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PV/T panels are innovative systems increasingly used in the building sector. As a matter of fact, in that context they allow a set of common problems to be addressed and often solved: lack of physical space and economic issues, always existing when PV and thermal panels are to be installed separately. Obviously, the main objective of PV/T panels is to enhance the electrical efficiency by cooling the PV cells, but the side positive effect is also the production of thermal energy, which can be suitably exploited with a proper configuration of the whole system and an appropriate design of its components. Their energy production and overall efficiency depend on several factors and therefore the effect of different system features should be investigated. In this work, a parametric analysis was performed to provide a contribution on this topic. The effects of the characteristics of the thermal storage on electrical and thermal system performances were analysed, also considering the influence of the thermal load magnitude. The conclusive considerations can be exploited by designers and researchers to maximize the efficiency of the systems in relation to the storage tank characteristics and both electrical and thermal loads.

Current policies addressing the energy efficiency of buildings aimed at the control of their overall primary energy demand, require not only that the edifice envelope has to be properly designed to optimize its thermal performances, but also that the eco-friendly properties of the involved building materials have to be properly taken into account, in order of assessing all the associated environmental costs. In fact, the design of envelope structures that are able to realize proper levels of thermal insulation and, in the same time, to employ materials characterized by low environmental impacts, are believed as the most effective strategies to be adopted in the aim of addressing the above-mentioned issues. In this regard natural materials, such as vegetal fibres or materials derived from the recycling of industrial/ agricultural waste, reveal very attractive characteristics. Indeed, recent studies on the use of natural materials in buildings concentrate on raw materials deriving from either agriculture, waste, or recycling processes. Such topics are the focuses of the present analysis. Specifically, this paper intends to provide a contribution in the field by identifying new types of environment-friendly composites, containing vegetal matters and ecological waste resulting from recycling activities. Outcomes of a series of performed laboratory analyses concerning the thermal conductivity of four different samples of assemblies, are quite promising and candidate these new composites – albeit further analyses are certainly recommended – as a practicable alternative to the mostly used traditional insulating materials.

The purpose of Heating, Ventilating and Air-Conditioning (HVAC) systems in museums is to properly control important microclimate parameters; such systems, in fact, apart from ensuring the visitors’ wellbeing, are requested to guarantee suitable indoor conditions for the proper conservation of the important cultural goods hosted by museums. Hence, in case of disservice, or interruption due to maintenance interventions, it is important to quantify the economic damage induced to exhibited and/or stored works of art (or even to the building museum itself). Accordingly, it is essential to guarantee the shortest possible period of disservice during which probable damages for the works of art could occur. Since curators are the most relevant subjects committed to properly run the museum, also for what concerns the indoor environmental conditions, the aim of this work is to propose two new comprehensive operative damage risk indicators to support curators in negotiating the stipulation of contracts with the external companies in charge of the management of the HVAC system, in order to preserve the works of art. Particularly, these indicators try to integrate, into the contracts, economic considerations related to the system's disservice period and/or planned interruptions. The feasibility of the proposed new indicators has been checked by means of an example application involving the “Museo Regionale” of Palermo (Italy).

The study describes a stand-alone photovoltaic system in which the storage is realized using electrolytic hydrogen, converted into electricity in fuel cells. The aim of the research is the optimization of the sizing of the system elements chain (photovoltaic generator, electrolyzer, tank, fuel cell) with respect to the electric load to fulfil. A positive annual balance between hydrogen production and consumption must be guaranteed; furthermore, energy production surplus that cannot be stored or converted into hydrogen due to batteries or tanks capacity limits must be avoided. The energetic analysis and that of hydrogen production and consumption have been carried out on an hourly basis using the HOMER software. The study shows that, being the load active in the evening and the system disconnected from the grid, excess energy cannot be exploited unless large tanks are used, if high gas pressures are to be avoided. Consequently, the system use in public areas or residential buildings, where visual impact generated by tanks is hardly acceptable and safety rules do not allow high gas pressures, is advisable only in grid-connected configurations. Such problems are by far reduced when a marked self consumption is present.

Greenhouse gas emission reduction and the control of excessive use of fossil fuels currently represent one of the main challenges of European energy policy and global Agreements, especially in order to limit dangerous climate changes. Particularly in EU such objectives are pursued through a wide range of regulation and incentive measures: strongly recommended are marked reductions in primary energy consumption and increase in the share of renewable energy.

This paper describes the results of experimental tests and computer simulation modelling aimed at evaluating the performance of an electrochromic (EC) window with respect to solar radiation control and the relative impact on the energy consumption of buildings of the residential type for two typical Italian climates. The research is carried out by a test-cell equipped with a small area EC double glazing unit and by a simulation program of buildings’ energy behaviour in transient regime. The experimental results show that EC devices which modulate solar radiation mainly by absorption, like the one investigated in this paper, generate secondary solar heat gains which entails a 20% decrease of the maximum potential energy flux reduction. Also, this effect could rise the temperature of the internal glass pane of the glazing to levels for which risk of thermal discomfort for the occupants may occur. The computer simulation modelling involves a residential building unoccupied during a large fraction of daytime in weekdays. The savings potential of the investigated EC window are calculated relative to a conventional clear float double glazing unit. Results show that the EC glazing may lead to a considerable decrease of the cooling energy demand (and of the total building energy consumption) in cooling dominated climates. The energy saving benefits become less marked in heating dominated climates and, for low values of the window-to-wall ratio, can be overcame by the increase in lighting and heating energy requirements that results in an increase of the total building energy demand.

Building envelope structures play a pivotal role in the energy behavior of edifices. They influence the heat exchanges between indoor and outdoor environment and might allow a proper exploitation of solar energy. Therefore, when properly designed, they can contribute to minimizing the overall energy demand of buildings, allowing achievement of the high energy performance that is the basis of the Nearly Zero Energy Building (NZEB) concept. In this context, window systems are generally considered as the crucial element to be correctly designed for energy efficiency purposes in view of the role they play in heat exchange processes and solar gain management. This paper outlines the methodology and the correspondent results of an analysis which aims to search for the optimal size of the window surface, which is the size allowing minimum overall energy consumption, in an office building whose structure and configuration represent a typical reference case for the Italian building stock. Several configurations were considered, varying the climate, the thermal features of the building envelope and the installed lighting electric power. Furthermore, the influence of a switchable shading device was assessed and the correlated comfort consideration reported. The analyses were performed using Energy Plus simulation code and the window dimensions were evaluated in terms of the ratio between the glazed surface and the gross facade area, which is referred to as window to wall ratio (WWR).

This paper analyzes the influence of solar radiation, considering both its direct and diffuse component, on the local thermal comfort of subjects in indoor environments. More precisely, an original equation for the assessment of the plane radiant temperature in presence of solar radiation is proposed. It can be used to evaluate the correspondent radiant asymmetry and therefore allows detailed analysis of local thermal discomfort conditions. Its reliability and feasibility have been tried out by means of an application to a simple case study and the obtained results proved that, in the studied environment, solar radiation affects the symmetry of the radiant field to a considerable extent, being the main cause of local discomfort due to not acceptable values of the radiant asymmetry. Therefore, the method can be used to verify the presence of zones not suited to human activities inside rooms and, in addition, it can be exploited by the procedures aimed at the classification of the comfort quality of indoor environments.

In outdoor as well as indoor environments, human thermal sensation strongly depends on the direct component of solar radiation incident on the body. Nevertheless, even though the direct component exerts the major contribute on this issue, especially in indoor environments and confined spaces, the diffuse and reflected components of the solar radiation also affects the thermal sensations of people. Despite this evidence, simple and reliable methods designed to take into account the effect of solar radiation on the indoor radiant field enveloping the human being in indoor environments are hardly available. This article aims to provide a contribute on this topic, proposing a model for the computation of the mean radiant temperature (MRT) in indoor environments in presence of solar radiation. The most innovative facet of the proposed model regards the computation of the effects of the radiation components reflected by the internal surfaces. Moreover, in order to try a preliminary validation of the model, an experimental campaign was also carried out and MRT values were measured in positions either directly irradiated by the sun or shielded from direct irradiation. The purpose of the measurements was to preliminarily analyze the extent of the accuracy with which the model might predict the rise of MRT due to solar direct irradiation.

The limitation of fossil fuel uses and GHG (greenhouse gases) emissions reduction are two of the main objectives of the European energy policy and global agreements that aim to contain climate changes. To this end, the building sector, responsible for important energy consumption rates, requires a significant improvement of its energetic performance, an obtainable increase of its energy efficiency and the use of renewable sources. Within this framework, in this study, we analysed the economic feasibility of a stand-alone photovoltaic (PV) plant, dimensioned in two configurations with decreasing autonomy. Their Net Present Value at the end of their life span was compared with that of the same plant in both grid-connected and storage-on-grid configurations, as well as being compared with a grid connection without PV. The analysis confirms that currently, for short distances from the grid, the most suitable PV configuration is the grid-connected one, but also that the additional use of a battery with a limited capacity (storage on grid configuration) would provide interesting savings to the user, guaranteeing a fairly energetic autonomy. Stand-alone PV systems are only convenient for the analysed site from distances of the order of 5 km, and it is worth noting that such a configuration is neither energetically nor economically sustainable due to the necessary over-dimensioning of both its generators and batteries, which generates a surplus of energy production that cannot be used elsewhere and implies a dramatic cost increase and no corresponding benefits. The results have been tested for different latitudes, confirming what we found. A future drop of both batteries’ and PV generators’ prices would let the economic side of PV stand-alone systems be reconsidered, but not their energetic one, so that their use, allowing energy exchanges, results in being more appropriate for district networks. For all PV systems, avoided emissions of both local and GHG gases (CO2) have been estimated.

This work proposes a simple methodology to assess pollution loads discharged by road traffic within a specific temporal and spatial domain, in the case that detailed disaggregated data about vehicle fleet composition are not available at local scale. The adopted methodology starts by defining a useful specific emission function that allows easy calculation of the total amount of pollutant emissions in a year. The function, called yearly average vehicle (YAV), is representative of the annual average emission factor of a homogeneous category of vehicles. The employment of the YAV permits easy assessment of different scenarios and allows the analysis of the influence of different items that could alter the global amount of pollutant emissions released by road traffic, such as improvements of emissive characteristics of vehicles, changes in the transportation demand, and variations of traffic flow path lengths. The procedure has been applied to the urban area of the Italian city of Messina, where public administration has recently adopted a measure aimed at alleviating the load of the traffic pollution inside the urban area.

This paper investigates the influence of solar radiation on thermal comfort inside an indoor environment and its effect on the building energy consumptions. Furthermore, it draws up a procedure which allows the rating of the thermal comfort quality of indoor environments in the presence of solar radiation, to be used in correlation with the energy classification of building in order to refer the energy performance to the indoor environmental conditions. Mean Radiant Temperatures (MRT) for a subject exposed to solar radiation in different positions of the environment were calculated, with an hourly time step and for a whole year. These values were utilized to assess the Predicted Percentage of Dissatisfied (PPD) and its variation with time and space, so that long term thermal comfort evaluations were able to be carried out and comparisons among irradiated and not irradiated positions were able to be made.

The achievement of high level personalized sets of comfort parameters is contemplated within the more general context of the so-called smart buildings, where people, by means of the new communication technologies, become active actors to the process of the singling out and control of the best indoor conditions. This Dynamic Intelligence approach would usefully contribute to a better energy efficient and environmental friendly management of buildings. Multi-Agent schemes are suitable tools in this aim, since they are able to manage the user-building-plant system where the adaptivity of people to the indoor conditions is suitably achieved. In this paper a contribution to a development of the classical Fanger’s model is presented, embodying into account user’s personal preferences referring to his cognitive-emotive-relational ambit. The proposed algorithm is based on a particular Multi-Agent aimed at the assessment of subjective indoor comfort. Such subjective adaptive model is here meant as a tool for achieving an optimal control of thermal comfort conditions in buildings.

The analysis here presented investigates the influence of electrical load on the operational performances of a plant for hydrogen production from solar energy and its conversion in electricity via a fuel cell. The plant is an actual one, currently under construction, in Reggio Calabria (Italy), at the site of the Mediterranean university campus, it is composed of a Renewable Energy Source (RES) section (photovoltaic panels), a hydrogen production section, and a fuel cell power section feeding the electrical energy demand of the load. Two different load configurations have been analysed and simulations have been carried out through HomerTM simulation code. Results allow interesting conclusions regarding the plant operation to be drawn. The study could have a remarkable role in supporting further research activities aimed at the assessment of the optimal configuration of this type of pioneering plants, designed for feeding electrical loads, possibly, in a self-sufficient way.

In the construction sector, responsible for the greatest amounts of energy consumption and greenhouse gas emissions, nowadays a significant turning point in the current scenario that qualifies building approach is taking place. In recent years, the ambitious nZEB (nearly Zero Energy Building), a building with very high energy performance, in which energy saving, cost-optimal vision and user well-being are assessed in a comprehensive way, has found legislative and operational implementation. Moreover, the adoption of increasingly challenging energy targets today offers important opportunities for the energy requalification and improvement of the overall quality of the building stock, particularly in the field of renewable plants. Within this frame in the paper, as a contribution to the analysis of benefits deriving from the use of RES (Renewable Energy Sources) plants in buildings, in terms of primary energy, cost, and greenhouse gas emissions, an intervention aimed at the satisfaction of the electric demand of a residential building through a photovoltaic plant, in different configurations (grid connected, stand-alone and storage on grid) has been analysed. For each configuration, balances between energy rates (production, load, grid exchange and/or battery store/withdrawal) have been hourly assessed in order to evaluate the Net Present Cost at the end of plant life. Moreover, a yearly primary energy balance has been determined, taking into account also thermal energy required to guarantee thermal needs (provided by a methane boiler), together with produced CO2 emissions.

The control of the use of fossil fuels, major cause of greenhouse gas emissions and climate changes, in present days represents one of Governments' main challenges; particularly, a significant energy consumption is observed in buildings and might be significantly reduced through sustainable design, increased energy efficiency and use of renewable sources. At the moment, the widespread use of renewable energy in buildings is limited by its intrinsic discontinuity: consequently integration of plants with energy storage systems could represent an efficient solution to the problem. Within this frame, hydrogen has shown to be particularly fit in order to be used as an energetic carrier. In this aim, in the paper an energetic, economic and environmental analysis of two different configurations of a self-sufficient system for energy production from renewable sources in buildings is presented. In particular, in the first configuration energy production is carried out by means of photovoltaic systems, whereas in the second one a combination of photovoltaic panels and wind generators is used. In both configurations, hydrogen is used as an energy carrier, in order to store energy, and fuel cells guarantee its energetic reconversion. The analysis carried out shows that, although dimensioned as a stand-alone configuration, the system can today be realized only taking advantage from the incentivizing fares applied to grid-connected systems, that are likely to be suspended in the next future. In such case, it represents an interesting investment, with capital returns in about 15 years. As concerns economic sustainability, in fact, the analysis shows that the cost of the energy unit stored in hydrogen volumes, due to the not very high efficiency of the process, presently results greater than that of directly used one. Moreover, also the starting fund of the system proves to be very high, showing an additional cost with respect to systems lacking of energy storage equal to about 50%. From the above, it can be deduced that, in the aim to obtain a quick, effective penetration of hydrogen into the market, it is at the moment indispensable to enact incentivizing policies, attributing to hydrogen production fares able to cover the additional costs due to its production, storage and reconversion.

One of the primary objectives of the 2002/91/EC European Directive [1] , recently replaced by the 2010/31/EU European Directive [2] , is referred to the need of drawing up a methodology leading to buildings energy certification, which allows evaluation of both energy consumptions and polluting impacts and takes into account both comfort conditions of indoor environments and outdoor climate. Indeed, the connection between comfort quality of indoor environments and energy performance of building is firmly remarked by the Directive, pointing out that the achievement of high levels of comfort quality involves an increase of energy demand. In this context, the need of connecting building energy performances to the comfort quality of living spaces has focused the researchers' attention on the development of procedures aimed at classifying indoor environments under the point of view of comfort conditions. In this paper, in order to try to suggest a simple approach to the indoor environmental quality classification, a proposed methodology will be presented. It could be applicable to either single environments or whole building and is based on the calculation of two indoor quality indexes: the Environment Quality Index, EQI, and the Building Quality Index, BQI. Starting from the values of the EQI and BQI indexes, the proposed methodology allows the classification of the indoor comfort level, referring it to a seven values scale.

This paper addresses an important problem in the evaluation of the thermal comfort of people living or working in the sort of confined spaces typical of current architecture. In the details, a new algorithm is proposed for the evaluation of the angle factors of people within rooms characterized by complex shapes, where the envelope components are not always mutually orthogonal. The algorithm is based on field data obtained by means of an experimental photographic apparatus which allows measurements of projected area factors of seated or standing people in such complex confined environments.

Thermal radiative exchanges of the human body with surrounding surfaces play an essential role in describing the thermal conditions of people in a given environment. Moreover, they could be induced by, among other causes, the presence of high intensity radiant sources, like lighting spots or infrared heating panels. This implies that a suitable set of radiation data related to human body anthropometry is required. This set of data mainly comprises the body surface area, the clothing area factor, the effective radiation area factor, and projected area factors. Several analytical or experimental methods may be utilized in order to compute these parameters. A detailed description of the most common of these will be illustrated in this study, pointing out their main features and their ease of application or otherwise. Thereafter, with reference to a field experiment conducted by means of purpose-built experimental apparatus, a detailed analysis concerning the determination of the values of clothing area factor, effective radiation area factor and projected area factors of a sample of standing and seated, and male and female subjects of the population of southern Italy will be described. In addition, the results of a study to determine differences in anthropometric parameters with regard to different gender and nationalities will be reported. The study will conclude by analyzing a specific case-study.

Publisher Summary A method for the automatic calculation of local comfort conditions in moderate indoor environment is been described in this chapter. It provides, among its output features, graphical maps of the PMV patterns. The program has been implemented on the commonly used operating system, and is characterized by a friendly usability, even by noncomputer expert users. The output of the code can be obtained not only in a graphical way but also in numerical formats. By using the program in conjunction with computer codes that provide the energy demand for climatization of buildings, it would be possible to evaluate the energy savings achieved in correspondence with the various adopted design choices. A computer code that is presented in this chapter allows a quick evaluation of local thermal conditions of thermal moderate confined environments. Starting from the knowledge of the indoor temperatures of the envelope surfaces, the program releases the local predicted mean vote. Depending on the user preferences, the percentage of dissatisfied, the mean radiant temperature, and the radiant asymmetry can also be obtained.

The Ecological Footprint (EF) method is applied here to assess alternative policies regarding the Municipal Solid Waste (MSW) management. This approach arises from two considerations. First, the MSW management certainly requires a great attention by politicians and technicians, due to its importance for effectively administrating and environmentally controlling urban contexts. On the other hand, the EF method, thanks to its holistic structure of analysis, supposedly provides a synthetic and effective measure of the sustainability of waste management systems, so allowing public administrations to prioritizing policies aimed at implementing environmental actions. Here the EF method is used for ranking different policies about the MSW management. The case study concerns the MSW management of Palermo and Ustica island. The suitability of this method for this purpose is assessed through the comparative environmental evaluation of the main segments composing the waste handling chain.

PV/T panels are innovative systems increasingly used in the building sector. Their energy production and overall efficiency depend on several factors related to the shares of electrical and thermal loads and to the working temperature of the operating fluid. Therefore, an optimal configuration should be found. In this work, a parametric analysis was performed to provide a contribute on this issue. The conclusive indications can be exploited by designers and researchers, to maximize the efficiency of the systems in relation to configurations and to both electrical and thermal loads. To this purpose a simulation model was designed and implemented in a spreadsheet, using Visual BasicTM functions.