarters and is the site of several governmental and institutional buildings, which were mainly built after 2000. Through a numerical approach, the microclimatic conditions are studied, during a representative summer day, at 3 different times: a past time (2000) before the construction of the main government buildings, a current time (2022), and a future time (2035) taking into account the new building constructions already planned for that area. The urban simulations are performed in ENVI-met, employing, for the past and current climate, weather data registered from the nearest weather station, and for the future one, provisional weather conditions developed according to the RCP 4.5 as 50% warming scenario, and RCP 8.5 as a 95% most warming scenario. Finally, by investigating 7 scenarios, the study shows the weight of climate change and of urbanization on the variation in microclimatic conditions in the considered area of Berlin. [ABSTRACT FROM AUTHOR]

The mismatching between the predicted and the operational performance of buildings designed to be nearly zero-energy underlines the importance to study the post-occupancy behavior, to understand if the building-HVAC system is capable to meet the variable conditions even due to the progressive climate change. The paper proposes a discussion about the operational performance of an existing nearly zero-energy building in the Mediterranean climate, during the heating and cooling seasons. The monitoring shows that the required electrical power is always lower than the nominal one, also because the external conditions are not extreme as the design ones. In the colder days, the difference in the required power is −21%. In summer, there is a delay of two hours between the external maximum temperature and the maximum required power. However, the monitored power is usually higher than the nominal one, with a maximum value of +11%. Considering all proposed combinations for the design calculation, it is demonstrated that the real performance cannot be predicted during the design, because indoor and external conditions influence the dynamic behavior of the building-HVAC system. [ABSTRACT FROM AUTHOR]

Buildings account for an important share of global energy consumption and CO2 emissions, so increasing energy efficiency in buildings is essential to ensure an energy transition and sustainable development. In this study, we evaluate the energy benefits obtained through the application of a double-skin façade (passive façade). Subsequently, this is combined first with an airflow network and a control logic for opening windows (active façade) and secondly with transparent photovoltaic modules. The proposed measures are applied to an office building at the University of Naples Federico II. Building's thermal and energy performance are evaluated using EnergyPlus software, starting from validated energy demands of the base buildings. Both passive and active façade provided a reduction in primary energy consumption for space conditioning, of about 17% and 28%, respectively, and in the total primary energy consumption, of about 4% and 9%, respectively. The best solution, with the maximum energy saving in total primary energy consumption, approximately 20%, is achieved with the active façade and with 80% of the outer layer of the double-skin façade covered by PV modules. The results show that transparent double-skin facades are promising and effective for energy retrofit. [ABSTRACT FROM AUTHOR]

[Display omitted] • High-efficient buildings and NZEB need operable and adaptive building components. • Multi-objective requisites are energy-saving, use of renewables, and indoor comfort. • DSF and responsive components can be useful for both retrofits and new buildings. • Recent examples of applications to both new and retrofit designs are reviewed. • Experiments and numerical studies should optimize design and management. The building sector is – directly or indirectly – the first pillar for application of technologies aimed at reducing energy wastes. To achieve sustainable growth goals, worldwide, the building stock needs to be re-developed from the energy viewpoint. This study focuses the attention on the building envelope, since it is the primary subsystem through which energy losses occur between inside and outside environments, by reviewing and discussing the most recent and cutting-edge researches in matter of double-skin and responsive façades for the building retrofit. Each study is investigated by characterizing the technology, the location (i.e. , the climatic conditions) and season of analysis, the building intended use and the main findings. The objective is identifying potentialities and recurrent benefits related to the discussed retrofit solutions – such as reduction of energy consumption and CO 2 -equivalent emissions, exploitation of renewables, conceptual transformation of the building envelope – but also barriers and criticalities – such as overheating risk, lower efficiency of transparent photovoltaics compared to traditional ones, high cost of responsive elements – which have to be addressed and solved in the future. In this vein, a comprehensive snapshot of the evolution of building envelope retrofit solutions is provided with original insights into current and future trends with a view to low- (or zero-) energy buildings. Despite the critical aspects and barriers to overcome, the potential advantages make most of the addressed technologies an important tool to achieve the sustainable renovation of the existing building stock, and therefore their potentialities must be deeply investigated and understood. [ABSTRACT FROM AUTHOR]

Energy Communities are based on principles of renewables, efficiency, local ownership, to improve energy supply and demand. This study evaluates performance of communities, moving from single buildings to the comprehensive performance. The method combines several tools, including DesignBuilder® and EnergyPlus for simulation, MATLAB® as optimization engine. To determine best options, three retrofit scenarios are compared using three performance indicators: primary energy consumption (PEC), CO 2 emission, and running cost (RC). Moreover, evaluation of the investment - with specific economic indicators for helping the citizen to be able to understand the profitability of each individual intervention and so to help him in the choice once an economic constraint - is set. The first retrofit scenario involves insulation of both opaque transparent envelopes, while the second is a retrofit of only systems, through replacement of existing ones and introduction of renewable sources and batteries. Results show how the third scenario - a retrofit trade-off between the first two - offers the greatest PEC, CO 2 emission, and RC reduction of 71.35%, 73.42% and 60.52%, respectively. Even from a purely economic view, the third intervention represents a better investment when considering annual economic savings, as shown by increasing net present values. [Display omitted] • Creating reliable and accurate building/community energy modeling. • Addressing the energy transition from a single building to a sustainable community. • Analyzing different energy retrofit scenarios for a community. • Adopting several performance indicators to compare different retrofit scenarios. • Assessing suitability of scenarios by investigating profitability of interventions. [ABSTRACT FROM AUTHOR]

• Artifact conservation and occupant comfort in a fourteen-century church. • Design of microclimatic control system in historical buildings. • CFD simulations and BES for the provision of indoor microclimatic conditions. • Experimental and numerical approaches for the evaluation of indoor microclimate. Heritage buildings represent part of a city's identity, and their conservation, as well as the preservation of the works of art they house, is indispensable. This study gives a contribution to the topic of indoor microclimatic analysis and control in building heritage, focusing on the environmental monitoring of an ancient church in the center of Naples (Italy). The measurement campaign, performed during two typical winter and summer periods, was a necessary preliminary step to examine the current indoor microclimate and to calibrate a dynamic energy model of the church. The numerical model was employed for coupled analyses of the church by performing BES (Building Energy Simulations) and CFD (Computational fluid dynamic) simulations. The monitoring revealed the inadequacy of current indoor microclimatic conditions for the conservation of the artistic heritage, and for the comfort of the occupants, therefore a heating and cooling system was designed paying attention to the historical/artistic value of the church. The results of BES and CFD simulations demonstrate an indoor temperature increase of up to 4.4 °C in winter and a decrease of up to 3 °C during the summer, by assuring the preservation of artifacts (e.g., too cold or too hot conditions can induce cracks of wooden materials) and improving occupants' thermal comfort. [ABSTRACT FROM AUTHOR]

[Display omitted] • Accurate building energy simulations need high modeling and computational burden. • ANN-based MPC is performed through a genetic algorithm for a nearly-zero energy building. • Multi-objective optimization of heating cost and thermal comfort is obtained. • Optimal control strategies for HVAC systems are achieved through MPC. • High benefits in terms of both heating cost and thermal comfort are proved. Using a simulation- and optimization-based framework that leverages artificial neural networks for the model predictive control of space heating operation, machine learning techniques are explored to predict the energy performance of a real nearly zero energy building located in Benevento (Southern Italy, Mediterranean climate). The framework's goal is to minimize heating energy costs and thermal discomfort by providing optimal values of setpoint temperatures on a day-ahead planning horizon based on weather forecasts. To achieve this, a Pareto multi-objective approach is applied, which considers thermal comfort via the adaptive theory of ASHRAE 55, assessing a comfort penalty function. The optimization problem is solved using a genetic algorithm in the MATLAB® environment. Objective functions are evaluated using the coupling between MATLAB® and EnergyPlus, which is used as building performance simulation tool. Multi-criteria decision-making is performed to select an optimal solution from the Pareto front while setting a limit to the comfort penalty. To test the framework, EnergyPlus weather data is used to simulate weather forecasts for typical days of the winter season. Two different economic scenarios are simulated in order to be able to analyze both conditions and given the variability of the electricity price. For the different days tested, the best results in terms of savings achieved through the proposed solution are on Feb. 28, corresponding to the coldest day and the highest energy cost, with daily savings of 26% compared to a reference control with a fixed setpoint of 21 °C, while maintaining similar comfort performance. The results suggest that optimized control is a crucial aspect of sustainable building design, and the proposed framework can be virtually implemented or integrated into automation systems for real-time model predictive control. [ABSTRACT FROM AUTHOR]

Highlights • The "Benevento" Nearly Zero Energy Building is described. • Results of a monitoring campaign in summer are shown. • The effectiveness of design choices is discussed. • A numerical model of the case study building is calibrated. • Comparison with a building representative of the building stock is proposed. Abstract Nowadays, the Nearly Zero Energy Buildings (NZEBs) represent the new target from 2019 onwards. The present study is focused on a single-family house (called BNZEB), placed in south Italy and specifically designed for a Mediterranean climate. The "Benevento" Nearly Zero Energy Building (that is why the name is "BNZEB") is built with the purpose to be, at the same time, a research laboratory, suitable for testing and measuring energy demands, renewable energy conversion, indoor environmental quality and other aspects of performances in a realistic context. More in detail, firstly the BNZEB is presented and described; then, the early results of a monitoring campaign are shown with the purpose to characterise the energy performance of this building during the summer season and verify the effectiveness of chosen design solutions. For this reason, the daily energy balance is proposed with the aim to evidence the impact of solar production and electric storage on building energy consumptions. It is really important the presentation and the discussion about the monitoring results because, very often, the real performance does not coincide with the expected one and further optimizations are needed. Subsequently, a numerical model of the case study building, suitable for performing transient energy simulations, is used to compare the BNZEB building with other buildings: (a) one representative of the constructive standard established by Italian law; (b) a second one typical of the not-refurbished buildings stock of the city. The aim of this last part is to understand how much the BNZEB's energy performances are better compared to reference buildings during the summer season. Finally, the replicability of BNZEB design in Mediterranean cities, like Lisbon, Montpellier, Madrid, Seville and Athens is evaluated. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Harlequin optimizes energy design by using genetic algorithm and smart sampling. • Three phases allow optimizing design variables for building geometry, envelope, systems. • Different energy, comfort, economy and environment targets are investigated. • The most sustainable, the cost-optimal, the lowest investment designs are achieved. • Harlequin is applied to optimize the energy design of a typical new Italian office. Abstract The comprehensive optimization of building energy design is fundamental to promote sustainability but it is an arduous issue that involves a huge domain of variables and objectives. The proposed investigation addresses this issue through a novel comprehensive framework – Harlequin – that performs a multi-phase and multi-objective design optimization. Three phases are carried out to optimize design variables related to the whole building-plants system, considering different energy, comfort, economic and environmental performance indicators. Phase 1 implements a genetic algorithm to achieve the Pareto optimization of envelope, geometry and space conditioning set points. Phase 2 performs a smart exhaustive sampling of design scenarios to find optimal energy systems. Phase 3 provides the most sustainable, the cost-optimal and the lowest investment (but energy-efficient) design solutions. Among these, the stakeholders can choose the best solution according to their wills and needs. Harlequin uses EnergyPlus (only in phase 1) and MATLAB® and it is so-called because building geometry and envelope are optimized for each exposure, thereby providing "Harlequin buildings". The novelty and scientific significance consist in ensuring a reliable design optimization by investigating a domain of variables and objectives, as comprehensive as never before. As a case study, Harlequin is applied to design a typical Italian office in Milan. Compared to a reference design, significant reductions of primary energy consumption (PEC), global cost (GC) and CO 2 -eq emissions can be achieved, depending on the chosen solution. The maximum reductions are 43.9 kWh p /m2 a for PEC, 63.9 €/m2 for GC (discount rate of 3%) and 12.3 kg/m2 a for CO 2 -eq. [ABSTRACT FROM AUTHOR]

The paper proposes a multi-objective optimization approach to address the energy design of the building envelope. A genetic algorithm (GA) is implemented by means of the coupling between MATLAB® and EnergyPlus to minimize primary energy consumption (PEC), energy-related global cost (GC) and discomfort hours (DH). The design variables concern the set point temperatures, the radiative properties of plasters, the thermo-physical properties of envelope components, the window type, the building orientation. The GA performs a Pareto optimization and finally two optimal solutions are recommended: the nZEB (nearly zero energy building) optimal solution, which minimizes PEC, and the cost-optimal solution, which minimizes GC. These solutions provide the optimal design strategies for the public and private stakeholders, respectively, which represent the main actors involved in building design. The approach is applied for the design of a new typical Italian residential building. Four locations are considered to investigate the typical Italian climates. The outcomes can give precious indications to rebuild the Italian residential stock with a view to energy-efficiency and cost-optimality, given that the optimal solutions provide low values of PEC – between 62.0 and 91.9 kWh p /m2a – and of GC – between 456 and 665 €/m2 – depending on the location. Image 1040241 • The methodology optimizes envelope energy design by using a genetic algorithm. • Primary energy consumption, global cost and discomfort hours are minimized. • The optimal most sustainable (nZEB) and the cost-optimal designs are achieved. • The methodology is applied to four different Italian climatic zones. • Original indications to rebuild the Italian residential stock are provided. [ABSTRACT FROM AUTHOR]

During the cooling season, the beneficial effects of cool colors and cool paints are multiple and undebatable. Really, it is not well-know their impact during the heating season, when a heated external surface could be useful in order to reduce the heat losses. This paper, by means of experiments and numerical simulations, investigates the effect of high-reflective and high-emissive coatings on the building energy performance in Mediterranean climate. Four coatings are used; among these, an acrylic white paint of household appliances or automotive sector has been tested since it is characterized by very fast drying, good adhesion directly to different type of materials, greater durability than traditional paints and lower costs. The experiments have been carried out by using the test-room of the University of Sannio; the results of wintertime monitoring campaign are presented. By means of simulations, using as case study a typical office building, the effect of combination of roof reflectivity, roof technology and insulation thickness is discussed. Research results can support design strategies for optimizing the yearly energy performance of the building, reducing environmental impacts but these also demonstrate the performance of unconventional cool material, as the acrylic paint, with a lower aging and maintenance needs. [ABSTRACT FROM AUTHOR]

The climate evolution towards a progressive increase of Earth's temperature is leading to many worrying consequences, involving different aspects of World life. Among them, a specific focus should be given to the resilience of building energy design to global warming, since the efficiency and effectiveness of energy conservation measures over time can be highly affected by climate change. In this vein, the paper applies a multi-stage, multi-objective approach to find robust cost-optimal energy retrofit solutions and to assess their resilience to global warming. The approach combines the software EnergyPlus and MATLAB ® to implement an optimization genetic algorithm and a smart research strategy. This framework allows to explore a huge solution domain by investigating sundry performance indicators, such as energy needs, polluting emissions and global costs, thereby ensuring a robust assessment of cost-optimality. Different cost-optimal retrofit solutions are found for different global warming and economic scenarios. Finally, a careful decision-making is performed to identify a recommended solution that provides the highest resilience to the cited scenarios, yielding the best trade-off among energy, environmental and economic performances. The approach is applied to a typical Mediterranean building, located in South Italy. The recommended solution includes the energy retrofit of the whole building envelope and the replacement of energy systems. It requires an investment around 100 €/m 2 and, in most scenarios, produces high potential benefits in terms of primary energy savings (42 ÷ 44 kWh/m 2 a), polluting emission reductions (11.5 ÷ 12.0 kgCO 2 -eq/m 2 a) and global cost savings (5 ÷ 78 €/m 2 ). [ABSTRACT FROM AUTHOR]

This study is focused on the evaluation of the effectiveness of vacuum insulation panel (VIP) for typical Mediterranean climate. The interest for this material is due to indisputable advantages in term of insulation performance both for new and refurbished buildings; mainly in retrofit design, adoption of lower thickness assure same results with less invasive interventions. The problem is the behavior during the summer period, not investigated in the available scientific literature. Numerical and experimental approaches are used in this paper to compare the performance of several wall packages integrating VIP with constructive technologies that result in different stationary and dynamic parameters. More in detail the results of a yearly measurement campaign in three real building of south Italy are presented; recorded data of the surface and the mean air temperatures as well as of the heat flux are commented. Data for one typical week of each season are evaluated to compare the wall made of concrete block and vacuum insulation material with a massive structure and also with a concrete wall with expanded polystyrene as insulation material. Furthermore, simulation results (by means of EnergyPlus) are presented to study, mainly during the summer, the effect of integration of vacuum insulation panel in multi-layered wall made of concrete blocks with different values of density and thermal conductivity; moreover these configurations are compared with a wall made of innovative insulated interlocking brick and with the wall types considered in the experimental phase. Using a typical office building as case study, energy consumptions and environmental and economic indexes are valuated. Experimental and numerical results show the effectiveness of solution with VIPs also for Mediterranean climate. [ABSTRACT FROM AUTHOR]

Facing the climate change is a common priority, due to ethical issues related to general concept of sustainability and livable future for the next generations. Moreover, ethical aims for contrasting energy poverty, heat-related diseases and deaths, availability of food and water, infections and viral-bacteriological risks, meteorological extreme phenomena, such as floods and intense and destructive precipitations, are stringent and pressing targets. All serious and independent investigations reveal future scenarios of an overall global warming that surely make worrying the evolution of quality of life on this earth. Each one has to do his part. In this study, the research is focused on renewable technologies for the passive cooling of buildings. Indeed, the space cooling is a strongly increasing use of energy and induces a vicious circle, being, at the same time, a cause and an effect of the anthropogenic overheating of the planet. The paper mainly reviews techniques for suitably governing the energy interaction between buildings and surrounding environment. The energy efficiency concerns the building envelope design, the use of efficient HVAC systems, adoption of renewable energy on-site. On the other hand, every energy conversion process determines waste heat, so that also a ‘free of operational cost’ solar cooling system however causes dissipation of heat into the ambient. Finally, renewables cannot be the unique solutions for supplying the energy required for the building use. Conversely, strategies for reducing the building cooling are needed, and these are reviewed in this study. In thermodynamics terms, the building is seen as part of the system and not the mere control volume. Greenery of facades and roofs, phase change materials, nocturnal convective cooling, evaporative and ground cooling, solar systems such as chimneys for improving the building ventilation are here discussed, as well as emerging technologies such as breathing walls and dynamic insulation. The reviewed studies, selected on the basis of more recent progresses concerning the investigated technologies, revealed potentialities but also criticalities in the design. [ABSTRACT FROM AUTHOR]

[Display omitted] • A dynamic envelope based on the double-skin façade technology is proposed. • The dynamism is achieved through the controlled opening of the window elements. • The system is analyzed for a real office building, in a Mediterranean climate. • A dynamic shading system, activated by temperature, is proposed. • Energy savings of 37% and 3% are obtained respectively in the cold and warm seasons. The history of our planet has always been characterized by climate change, but the way in which this change has been taking place in recent decades puts us in front of a real climate crisis, for which man is primarily responsible. Among the sectors affected by the energy transition process, that of construction is in the foreground, especially with reference to existing buildings. This study proposes a dynamic envelope based on the double-skin façade (DSF) technology as retrofit measure for an existing building office located in a city with a Mediterranean climate. The methodology used is of an experimental type, using DesignBuilder® and EnergyPlus software, for the energy modeling and simulation phases respectively. The responsiveness of the proposed facade is obtained through the controlled opening of the windowed components of the internal and external surface of the DSF, which allows for the establishment of an airflow. Furthermore, for the summer season, a shading system with dynamic activation controlled by the temperature is proposed. Compared to the current state of the building, the impact on energy consumption for the thermal load is between −17.8 % and −37 %, while for the cooling load it is between +9 % and −3%, based on the configuration adopted. With the best solution, a total primary energy saving of 20 % is obtained. [ABSTRACT FROM AUTHOR]

[Display omitted] • The transition of building districts to sustainable energy communities is addressed. • The case study is set in a real social housing district in Naples, South Italy. • Brute-force optimization is used to drive the transition maximizing sustainability. • Design variables include envelopes, energy systems, renewables, storage, control. • A multi-objective approach is applied to trade-off sustainability and costs. The decarbonization of the energy industry is essential to achieve a future net-zero energy system. To maximize the capacity of citizens to contribute to the clean energy transition, sustainable energy technologies are mandatory. Accordingly, the development of nearly-zero energy districts and communities is up-to-date, and, about it, the net-zero energy goal requires a challenging combination of building design and retrofit, renewable energy sources, energy storage systems. This manuscript investigates several alternative solutions for a shared energy system, to turn a 29-building social housing district in Naples, Southern Italy, in a nearly zero-energy community. The method is quite articulated, based on various numerical approaches, applied by the cycling use of many programs, namely: DesignBuilder® for the building modeling, EnergyPlus as simulation tool, and MATLAB® as optimization engine. A sustainability index based on emissions is introduced. A first optimization is carried out to maximize the sustainability index of the energy community, with a brute-force algorithm used to investigate several design variables, that address building envelopes, energy systems, renewables, electric storage, and operation strategies, resulting in 2,224,044 solutions explored. A second multi-objective optimization is then performed on a limited number of solutions, to evaluate not only the energy-environmental aspects but also the economic ones. The analyzed solutions have a minimum sustainability level equal to 85% and it shows a suitable combination of common buildings retrofit measures. Finally,in order to be able to achieve generalizable results, possible energy and economic targets are outlined: sustainability levels of 85%, 90%, and 95% with an investment budget of up to 150–200 €/m2. [ABSTRACT FROM AUTHOR]

The cost-optimal analysis provides the most cost-effective energy retrofit solutions. This can strongly support the deep renovation of buildings. However, an outstanding question arises: How to achieve the robust assessment of cost-optimal solutions, feasible for any building? The paper answers this question by proposing a new multi-stage framework for c ost-optimal a nalysis by multi-objective optimi s ation and a rtificial neural networks, called CASA. It couples EnergyPlus and MATLAB ® . A genetic algorithm allows to select recommended retrofit packages by minimizing energy consumption and thermal discomfort. Among these packages, the cost-optimal solution is identified. It is robust because the algorithm explores a wide domain of retrofit scenarios. The optimization procedure uses artificial neural networks to predict building performance. Large-scale uncertainty and sensitivity analyses are conducted to support the generation of the networks. These latter are tested against data provided by current literature with excellent results. The networks’ applicability to whole building categories and rapidity of evaluation make the procedure feasible for any building. For demonstration, CASA is applied to a reference office building located in South Italy, by investigating the related category. The achieved cost-optimal solution produces global cost savings around 42.4 €/m 2 , and significant reductions of energy consumption, discomfort hours and polluting emissions. [ABSTRACT FROM AUTHOR]

Building activity is the sector that affects for the most part the anthropogenic climate change. Indeed, even if differences can be found among countries, according to the level of development and climates, buildings require about 30–40% of the overall energy demand, with similar share concerning the greenhouse emissions. According to the more recent EU Directives in matter of energy efficiency in energy use, a great attention has to be paid to energy refurbishments of existing buildings. Indeed, the turnover rate of the EU building stock is generally low in fully-developed countries, so that the energy retrofits are also more important compared to new nearly zero-energy buildings. The proposed investigation concerns the demonstrative role of the public hand, whose necessity is underlined by the EU Directives 2010/31/EU and 2012/27/EU, through a multi-step and multi-objective optimization of an educational building of an Italian University. All preliminary investigations aimed at a reliable modelling, the iterative method that combines genetic algorithms and transient energy simulations tailored on calibrated numerical models make the investigation complete and repeatable. All levers of energy efficiency have been pressed, and thus the refurbishment of building envelope, HVAC systems, integration of energy supply by renewables. The multi objective optimisation concerns costs, incentives, indoor comfort, energy demands for heating and cooling and a novel approach is proposed for choosing the best configuration of retrofit. It is resulted that the most profitable energy efficiency measures involve the modernization of energy systems, even if also the retrofit of the building envelope can be profitable under favourable financial conditions. The cost-effective refurbishment reduces the primary energy demand up to a value of 12 kWh/m 2 a, so that the building can be surely considered as nZEB. [ABSTRACT FROM AUTHOR]

Zero-energy and zero-carbon buildings would be a huge opportunity for contrasting the climatic changes and, more in general, the deterioration of the microclimate inside and around cities. About it, a question appears compulsory: are zero-energy and zero-carbon concepts applicable at urban scale? This paper tries to answer to this question, by discussing the possible effects of the application of appropriate city planning techniques when a new settlement is designed. An integrated approach to urban planning is applied to a case study, for promoting the design of buildings with very low (or zero) energy needs, characterized by high indoor comfort conditions, by taking into consideration whole city areas, with different kinds of services. Passive heating, cooling and daylighting techniques have been combined, as well as the integration of renewable sources, in order to minimize the energy demand and environmental impact, for having a sustainable 'urban balance' and in general, a sustainable urban growth. As real case study, the design of the holiday village 'Olympiad' is presented; it should be built in an unstructured seaside area in Greece. Several indexes are introduced to evaluate the global sustainability of the settlement, through the application of the definition of 'on-grid ZEB' with reference to each building as well as for the entire village. This kind of research could help city planners for a growth inspired to general goals of urban sustainability. [ABSTRACT FROM AUTHOR]

The issue of the summer indoor overheating in modern buildings is investigated. Indeed, mainly for heating dominated climates, usually there is a great attention to the design of measures for reducing the energy losses in winter, while the summer comfort often is secondary or neglected. On the other hand, just where the warm season is not so hard, passive energy measures have to be deeply exploited, in order to avoid the installation of air-conditioning systems, with positive effects on both the building and city scales (e.g., the reduction of urban heat islands). After a general overview of the overheating phenomenon, a case report is proposed, where, even if the summer ambient conditions are not extreme, thermal discomfort has been registered during the first years of operations. The office building, recently built in Berlin, fulfils the German requirements of energy efficiency and heat protection in summer. It is not equipped with mechanical systems for the space cooling. According to the new international approach of the cost-optimality, this study investigates strategies for improving the indoor conditions – evaluated by means of the adaptive criteria – during the cooling season, by analyzing various solutions for reducing the heat gains. By means of calibrated numerical models, validated by comparisons with measurements of indoor air temperatures (free-running building), transient energy simulations have been performed. The target of investigation is the research of the optimal solution of solar shadings (i.e., typology and management), in order to find the best compromise in terms of thermally comfortable hours, use of artificial lighting, operational and investment costs. [ABSTRACT FROM AUTHOR]

The evaluation of performance of historical masonry buildings requires a multidisciplinary approach. Indeed, the use and functionality of a building is a multidisciplinary item related to various issues as structural and thermal aspects, acoustic requirements and efficiency of active energy systems. Since these buildings are often used for strategic, educational and recreational facilities (offices, hospital, barrack, school, university, library, museum) or as residences, they frequently need both structural interventions for warrant safety under static and dynamic actions and energy refurbishment for warrant a comfortable and optimal use of the building depending on its specific use. Since the energy refurbishment can be easily associated to structural consolidation or functional reorganization works, this paper is aimed to introduce a methodological approach with reference to both structural behavior and energy performance for the space heating and cooling. The main steps are the survey, the diagnosis, the creation of a numerical Finite Element model necessary for the verification of the structural safety, the validation of a dynamic model for energy performance assessment and the choice of criteria and techniques of interventions. The proposed approach combines both structural and energy analyses, based on a detailed identification of the building, carried out by means of in situ tests and surveys. As case study, the proposed approach has been applied to Palazzo Bosco Lucarelli, a historical masonry building located in the ancient center of Benevento (South Italy). [ABSTRACT FROM AUTHOR]

How to predict building energy performance with low computational times and good reliability? The study answers this question by employing artificial neural networks (ANNs) to assess energy consumption and occupants' thermal comfort for any member of a building category. Two families of ANNs are generated: the first one addresses the existing building stock (as is), the second one addresses the renovated stock in presence of energy retrofit measures (ERMs). The ANNs are generated in MATLAB ® by using the outcomes of EnergyPlus simulations as targets for networks' training and testing. A preliminary ‘Simulation-based Large-scale sensitivity/uncertainty Analysis of Building Energy performance’ (SLABE) is conducted to optimize the ANNs' generation. It allows to identify the networks' inputs and to properly select the ERMs. The developed ANNs can replace standard building performance simulation tools, thereby producing a substantial reduction of computational efforts and times. This can allow a wide diffusion of rigorous approaches for retrofit design, which are currently hampered by the excessive computational burden. As case study, office buildings built in South Italy during 1920–1970 are investigated. Comparing the ANNs' predictions with EnergyPlus targets, the regression coefficient is between 0.960 and 0.995 and the average relative error is between 2.0% and 11%. [ABSTRACT FROM AUTHOR]

[Display omitted] • Simulation- and optimization-based model predictive control is implemented. • A nearly zero energy building in Mediterranean climate is the case study. • Energy cost & discomfort – Fanger & adaptive – are minimized via a Pareto approach. • Cooling setpoints are optimized on a daily horizon based on weather conditions. • Optimal solutions can reduce both cost & discomfort vs a fixed setpoint strategy. The space conditioning of buildings is liable for more than 10 % of World final energy uses and related CO2-eq emissions. Such share must be drastically reduced to pursue sustainability by optimizing both energy design and devices control. In this frame, space cooling is assuming an increasing weight owing to climate change. Accordingly, this study applies a simulation- and optimization-based framework for the model predictive control (MPC) of space cooling systems. The case study is a nearly zero energy building located in Benevento – Southern Italy, Mediterranean climate – featuring an efficient air-source multi-split system for cooling. The framework is envisioned to provide optimal values of setpoint temperatures on a day-ahead planning horizon to minimize energy cost and thermal discomfort, based on weather forecasts. Accordingly, a Pareto multi-objective approach is applied considering different discomfort indicators to compare the Fanger theory with the adaptive one of ASHRAE 55. The optimization problem is solved by running a genetic algorithm – variant of NSGA II – under MATLAB® environment. The objective functions are assessed via the coupling between MATLAB® and EnergyPlus, using a validated building energy model. The multi-criteria decision-making is performed by setting a limit to discomfort to pick an optimal Pareto solution. The framework is tested addressing a typical day of the cooling season and using monitored weather data to simulate weather forecasts. Different optimal solutions are provided to fit different comfort categories. Compared to a reference control at fixed setpoint – 26 °C – the proposed solutions with similar comfort performance ensure cost savings around 28 %. Besides the proposed hypothetical implementation, the framework can be integrated in automation systems for real-time MPC. The novel contributions of this study lie in the methodology to combine MPC with different thermal comfort models as well as in the results, which provide deeps insights about the application of MPC for the space cooling of nearly zero energy buildings in a balanced climate. [ABSTRACT FROM AUTHOR]

Nowadays the study of Net Zero Energy Buildings (NZEBs) is fundamental, because they are the main strategy to reduce the building energy demand and CO 2-equivalent emissions. This paper analyses a case study concerning a multipurpose building located in Palermo (Southern Italy), and evaluates the benefits related to the use of an earth-to-air heat exchanger in a NZEB, in terms of energy saving and reduction of CO 2-equivalent emissions, for a Mediterranean climate. The chosen building envelope is thermally performing. The HVAC system consists in fan-coil units connected to an air-to-water heat pump, and mechanical ventilation. The energy demand is reduced by an earth-to-air heat exchanger that pre-heats the ventilation outside air in winter and cools it in summer. The optimization of the heat exchange with the ground is a key-element to reduce the primary energy requirements and CO 2-equivalent emissions, especially during summer. Moreover, this paper assesses the possibility to obtain a NZEB using only on-site renewable energy (on the roof of the building), with and without the earth-to-air heat exchanger. The energy analysis is carried out by means of a dynamic building simulation engine, namely EnergyPlus. In addition, a thermal performance and an environmental analysis are performed. [ABSTRACT FROM AUTHOR]

Design criteria for a residential nZEB in Mediterranean climate are discussed. The integrated design procedure focuses on the problem of a large number of available building variants concerning the building envelope. The aim is to search the ones that minimize winter and summer energy demand without compromising thermal comfort. The adopted methodological approach combines the use of dynamic energy simulation tool (EnergyPlus), based on a one-dimensional conduction finite difference solution method, and a constrained multi-objective optimization algorithm. For four cities (Madrid, Nice, Naples, Athens), several passive strategies are compared: thermal properties of the building envelope, adoption of phase change materials with different melting temperatures, cool roof solutions, several window/wall ratio values, some external and internal shading systems. The results allow to evidence that it is difficult to understand the best trade-off between summer and winter performance, by assuring high standard of thermal comfort when the aim is to reach NZEB objectives in Mediterranean climate. However, some guidelines are indicated, starting from the discussed results. [ABSTRACT FROM AUTHOR]

The German Federal Government put its first net zero office building in operation in 2013 anticipating EU requirements for all public administrations to solely built “nearly zero energy buildings” from 2019 onwards. The two-storey building is situated in Berlin and has been designed for having an overall annual energy demand lower than the in-situ conversion of renewable energies. The paper shows the results of the first year of the operation. The overall annual electric usage is near to the expected value. Nevertheless, intensive monitoring showed differences between the expected and the measured electric usage in the areas of heating and domestic hot water (+172%), ventilation (−36%), lighting (−33%), equipment and auxiliaries (−14% and −13%, respectively), yield of the PV-system (+32%). A numerical model was created to investigate these deviations as well as to evaluate the impact of possible actions aimed at further improving the energy demand of the building. The model was calibrated with measured data, data from surveys, occupancy schedules, and validated by means of different indexes, among which the mean bias error (MBE). The MBE between monitored and simulated energy performance is below ±2% for all stated areas of energy usage. Analogously, the energy needs for cooling, monitored and simulated, as well as the trends of the indoor air temperature in both heating and cooling seasons, are in a very good agreement. In detail, the monthly MBE for the indoor temperature, in specific summer and winter periods and in the considered rooms, is below the threshold of ±5%, with values slightly higher (anyway lower than ±6%) only at the ground floor. Finally, the paper shows that the reasons for the detected deviations in electric energy usage can mainly be related to the usage pattern of the building and to the occupants’ behavior. In order to ensure energy efficiency as high as planned, a suitable monitoring of the energy performance is fundamental. It enables the calibration and validation of tailored energy models to detect possible malfunctions as well as propose actions aimed at further reducing the energy usage of the building. [ABSTRACT FROM AUTHOR]

Technology transfer, scientific research and education could have a key role in Mediterranean regions, in order to reduce the environmental impact of the building sector. Recently, the Department of Engineering of University of Sannio has developed a laboratory suitable for performing researches on the dynamic interactions between building envelope components, indoor environment and mechanical systems for a typical climate of south of Italy. The work described within this paper is a part of this large-scale project. Its goals are: (a) to design, test and validate a poly-equipped test room, (b) to perform transient tests to determine performances of common and innovative building components and alternative HVAC systems. More in detail, this paper focuses on the first goal, with the aim to generalize the design approach, requirements and capabilities of calibrated outdoor test facilities, specifically thought for Mediterranean climate. The facility has undergone a substantial amount of characterization tests, aimed at determining its response under yearly operations. The primary conclusions are that the new test facility is usable for a wide range of environmental and indoor conditions, it is functional and has been validated through characterization and preliminary investigations of the behavior of the thermal envelope. Moreover, some experimental results are here analyzed, by evidencing the potentialities of vacuum insulation panels for improving the performances of the thermal envelope, for what concerns both winter and summer seasons. Then, some numerical analyses have been carried out. A 3D CFD model has been calibrated for studying the real distribution of temperatures and water vapor partial pressures within VIP panels. Furthermore, a dynamic energy model of the test cell has been developed by means of Energy Plus, with the aim to use its capability to compare potential configurations that would be installed in future researches, or to evaluate energy, environmental and economic issues. [ABSTRACT FROM AUTHOR]

COVID-19 pandemic has caused an economic crisis, and also the building sector has suffered consequences. Indeed, an increase in the building energy consumption, mainly in the residential sub-sector, was registered, due to higher energy use. European Union has enacted a strategic plan to combat this crisis by promoting environmental sustainability and giving a key role to the building sector. This study provides an overview of the implementation state from EU countries, of the European policies in terms of building energy efficiency and draws attention to the adopted financial programs and incentives to promote an energy-efficient built environment. It is shown that more than 70% of Member States have transposed the EU Energy Performance of Building Directives and all of them have activated plans or programs to finance the building energy renovation, mainly in the residential sector. A focus is made on the Italian case, by considering the recently introduced tax deduction of 110% (divided into a number of annual rates) that promotes specific energy efficiency measures for existing buildings, in the vein of new requirements provided by the Directive EU 844/2018. In this investigation, three residential buildings are selected, and, by employing both semi-stationary and dynamic approaches, a critical analysis of several passive and active energy efficiency measures is performed. The variability of climatic conditions and building markets are considered in energy and economic evaluations: the building case studies are located in different Italian climatic regions and have different construction ages. Considering the energy, environmental and economic indicators, it is shown how the new Italian funding program can boost the diffusion of energy efficiency interventions which imply the best energy performance, and not the best cost/benefit ratio. The study points out achieved goals, criticalities, and new perspectives after years of energy policies in Europe. [ABSTRACT FROM AUTHOR]

The ‘Energy Performance of Buildings Directive’ Recast (i.e., 2010/31/EU) establishes that building energy retrofit should pursue “cost-optimal levels”. However, a reliable and rigorous cost-optimal analysis is an arduous and computationally-expensive issue, especially for complex buildings such as hospitals. The paper tackles this issue by providing a novel methodology to identify robust cost-optimal energy retrofit solutions. Multi-stage and multi-objective (Pareto) optimization is performed with the aim of minimizing the computational burden required to achieve reliable outcomes. The methodology combines EnergyPlus and MATLAB® and includes two optimization stages, preceded by a preliminary energy investigation that performs Latin hypercube sampling and sensitivity analysis. The preliminary investigation and the first optimization stage, which runs a genetic algorithm, aim at detecting efficient energy retrofit measures (ERMs) to reduce thermal energy demand for space heating and cooling. In the second optimization stage, these ERMs are combined with further ERMs, addressed to improve the efficiency of energy systems and to exploit renewable energy sources. Investment cost, primary energy consumption and global cost related to the resulting retrofit packages are investigated by means of smart exhaustive sampling. Finally, the cost-optimal solution is identified both in presence of a limitless economic availability and of limited budgets. The methodology is applied to a hospital reference building (RB), which represents hospitals built in South Italy between 1991 and 2005. The RB is defined by using an original approach, as required by the complexity of the examined building category. The achieved cost-optimal retrofit packages imply a reduction of primary energy consumption up to 67.9 kW h/m 2 a (12.2%) and of global cost up to 2932 k€ (24.5%) with a maximum investment of 1236 k€. [ABSTRACT FROM AUTHOR]

Efficient HVAC devices are not sufficient to achieve high levels of building energy performance, since the regulation/control strategy plays a fundamental role. This study proposes a simulation-based model predictive control (MPC) procedure, consisting of the multi-objective optimization of operating cost for space conditioning and thermal comfort. The procedure combines EnergyPlus and MATLAB ® , in which a genetic algorithm is implemented. The aim is to optimize the hourly set point temperatures with a day-ahead planning horizon, based on forecasts of weather conditions and occupancy profiles. The outcome is the Pareto front, and thus the set of non-dominated solutions, among which the user can choose according to his comfort needs and economic constraints. The critical issue of huge computational time, typical of simulation-based MPC, is overcome by adopting a reliable minimum run period. The procedure can be integrated in building automation systems for achieving a real-time optimized MPC. The methodology is applied to a multi-zone residential building located in the Italian city of Naples, considering a typical day of the heating season. Compared to a standard control strategy, the proposed MPC generates a reduction of operating cost up to 56%, as well as an improvement of thermal comfort. [ABSTRACT FROM AUTHOR]

• The resilience of a building designed to be nearly zero energy is evaluated in Mediterranean climate. • Weather file defined with monitored data are used for a short-term analysis. • Projections of climate changes are considered in the construction of weather files. • The net primary energy will decrease (–23%) and the in-situ renewable adoption will increase (85%). • Overheating will occur in the intermediate months with the need to turned on the cooling system. The paper is focused on the evaluation of how the climate changes can influence the performance of buildings designed to be nearly zero energy (nZEB) and on the evaluation of the resilience in term of energy balance. A real case study is used; it is named BNZEB, a single-storey dwelling built in Benevento (South Italy, Mediterranean climate). With five-years monitored meteorological data, both a short-term and medium-term analysis is developed; the first one consists in the evaluation of the energy behavior compared to the first operating year. Then, the energy performance is evaluated considering the medium-term climate projections generated using the CCWorldWeatherGen tool. This analysis, with reference to the case study, suggests to designers and researchers that, in a typical Mediterranean climate, the reduction of the heating demand could compensate the increment in the cooling request. In the worst climatic scenario, the net primary energy could change from 25.4 kWh/m2 year (first year of life, 2017) to 19.5 kWh/m2 year (projection to 2050) with a rate of self-consumption of 85% (80% for 2017). However, a critical point is the operating period of the cooling system. Indeed, an indoor overheating problem could occur during the spring with operative temperature higher than 30 °C; this indicates that in future, the occupants will require higher number of operating hours with most frequent switch off. This could change the results of the energy balance, reducing, for instance, the imbalance between production and consumption that currently occurs in the intermediate periods. [ABSTRACT FROM AUTHOR]

In order to deliver the European energy and climate objectives to 2050, significant changes are essential in the building sector, especially regarding the existing stock. Indeed, there is a huge potential for action, also regarding historic buildings. In this regard, today the question is: how to combine the building protection requirements and the application of energy efficiency measures? This paper tries to answer, evaluating if the refurbishment of historic architectures, in order to achieve very low energy need, is possible and economically feasible. More in detail, the applicability of the cost-optimal methodology (EPBD Recast 2010/31/EU) for historic buildings is discussed, by adopting the macroeconomic perspective, in order to take into account of the energy, environmental and economic impacts of about 60 packages of energy efficiency measures. The study is aimed to introduce a methodological approach to define reference buildings for historic architectures, through in-situ investigation of structural and energy peculiarities and, as real case study, the refurbishment of an Italian building of the XV century is presented. Moreover, guidelines are proposed to properly select energy efficiency measures, according to a point of view of cost-optimality. Conservation, aesthetical requirements, structural and energy issues are considered, as well as the incidence of all economic factors. [ABSTRACT FROM AUTHOR]

The paper proposes a method for reliable energy diagnoses, aimed at integrated design of energy refurbishment of existing buildings, with reference to historical architectures. The approach is structured according to three main phases: (a) the building performance assessment, by combining in situ monitoring and documental information; (b) the numerical studies by hourly energy simulations with a deepening about the calibration methodology; (c) the investigation of potential energy savings, environmental benefits and economical profitability of selected energy efficiency measures. The case study is an educational building of the University of Sannio, located in the ancient center of Benevento (Southern Italian city). The knowledge of the historical energy requests, combined with several measurements (e.g., schedules of indoor temperatures, activation of HVAC system) and with in situ investigation (e.g., infrared thermography and heat flow measures) allowed the calibration of the numerical model. Moreover, several actions for the energy rehabilitation have been implemented, by taking into account the historical value of the building and of its context. The achieved results show that the selection of the energy efficiency measures is a multi-objective optimization problem and – even if heritage buildings require respect of several constraints – however satisfactory energy savings are available. [ABSTRACT FROM AUTHOR]

The recast version of the Energy Performance of Buildings Directive (2010/31/EU) proposes a comparative methodology aimed at defining the energy performance of buildings “with a view to achieving cost-optimal levels”. Really, how can the cost-optimal technologies be detected? Moreover, how can the most proper packages of energy efficiency measures be chosen in order to obtain the cost-optimality? This paper would provide answers to these questions, by proposing a new methodology for the evaluation of the cost-optimality, by means of the multi-objective optimization of energy performance of buildings and indoor thermal comfort. The optimization procedure is developed by means of the coupling between MatLab and EnergyPlus, by implementing a genetic algorithm, and it allows the evaluation of profitable and feasible packages of energy efficiency measures applied to buildings. Then, following the adoption of these packages, the global cost over the lifecycle of the building is calculated, in order to identify the cost-optimal solution. After the presentation of the methodology, the developed method is proposed for the optimization of the energy retrofit of an existing building. Furthermore, the method can be applied also for new architectures, by considering reference buildings. [ABSTRACT FROM AUTHOR]

Highlights: [•] A home-made code for transient evaluation of thermal bridges was validated. [•] The model validation has been carried out by means of experimental measures. [•] The heat flux was measured through a set of thin film heat flux sensors. [•] The code is reliable, with errors in the range −12% to 6% and average values close to zero. [Copyright &y& Elsevier]

Highlights: [•] Building envelope refurbishment by means of PCM plaster has been investigated. [•] The analyzes vary melting temperature, thickness and location of PCM plasters. [•] The reduction of cooling need is evaluated for five Mediterranean climates. [•] Masonry-insulated buildings have been studied in realistic operating conditions. [•] Guidelines are proposed for optimizing energy savings by means of proper PCM. [ABSTRACT FROM AUTHOR]

Highlights: [•] Starting from energy audit of single buildings, a whole city center is analyzed. [•] The proposed methodology investigates energy demands for space heating and cooling. [•] The calculation procedure is based on various input sources, including surveys and literature. [•] At urban scale, an energy planning is proposed, using the Geographic Information System. [•] “Urban-energy maps”, related to heating and cooling performance, are developed. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel analysis approach for the energy retrofit planning of districts/neighborhoods is proposed. • The stochasticity of the occupant behavior together with the global warming are considered. • The energy, the financial and the environmental benefits are maximized. • Different energy retrofit combinations are examined. • The methodology is applied to an existing neighborhood ubicated in Naples (Italy). Buildings are responsible for around 40% of energy consumption and CO 2 -eq emissions at the European Union (EU) level, thus, it is widely recognized that the pathway towards sustainability should pass through an important renovation of the building stock. This study proposes a novel approach for planning the energy retrofit of neighborhoods of buildings. The main novelties introduced are: 1) considering the stochastic human behavior that deeply affects energy demand, by setting the usage profiles according to normal distributions; 2) considering the effects of global warming on energy retrofit measures (ERMs), by assuming different Representative Concentration Pathways (RCPs) as boundary conditions. The proposed approach is based on the coupling between EnergyPlus, used as dynamic energy simulator, and MATLAB®, used as postprocessing engine. The year 2035 is considered as the reference year of the analysis, because it is a mid-term time horizon. As case study, an existing neighborhood in Naples (Italy) has been investigated, with the aim to determine the ERMs combination that minimizes primary energy consumption (PEC), running cost (RC) and CO2-eq emissions. Three different RCPs have been considered: RCP 4.5 50% warming, RCP 8.5 50% warming and RCP 8.5 95% warming. For each of them, six different scenarios have been investigated – i.e., neighborhood as built and five retrofit combinations. Results show that for all the RCPs the retrofit combination that includes all ERMs – i.e., measures on the envelopes and on the primary energy systems – produces the highest reductions of PEC, RC and CO 2 -eq emissions. [ABSTRACT FROM AUTHOR]

Abstract: The study investigates a critical application in the field of energy demand for air-conditioning: the health care facilities. These buildings are quite energy-intensive, because of necessity of high microclimatic control, need of numerous air changes and, contemporarily, strict set points required for temperature and relative humidity. The achievable energy savings by improving the thermal–physical characteristics of the building envelope are examined, with reference to a medium-size hospital, located in Mediterranean climate. The indoor comfort conditions have been analyzed as well as the reduction of energy demands, depending on the HVAC system. Indeed, the active plants are characterized by quite different energy demands, due to different achievable quality of microclimatic control and indoor air. The refurbishment of the building envelope, as demonstrated, is always convenient, by considering all possible point of views, and thus energy savings, better indoor microclimate, reduction of polluting emissions, technical and economical feasibility. Finally, even if ventilation loads induce the highest heating and cooling demands, however the envelope refurbishment is an effective retrofit action. [Copyright &y& Elsevier]

Abstract: Several studies show the potential benefits achievable by recurring to roof vegetation. Really, little literature investigates the economic feasibility of such solution. The paper verifies utility of green roofs, under environmental and energy point of views, by considering all the aspects that influence their performances. With reference to several climates, intensity of rainfalls, needs of irrigation and kind of building use, a large parametric analysis evaluates the technical and economical feasibility of green roofs applied to a modern office building, considering various vegetations and different external coatings. The scarce amount of rainfall – and thus the irrigation cost – can nullify the savings in energy demand for air-conditioning. Moreover, even if green roofs show satisfactory performance if monthly rainfalls do not imply significant additional watering – the economic investigation shows scarce convenience for well-insulated buildings, above all if the higher initial cost of a green roof, compared to traditional roofing coating, is computed. Finally, cool roofs, by means of high-reflective and high-emissive coatings, are suitable solutions in warm climates, strongly improving the summer performances, with low extra costs for installation and maintenance. [Copyright &y& Elsevier]

Abstract: In the museum environment, the temporal stability and the spatial uniformity of the indoor microclimatic parameters are necessary primarily for the correct artwork conservation and then for the occupant thermal comfort. Therefore, a HVAC system is usually necessary. This paper above all emphasizes the integration of Building Energy Performance Simulation (BEPS) and Computational Fluid Dynamics (CFD) codes. This coupled numerical approach can provide accurate information about both the HVAC system energy request and the indoor microclimatic control (temporal and spatial distribution of the parameters). Then, a case study concerning a typical museum exhibition room is examined. The annual energy request for three types of all-air system, as well as the temporal variation of indoor temperature and relative humidity, is evaluated by means of a BEPS code. Energy savings can be obtained using a system with desiccant wheel (11%) or enthalpy wheel (9%), compared to the base system. As regards indoor relative humidity control, this is more critical for summer conditions, and the best performance is obtained by the system with desiccant wheel. Then, the spatial microclimatic control is analyzed by means of a CFD analysis, for various thermal load conditions and different air diffusion xequipments. The best performances are obtained by using the swirling (vortex) diffusers; also the perimetrical stripes of slot diffusers show satisfactory performances. Finally, in order to evaluate the ability of air diffusion equipments to assure good ventilation effectiveness, an analysis of the mean age of air is carried out too. [Copyright &y& Elsevier]

Abstract: Thermal bridges are weak areas of the building envelope, determining heat flows higher than those characterizing the common dispersing surfaces (i.e., walls without discontinuities). This phenomenon induces uncontrolled thermal losses and hygiene problems, connected to the possible vapor condensation and mold growth. Presently, the numerical codes for the energy audits, as, for instance, EnergyPlus, carry out zero-dimensional (indoor air) and one-dimensional (conduction heat transfer) analyses, approximately estimating the thermal bridge effects on the seasonal heating demand of buildings. In this paper, results obtained by means of the simplified 1-D models are compared to those obtained by more sophisticated models 2-D or 3-D, in order to point out differences in terms of equivalent conductivity and thermal transmittance. Then, dynamic simulations compare the outcomes in terms of seasonal energy consumption. A typical office building has been considered, analyzing – according to three different approaches – the thermal bridge represented by the roof structure. The outcomes, with reference to several Italian climates, show that a proper modelling is necessary. In particular, an over estimation of the heat losses, determined by an approximate evaluation, induces higher cost of refurbishing, higher cooling energy requests in summer, minor thermal comfort in naturally ventilated buildings. [Copyright &y& Elsevier]

Abstract: The European Energy Efficiency Building Directive 2002/91/CE, as well as other acts and funding programs, strongly promotes the adoption of passive strategies for buildings, in order to achieve indoor thermal comfort conditions above all in summer, so reducing or avoiding the use of air conditioning systems. In this paper, the energy performances achievable using an earth-to-air heat exchanger for an air-conditioned building have been evaluated for both winter and summer. By means of dynamic building energy performance simulation codes, the energy requirements of the systems have been analysed for different Italian climates, as a function of the main boundary conditions (such as the typology of soil, tube material, tube length and depth, velocity of the air crossing the tube, ventilation airflow rates, control modes). The earth-to-air heat exchanger has shown the highest efficiency for cold climates both in winter and summer. The possible coupling of this technology with other passive strategies has been also examined. Then, a technical-economic analysis has been carried out: this technology is economically acceptable (simple payback of 5–9 years) only in the cases of easy and cheap moving earth works; moreover, metallic tubes are not suitable. Finally, considering in summer a not fully air-conditioned building, only provided with diurnal ventilation coupled to an earth-to-air heat exchanger plus night-time ventilation, the possible indoor thermal comfort conditions have been evaluated. [Copyright &y& Elsevier]

Abstract: The paper suggests a multi-criteria approach for the energy refurbishment of historical buildings, proposing methodologies for the performance analysis, coupling several experimental and numerical studies. The target consisted in a rigorous evaluation procedure, in order to guarantee the necessary reliability of a numerical model of the system “building envelope/technical plants”, on which testing the technical and economical convenience of energy retrofit solutions. The paper collects the long work carried out by several Institutions during the last years, on Building “Palazzo dell’Aquila Bosco-Lucarelli”, a historical building located in Benevento (Southern Italy), currently analyzed in order to define the technical adoption of possible improving actions. The carried out studies, beyond the proposition of an operational methodology, are aimed to evidence a best-practice specified for the Italian territorial context, which has several historical buildings needing restoration. Carefully applied investigations, based on various methodologies and through several instrumentations, allowed the definition of a numerical model correspondent to the real building, defined also comparing the results with the historical requests of gas and electricity. Moreover, dynamic energy simulations tested the effectiveness, singularly and coupled, of several solutions for the building energy optimization. A significant potentiality of energy and economic optimization has been demonstrated. [Copyright &y& Elsevier]

Abstract: For the conservation of cultural heritage, museums need appropriate HVAC systems. Besides the time stability of the microclimatic parameters in the exhibition rooms, a high spatial uniformity is necessary and, thus, an optimal performance of the air diffusion systems. Using numerical codes based on Building Energy Performance Simulation (BEPS) and Computational Fluid Dynamics (CFD) techniques, in this paper an analysis has been carried out to compare different suitable air diffusion equipments, as regards uniformity of thermal-hygrometric and kinetic fields in a modelled typical exhibition room. For various part load conditions, the values of thermal-hygrometric parameters in different volumes of the room have been evaluated, as well as an innovative spatial thermal-hygrometric performance index. Globally estimating indoor temperature, relative humidity and their uniformity, for high exhibition rooms (5 m) the swirling diffusers have shown the best average performances, followed by the perimetrical stripes of slot diffusers, while for very high rooms (9 m) nozzles have resulted preferable. [Copyright &y& Elsevier]

Buildings account for around one third of World energy consumption and polluting emissions, thus their energy retrofit is crucial aiming at reducing the human impact on the environment. In this context, worldwide, public grant policies and stringent requirements have been adopted to promote energy efficiency in the building sector. This study proposes a comprehensive analysis to drive the energy retrofit of building neighborhoods by examining energy efficiency measures involving envelope components, heating, ventilating and air conditioning systems, photovoltaics. The effects of the creation of a local energy community that shares the photovoltaic production are taken into account too. Finally, the Italian "Superbonus 110%" public grant policy is considered, and some insights are given. More in detail, the analysis aims at minimizing at the same time the primary energy consumption and the global cost, satisfying both the public and the private stakeholders. It makes use of different software: CADMapper® and SketchUp® for modeling the geometry of the neighborhood; DesignBuilder® for realizing the first raw energy model; EnergyPlus to refine the energy model and to perform dynamic energy simulations; MATLAB® to post-process the results of the simulations. As case study, an existing neighborhood located in Naples (Italy) is investigated and three suboptimal solutions are proposed: nZEB solution, cost-optimal solution and utopia solution. Sensible reductions in energy consumption and global cost can be achieved in presence of public grants, i.e., up to 69.2 kWh/m2a and 153.6 €/m2, respectively. [Display omitted] • A comprehensive analysis for the energy retrofit of neighborhoods is conducted. • Energy retrofit measures affect envelopes, HVAC systems and photovoltaics. • 3 optimal solutions are proposed: nZEB, cost-optimal, utopia (tradeoff). • The Italian "Superbonus 110%" public grant policy is taken into account. • A neighborhood in Naples (Italy) is examined. High potential benefits are achieved. [ABSTRACT FROM AUTHOR]

This study offers deep insights into the link between climatic stress and building heating performance. Two representative Italian residential buildings – existing and newly-built, respectively – are investigated by predicting heating demand for 63 locations, covering all typical national climates. Two simulation software are used – i.e., TERMUS® and EnergyPlus –, to compare a standard semi steady-state approach with a more accurate dynamic one. The comparison enables to understand the influence of the climatic stress on different levels of building modeling/simulation. Notably, the semi steady approach can provide reliable outcomes (close to the dynamic one) for existing buildings in cold climates. Then, a sensitivity analysis is conducted to investigate the correlation between climatic parameters and yearly heating demand, showing that the heating degree day index does not provide a complete explanation of such demand. Indeed, it does not take into account latitude and/or solar radiation, whose influence is not negligible. Therefore, a novel heating stress index is proposed, including normalized heating degree day and latitude. Its expression is optimized through a Pareto approach to ensure the best fitting/regression of yearly heating demand for both building typologies. The achieved determination coefficient (R2) is 0.990 for the existing building, 0.995 for the newly-built one. Finally, climatic stress curves are achieved to predict heating demand and related running cost as a function of the proposed index, providing a user-friendly but reliable tool to forecast building heating needs. [Display omitted] • Proper heating climatic stress indices support building heating demand prediction. • Simulations, sensitivity/regression analysis are performed to obtain deep insights. • 2 typical (existing, new) residential buildings are studied in 63 Italian locations. • Degree days should consider sun-radiation/latitude to better predict heating needs. • Novel reliable heating stress index & climatic stress curves are provided. [ABSTRACT FROM AUTHOR]