Search

According to the recent EU Directives on building energy efficiency, the Italian government is paying particular attention to energy refurbishments of buildings by enacting energy measures and obtaining significant results. In particular, the Italian government is providing economic incentives to citizens or public administrations that improve the envelope of the energy performance of a building. However, according to strict national regulations concerning building heritage, most actions cannot be applied to historic buildings, even though they represent approximately 30.1% of all buildings. In this context, the energy retrofits for Italian buildings are not simple but necessary. Therefore, in this work, a public historic building was simulated, and some permitted retrofit actions were applied to analyse the effectiveness of national measures in four different climatic zones. The results showed that the same applied action that reduces the primary energy consumption in some zones will significantly increase consumption in other zones, even if the zones fall within the same case-law. Finally, the results highlight two main unsolved issues: the renewable energy source installation of a historic building and a strong distinction between measures and economic incentives around the Italian peninsula, which has very different climate conditions.

This study investigates energy efficiency in buildings. The accurate evaluation of energy consumption in existing buildings is a difficult task, particularly due to the Mediterranean climate, which is in the temperate zone. Among the various analytical models, the most effective measurement of the energy consumption of buildings is the dynamic type. In evaluating the energy consumption of buildings, the greatest contribution is provided by opaque components and particularly by the external walls of that building. In the model, which is reported in the EN ISO 13786, the thermal properties (the specific heat (J/kgK) and thermal conductivity (W/mK) of the layers of the wall were tested, and the technical standard reported that the physical properties (from which they derive the phase shift and decrement factor) transferred through the wall when a sinusoidal wave temperature variation was applied in a periodic steady state. We propose an inverse approach to measure the sinusoidal periodic steady state (temperature and thermal flux) on the two faces of the wall. With this approach, it is possible to obtain the thermal properties of the wall through an inverse analytical model. The model was applied in a real experiment on a full-size wall in a climatic chamber to verify the dynamic thermal and physical properties of the layers.

The demand on reducing energy consumption of buildings, recently became tighter and tighter, as well as the need of shortening the building materials’ supply chain. It is generating a growing attention to natural and local construction materials and opening new and interesting research scenarios. The use of novel materials makes necessary reaching a deeper and appropriate understanding of their thermal performances by means of an accurate thermal characterization. The present research has been addressed at testing and verifying the thermal performance of Sardinian local masonry materials (hollow clay blocks and adobe bricks) and three different natural insulations: cork, sheep-wool and reeds. By the use of a dedicated hot box apparatus, working on full-scale wall models, the thermal resistance of eight different samples has been measured and then compared with the theoretical values calculated according to current standards. The results show that the measured values are by far higher than the calculated ones and that the use of local natural materials, if not accompanied by a rigorous standardization of production and installation procedures, can lead to overestimate their thermal performances.

Today, evaluation of thermohygrometric indoor conditions is one of the most useful tools for building design and re-design and can be used to determine energy consumption in conditioned buildings. Since the beginning of the Predicted Mean Vote index (PMV), researchers have thoroughly investigated its issues in order to reach more accurate results; however, several shortcomings have yet to be solved. Among them is the uncertainty of environmental and subjective parameters linked to the standard PMV approach of ISO 7730 that classifies the thermal environment. To this end, this paper discusses the known thermal comfort models and the measurement approaches, paying particular attention to measurement uncertainties and their influence on PMV determination. Monte Carlo analysis has been applied on a data series in a "black-box" environment, and each involved parameter has been analysed in the PMV range from -0.9 to 0.9 under different Relative Humidity conditions. Furthermore, a sensitivity analysis has been performed in order to define the role of each variable. The results showed that an uncertainty propagation method could improve PMV model application, especially where it should be very accurate (-0.2 < PMV

The public buildings sector represents one of the most intensive items of EU energy consumption; the application of retrofit solutions in existing buildings is a crucial way to reduce its impact. To facilitate the knowledge of the energy performance of existing non-residential buildings and the choice of the more adequate actions, Public Administrations (PA) should have the availability of proper tools. Within the Italian project "POI 2007-13", a database and a decision support tool, for easy use, even to a non-technical user, have been developed. A large set of data, obtained from the energy audits of 151 existing public buildings located in four regions of South Italy have been analysed, elaborated, and organised in a database. This was used to identify the best architectures of two ANNs and to train them. The first ANN provides the actual energy performance of any building; the second ANN assesses key economic indicators. A decision support tool, based on the use of these ANNs is conceived for a fast prediction of the energy performance of buildings and for a first selection of energy retrofit actions that can be applied.

In this paper, we present Overgrid, a fully distributed peer-to-peer (P2P) architecture designed to automatically control and implement distributed demand response (DR) schemes in a community of smart buildings with energy generation and storage capabilities. As overlay networks in communications establish logical links between peers regardless of the physical topology of the network, the Overgrid is able to apply some power balance criteria to its system of buildings, as they belong to a virtual microgrid, regardless of their physical location. We exploit an innovative distributed algorithm, called flow updating, for monitoring the power consumption of the buildings and the number of nodes in the network, proving its applicability in an Overgrid scenario with realistic power profiles and networks of up to 10,000 buildings. To quantify the energy balance capability of Overgrid, we first study the energy characteristics of several types of buildings in our university campus and in an industrial site to accurately provide some reference buildings models. Then, we classify the amount of ``flexible'' energy consumption, i.e., the quota that could be potentially exploited for DR programs. Finally, we validate Overgrid emulating a real P2P network of smart buildings behaving according to our reference models. The experimental results prove the feasibility of our approach.

Purpose The purpose of this paper is to address a project for lighting an old town in Italy. Its originality lies in the holistic approach that aims to fulfil several objectives. One is to reduce energy consumption by using efficient lamps and advanced control systems; the second one is to make the network viable and useful for many purposes by integrating ICT devices; the third one is to provide a new identity to the older part of the city by using new technologies and design concepts; while the last one is to ensure street and pedestrian safety according to codes and standards. Design/methodology/approach The plan of the city of Bagheria and the stock of luminaires of the city are analysed. A multidisciplinary approach has been adopted in order to: analyse the existing lighting infrastructure highlighting critical areas; design a new displacement and select typologies of luminaries able to provide proper light quality and distribution; propose an aesthetic solution and technical design for relevant historical building; and to include in the design process the concept of a new multifunctional pole. Together with an analysis of social benefits, an assessment of economic costs and benefits are discussed. Findings The project allows good energy savings, meets the standard requirements and gives a relevant and strategic improvement in social and environmental management of the city. Originality/value The work provides an example of integrated design of street lighting infrastructures for urban renovation in old cities in degraded environments.

Thermal comfort and energy saving have become a priority for construction industry professionals. An important parameter of the comfort is the mean radiant temperature and its dependence on the building envelope. In the present research, a dynamic physical model has been studied in a climatic chamber, linked to the specific heat (C), density (r) and thermal conductivity (l). The heat capacity is usually quantifiable in small, homogeneous and uniform samples by the application of calorimetric methods. Consequently, the building energy consumption assessed through calorimetric methods, is often quite different from the energy consumption measured in situ. In this work an experimental model for the assessment of specific heat of real-size building components is proposed. Such a parameter was determined by measuring the heat flow through a building wall. The model has been validated by comparing the evaluated properties of known materials for different thermal gaps.

Existing street lighting systems, in most of South Italy cities, are often inefficient due to the obsolescence of lamps and luminaires and of ineffective light control systems unable to implement efficient on-off and dimming strategies. Energy efficiency improvement, in street lighting systems, is often one of the key actions to be adopted by Public Administration in their Sustainable Energy Action Plan in the framework of the “Covenant of Majors” activities. As a task of FACTOR 20 project, a set of planning options has been analysed and proposed. Particularly, street lighting efficiency projects have been studied for representative case studies. A detailed survey of the public lighting systems, in Comiso, allowed represent current performance figures such us installed power, luminance and illuminance levels in roads categories, electricity consumption, switching and dimming schedules. A project of system upgrade has been elaborated. To do this, many lighting simulations, energy and economic assessments in three scenarios have been performed. The obtained results show that high improvements of the lighting quality are foreseeable together with large energy and economic saving. An economic sensitivity analysis, has shown how the performance can change. The proposed methodology can be applied in many similar South Italy cities.

The strict energy saving standards are based on the declared values of the materials, i.e. U-value, thermal conductivity or thermal capacity. To this end, proper knowledge of the thermophysical properties of the wall components is needed, especially with regard to new lightweight technologies that are being used in building construction/refurbishment, under the dynamic conditions of the Mediterranean climate, where one of most important parameters of building materials is their heat capacity because of the influence of solar radiation energy. With this regard, the actual heat capacity value, obtained in laboratory tests, is typically quite different from the nominal one. So, this paper reviews several methods of calculating the heat capacities of materials and several worldwide applications, with the aim of providing an overview of the thermal behaviour of lightweight insulation materials and their implications for energy and indoor comfort. Finally, the authors propose a simple method able to evaluate the specific heat capacity of real scale building materials with a ~5% of uncertainty.

Sustainable urban development, especially in disadvantaged regions, has increasingly gained a major strategic priority. New settlements and urban regeneration programs have to achieve an improvement of social life quality, promote economic growth and increase environmental protection practices and proper use of local resources. In this framework, building environment development must exploit natural resources with responsible approach by using local materials and traditional techniques. In this end, indoor comfort and energy consumption have to match the territories needs. Low energy and passive heating/cooling techniques should be considered as a valid option in many building projects. The paper reviews some models evaluating thermohygrometric comfort in natural ventilated buildings, based on adaptive approaches. A focus is given on Mozambican building traditions, and, finally it proposes a case study where, by the recovery of Mozambican old traditions, a new healthcare facility is designed to be energy autonomous also including large use of natural ventilation.

Building occupants are important factor in giving information on indoor conditions such as comfort, productivity, building performance and occupants ́ health. Even that, being their appraisal mainly based on subjective judgments, it is difficult to set up a standard and objective method for this purpose. The present work aimed to describe, analyze and compare the most common tests on this topic, in order to highlight critical, failings and strengths.

Currently, many effort have been done to enable energy saving issues in building design and many definitions have been introduced for most performing constructions based on energy balance between energy demand and supply. Recently, the Net Zero Energy Building theory has bypassed old Passive House concept but many questions still remain open. Present work aims to estimate how NZEB requirements matching could be affected by the choice of their definition and the choice of weighting factor system, to be count in the energy balance. NZEB concept is mainly referred to new buildings design. Its application to existing buildings is for sure an hard task provided the architecture and physical constraints are often problematic. Nevertheless, the benchmarking approach able to assess the building performance according to the NZEB objective can be utilized for other two purposes. The first one is to assess how an existing building is far from the performances of a NZEB. The second one is to assess the contribution of a conventional retrofit in improving its energy balance.

Sustainability of energy supply strategies in small islands has been emerging as a severe issue, due to the large margins for improvement and rationalization of the most frequently adopted solutions. In most of the European islands, large amounts of heat are wasted by the operation of engine-based power plants; conversely, heat is produced by boilers (supplied by liquid fuels) or by electric equipment for a number of different uses, like domestic hot water production or space heating in winter. In this paper a techno-economic analysis is proposed to assess the feasibility of CHP-retrofit of the existing power plants and the possible utilization of the recovered heat to supply, via a district heating and/or cooling network, the energy requests of civil energy users (both in the tertiary and in the residential sector). The analysis is accurately performed for six islands located in Italy and characterised by different context conditions from a demographic, geographic and climatic viewpoint, so as to get a comprehensive understanding of the factors that favour/obstruct the economic feasibility of the examined technical solution. As expected, due to the low “linear heat density” usually observed in small islands and to the complex orographic profiles, the investment usually resulted “far from being attractive”; only in the case where public incentive or support mechanism is adopted, the possible integration of the existing power plants with heat recovery devices and a district heating network resulted in moderately attractive, especially in the largest examined islands due to their highest heat loads.

Italian energy policy has determined important keystones in building energy efficiency regulations and their application throughout the country. However, there is still much work to be done in order to make sustainable societies and territories, especially in historical contexts that have the greatest potentiality of energy saving. In detail, in the framework of conservation, restoration, refurbishment, and retrofit actions, the debate among scientists, administrators and skilled people is still open due to the many aspects yet to be considered and solved. In this paper, the state of the art of Italian residential building heritage has been reviewed, while energy retrofit issues and viable solutions have been investigated by collecting literature examples and experiences, focusing on common retrofit measures on historical buildings per thematic area. Finally, the advantages and disadvantages of each action have been discussed. Anyway, two main aspects have to be solved yet: the high Payback Times and the restriction about Renewable Energy Sources installation on this kind of buildings.

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

Proper assessment of indoor daylighting conditions can significantly reduce energy consumption due to artificial lighting and can improve indoor visual comfort. This paper gives a critical review of the fundamental aspects of daylighting indices with the aim to provide a broad overview of methods and indices available to assess daylighting from varying points of view. Assessments cover distribution, availability over time and in specific climatic contexts, uniformity in the space, visual comfort issues and the relations between each of these aspects and a proper building and lighting design. A special focus on the assessment of indoor spatial and temporal uniformity is given. An analysis of the application of daylighting design by researchers and designers according to several area of interest is also presented.

The paper focuses on the evaluation of the impact of Building Automation Control Systems (BACS) and Technical Building Management (TBM) systems on the performance of the lighting system in a residential building. In particular, this work shows a laboratory setup, installed at the DEIM of the University of Palermo, for simulating a typical apartment. The paper describes the laboratory, the lighting system and the BAC system installed and the test facility for evaluating the electricity consumption in presence and in absence of automation. The laboratory has been built within a research project funded by the Italian Minister of University and Research in the framework of the PON Smart Cities and Communities and Social Innovation "I-Next" (PON04a2_H).

The indoor visual comfort of subjects faced with indoor ambient lighting varies with the position of the subject and is not constant over time. Average performance indexes, such as the mean value of Daylight Factor and Daylight Autonomy, are commonly used to analyse lighting distribution. These indexes, however, don’t properly take into account either the spatial or the time distribution of values affecting the non-uniformity of environmental lighting. Indeed, these are limited to the definition of a mean value or to the assessment of time availability of daylighting. This paper examines spatial and temporal non-uniformities in indoor lighting as possible causes of discomfort for occupants. The goal is to propose and verify possible supplementary tools to integrate traditional methods of evaluating ambient indoor lighting. Use of the entropy theory with a probabilistic approach can help to obtain more detailed information about the environment. The authors have developed a case study of several sample environments and have analysed the relationships between lighting parameters and typical indices of information theory. Results show that this approach could be a useful way for predicting possible indoor visual comfort issues and for developing a preliminary assessment to a sustainable building design. The indoor visual comfort of subjects faced with indoor ambient lighting varies with the position of the subject and is not constant over time. Average performance indexes, such as the mean value of Daylight Factor and Daylight Autonomy, are commonly used to analyse lighting distribution. These indexes, however, don’t properly take into account either the spatial or the time distribution of values affecting the non-uniformity of environmental lighting. Indeed, these are limited to the definition of a mean value or to the assessment of time availability of daylighting. This paper examines spatial and temporal non-uniformities in indoor lighting as possible causes of discomfort for occupants. The goal is to propose and verify possible supplementary tools to integrate traditional methods of evaluating ambient indoor lighting. Use of the entropy theory with a probabilistic approach can help to obtain more detailed information about the environment. The authors have developed a case study of several sample environments and have analysed the relationships between lighting parameters and typical indices of information theory. Results show that this approach could be a useful way for predicting possible indoor visual comfort issues and for developing a preliminary assessment to a sustainable building design.

Italy, like several Mediterranean countries, holds a very large number of cultural artifacts that are often exhibited and saved inside museums. Museums are usually part of historical buildings that, not rarely, originally had a different intended use and that have been currently transformed in place for conservation and for exhibition of works of art. The use of historical buildings as museums leads to limitations in the management and distribution of exhibition space, in design and managing HVAC systems and in the achievement of targets relating to the continuous monitoring of the microclimate for people comfort and for preservation of works of art. Moreover, the costs of the operation and maintenance of the HVAC system for this particular type of confined environment are often very expensive and the proper optimization of the required operations plays a main role. In this paper, authors propose a new decision support tool for curators regarding the operation and maintenance management of HVAC systems in museums especially in the case of their belonging to cultural heritage buildings.