Ageing Effects on the Thermal Performance of Two Different Well-insulated Buildings

Abstract To guarantee a comfortable accommodation to those who had their house destroyed or unfit due to the earthquake that in 2009 hit the city of L'Aquila, the "C.A.S.E. Project" (italian acronym for Complessi Antisismici Sostenibili ed Ecocompatibili – anti-seismic sustainable and environment -friendly complexes) was foreseen and realized: it entailed the realization of complexes of buildings, built according to italian seismic and energy-efficiency requirements. After 7 years, the ageing effects on the thermal performance of the opaque envelope have been investigated out with thermographic surveys and heat flow meter measurements, on two buildings realized with different typologies, both belonging to C.A.S.E. Project

Non-destructive techniques (NDT) for the diagnosis of heritage buildings: Traditional procedures and futures perspectives

It is estimated that EU cultural heritage (CH) buildings represent 30% of the total existing stock. Nevertheless, all actions in terms of refurbishment need a deep knowledge based on the diagnosis of the built quality. For this reason, the paper aims to provide a comprehensive review about the applicability of non-destructive techniques (NDT) and advanced modelling technologies for the diagnosis of heritage buildings. Considering a time span of two decades (2001–2021), a bibliometric analysis was performed, using data statistics and science mapping. Subsequently, the most relevant studies on this topic were evaluated for each technique. The main findings revealed that: (i) most of studies were conducted on Southern European countries; (ii) 36% of publications were journal papers and only 2% corresponded to reviews; (iii) “photogrammetry” and “laser applications” were identified as consolidated techniques for historic preservation, but they are only linked with HBIM and deep learning; (iv) a significant gap on quantitative NDT was detected and consequently, future researches should be performed to propose a common diagnosis protocol; (v) artificial neural networks have several barriers (i.e. data privacy, network security and quality of datasets). Hence, a holistic approach should be adopted by the European countries

room and window geometry influence for daylight harvesting maximization effects on energy savings in an academic classroom

Abstract Lighting systems have a fundamental role for the overall buildings energy consumption. Therefore, remarkable efforts are required for optimizing the lighting systems energy use and for finding new daylight harvesting solutions. In this paper, the impacts on daylight harvesting provided by different room and window geometries and their effects on energy savings are presented. An academic classroom with only one window is chosen as case study and it is supposed that the window orientation is modified according to the four cardinal points. A climate-based approach was chosen for the multiple simulations, carried out via DIVA software, by assuming: square and rectangular classroom geometries with the same total area; square and rectangular window shapes having Window to Floor Ratios (WFRs) equal to 8% and 12%; two different dimmable lighting systems, in order to quantify the energy savings, by considering fluorescent and LED dimmable lamps. The daylight analysis, performed by evaluating both the Daylight Factor (DF) and the Daylight Autonomy (DA), showed that room and window geometries have high influence on daylight harvesting maximization, allowing remarkable energy savings (up to 48.5%) with respect to non-dimmable lighting system. In particular, the best energy result, equal to 467.5 kWh/yr, was obtained with rectangular room and window geometries coupled with LED lamps and WFR equal to 12%

The energy efficiency challenge for a historical building undergone to seismic and energy refurbishment

Abstract The renovation of historical buildings assumes a crucial role in the renovation processes of a historical city, and it is important to foresee appropriate interventions. A case study in L'Aquila city center is proposed in this work. The building, belonging to listed buildings for its historical value, being built in the 1930s, underwent to seismic and energy refurbishment, since it was damaged by the earthquake of 2009. The solution proposed aimed at improving the energy efficiency of the structure, by using an additional insulating layer, made of natural material (i.e. hemp), on the inside of the wall. The ceilings of the unheated spaces have been insulated, too, by using pure cellulose flocks. Moreover, an endothermic membrane has been employed on the external walls of the building. Analyses on the envelope were carried out by using thermographic inspections, performed both in summer and in winter seasons, and by measuring the total thermal transmittance of the wall assembly before and after the refurbishment with the help of a heat flow meter

Thermal comfort monitoring in office buildings: A case study

In the framework of EPBD Directive revision, the EU is pushing Member States to pay more attention to IEQ conditions in buildings, by introducing specific requirements to be verified in the calculation methodology implemented in the national building codes. In this paper, the extensive field monitoring of an office building, carried out in the heating, cooling and intermediate seasons of 2022-2023, is described. Main thermo-hygrometric quantities have been measured in different rooms, considering the occupancy profile, users’ behaviour and appliances use. Results showed overheating conditions in offices exposed to the south façade, mainly due to solar radiation and internal heat gains. Surprisingly, north-facing offices with heating terminals running are colder than south-facing ones with HVAC systems turned off. Further differences were found in the temperature analysis of free-floating conditions, showing deviations up to 4 °C on average, between south and north facing rooms. For each room, thermal comfort issues were assessed in accordance with EN 16798-1, by calculating Fanger Indexes (PMV and PPD), and by adaptive method in the HVAC systems off-work periods. These findings represent the first results of an in-depth analysis of thermal comfort and IEQ conditions, aimed at assessing how the IEQ conditions can address the building energy audit, increasing, at the same time, energy performance and IEQ levels

Modeling and Optimization of the Thermal Performance of a Wood-Cement Block in a Low-Energy House Construction

The reduction of building energy consumption requires appropriate planning and design of the building’s envelope. In the last years, new innovative materials and construction technologies used in new or refurbished buildings have been developed in order to achieve this objective, which are also needed for reducing greenhouse gases emissions and building maintenance costs. In this work, the thermal conductance of a brick, made of wood and cement, used in a low-rise building, was investigated with a heat flow meter (HFM) and with numerical simulation using the Ansys® software package (Canonsburg, PA, USA). Due to their influence on the buildings’ thermal efficiency, it is important to choose an appropriate design for the building blocks. Results obtained by the finite element modeling of the construction material and by in-situ analysis conducted on a real building are compared, and furthermore a thermal optimization of the shape of the material is suggested

Shading and layout influence on flats energy performance of an apartment building

Giving the need for environment protection and energy need reduction, especially in the building sector, it is important to clearly understand what influences, and to what extent, buildings’ energy performance. In this work, an apartment building has been considered, and the influence of shadings and of flats layout on the energy performance ratings are evaluated. The case study is a building of the ‘90s, which has been demolished and re-built (2016) according to the actual energy requirements. For each of the 16 flats of the building, the energy certificate has been retrieved in the two configurations: before and after reconstruction. From the analysis of the specific energy consumption, and of their components (i.e. energy need for ventilation, transmission losses, solar gains), in the two configurations, a comparison amongst the flats has been drawn. Results show that the apartment layout influences the solar gains, but this influence (in percentage) is higher in the “ex-ante” configuration than in the “ex-post”. Similarly, the energy gains are more relevant in the “expost” configuration, in which some apartments, although having higher dispersing surface, result to be more efficient due to their favourable exposition

How pandemic affects occupants’ buildings perception: questionnaires investigation and preliminary results

The COVID-19 pandemic has changed the living habits all over the world. Countries experienced multiple lockdowns, causing offices, restaurants, school and almost all the economic activities to close. The saying “stay home stay safe”, to which we were invited for preventing the virus spread, and the rise of smart-working, lead to an exponential increase in the time spent in our homes. In this sense, the way to live our homes has changed. Spaces and rooms that (before pandemic) were occupied for just a few hours a day, have become the main places for studying, working, playing or even have fitness. More than ever, people had to face the energy related problems of their house: air leakages, energy losses, expensive billings, and thermal discomfort. This study arises from considerations on buildings use after the pandemic, and it addresses the consequences of COVID-19 to building perception. Anonymous questionnaires were proposed broad wide, asking through a multi-stage survey to compare the feeling before and after the pandemic, also in comparison to the billing of the energy carriers. Results have been analysed, showing how the pandemic has changed the living perception

Approaching the validation of building energy models: billing vs indoor environmental data

To understand the real building energy consumption, and to identify the best energy improvements (due to energy refurbishment and/or HVAC replacement), the energy audit is recommended, but it generally entails the realization of an energy model of the building itself. The main issue of this approach is the collection of data, needed to verify the reliability of the energy audit results. Currently, to validate buildings energy model retrieved by hourly semi-stationary software, is it possible to refer to: (i) bills related to energy carrier (i.e. natural gas and/or electricity); (ii) monitored indoor parameters. The aim of the paper is to understand which of the two is more suitable for the purpose. In this work, the two options are investigated considering, as case study, a family house located in central Italy, whose envelope thermophysical properties and HVAC systems are known, and whose bills and indoor environmental conditions (air temperature and relative humidity) were archived since December 2019. Results from the two validation methods are very close to each other; particularly, results show that energy audit performed with indoor environmental parameters better fits the real consumption, but it entails more complex validation procedure