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The recent worldwide environmental issues impose to decrease the energy consumption and the greenhouse gas emissions from the construction sector. To improve productivity and to decrease the negative effects on the environmental and social activities, particular attention is placed on precast systems. A multi-objective analysis has been carried out in order to identify high energy efficiency external walls for Zero Energy Buildings (ZEBs) in warm climate, encouraging eco-friendly building materials. The definition of the external walls for Mediterranean climate has been carried out through the integration of a multi-criteria optimization. ModeFRONTIER rel.4.3 environment has been used with calculation procedures to evaluate the dynamic performance of building components developed in MatLab rel.7.0 environment. The optimization has been carried out in terms of steady thermal transmittance, periodic thermal transmittance, decrement factor, time shift, areal heat capacity, thermal admittance, surface mass, small thickness, eco sustainability score, light-weight and costs. The results shows the possibility to reach high energy performance with light and thin solutions, considering the superficial mass and the internal areal heat capacity. The best solutions present repetitive features: high surface mass for the first layer (internal side), eco-friendly insulating materials for the middle layers and common insulating materials for the outer layer. The aim is to show a method to design high efficiency precast external walls of new low-cost residential buildings among which the designers can choose the proper solution for his application, according to the Pareto front of the multi-objective problem.

This study presents the retrofit acoustic dq1esign of the Italian theatre “Cavallino Bianco”. In its historical configuration, the hall had a curved roof with a pressed-plant fiber ceiling, which was demolished and replaced with a wooden roof without a false ceiling, leading to an increase in volume and a worsening of the reverberation time. This study proposed the realization of a wave ceiling and the application of sound-absorbing and reflecting panels on the walls, which have already been implemented. These modifications have affected the acoustic characterization of the theatre, as shown both through on-site measurements during the main construction phases and through numerical simulations. The reverberation time, clarity index, and speech transmission index (STI) are evaluated considering all the variations in the hall over different construction times, and the optimal solution is identified with regard to different specific uses. The final configuration with the new roof, by reducing the volume of the hall and using sound-absorbing materials, significantly reduces the reverberation time (e.g., at 2000 Hz, this reduction is from 2.33 to 1.47). In addition, the hall at full capacity with chairs and people shows evident improvement in terms of the clarity index, allowing the theatre to be used for a wide range of musical genres such as instrumental, symphonic, and opera performances. As regards the Combos 00 (concrete roof without vertical sound acoustic panels) and 01-a/b/c (wooden roof with draped curtains), the STI values are never lower than 0.42 and never higher than 0.70; therefore, the room never experiences poor or excellent conditions at any point. The Combos 01-a and 01-b, which have a non-performing C80, have a good STI index, confirming the difficulty of achieving a configuration that can be optimal a variety of uses. Combo 01 (wooden roof without vertical sound acoustic panels and no draped curtains), which has a good C80 value, presents a lower STI value, with an average performance. The STI values of Combo 02-a (characterized by wave false ceiling and vertical sound acoustic panels) are never lower than 0.52 and never higher than 0.60; therefore, neither poor nor excellent conditions are experienced in the room, but there is still a slight improvement over the combos 00 and 01.

This paper addresses the effects of long-term climate change on retrofit actions on a school building located in a Mediterranean climate. Dynamic energy simulations were performed using Termolog EpiX 11, first with conventional climate data and then with future year climate data exported from the CCWorldWeatherGen computational software. To date, many incentive actions are promoted for school renovations, but are these measures effective in preventing the discomfort that will be found due to overheating generated by climate change? Today, one of the main objectives in retrofit measures is the achievement of ZEB (Zero Energy Building) performance. Achieving this target requires first and foremost a high-performance envelope. This study evaluates the impact of retrofit strategies mostly applied to the school building envelope, over the years, considering three different time horizons, until 2080. Thermal performance indices and indoor operative temperature under free-floating were evaluated. The results highlight that, with a changing climate, it is no longer possible to assume a constant static condition to evaluate retrofit actions, but it is necessary to develop a predictive mathematical model that considers the design variability for future years. There is an urgent necessity to ensure both the safety and comfort of buildings while also anticipating future variations in climate.

This paper proposes a critical review of the different aspects concerning magnetic refrigeration systems, and performs a detailed analysis of thermodynamic cycles, using mathematical models found in the literature. Langevin’s statistical mechanical theory faithfully describes the physical operation of a refrigeration machine working according to a magnetic Ericsson cycle. Results of mathematical and real experimental models are compared to deduce which best describes the Ericsson cycle. The theoretical data are not perfectly consistent with the experimental data, there is a maximum deviation of about 30%. Numerical and experimental data confirm that very high Coefficient of Performance (COP) values of more than 20 can be achieved. The analysis of the Brayton cycle consisted of finding the mathematical model that considers the irreversibility of these machines. Starting from the thermodynamic properties of magnetocaloric materials based on statistical mechanics, the efficiency of an irreversible Brayton regenerative magnetic refrigeration cycle is studied. Considering the irreversibility in adiabatic transformations, the lower limit of the optimal ratio of two magnetic fields is determined, obtaining a valid optimization criterion for these machines operating according to a Brayton cycle. The results show that the Ericsson cycle achieves a higher Coefficient of Performance than the Brayton cycle, which has a higher cooling capacity as it operates with a larger temperature difference between the magnetocaloric material and source.

In recent years, research has shown a growing interest in the use of hybrid wind photovoltaic (PV) systems that provide better performance compared to the use of a single component due to complementarity in meeting electricity demand. Over the past twenty-five years, hundreds of articles have addressed the topic of hybrid systems considering different configurations and final uses and, over the past decades, many reviews have made a comprehensive summary of various results obtained. However, some reviews deal with the research in a too general and qualitative way, without providing quantitative data, and other reviews are too focused on a specific topic aspect. To provide a qualitative-quantitative prospect of the research trend in the last twenty-five years, the present work is aimed at carrying out a literature review and statistical analysis starting from data extracted from the 550 most relevant and recent articles concerning hybrid systems, published between 1995 and 2020. The review aim was to produce an upgradable matrix literature database that schematizes the content of all articles in terms of different categories, such as the geographical distribution, their component configurations, operating mode and the auxiliary components used to support it, their intended uses and study methodologies (simulation, experimental, economic, energy, environmental and social analysis etc.) and software used. In addition, all the optimization algorithm, energy, economic, environmental and social indicators available in the literature were extracted and elaborated to identify the most used. The 550 articles were analysed, compared, and classified into several categories to provide an overall framework of the state of the art. The objective is to clearly and appropriately show important trends and findings in the development of hybrid wind and solar PV experimental, simulation and optimization projects. Data are elaborated to obtain a statistical analysis for each category or a combination of categories. In particular, the analysis highlighted that research is more focused on testing systems in warm or temperate localities, with the Koppen climate groups B and C prevalent over the others. From the geographical point of view, Asia is the continent most involved in world research (with China, India and Iran the first three countries for total publications produced). However, also in other parts of the world, a growing interest was noticed in this technology. The prevalent tested system configuration mode is the stand-alone hybrid systems, in a wide variety of climates and especially for residential uses. Simulations are mostly implemented in the analysed publications, mainly through HOMER and MATLAB software. Parametric analysis is widely used for optimal system design with a large variety of techniques. In particular, the system performance is examined mostly from an energy point of view. Economic analysis is also very common, alone or in combination with energy analysis. The most frequently used optimization algorithms are the particle swarm optimization (PSO) and genetic algorithm (GA), while the loss of power supply probability (LPSP) and renewable fraction (RE) for the energy analysis, the net present cost (NPC) and cost of energy (COE) for the economic analysis and the emissions (E) of CO2 for the environmental analysis are most widespread indicators. Finally, an analysis on the size of the system components is performed to study which renewable source is more preferred at low and high installed power, for stand-alone, grid-connected systems and overall, considering different intended uses. The analysis highlights that PV systems are preferred at low installed powers, especially for residential use and stand-alone mode, while wind systems, in addition to being extensively used for low installed powers, demonstrates higher employment compared to PV systems as the power increases. The paper findings and upgradable matrix literature database are proposed as a valuable tool for engineers, experts and national and international policymakers.

This dataset supports the research article “Complete greenhouse dynamic simulation tool to assess the crop thermal well-being and energy needs” [1] . In the agricultural sector, the use of energy can be very intensive [2] and the simulation of solar greenhouses is a very complex work [3] . This dataset provides the results of thermal modeling and dynamic simulation of a solar greenhouse considering simultaneously several thermal phenomena. The analysis was performed by TRNSYS 17 software (TRaNsient SYstem Simulation). The results obtained consider different phenomena that affect the thermal behavior of the greenhouse, including evapotranspiration produced by plants, heat exchange with the soil and the presence of artificial lights. Different models are presented for the calculation of the convective coefficient that best suits the presence of glass surfaces, considering the different discretization of the internal volume (single thermal zone and twenty thermal zones). The parameters that influence the thermal behavior of the greenhouse are analyzed on an hourly basis, the model has been validated with EnergyPlus. The data allow the researcher to choose a suitable greenhouse model in the case of free-floating model or in the presence of an air conditioning system.

The data describe supplementary materials supporting the research article entitled “Worldwide geographical mapping and optimization of stand-alone and grid-connected hybrid renewable system techno-economic performance across Koppen-Geiger climates” (Mazzeo et al., 2020). Hybrid renewable energy systems are increasingly adopted worldwide as technically and economically effective solutions to achieve energy decarbonization and greenhouse gas reduction targets. This data article includes the results of worldwide techno-economic optimization of stand-alone and grid-connected photovoltaic-wind hybrid renewable energy systems designed to meet the electrical energy needs of an office district. The technical simulations have been performed in TRNSYS 17 (Transient Energy System) environment. A total of 48 different locations around the world have been chosen across Koppen-Geiger climates with different latitudes and homogeneously distributed over the whole globe, considering very different climates. The analyses have been conducted for 343 different system power configurations, considering both stand-alone and grid-connected systems. A total of 16464 dynamic simulations were performed, summarized in yearly energy output from each component and in energy and economic indicators.

Greenhouse technology is an important energy consumer sector representing an indispensable solution for modern methods of crop production. In the greenhouse envelope and system design phase, thermodynamic performance simulation tools are required. The greenhouse simulation is still a very complex task despite many building tools are available in the literature. This work aims to overcome this gap by proposing a reference methodology to accommodate the building TRNSYS software for a greenhouse able to consider simultaneously different thermal phenomena with detailed modelling of: dense volume discretization, 3D shortwave and longwave radiative exchange, air flow exchanges, presence of lamps with their exact 3D position, ground and plant evapotranspiration, and convective heat transfer coefficients. A standard hourly simulation of the one-zone greenhouse was validated with another recognized tool, showing excellent agreement throughout the year. The main parameters affecting the greenhouse thermal balance were investigated in both a free-floating and continuous regime. The investigation has shown that a standard simulation is accurate to only reproduce the thermal response in a free-floating regime; instead, the detailed simulation has led to overall cooling and heating energy needs in the continuous regime, respectively, of 51.4 kWh/m3 and 49.1 kWh/m3, avoiding to obtain very high errors.

This paper proposes the application on microscale of an innovative trigeneration system with micro CAES (Compressed Air Energy Storage) – TES (Thermal Energy Storage) and the integration of renewable energy production, focusing on the potential use for air conditioning and domestic hot water systems. The system allows storing mechanical energy in the form of elastic and thermal potential of compressed air through two thermal storage units, HTTES (High Temperature Thermal Energy Storage) and LTTES (Low Temperature Thermal Energy Storage). The proposed system is tested on a single-family building in a warm climate. The analysis is carried out for integrated and independent operating modes. In integrated mode, the LTTES refrigerant charge and the vapor compression chiller operate simultaneously to cover the building's thermal load. In this case the energy expenditure is only related to the power supply of the chiller. In independent mode, the cold storage and the chiller work alternately during evening operation to limit the absorption of energy from the distribution network. The results show that, in integrated operating mode with partial recirculation and internal temperature conditions of 26 °C and 50% of relative humidity, the system reaches, in relation to the peak thermal load, a maximum operating time of 236 min. The minimum operating time of 26 min is reached using the full external air operating mode with an internal temperature of 26 °C and relative humidity of 40%. In independent operation mode, it is possible to sustain the evening thermal load for up to a maximum of 5 h without electricity absorption from the distribution network.

In the last years, a significant interest in research in stand-alone (SA) and grid-connected (GC) photovoltaic (PV)-wind hybrid renewable energy systems (HRES) is observed for their complementary in the satisfaction of the electrical energy demand in many sectors. However, direct comparisons between the techno-economic performance of two system modes under the same operating conditions are rarely carried out. Additionally, most of the researches are limited to specific weather conditions. This work aims to bridge the lack of this type of investigations providing a worldwide techno-economic mapping and optimization of SA and GC PV-wind HRES to supply the electrical demand of an office building district. For this purpose, energy and economic optimization problems were formulated to find the optimal SA and GC systems worldwide among 343 HRES system power configurations located in 48 different localities, uniformly divided in the sub-group of the Koppen classification. The energy reliability and economic profitability of optimal systems were geographically mapped worldwide. In general, the energy or economic optimizations of SA HRES do not lead to highly profitable systems; instead, feed-in-tariff to sell the energy in excess assures viable GC HRES in many localities. However, economically optimal SA and GC HRES, respectively, do not everywhere comply with the threshold value of 70% of the satisfied energy required by the load and are characterized by a high level of energy exchanged with the grid. The study highlighted that the most suitable climate conditions to install a SA HRES are: (i) Toamasina (Madagascar) from an energy point of view, with 76% of load satisfied and 76% of the energy generated utilized to supply the load; (ii) Cambridge Bay (Canada) from an economic point of view, with 11.1% of the capital cost recovered each year; instead, the most suitable climate conditions to install a GC HRES are: (iii) New Delhi (India) from an energy point of view, with 48% of energy exchanged with the grid per each kWh required by the load; (iv) Lihue (Hawaii, United States) from an economic point of view, with 24.3% of the capital cost recovered each year.

The growth of economies and the world population has led to an increase in the electricity demand, toward a disproportionate use of fossil fuels. The PV-wind hybrid system is considered an optimal solution in terms of technical efficiency and costs to reduce the use of fossil sources. The strong variability of renewable energies generated by solar and wind systems in different locations around the world sometimes leads to the need to use battery storage systems. In addition, the self-consumed energy produced by the hybrid system is strongly dependent on the load trend. Owing to the strong influence of the climatic conditions on a hybrid system energy performance, its optimal sizing is a very complex issue that must be addressed in each weather condition. This paper presents an energy feasibility study of a PV-wind-battery hybrid system considering different yearly climatic conditions in the world, according to the Koppen classification. The system is used to supply electrical energy to a district composed of five office buildings. The electrical load consists of artificial lighting systems, electrical office devices and electric vehicle charging stations. The effects produced by different yearly climatic conditions on three hybrid systems, characterized by the same overall nominal powers and different photovoltaic and wind nominal powers, were investigated. TRNSYS 17 was used for the dynamic simulation of the hybrid system. The overall aim is to identify the most proper climatic conditions by means of the optimization of several energy indicators: maximization of the self-consumed renewable energy and of the renewable energy produced utilized to supply the load, namely minimization of the energy imported from and exported to the grid. For this issue, a global indicator, that measures the energy exchange of the hybrid system and load with the grid, is proposed to select the optimal trade-off localities and hybrid systems.

Electric production data of a grid-connected hybrid system are presented. The system consists of a photovoltaic generator, a wind micro-generator in the presence (HPWBS) or absence (HPWS) of an electric storage system. In such a system, the power generated by RES (Renewable energy sources) is sent directly to balance the load.A residential use has been analysed in warm climate. The analysis has been carried out by TRNSYS 17 (Transient System Simulation) software and the mathematical modelling and the energy balance of the system have been shown in “Energy reliability-constrained method for the multi-objective optimization of a photovoltaic-wind hybrid system with battery storage” [1]. The annual energy performance has been evaluated, in terms of dimensionless balance of the generated energy and dimensionless balance of the energy required by the load, for 375 hybrid system configurations. These configurations were obtained by varying the photovoltaic power, the wind power and the battery storage capacity, considering different hourly average daily values of the load.

This data article relates to a multi-criteria process applied to slab-on-ground floor for buildings in warm climate. The input data of the analysis are the building materials with their thermal properties, sustainability characteristics and supply and installation costs. The multi-criteria analysis has been performed with the software modeFRONTIER. The computational procedures in accordance with the UNI 13786 (Thermal performance of building components, Dynamic Thermal Characteristics, Calculation Methods) has been carried out in MatLab language. The methodology is presented in the articles “High performance precast external walls for cold climate by a multi-criteria methodology” (Baglivo and Congedo, 2016) [1] , “Design method of high performance precast external walls for warm climate by multi-objective optimization analysis” (Baglivo and Congedo, 2015) [2] , “Multi-Objective Optimization Analysis For High Efficiency External Walls Of Zero Energy Buildings (Zeb) In The Mediterranean Climate” (Baglivo et al., 2014) [3] and “Multi-criteria optimization analysis of external walls according to ITACA protocol for zero energy buildings in the Mediterranean climate” (Baglivo et al., 2014) [4] , for the identification of high efficiency external walls. The set of possible optimal configurations identified by the source of Pareto have been collected into different categories of slab-on-ground floor, focusing on slab-on-ground floor with concrete, slab-on-ground floor with gravel and slab-on-ground floor with crawl space. The dataset provides a set of high efficiency solutions through the combination of commercial and eco-friendly building materials.

A multi-objective optimization method for the dimensioning of hybrid photovoltaic-wind-battery systems HPWBS characterized by high-energy reliability is proposed. The energy reliability-constrained (ERC) method permits choosing the most proper indicators combination to be constrained or optimized as a function of the specific application. The ERC method is applicable to grid-connected and stand-alone hybrid systems with and without storage battery, for residential as well as for other uses. The reliability indicators defined are: the photovoltaic-wind fraction, energy fraction required by the load satisfied by the HPWBS; the utilization factor, energy fraction produced sent to the load; the manufacturability that characterizes the energy produced sent to the load in relation to the nominal power of the system. The ERC method was employed for the multi-objective optimization of a grid-connected hybrid system with and without storage battery for the electric energy supply to an urban residential building in a Mediterranean climate. A parametric analysis, for different loads, by varying the photovoltaic and wind power and the battery storage capacity, was developed to evaluate the annual energy reliability in a dimensionless form of 450 system configurations. The results allowed obtaining empiric correlations to be used in the system design. Finally, the ERC method application allowed achieving optimal system configurations with greater reliability compared with those provided by the Pareto-front method.

The analysis of urban districts involves many critical issues and different design constraints related to the urban context. The characteristics of district area are based on climatic properties, geometrical design, type and number of buildings, places of construction, distances, shading patterns. This work proposes a tool able to integrate heterogeneous data coming from different users on different spatial and territorial scales, to implement efficient management of energy flows in the district. The proposed protocol is an extension of the Apulia ITACA – Building Protocol to the assessment of urban areas. It permits to evaluate any type of district, without limitation of extension and with any number of buildings. The objectivity of the evaluation using indicators applied to various thematic areas including site quality, resource consumption, environmental loads, indoor environmental quality, and quality of services is granted. It is based on a global scoring system, using the weighting on the usable surface of the buildings present in the selected urban area. The protocol permits to display the interactions between each variable within the district, evaluating the benefits in terms of costs of the targeted interventions. This work is split into two parts: Part I: the model and Part II: the case study.

Nowadays, the goal of national and international policies is to define strategies to achieve Zero Energy Districts (ZEDs). The transition from ZEBs to ZEDs entails an increase in complexity and one of the main challenges is the definition of criteria for assessing the district sustainability performances. Part I of this paper presents a new methodology for assessing all aspects related to the sustainability of a district. The new Apulia ITACA - District Protocol is the extension to the district level of the existing and widely used Italian Apulia ITACA –Building Protocol. The proposed Protocol permits the assessment of any type of district, with no extension limitations. Part II shows an application of the Protocol for the evaluation of the current state of a small district of Lecce, a city in the south-east of Italy with a Mediterranean climate. The district falls in a peripheral social housing area and is composed of two residential buildings and a school. Several strategies have been proposed to improve the overall score of the district, showing both an ideal and realistic renovation. The high flexibility of the protocol in the direct identification of the weaknesses and strengths of the district was demonstrated.

The European Energy Performance of Buildings Directive (EPBD) recast proposes, a comparative methodology to calculate cost-optimal levels of minimum energy performance requirements for buildings. This paper presents a method able to select the best retrofit action for lighting system, selectively analysing the daylight conditions and applying the cost-optimal methodology for different scenarios proposed for two existing educational buildings located in Italy. With the aim to improve both energy efficient and visual comfort conditions, the retrofit scenarios include lighting solutions with different combinations. They consider the replacement of lamps with more efficient lighting sources and the application of lighting control.

"Efficient Solutions and Cost-Optimal Analysis for Existing School Buildings" (Paolo Maria Congedo, Delia D'Agostino, Cristina Baglivo, Giuliano Tornese, Ilaria Zacà) [1] is the paper that refers to this article. It reports the data related to the establishment of several variants of energy efficient retrofit measures selected for two existing school buildings located in the Mediterranean area. In compliance with the cost-optimal analysis described in the Energy Performance of Buildings Directive and its guidelines (EU, Directive, EU 244,) [2], [3], these data are useful for the integration of renewable energy sources and high performance technical systems for school renovation. The data of cost-efficient high performance solutions are provided in tables that are explained within the following sections. The data focus on the describe school refurbishment sector to which European policies and investments are directed. A methodological approach already used in previous studies about new buildings is followed (Baglivo Cristina, Congedo Paolo Maria, D׳Agostino Delia, Zacà Ilaria, 2015; IlariaZacà, Delia D'Agostino, Paolo Maria Congedo, Cristina Baglivo; Baglivo Cristina, Congedo Paolo Maria, D'Agostino Delia, Zacà Ilaria, 2015; Ilaria Zacà, Delia D'Agostino, Paolo Maria Congedo, Cristina Baglivo, 2015; Paolo Maria Congedo, Cristina Baglivo, IlariaZacà, Delia D'Agostino,2015) [4], [5], [6], [7], [8]. The files give the cost-optimal solutions for a kindergarten (REF1) and a nursery (REF2) school located in Sanarica and Squinzano (province of Lecce Southern Italy). The two reference buildings differ for construction period, materials and systems. The eleven tables provided contain data about the localization of the buildings, geometrical features and thermal properties of the envelope, as well as the energy efficiency measures related to walls, windows, heating, cooling, dhw and renewables. Output values of energy consumption, gas emission and costs are given for a financial and a macro-economic analysis. This data article provides 288 and 96 combinations for REF1 and REF2, respectively. The output values are obtained using the software ProCasaClima 2015v.2.0.

A large part of primary energy is used for heating and cooling the buildings. The exploitation of renewable resources in the building sector is still critical to ensure a high level of energy and environmental sustainability. Nowadays, a great attention is focused on geothermal energy, which reduces heating and cooling in buildings, allowing natural pre-heating and pre-cooling of the inlet air. The effect of different burial depth and thermal conductivity of ground on thermal performance of HAGHE under transient conditions has been analyzed. The results show that the transient thermal performance of HAGHE is independent from the thermal conductivity of the ground but is dependent on burial depth. In this work, it is presented the experimental validation of a mathematical model implemented by the CFD Fluent for the simulation of heat exchange that takes place within a HAGHE for geothermal heat pumps. The validation of the model is based on a comparison between the experimental data, obtained from the software, and real data, for a HAGHE located in the town of Rubiana (Turin-Italy).

The international scientific community believes unequivocally that, at the origin of the climate change, there are anthropic factors mainly linked to the construction sector and to the disproportionate use of fossil energy sources. The selection of building materials plays a key role in the reduction of energy consumption, especially in the Mediterranean area, where the internal overeating risk is high if the solar radiation is not controlled and the free supply of internal heat is poorly managed. Traditionally, in the Italian context, the slab-on-ground floor is made in concrete or more rarely in stone. However, it is usually recommended to minimize the use of concrete as it has a strong environmental impact, reinforced concrete is still the most recommended solution for foundations, both for regulatory and practical reasons. The present study proposes a methodology for the design of high efficiency slab-on-ground floor for warm climate through optimization code performed with the software modeFRONTIER. Starting from the traditional floor structures, the multi-objective methodology stands as an advanced step for the identification of new configurations, favoring the management of many variables, such as thermal, environmental and economic aspects. The results are characterized by high presence of local and eco-friendly materials and reduced costs. At the end, this work demonstrates that it is possible to obtain high performance solutions with also very few numbers of layers.