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The European building sector is responsible for approximately 40% of total energy consumption and for 36% of greenhouse gas emissions. Identifying technological solutions capable of reducing energy consumption and greenhouse gas emissions is one of the main objectives of the European Commission. Ground source heat pumps (GSHPs) are of particular interest for this purpose, promising a considerable reduction in greenhouse gas emissions of HVAC systems. This paper reports the results of the energetic analysis carried out within the EU research project GEO4CIVHIC about the performance of geothermal heat pumps working with low-GWP refrigerants as alternatives for R134a and R410A. The work has been carried out through computer simulations based on base and regenerative reverse cycles. Several heat sink and heat source temperature conditions have been considered in order to evaluate the GSHPs’ performance in the whole range of real conditions that can be found in Europe. Particular attention has been paid to the evaluation of compression isentropic efficiency and its influence on the overall cycle performance when dealing with steady-state heat pump simulations. To do so, five different scenarios of isentropic efficiency calculation have been studied and discussed.

In the residential sector, biomass appliances are widely used for space heating and often combined with other systems. This work aims at comparing the final and primary energy consumption of different configurations, including a conventional and a ducted pellet stove and a wood log stove using air as heat transfer fluid. A dynamic analysis of the interaction between biomass stoves and conventional heating systems, such as gas boilers and radiators, is carried out within a typical single-family house in a mild climate, using TRNSYS software. In addition, natural ventilation of the building is considered using CONTAM, with a focus on external infiltrations and internal air circulation due to the buoyancy effect. Results show that the biomass device in one room promotes the airflows between adjacent thermal zones, enhancing the heat distribution through door openings, in particular when an air ducted stove is present. The final energy consumption resulting from simulations with wood-burning stoves is 21% higher than pellet stoves. The pellet stove results in similar final energy and a 30% increase in overall primary energy, while the wood stove increases the final energy by 22% and approximately 40% of overall primary energy compared to the case of a traditional gas system coupled to radiators which is considered as reference. Nevertheless, non-renewable primary energy savings are higher than 50% with pellet stoves and 60% with wood-log stoves.

Today, coal is responsible for 40% of annual CO2 emissions. At the same time, global warming causes climate changes accompanied with catastrophic meteorological phenomena all over the world. After the 2015 Paris Agriment many countries set ambitious energy policy to reduce the annual greenhouse gas emission. The 2021 UN Climate Change Conference, COP26 - Glasgow, ended with the adoption of a less stringent resolution than some anticipated: countries only agreed to “phase down” rather than “phase out” coal. Is possible the realization of the Paris Agreement after COP-26? For achieving this ambitious targets in such conditions, the support of the multi-disciplinary scientific knowledge is needed. Since 2002 a series of SDEWES Conferences were founded. This paper presents an overview of published researches in special issues of leading journals dedicated to the series SDEWES Conferences, including also the papers in current special issue presented on Conferences held in 2020: 2nd LA SDEWES Conference - Buenos Aires, 1st AP SDEWES Conference - Gold Coast, 4th SEE SDEWES Conference - Sarajevo and 15th SDEWES Conference - Cologne. The focus is on five main fields: (1) energy system analysis ; (2) energy savings in the building sector ; (3) district heating ; (4) electrification of transport and (5) water-energy nexus. Undoubtedly, the researches presented in this special issue as well as in previous ones, will contribute to the achievement of the goals of the Paris Agreement in difficult conditions after COP26.

The increase in the energy demands of residential neighborhoods constitutes a huge challenge to be faced. A viable option lies in the insertion of both renewable energy production systems and cogeneration units within urban territories. On-site production allows for the satisfaction of the heating and electrical demands of end-users and favors the distribution of produced energy within the neighborhood, especially under the regulatory framework of energy communities. This paper proposes a tool to model heating and electricity networks integrated with cogeneration units and PV panels installed in urban areas. The tool accounts for the following possibilities: (i) energy flow management and power sizes of both heating and electric networks, and (ii) evaluation of the electricity sharing configurations arising within energy communities. To better clarify the capability of the tool in supporting energy analysts and decision-makers, a densely populated area in Southern Italy is proposed as a case study. Regarding thermal distribution, results demonstrated that it is better to plan pipelines extended up to 300 m to take full advantage of the insertion of the CHP in the areas. Different considerations apply to the electrical distribution; here, an energy community extended over a geographical area with a radius of around 100 m is sufficient to guarantee an almost fully connected grid and obtain in any case exceeding production to be released to the centralized network.

Water scarcity in many regions of the world and the global demographic growth make the desalination of seawater and/or brackish an effective solution to meet the growing demand for freshwater. Nowadays, reverse osmosis has the largest share of the global installed desalination capacity. The impelling need to reduce greenhouse gas emissions has been pushing the search for sustainable technologies to produce the electricity needed to power reverse osmosis plants. Among solar technologies, little attention has been paid to the possibility of powering reverse osmosis with electricity from the dish-Stirling concentrator. To fill this knowledge gap, this paper assesses the energy-saving potential of a reverse osmosis plant coupled with a cogenerative dish-Stirling concentrator on a small island in the Mediterranean Sea. A model of the integrated systems was developed based on data measured on a real dish-Stirling concentrator, and variation of the energy consumption of the reverse osmosis plant with the temperature of the feedwater solution was also accounted for. Hourly simulations showed that almost 36% of the annual water demand could be covered by driving the plant using electricity from the concentrator, and the solar fraction of the electricity consumed by the reverse osmosis plant accounted for 57%. Finally, the analysis revealed that only a 1% decrease in solar fraction resulted when the heat recovered from the concentrator is not used for the feedwater preheating.

Thermal grids are well-established technologies that can cover the thermal demands of buildings in a more sustainable way. The lower operating temperature will allow not only for the integration of heat produced by thermal renewable energy sources but also for the storage of surplus electricity from the grid using power to heat technologies. To ensure a wider diffusion of this technology, it is important to propose a method for the cost allocation among producers connected to the grid. In this regard, this paper proposes Exergoeconomics as a possible solution. To show the capabilities of the method, some operating scenarios are compared for a cluster of five buildings in the tertiary sector interconnected by a thermal grid, where heat is produced by a cogeneration unit, heat pumps, and an industrial process. Thanks to the exergy and exergoeconomic unit costs, insights into the cost formation process of the heat consumed by users are provided. Results indicated that the substitution of the cogeneration plant with a centralized heat pump and waste heat could reduce the unit exergy cost of the heat supplied to the users. In addition, the analysis revealed a great sensitivity of the heat unit cost to the price of the waste heat recovered from the industrial process.

Variable-speed packaged rooftop units have been increasingly adopted in the commercial sector. If not properly maintained, the fouling of heat exchangers and the improper refrigerant charge could increase energy consumption. In this work, the response of variable-speed rooftop units to evaporator fouling is investigated based on experiments on a variable-speed 17.5 kW rooftop unit. A novel testing procedure is proposed, aimed at covering a broad range of operating conditions by a reduced number of tests. Two opposite cases were investigated: (i) even in presence of fouling, the controller can restore the required cooling capacity, and (ii) the intensity of the fouling does not allow the controller to restore the cooling capacity. While in the former case an increase in the indoor fan rotating speed is observed, with no variations in the evaporating pressure and the inlet temperature of cooled air, in the latter one the mismatch between the cooling load and the capacity induces a deviation of the indoor air condition from the setpoint. A regression model is proposed to quantify these deviations. Experimental results showed that in a faulty scenario, the maximum cooling capacity deliverable could decrease up to 15-20 %, and the indoor fan consumption increased up to 40%. In case of heavy faults involving cooling capacity shortage, a 2.3 °C deviation from the indoor setpoint temperature was estimated by the proposed regression model.

Variable-speed reversible heat pumps are increasingly adopted for space heating and cooling in residential and tertiary sectors. It is recognized that these systems will play a key role in medium- and small-scale 4th generation district heating and cooling networks. Indeed, with the high penetration of intermittent renewable energy sources, such technology could help reduce issues related to the surplus of electricity from renewable energy sources by converting it into heat or cold. To reliably assess the benefits achievable in these emerging applications, it is necessary to develop models which can simulate not only the steady-state operation but also the dynamic response of the system with various boundary conditions (e.g., users’ demand, environmental conditions, etc.). However, heat pump operation is usually assessed by highly simplified models, which consider a Coefficient of Performance value available from the producer at fixed rating condition (eventually corrected to account for off-design operation), being the electrical modelling and embedded controls usually omitted. This paper aims at filling this knowledge gap. Starting with a reversible heat pump operating in cooling mode, this paper developed an integrated thermodynamic and electrical modeling, while considering details on refrigerant circuits, electrical motor, and embedded control. Results showed that the model can simulate the transient and steady-state operation of variable-speed chillers coupled to an induction motor, and the chilled water temperature set-point was duly maintained. Results give a full insight into the electrical and thermodynamic aspects while accounting for the effects of the inertia of the hydronic circuit on the COP of an air-cooled. Results present a faster 2% settling time for low values of inertia that serves the hydraulic system with a high overshot for water temperature.

The increasing share of renewable energy sources in energy systems will lead to unpredictable moments of surplus/deficit in energy production. To address this issue, users with heat pumps can provide support to power grid operators through flexible unit operation achieved via Demand Response programs. For buildings connected to low-temperature heating networks with ensured third-party access, further room for flexibility can be explored by investigating the production of surplus heat that can be sold to the network. A key aspect lies in the identification of the energy pricing options that could encourage such flexible operation of a heat pump by “thermal prosumers”. To this aim, the present study investigates the impact of ad hoc variations in the electricity purchasing price through discounts or penalties included in the “network cost” component of the price on cost-effective operation of a heat pump connected to the thermal network. To discuss the effects of different pricing options in terms of increased flexibility, an office building located in Italy and equipped with a high-temperature heat pump is adopted as the case study. A heuristic profit-oriented management strategy of the heat pump is assumed, and dynamic simulations are performed. The results indicate that at current electricity prices, the heat pump operation is profitable both when supplying the heat to meet the building’s requirements and when producing surplus heat for sale to the thermal network. In addition, it is revealed that the penalties applied to the electricity purchasing price are effective in encouraging changes in the heat pump operation strategy, reducing its average production (the building increasingly relying on buying heat from the network) and the associated electricity consumption by 46.0% and 79.7% in the “light” and “severe” local power deficit scenarios, respectively.

Drying processes in porous materials and their optimization are of interest in research and in many industrial applications. X-ray micro-computed tomography presents a versatile instrument for the ...

Following the 2015 Paris Agreement and other agreements which have been signed after, sustainable energy development is becoming the major goal in many countries. EU have set the targets to reduce the annual greenhouse gas emission by 40% in 2030 and 80% for 2050 compared with 1990 levels. For achieving this ambitious energy policy, three major technological changes are available: energy savings on the demand side, efficiency improvements in the energy production, and replacement of fossil fuels by various sources of renewable energy. Also, for realization cited three major technological changes the support of the multi-disciplinary scientific knowledge is needed. Therefore, from the beginning of the 21st century, since 2002, a series of Sustainable Development of Energy, Water and Environment Systems (SDEWES) Conferences were founded. This paper presents an overview of published researches in special issues of leading journals dedicated to the series SDEWES Conferences, including also the papers in current special issue. The focus is on five main fields: (1) energy policy and analysis of smart energy systems; (2) energy savings in the building sector; (3) co/polygeneration - integrated heating, cooling and electricity systems and district heating; (4) biomass for energy; and (5) measurement of energo-environmental sustainability of processes and systems. Researchers are focused on the development of methods, policies and technologies for both efficient production of energy, mainly from renewable sources, and consumption in industry, buildings and transport. Undoubtedly, the researches presented in the papers in this special issue as well as in previous ones, dedicated to SDEWES conferences, will contribute to the promotion of sustainable development and thus to the achievement of the goals of the Paris Agreement.

Il cambiamento climatico sta diventando un argomento sempre più pressante per governi e attori economici ed è evidente come le attività umane siano una delle sue principali cause; a sua volta, esso si ripercuote su molteplici aspetti della vita umana. Per mitigare gli effetti delle attività umane sul clima e sviluppare un buon grado di resilienza ai cambiamenti climatici, molteplici iniziative sono state sviluppate. La ricerca riportata in questa tesi si propone di fornire agli attori impegnati nello sviluppo di tali politiche una metodologia da sfruttare nella redazione dei loro piani di adattamento climatico e mitigazione. Nello sviluppo dei piani di adattamento la corretta analisi dei dati climatici storici è fondamentale. Di conseguenza in questa ricerca è stata sviluppata una metodologia che include l’analisi della qualità del dato climatico grezzo, come utilizzarlo nel dimensionamento degli impianti (con focus specifico su quelli di raffrescamento) e come creare dati di input affidabili per le simulazioni energetiche degli edifici. L’analisi, applicata al territorio italiano, ha evidenziato una buona qualità del dato climatico rilevato in Italia ed ha portato ad una revisione della Norma EN ISO 15927-2 per la selezione dei Giorni di Progetto Estivi. Infine è stato generato il Test Reference Year (TRY), un anno fittizio capace di rappresentare il clima di un periodo analizzato, per la località di Trieste. Allo stesso modo anche l’analisi del cambiamento climatico risulta fondamentale nella stesura di politiche di adattamento e mitigazione ed è stata affrontata nel presente lavoro. Partendo dalla valutazione delle prestazioni dei modelli climatici, passando poi alla loro correzione per renderli più affidabili nelle proiezioni, fino al loro utilizzo per analisi sul clima futuro. In particolare sono stati sfruttati per lo studio dell’evoluzione dei fenomeni termici estremi e per la proiezione nel futuro del dato climatico attuale. Le analisi hanno evidenziato difficoltà dei modelli nella proiezione di alcuni parametri climatici che hanno portato quindi alla correzione dei modelli stessi. Lo studio sul clima futuro si è focalizzato sull’evoluzione di ondate di calore e di gelo per la località di Trieste evidenziando una tendenza all’incremento per le prime ed alla diminuzione per le seconde. Infine il TRY di Trieste è stato proiettato nel futuro usando vari modelli climatici, evidenziando grandi differenze tra le varie proiezioni, comunque tutte generalmente tendenti ad un riscaldamento del clima. Vista la natura storica del patrimonio edilizio italiano, spesso non vi è la possibilità di intervenire esternamente sull’involucro degli edifici, essendo le facciate vincolate artisticamente. In Italia assumono quindi importanza le tecniche di isolamento interno; risulta quindi importante verificare l’affidabilità di queste tecniche. Sono state quindi effettuate analisi CFD sul comportamento dei sistemi di isolamento interno per pareti. Queste hanno evidenziato come trascurare l’effetto dei montanti di sostegno del pacchetto stesso porti a rilevanti errori nella valutazione delle performance del sistema. Data l’incertezza riguardante molti degli aspetti che influenzano le prestazioni energetiche degli edifici, clima in primis, risulta importante considerare questo aspetto nell’esecuzione delle analisi energetiche. Sono state quindi eseguite delle ottimizzazioni sui processi di riqualificazione energetica di un edificio in funzione dell’incertezza dei fattori d’analisi. Considerando molteplici obiettivi da conseguire e diversi parametri stocastici, tra cui il dato climatico, l’analisi ha evidenziato come sia importante considerare la variabilità dei parametri inclusi nelle analisi, con particolare riguardo alle condizioni ambientali in cui i manufatti si troveranno nel futuro. Climate change is becoming an increasingly pressing issue for governments and economic actors and it is evident that human activities are one of its main causes; in turn, it affects many aspects of human life. To mitigate the effects of human activities on the climate and develop a good degree of resilience to climate change, multiple initiatives have been developed. The research reported in this thesis aims to provide to the actors involved in the development of such policies a methodology to be exploited when drafting their climate adaptation and mitigation plans. Starting from the needs highlighted by the Municipalities participating in the SECAP projects, the research was then focused on some main topics. When developing adaptation plans, the correct analysis of historical climate data is essential. Consequently, in this research a methodology including the analysis of raw climatic data quality, how to use it in the sizing of the plants (with specific focus on the cooling ones) and how to create reliable input data for the energy simulations of buildings was carried on. The analysis, applied to the Italian territory, highlighted a good quality of the climatic data detected in Italy and led to a revision of the EN ISO 15927-2 standard for the selection of Cooling Design Days. Finally, the Test Reference Year (TRY), a fictitious year capable of representing the climate of an analyzed period, was generated for the location of Trieste. In the same way, also the analysis of climate change is fundamental in drafting the adaptation and mitigation policies and has been addressed in this work. Starting from the evaluation of the performance of climate models, then moving on to their correction to make them more reliable in the projections, and then how to use them for analysis on the future climate. In particular, they have been exploited for the study of the evolution of extreme thermal phenomena and for the projection of the current climatic data into the future. The analysis revealed difficulties of the models in the projection of some climatic parameters, which therefore led to the correction of the models. The study on the future climate focused on the evolution of heat waves and cold spells for the location of Trieste, highlighting an increasing trend for the formers and decreasing for the latters. Finally, the TRY of Trieste was projected into the future using various climate models, highlighting great differences between the various projections, however all generally tending to a warming of the climate. Given the historical nature of the Italian building stock, it is often not possible to intervene externally on the building envelope, because of the facades being artistically bound. Therefore in Italy internal insulation techniques have great importance; it is therefore important to verify the reliability of these techniques. CFD analysis were then carried out to study the behavior of internal insulation systems for walls. The principal result was that neglecting the effect of the supporting studs of the package leads to significant errors in the evaluation of system performance. Given the uncertainty regarding many of the aspects that affect the energy performance of buildings, climate first, it is important to consider this aspect when performing energy analysis. Optimizations were then performed on the energy requalification processes of a building considering the uncertainty of the analysis factors. Considering multiple optimization objectives and various stochastic parameters, including climatic data, the analysis highlighted the importance to consider the variability of the parameters included in the computation, with particular regard to the environmental conditions in which the artifacts will work in the future.

An analytical model for predicting the competitive evaporation of two and three sessile drops is proposed, based on an analytical solution, in terms of Mehler functions, of the steady species and energy conservation equations for the gaseous phase. The assessment through a comparison with accurate numerical solutions of the species conservation equations is reported in order to quantify the accuracy of the analytical solution. The model is validated against three available sets of experiments on two and three sessile drops on a line array. The decrease of the evaporation rate caused by the vicinity of sessile drops is reported in terms of a screening coefficient given by a relatively simple analytical expression. The influence of wall wettability on the evaporation of pairs of sessile drops is analyzed, and a parameter is proposed to quantify the effect of geometry in a unified way.

The “Most Easy, Efficient and Low Cost Geothermal Systems for Retrofitting Civil and Historical Buildings” (GEO4CIVHIC) project aims to accelerate the deployment of shallow geothermal systems for heating and cooling purposes when retrofitting existing and historical buildings. Analyzing the implementation process of borehole heat exchangers (BHEs), allows the understanding of how to promote the long-term sustainability of shallow geothermal energy systems. The thermal interference between BHE systems represents a problem, especially due to the increasing deployment of this technology and its spread in densely built-up areas. The main goals of this paper are: a) to analyze the design phase of a BHE system in order to prevent mutual thermal interference, b) to propose a model that encloses phases to adopt an integrated approach for preventing long term thermal interferences, c) to give technical and management suggestions to minimize thermal interference between closed-loop geothermal systems. The method developed follows the following steps: 1) literature review to determine what are the main drivers for thermal interference between shallow geothermal systems, in the context of the GEO4CIVHIC project case study sites; 2) to create a conceptual model to limit thermal interference at both design and operational phases; 3) to apply the developed method to real and virtual case studies in countries with different regulatory frameworks and to test its main strengths and weaknesses. The application of this conceptual model to specific case studies provides evidence of critical planning and operational characteristics of GSHP systems and allows the identification of measures to mitigate impacts of thermal interference to be identified.

An analytical evaporation model for multi-component spherical and spheroidal drops, based on the analytical solution of the Stefan–Maxwell equations is proposed to study the multi-component steady diffusion in the gas phase. A comparison with the ‘classical’ approach based on the Fick’s law is reported for three families of liquid mixtures, namely alkanes, alcohols and water solutions of alcohols under a wide range of operating conditions. The local vapour fluxes of each vaporising species on the drop surface are correlated with the local Gaussian curvature. The effects of drop shape and of the modelling of constitutive equations on the evaporation rates are discussed. Comparison of the present model with experimental measurements of different compositions of tetradecane–hexadecane drops vaporising in stagnant air shows a rather satisfactory agreement.

A previously developed model for mono-component droplet evaporation is revisited using new mathematical tools for its analysis. The analysis is based on steady-state mass, momentum, and energy balance equations for the vapor and air mixture surrounding a droplet. The previously obtained solution to these equations was based on the assumption that the parameter ε (proportional to the squared ratio of the diffusion coefficient and droplet radius) is equal to zero. The analysis presented in the paper is based on the method of integral manifolds, and it allowed us to present the droplet evaporation rate as the sum of the evaporation rate predicted by the model based on the assumption that [Formula: see text] and the correction proportional to ε. The correction is shown to be particularly important in the case of small water and methanol droplets (diameters less than 5 μm) evaporating in air at low pressure (0.1 atm.). In this case, this correction could reach 35% of the original evaporation rate. In the case of evaporation of relatively large droplets (with radii more than 10 μm) in air at atmospheric and higher pressures, these corrections are shown to be small (less than [Formula: see text] of the evaporation rate predicted by the model based on the assumption that [Formula: see text]).

The large size of a glazed component allows greater access to natural light inside and a wider view of the outdoors while protecting the inside from extreme weather conditions. However, glazed components make buildings energy inefficient compared to opaque components if not designed suitably, and sometimes they create glare discomforts too. In order to protect against excessive natural light and direct sunlight and for privacy, dynamic shading devices are integrated into the glazed façade. In this study, the impact of various glazing and shading design parameters has been investigated by performing uncertainty and sensitivity analyses. The uncertainty analysis indicates that the variance coefficients for the source energy use, lighting energy use, useful daylight illuminance (UDI), and shade-deployed time fraction are in the ranges of 15.04–30.47, 39.05–45.06, 40.57–49.92, and 19.35–52%, respectively. The dispersion in the energy and indoor visual performance is evident by the large variation in the source energy consumption and UDI (500–2000), which vary in the ranges of 250–450 kWh/(m2-year) and 5–90%. Furthermore, a sensitivity analysis identified the window-to-wall ratio (WWR), aspect ratio (ASR), glazing type (Gt), absorptance of the wall (Aw), and shade transmittance (ST) as major influences of the parameters. Each of the identified parameters has a different proportionate impact depending on the façade orientation and performance parameters.

The increasing freshwater demand is pushing the development and adoption of desalination technologies. In this framework, electrodialysis has a consolidated role in brackish water desalination, but to make it competitive with other technologies for the desalination of more concentrated solutions (e.g., seawater), the specific energy consumption should be reduced. Exergy analysis provides a useful tool for determining the contribution of each thermodynamic inefficiencies on the process efficiency and the specific energy consumption. In this regard, this paper presents an exergy analysis of the electrodialysis process. A 1-D model is used for evaluating the performance of industrial-scale systems, consisting of a single or a double-stage configuration, and fed by brackish water, concentrated brackish water, or seawater. The analysis is devoted to quantifying the effects of irreversibility sources, focusing especially on the non-ideal membrane behavior. Results highlight that the ohmic resistance of solutions and membranes along with undesired transport phenomena play a major role. More specifically, passing from an “ideal” to a “real” process, the maximum value of the exergy efficiency decreases by about 6% in the case of brackish water and 16% in the case of seawater. Besides, results reveal that the water permeability of membranes is detrimental to the exergy efficiency, leading to an 8% reduction in the case of seawater desalination. The development of improved membranes with low resistances slightly enhances the exergy efficiency with negligible influence on the performance of the system. The adoption of the double-stage strongly reduces the specific exergy consumption, and in the second stage, the exergy destruction due to uncontrolled mixing phenomena becomes more important than the one caused by the membrane resistance. The results shed a light on the main actions to be undertaken by industries and engineers for improving the performance of electrodialysis systems.

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.

Social houses built after the Second World War to accommodate workers and low-income families represent one of the major energy consumers and greenhouse gas emitters in the residential sector. Plans for their renovation are underway in all European countries, and the process is more complicated for Italian cities due to the lack of space and the large number of historical buildings. This study addresses this challenge by proposing a methodology to renovate a low-income district in the city of Venice using CityBES to model and evaluate energy conservation measures. CityBES is a web-based tool that allows users to employ urban building energy modeling for large-scale energy and retrofit analyses of building stocks. In the case study conducted for Venice's Santa Marta district, due to the particular context, four common energy conservation measures covering both the building envelope and heat generation boilers have been applied. The evaluation of energy-saving performances at the district level showed that the four measures together achieved 67% energy savings, an abatement in energy cost equal to 67%, and annual carbon dioxide emissions reduction of 1.1 MtCO2. The case study demonstrates a method and workflow replicable for energy retrofit analysis of building stocks in other historical districts.