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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]

The European policy framework is focused on reducing energy consumption in the building sector. The recast of Energy Performance of Buildings (EPBD) Directive establishes that minimum energy performance requirements have to be set to achieve cost-optimal levels. A methodology is developed to assess energy and cost effectiveness in new buildings located in the Mediterranean area. Several energy efficiency technical variants are applied to a multi residential reference building selected as a representative model of the national building stock. Primary energy consumption and global costs are evaluated in a number of configurations to derive the cost-optimal solution. The paper shows how economical high efficient buildings can be obtained at a design stage for a warm climate. The selected configuration decreases primary energy consumption by 90% and CO 2 emissions by 88% with respect to the baseline building. Results appear useful for comparison with other climates and building types. The paper also points out that the methodology is suitable to guide and support the choice of cost effective energy efficiency measures in compliance with EU requirements. [ABSTRACT FROM AUTHOR]

Abstract: The increase of peak and energy demand during the cooling season is becoming a crucial issue, as well as the intensification of the urban heat island effect. This trend is observed at several latitudes, including areas where overheating was unknown at building and urban levels. This phenomenon involves different issues: reduction of greenhouse gases, quality and comfort in outdoor and indoor environment, security of energy supply, public health. The building sector is directly involved in this change and adequate solutions can provide great benefit at energy and environmental levels. Roofs in particular are envelope components for which advanced solutions can provide significant energy savings in cooled buildings or improve indoor thermal conditions in not cooled buildings. Cool materials keep the roof cool under the sun by reflecting the incident solar radiation away from the building and radiating the heat away at night. Roofs covered with vegetation take benefits of the additional thermal insulation provided by the soil and of the evapo-transpiration to keep the roof cool under the sun. These two technologies are different in: structural requirements, initial and lifetime maintenance costs, impact on the overall energy performance of buildings. This paper presents a numerical comparative analysis between these solutions, taking into account the several parameters that affect the final energy performances. By means of dynamic simulations, the paper depicts how cool and green roofs can improve the energy performance of residential buildings in different localities at Mediterranean latitudes. [Copyright &y& Elsevier]

Nowadays green roofs are a well-consolidated technology used in several countries since these systems can be employed both to generate considerable energy savings and to improve the thermal performances of buildings. This paper deals with an experimental analysis of an extensive green roof, installed on a building of the University of Calabria (Italy, Lat. 39.3° N). The thermal performances of different layering solutions are analysed under typical Mediterranean climate conditions with reference to a traditional roof system. The analysis showed that the green roof is able to reduce the temperature at the interface with the structural roof, on average, by 12 °C with respect to a black bituminous roof in summer and to maintain, on average, a value that is 4 °C higher in winter. The measured temperatures allowed to calculate the transferred heat through the building roof, showing negative heat fluxes for the whole period and a reduction of the thermal energy entering the indoor environment of 100% in summer, proving the passive cooling effect of the green roof, and a reduction between 30% and 37% of the thermal energy exiting the indoor environment in winter. The experimental data have been employed also to conduct a dynamic characterization of the different vegetated solutions, showing that the different green roofs solutions are able to generate values of decrement factor varying between 0.135 and 0.193 and a time lag between 3.1 h and 4.8 h, which can substantially improve the dynamic properties of traditional roof structures, especially in the case of roofs with limited dynamic performances. [ABSTRACT FROM AUTHOR]

Sustainable energy planning includes various requirements, conflicting or not. Thus, any decision making is directly related to analytical procedures and management of a wide range of information (technological, environmental, economic and social). Multi-criteria analysis is a valuable tool, which is suitable to assemble and to manage many variables (quantitative as well as qualitative ones), assessed in different ways, thus offering reliable support for decision making. This analysis scopes to facilitate the photovoltaic (PV) integration in buildings, which combines benefits from shading, power generation, and esthetics. This paper performs a multi-criteria analysis of monocrystalline PV panels mounted on typical south-facing shading devices of office buildings in the Mediterranean region. In total, thirteen different options of shading devices were assessed against a series of criteria which include PV panels’ energy production, buildings’ energy optimization criteria (heating–cooling–lighting loads) and users’ comfort criteria (outdoor view–glare–esthetic aspects). Six different rankings were obtained by the analysis, each one reflecting the priorities and interests of different economic and social groups involved in the design and promotion of integrated PV systems in buildings. The analysis revealed that “Brise soleil full façade” is the most proper shading device when the PV system is mounted on it; in contrary “Canopy inclined double” or “Louvers horizontal inwards inclined” or “Simple window” seem to be the least suitable. [ABSTRACT FROM AUTHOR]

In Europe and worldwide several legislations are adopting comfort models that include the variability of occupants behaviour based on the external climate conditions. The latest adaptive comfort methods consider outdoor temperature not only as a steady variable but also as the representation of occupants past thermal history. The paper presented deals with a summer environmental monitoring carried out in a Sardinian earth building. These traditional houses are very often without AC systems and the control of summer conditions is based mainly on natural ventilation. By the use of adaptive comfort model, the different thermal performance between the upper and lower floor of the two storey building are investigated. Different models have been implemented, some included in current technical standards, some other still experimental. The results show the capability of the case-study to provide comfort conditions, but only in the lower floor. The upper floor that traditionally was used as a depository and now hosts the bedrooms shows overheating problems. The change of use, in this case, is the main cause of the bad performance, as highlighted by the microclimatic survey. [ABSTRACT FROM AUTHOR]

The paper focuses on the assessment of the windows’ contribution to the energy performance of buildings in the warmer regions of Europe. This is derived by calculating the cooling energy index q c and the area weighted energy needs for different window configurations installed on a reference room for two different building uses, office and residential. The examined window types differed with regard to their thermophysical and optical properties ( U - and g -value), geometry (frame and window fractions) and orientations. The energy parameters used for the performance assessment were calculated with the help of a dynamic simulation tool for a location with a representative Mediterranean climate. The extensive multi-parametric analysis exhibited interesting results. It was found that for the cooling mode the energy performance of windows in warm climates is influenced significantly by their thermophysical properties. More specifically, the impact of solar transmittance is significant and its optimal selection can contribute in minimizing the energy consumption, especially in environments with controlled ventilation, such as offices. On the contrary, advanced fenestration products with low thermal transmittance seem to behave unfavorably, since their extremely low thermal transmittance prohibits the dissipation of heat toward the ambient environment and results ultimately in higher cooling energy loads. [ABSTRACT FROM AUTHOR]

Abstract: Cooling down buildings and cities is becoming a priority as a consequence of global increase of air temperatures. This effect determines the growing of energy consumption for cooling, as well as the spread of urban heat island effect. Cool materials are characterised by high solar reflectance and high infrared emissivity. These two properties allow the material to stay cool under the solar radiation. Cool materials are deserving attention to mitigate surface temperatures in buildings and urban materials. This paper presents the first results of the potential benefits of cool materials applied on solar protection devices. Shutters are used for security and for solar shading in Mediterranean countries. These components are generally characterised by high solar absorbance, due to the colours traditionally used. An experimental campaign was carried out to measure and compare the optical and thermal properties of conventional and cool coloured materials. The results were used as input to assess the impact of these products in Italian dwelling, taking into account several variables: climatic zone, insulation level, and operative conditions. The cooling energy demand and the thermal comfort conditions were calculated with an hourly heat balance building simulation tool. [Copyright &y& Elsevier]

Abstract: Fenestration has always been regarded as the weak element in the building envelope due to its role in determining of the energy balance of a building. At the same time, cooling performance is becoming a significant parameter for evaluating the energy performance of buildings in Europe. Due to the plethora of window products with advanced properties currently existing on the market, it is not always easy for engineers to select the optimum solution. In this paper, the cooling performance of windows in the warmest part of Europe is evaluated with regard to their geometrical, thermophysical and optical characteristics, as well as their shading provisions. The analysis shows that the contribution of the windows in determining cooling loads is maximized when their solar transmittance is high and their thermal transmittance is low. Moreover, in the Mediterranean regions the increased thermal efficiency of transparent elements in buildings with controlled ventilation, such as offices, prohibits the dissipation of heat toward the ambient environment and ultimately result in higher cooling energy loads. [Copyright &y& Elsevier]

Abstract: Jordan heavily relies on imported oil and gas for meeting its energy need as the same time the construction sector consumed more than half of the total electricity consumption in Jordan in 2008. In order to provide the occupants with thermal comfort at least cost, applying energy saving measures into early design stage can be significant to achieve this goal. This paper discusses an assessment of best orientation of the building, windows size, thermal insulation thickness from energetic, economic and environmental point of view for typical residential building located in Mediterranean region. The results show that about 27.59% of annual energy consumption can be saved by choosing best orientation, optimum size of windows and shading device, and optimum insulation thickness. The Life Cycle Cost (LCC) is reduced by 11.94%. The specific energy consumption per square meter is 64kWh/m2 a. [Copyright &y& Elsevier]

Abstract: In the Mediterranean area, there is increase in demand for summer cooling satisfied by electrically driven units in domestic and small commercial sectors; this involves electric peak loads and black-outs. Consequently, there is an increasing interest in small scale polygeneration systems fuelled by natural gas. In this paper, attention is paid to a test facility, located in Southern Italy, to carry out experimental analysis on a small scale polygeneration system based on a natural gas-fired Micro-CHP and a desiccant HVAC system. The MCHP provides thermal power, recovered from engine cooling and exhaust gas, for the regeneration of the desiccant wheel and electric power for the chiller, the auxiliaries and the external units (computers, lights, etc.). The HVAC system can also operate in traditional way, by interacting with electric grid and gas-fired boiler. An overview of the main experimental results is shown, considering both the desiccant wheel and the global polygeneration system. The experimental results confirm that the performances of the desiccant wheel are strongly influenced by outdoor thermal-hygrometric air properties and regeneration temperature. The polygeneration system guarantees primary energy savings up to 21.2% and greenhouse-gas emissions reductions up to 38.6% with respect to conventional HVAC systems based on separate energy “production”. [ABSTRACT FROM AUTHOR]

Abstract: It is well known that it is necessary to insulate the buildings to decrease the thermal demand and to decrease the use of heating and cooling. Due to the high cost of fossil fuels and to the necessity to reduce CO2 emissions, and also due to the new building regulations more attention is paid to the insulation of buildings. Different insulation materials are available in the market. Usually, they are compared by their thermal conductivity and with theoretical calculations, but there are no experimental comparisons available, where the behavior of such insulation materials in a building is compared over time. This is why the authors started a comparison of three typical insulation materials, polyurethane, polystyrene, and mineral wool. For this purpose, four house-like cubicles were constructed (with a size of 2.4m×2.4m×2.4m) and their thermal performance throughout the time was measured. The cubicles were built under a conventional Mediterranean construction system, differing only in the insulation material used. During 2008 and the first months of 2009 the performance of these cubicles was evaluated, and the results are presented in this paper. [Copyright &y& Elsevier]

Abstract: Trigeneration systems, also known as Combined Heat, Cooling and Power (CHCP) systems, are interesting alternatives to supply different energy services in urban districts and in large buildings, particularly in warm areas such as Mediterranean countries. These systems can provide substantial benefits from economic, energetic, and environmental viewpoints, since the cogenerated heat can be used for heating in winter as well as cooling in summer with an absorption refrigerator. This paper develops an optimization model using Mixed Integer Linear Programming (MILP) to determine the type, number and capacity of equipment in CHCP systems installed in the tertiary sector as well as to establish the optimal operation mode for the different plant components on an hour-by-hour basis throughout the year. The objective function to be minimized is the annual total cost. The optimization model considers the legal constraints imposed to feed the surplus autogenerated electricity into the grid at a regulated feed-in tariff. The optimization model is applied to design a system providing energy services for a hospital located in the city of Zaragoza (Spain). The effects of the financial market conditions and energy prices in the optimal structure of the system are analyzed. [Copyright &y& Elsevier]

In summer natural ventilation is the most effective passive cooling system of the Mediterranean area. The correct exposure of the buildings and of the urban morphology to prevailing winds allows reducing the cooling loads also in non-bioclimatic buildings, without any cost. This paper points out the cooling capacity and the possibilities of energy saving offered by a correct natural ventilation by means of the simulation of a non-bioclimatic building, that is, a building having common characteristics as for construction materials and technologies. [Copyright &y& Elsevier]