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In recent years, building stock models have been developed by researchers to examine the aggregate performance of stacks of buildings within large areas, thereby giving rise to the concept of urban building energy models (UBEMs). The input data for such models consists of geometric and non-geometric attributes of the buildings, in addition to meteorological information. In this perspective, the acquisition of precise and comprehensive data poses a challenge, as the existing datasets often lack certain parameters or are not in a standardized format. This study aims to address the challenges by proposing a workflow for generating an input data frame tailored for incorporation into UBEMs. The data frame should include all the essential parameters of the buildings, and its constitution should be reflective of the real-world data. Moreover, the proposed workflow should remain consistent with databases available at national or regional levels. Acknowledging this non-uniformity in databases across regions, the methodology proposed in this study strategically considers various alternatives. For this reason, the proposed automatized workflow ensures flexibility and adaptability to changes in data availability. The workflow proposed in this study is a QGIS based geographical calculation method. The method can combine data from various sources into one shapefile that can be used to simulate the energy performance of buildings in urban areas.

Buildings are among the primary contributors to global energy consumption, and reducing their demand is one of the challenges that need to be considered for a sustainable future. Zero Energy Buildings (ZEB) represent one of the most promising strategies in this endeavor, and in this sense, the UniZEB project addresses this issue with an innovative approach. It is a Zero Energy Building Laboratory of the University of Padova, built up from a collaboration between local companies, students, and researchers, featuring high performance HVAC and envelope technologies integrated with renewable energy sources. The present work offers an overview of the project, showing some of the already-faced challenges, as well as future opportunities of research and study. The purpose of the laboratory is indeed to offer the students the possibility to put in practice the knowledge they gain through university, as well as exploring new subjects through recent research topics, e.g., the development of a sensor network for the monitoring of the building, the dynamic model calibration, able to compare expected and current energy demand. The paper aims also to demonstrate the potential of a project like UniZEB, proving how research, innovation, and collaboration can shape the future of sustainable construction.

In this work, the climatic chamber CORE-CARE is presented. The laboratory was built at the Industrial Engineering Department of the University of Padova, in order to further investigate issues related to indoor environmental quality, the comfort perceived by people in confined spaces and thermal performance of radiant systems. CORE-CARE is equipped with radiant panels in each surface, which can be controlled separately. The room presents two real windows on the East side, equipped with shading systems. Furthermore, the mechanic controlled ventilation system installed in the room can act as integration of sensible or latent heat both in heating and in cooling conditions. The climatic chamber is provided with a data acquisition system, consisting of 38 sensors, that allow the evaluation of the surface temperatures in different positions, the air temperature at different heights, the mean radiant temperature, relative humidity and CO2 concentration. The CORE-CARE chamber is thermally characterized using a detailed model developed at the Industrial Engineering Department of the University of Padova and the simulations results are compared with test measurements. Moreover, the impact of radiant asymmetry is investigated.

Nowadays, the search for new solutions to the pandemic situation caused by the spread of SARS-CoV-2 is one of the most important issues worldwide. The difficulties encountered in finding an effective cure for the infection and the ongoing vaccination campaign place a priority on minimising the transmission of this disease. This paper deals exclusively with the airborne route of transmission for COVID-19, proposing a model for the evaluation of infection risk. It starts from the well-known Wells-Riley model and its successive modifications and tries to couple it with a zonal model which analyses the air movement in an indoor environment. The objective of this model is evaluating whether the infection risk depends considerably on the position of the infected subject and the susceptible person in the room and how different ventilation concepts affect these aspects. The model was applied to an office room with a mixing ventilation system. The results obtained concern the sub-division of the considered volume in four cells, each one perfectly mixed. The evaluation of infection risk in different positions was carried out and an analysis on the parameters affecting this value was performed.

Revised EPBD directive has set ambitious targets for renovation. It is stated that Member States shall establish a long-term strategy facilitating the cost-effective transformation of existing buildings into nearly-zero energy buildings. The long-term strategy should set out a roadmap with a view to the long-term 2050 goal of reducing greenhouse gas emissions in the European Union. This creates the need for cost-efficient renovation solutions which can be implemented in large scale. The impact assessment shows that roughly a doubled renovation rate of 3 % would be needed to accomplish the energy efficiency ambitions in a cost-effective manner. The objective of this study is to specify renovation concepts with adequate heating and ventilation, based on Estonian and German apartment buildings and corresponding local solutions. Energy performance and sizing analyses were conducted for selected multifamily apartment buildings typical for 1960-70es with three different renovation concepts. Energy calculations were conducted with national energy calculation methods and national energy requirements for major renovation. In the renovation, the building envelope insulation, air tightness, and heating and ventilation systems were improved so that the renovated building complies with national nearly zero-energy requirement for major renovation.

The present paper shows the background analysis to develop the optimization strategy of a neighborhood heating network sited in Padua, including it in a wider project of district renovation. The case study accounts several different end users: scholastic and offices buildings, a social housing residence and residential buildings. The analysis starts from a systematic assessment of the buildings, evaluating the need of refurbishment of the envelope and of the distribution system. Further analysis focuses on the optimization of the existing heat generation system, integrating three condensing boilers, with an air to water heat pump and a ground source heat pump, which work more efficiently during base-load periods. The management of the district heating network have been investigated using the dynamic simulation tool TRNSYS, the control strategy of the delivery temperature has been tested based on the outside temperature and verifying to satisfy comfort conditions inside the buildings. A sustainable solution is the recovery and drainage of rainwater, that can be reused for the toilets’ flushing. Therefore, the project solution identified aims at a more rational use of energy sources, which is the simplest and cheapest way to proceed on the decarbonization path that is a mid-term target for the Padua administration.

Since the beginning of this century, according to EPBD Directive, Italian legislation has been focusing on existing buildings’ retrofit, as they represent a large part of the national building stock. In this context, the most difficult challenge is preserving heritage and obtaining energy saving at the same time, which is the aim of the European Standard EN 16883 published in 2017. Currently there are few energy efficiency actions that can be applied to improve the energy performance of these buildings, due to the strict regulation on ‘protected status’. The case study presented in this paper gives an overview of refurbishment solutions that can get around Italian legislation for one of the oldest heritage buildings in Padova. The building complex that can be seen nowadays is the result of the grouping of several surrounding buildings, renaissance palaces and medieval towers. Energy simulations have been implemented using EnergyPlus software. The thermal behaviour of the building has been investigated considering the peculiarities of the envelope and real weather data. Internal loads and generation system schedules have been estimated based on the information obtained from the system monitoring the energy consumption. Envelope and system retrofit have been considered.

The following article describes an extract of the results of experimental investigations on the topic of thermal comfort as a function of radiation asymmetry. The investigations were carried out in the climate chamber [1, 2] of the TU Dresden with the help of subjects. The radiation asymmetry was imprinted by subdividing the climate chamber into two vertically superimposed half-rooms, one of which was heated and the other cooled. In this way, 46 experiments on the heating or cooling ceiling were carried out. The measurement results show an inseparable link between the radiation asymmetry, the vertical air temperature difference and the air velocity. The subject assessed the room climate much more negatively than the ISO 7730 [3] would predict according to the state of the art.

Ground Source Heat Pumps (GSHP) are gaining interest for many applications and a very difficult task is to look at their affordability in urban environments with limited spaces. For this reason, the EU project GEO4CIVHIC has been funded. In order to set up different cases with different levels of retrofit and try to generalize results, the project focuses the activity on archetypes, i.e. buildings which may represent the usual type of building which may be found more frequently in urban environments around Europe. The analysis of the archetypes has been based on literature review and analysing the existing databases of buildings in Europe. The work allowed to determine a reference building for single family house and a building representing an apartment block for multi-users. In this latest case two types of possible uses have been examined: residential building and office building. In order to set up different levels of retrofit and cost-effective solutions, three different climates have been defined: warm climate, mild climate and cold climate. The climatic conditions do not only affect the energy demand of the building and the peak power needed for heating and cooling, but also determine different ways of buildings’ construction and define different levels of insulation. Last but not least, the buildings have been also subdivided into existing buildings, i.e. built up from 1960 to 2000 and historic buildings, i.e. buildings earlier than 1960. The paper presents the first step of the research which permitted to define the different archetypes, their dimensions and way they are constructed. Moreover, the different simulations allowed to define the energy needs of the buildings as well as the peak power for heating and cooling. This allows to create a matrix for the different levels of retrofit solutions which will be associated to related costs for a cost-benefit analysis to check the most achievable solutions.

For promoting the diffusion of GSHP and making the technology more accessible to the general public, in the H2020 research project “CHeap and Efficient APplication of reliable Ground Source Heat exchangers and PumpS” (acronym Cheap-GSHPs) a tool for sizing these systems has been developed, as well as a Decision Support System (DSS) able to assist the user in the preliminary design of the most suitable configuration. For all these tools a common platform has been carried out considering climatic conditions, energy demand of buildings, ground thermal properties, heat pump solutions repository, as well as renewable energy database to use in synergy with the GSHPs. Since the aims of the tools are different, there are different approaches. The design tool is mainly addressed to designers. The calculation may be done in two ways: with a simplified method based on the ASHRAE approach and with a detailed calculation based on the numerical tool CaRM (Capacity-Resistance method). The DSS final aim is to support decision-making, by providing the stakeholders at all the level with a series of scenario. The Cheap-GSHPs project has developed a DSS tool aimed at accelerating the decision-making process of designers and building owners as well as increasing market share of the Cheap-GSHPs technologies. Hence the DSS generates different possible solutions based on a defined general problem, identifying the optimal solution. Both tools are presented in the paper, showing the potentialities provided by both software.

Demands for energy savings, thermal and visual comfort and a high-tech image for new building envelopes can be met with a Double Skin Façade (DSF). These kinds of building envelopes are widely encouraged, proposed and increasingly designed by architects. Naturally ventilated DSFs seem very interesting from an energy point of view, but a good design is crucial to improve the energy savings and the proper operation of the system. Computational Fluid Dynamics (CFD) can play an important role in evaluating and improving the thermal behaviour of a DSF. This paper shows, through a sensitivity analysis, a good strategy for carrying out a CFD simulation of this special building envelope.In this work the validations of the results are based on experimental data from the literature.The paper provides a discussion that highlights which factors are important in the simulation, and which increase model complexity without improving the prediction capacity. The results show that, for a DSF characterized by a prevalent bidirectional flow, the additional effort required to make a 3D model is not justified by a significant improvement of the results. This work shows also that the accuracy can be improved by modelling outdoor ambient. The performance of k-ε and k-ω, the two most commonly used turbulent models for simulating the naturally ventilated DSF is evaluated.

Demands for energy savings, thermal and visual comfort and a high-tech image for new building envelopes can be met with a Double Skin Façade (DSF). These kinds of building envelopes are widely encouraged, proposed and increasingly designed by architects. Naturally ventilated DSFs seem very interesting from an energy point of view, but a good design is crucial to improve the energy savings and the proper operation of the system. Computational Fluid Dynamics (CFD) can play an important role in evaluating and improving the thermal behaviour of a DSF. This paper shows, through a sensitivity analysis, a good strategy for carrying out a CFD simulation of this special building envelope.In this work the validations of the results are based on experimental data from the literature.The paper provides a discussion that highlights which factors are important in the simulation, and which increase model complexity without improving the prediction capacity. The results show that, for a DSF characterized by a prevalent bidirectional flow, the additional effort required to make a 3D model is not justified by a significant improvement of the results. This work shows also that the accuracy can be improved by modelling outdoor ambient. The performance of k-ε and k-ω, the two most commonly used turbulent models for simulating the naturally ventilated DSF is evaluated.

In this study the indoor environmental quality (IEQ) of an energy efficient 9400 m2 Italian office building was investigated using an Italian-language version of the Center for the Built Environment’s web-based survey. This survey allows the building’s IEQ performance to be compared against a large database of previously surveyed buildings. In addition, it permits the specific causes of dissatisfaction to be identified. The study building was compared with 66 buildings having LEED certification. The analyzed building obtained scores higher than the median of the 66 LEED buildings in the categories: acoustic quality, thermal comfort, general satisfaction, air quality and office furnishings, and lower than the median in: cleanliness and maintenance, office layout and lighting. The subcategories: visual and acoustic privacy scored low. For these, layout and operational interventions were proposed. The building survey showed that high simulated energy efficiency and high measured IEQ can be accomplished simultaneously.

Attraverso un questionario elaborato dal Center for the Built Environment dell’Università della California gli occupanti della Camera di Commercio di Bolzano sono stati invitati a dare un giudizio sulla qualità degli ambienti in cui lavorano.

The personal ventilation (PV) system decreases the pollutant concentration mostly in the microenvironment at the workstation, but it can also increase the contaminant in other zone of the room. Therefore, occupant’s exposure to pollutant depends on the ratio of time occupant stays at the workstation over total time he/she stays in the room. This ratio is named occupied density (OD).An index, using a modified definition of OD, is developed to compare and quantify the variation in terms of inhaled pollution by occupant in a room with PV in conjunction with a total-volume ventilation system. The index is applied to data collected during full-scale room measurements.The results show that the index can be used at the design stage for assessment the benefit of PV when applied in practice for office buildings with different OD. It is for example demonstrated that if the occupied density is lower than 0.5 the use of displacement ventilation alone will be advantageous with regard to human-produced contaminates in comparison when it is combined with PV system.

Cooling energy savings and improved thermal comfort in hot climates can be achieved using cool roofing materials. High solar reflectance and infrared emittance values reduce the amount of absorbed solar radiation and the surface temperature of a material exposed to sun radiation, consequently the heat transfer into the building is lowered. A reduction of the urban heat island effect, caused by the presence of high absorption surfaces and the lack of vegetation, may be obtained using cool roofing materials.Computer energy simulations have been used to assess the energy savings and temperature profiles consequent to the application of a cool roofing material when applied to industrial premises in three Mediterranean cities: Genoa, Madrid and Cairo. In particular, the related influence on cooling energy demand and maximum temperature at the outside face of the roof are analyzed, varying the roofing material and the insulation thickness.The results of this study showed that using a cool roofing material in the Mediterranean area for industrial premises leads to significant sensible cooling energy savings, up to 42%. Moreover, it was obtained that the maximum roof outside surface temperatures decrease of 40÷50°C when cool roofing materials are applied.