Nearly-zero Energy Research Articles

Multi-pronged strategies for enhancing building envelopes toward nearly-zero energy in hot climatic regions

Abstract Growing concerns about climate change and rising energy demands necessitate advancements in building energy efficiency. This study investigates the effectiveness of radiative coatings and thermal insulation, both individually and combined, in reducing energy consumption and carbon footprint for buildings in hot and humid climates. This research contributes to a growing body of knowledge by comprehensively evaluating the combined effects of these strategies. A comparative analysis was conducted using data on energy usage and carbon emissions.
The research highlights the effectiveness of envelope-enhancing techniques in reducing energy consumption and carbon emissions. The application of radiative coating led to a significant 13.1% decrease in energy usage, totaling 681.95 MWh, and corresponding emissions of 482.14 tons of CO2. Radiative coating offers the most cost-effective solution with an LCOS of $0.045/kWh. When integrating thermal insulation with radiative coating, there was a substantial 12.0% reduction in energy consumption, amounting to 690.39 MWh, and emissions of 488.11 tons of CO2. The integrated model provides significant energy savings at a slightly higher LCOS of $0.052/kWh, making it a balanced choice between efficiency and cost-effectiveness compared to using thermal insulation alone. Moreover, the study emphasizes that the combination of Glazing Integrated Photovoltaic (GIPV) with radiative coating can lead to the creation of nearly zero-energy buildings, resulting in a significant energy savings of 34.9%. These results underscore the efficacy of these technologies in achieving significant energy savings and environmental benefits.
This study demonstrates that radiative coatings significantly reduce energy consumption and carbon footprints. The combined method with thermal insulation reduces energy, suggesting further optimization strategies in hot and humid conditions. The results of this investigation recommend utilizing Glazing Integrated Photovoltaic (GIPV) to achieve nearly zero-energy buildings. Such integrated solutions not only improve energy efficiency but also make a substantial contribution to environmental sustainability in the building sector.

Analysis of synergistic influence of multi-scale design parameters on nearly-zero energy office blocks performance based on architectural morphological classification and parametric modeling

Analysis of synergistic influence of multi-scale design parameters on nearly-zero energy office blocks performance based on architectural morphological classification and parametric modeling

Determining Payback Period and Comparing Two Small-Scale Vertical Axis Wind Turbines Installed at the Top of Residential Buildings

In recent years, residential buildings have seen a notable increase in energy consumption. To address this, it is crucial for researchers to invest in renewable energy technologies, aiming to develop highly sustainable and nearly-zero energy buildings. Many countries are started to commit to this goal, seeking to phase out fossil fuels due to their harmful environmental effects. Wind energy stands out as a promising renewable resource, especially in areas with strong wind patterns. This study focuses on a case in Karaburun, Izmir province, Türkiye, where annual wind speeds range from 6 to 8 m/s and evaluates the performance of two types of small-scale Vertical Axis Wind Turbines (VAWTs) in reducing energy consumption in a three-story residential building, along with associated costs. Utilizing advanced simulation tools like ANSYS Fluent and DesignBuilder Software, the study examines Ice-Wind VAWTs and Savonius VAWTs. The findings reveal that installing 15 Ice-Wind VAWTs on the building's roof can reduce energy consumption by approximately 22.5%, with each turbine costing about $2000 and a payback period of around 14.57 years. Conversely, using 15 Savonius VAWTs can reduce energy consumption by 36%, with each turbine costing about $2300 and a payback period of around 8.93 years. These results indicate that the Savonius turbine offers a faster return on investment compared to the Ice-Wind turbine under the specified conditions. Overall, this study highlights the significant benefits and cost implications of integrating renewable energy solutions like VAWTs into residential buildings.

Optimal allocation of multiple energy storage in the integrated energy system of a coastal nearly zero energy community considering energy storage priorities

Energy storage technologies play a vital role in the low-carbon transition of the building energy sector. However, integrating multiple energy storage (MES) into integrated energy system (IES) in high-demand coastal communities remains a challenging task. This study proposes a novel regional IES that incorporates batteries, compressed air energy storage, and thermal energy storage for the simulated coastal community in Hong Kong; then developed the multi-objective optimization considering matching, economic, and environmental performance on MES capacity allocation with specially consideration of three energy management strategies under different energy storage priorities. The results show that all three storage priorities perform favorable outcomes across all objectives; compared to a reference scenario without storage, they achieve a relative net present value (NPVr) over 40 million HKD, a 0.29 improvement in matching performance, and over 2600 tCO2 in carbon emission reduction. Moreover, the renewable energy consumption rate exceeds 90 %, and the annual electricity import demand reduction rate exceeds 50 %. Sensitivity analysis highlights that larger energy storage capacities do not necessarily yield better outcomes, emphasizing the importance of synergistic interactions among multiple storage technologies. The presented energy system with MES and the optimal allocation approach herein may provide valuable insights for future energy planning in nearly-zero energy communities.

Hygrothermal Performance of Prefabricated Insulation Elements for Serial Renovation of Apartment Buildings in a Moderately Continental German Climate

The reduction of energy use in the buildings is expected to be reached by fulfilling several requirements of the low- and nearly-zero energy buildings (nZEB) policy. The improvement of the energy performance of the building envelope and the service systems of the existing buildings offers great potential for energy savings as the annual replacement of the existing stock is only 1 to 2%. The efficient way to accomplish the purpose and global goals of the nZEB is to apply the integrated design process, development, and application of prefabricated insulation elements on a large scale. In this project, in the Berlin area of Germany, prefabricated timber frame insulation elements were designed for the external insulation of the envelope of the apartment building in the serial renovation process, with the thermal transmittance of the external envelope U external-wall = 0.14–0.16 W/(m2·K). In the current study, the potential hygrothermal risks and their effect on highly insulated multi-story apartment building envelope were analyzed. The study contained a set of hygrothermal analyses to ensure the moisture safety of highly insulated facade structures and the selection of materials from the perspective of hygrothermal performance and low risk of degradation. This research found that the risk of mold growth is high if timber elements are installed without protective measures against drying-out built-in moisture, wind-driven rain, and other weather conditions. The initial moisture content of the external concrete slab, to be considered critical, is 90 kg/m3, and the drying out period is longer than the covered with new layers constructions can sustain if a proper vapor control layer is not added between the existing moist wall and installed insulation elements. Furthermore, the wind barrier layer with high thermal resistance and vapor permeability of the installed insulation element helps to minimize the risk of mold growth. A careful analysis and selection of materials allow to design moisture-safe timber frame insulation elements and provide low thermal transmittance of renovated building envelopes. The results showed that before the final design and installation of the insulation elements, a thorough hygrothermal analysis of the original external envelope with actual climatic conditions and moisture loads must be realized.

Straw bale construction towards nearly-zero energy building design with low carbon emission in northern China

With the aim of achieving carbon neutrality, bio-based construction is of increasing interest for decarbonization globally. Among the potential candidates, straw bale is promising due to its ready availability and energy efficiency benefits. However, thermal conductivities of straw bales can vary greatly due to construction details, which may lead to failures in meeting nearly-zero energy building (nZEB) design standards in real practice. In the context, this study applied thermal property and carbon emission assessment of full-size straw bale walls (SBWs) and construction of an experimental building in northern China. The results demonstrated that the thermal conductivities of different monitoring portions of the SBWs ranged from 0.067 to 0.088 W·m−1·K−1. This resulted in U-values (0.16 W·m−2·K−1) marginally higher than the lower limits of nZEB design, indicating the importance of addressing thermal bridging issues of SBWs. The SBWs without additional insulation layers therefore can satisfy nZEB design standards in the severe cold region after certain adjustments. Besides, when not accounting for carbon sequestration, SBWs generated the lowest emissions among the schemes in meeting U-value limits for nZEB design (at least 14.6% lower than those of timber walls), with increasing emission reductions as U-value limit decreased. The results indicated that SBW demonstrated effectiveness in carbon reductions with high thermal performance. The findings of the research can facilitate application of straw bales and development of clean construction and net-zero design in northern China.

Towards Nearly Zero-Energy Buildings: Smart Energy Management of Vehicle-to-Building (V2B) Strategy and Renewable Energy Sources

As countries worldwide strive for net-zero emissions, electric vehicles (EVs) have gained significant momentum. EVs, particularly through Vehicle-to-Everything (V2X) technology, including Vehicle-to-Building (V2B), are recognized as key enablers for achieving nearly-zero energy buildings (NZEB). This research presents an advanced Smart Energy Management System (SEMS) with a novel V2B strategy, offering precise one-hour resolution to reduce grid reliance and optimize peak load management. The SEMS coordinates building energy and EV charging while harnessing the potential of renewable energy resources and battery storage systems. By carefully scheduling EV charging and discharging activities, it maximizes the efficient use of available energy resources. Importantly, the algorithm integrates real-world EV parking patterns, accounting for factors such as fleet composition, parking durations, and charging priorities. Economic evaluation encompasses not only direct EV battery degradation costs but also external expenses associated with environmental impacts. Simulation outcomes underscore a remarkable reduction in building grid power demand (65%) and a substantial decrease in carbon emissions (64%). The PV+V2B Scenario emerges as the preferred choice, striking an optimal balance between initial investment costs, energy savings, and carbon footprint reductions. This study holds great academic and practical significance, contributing to the advancement of smart, sustainable, and economically viable net-zero cities.

Comparison of the embodied and operating energy in agricultural greenhouses and in residential buildings

The increase of the energy efficiency in buildings and greenhouses is important for reducing the use of fossil fuels and the emissions of greenhouse gases. Energy efficiency evaluation requires the consideration of both the embodied and the operational energy. Many estimations regarding the embodied and the operational energy in various types of buildings have been reported so far. However, studies regarding the embodied energy in agricultural greenhouses are rare while there are many estimations regarding their operational energy. The goal of our study is the comparison of the embodied and the operational energy in residential buildings and in agricultural greenhouses. The embodied and operational energies are compared in greenhouses as well as in low-energy and in conventional residential buildings. Our results indicate that the ratio of embodied energy to life-cycle energy in low-energy residential buildings and in nearly-zero energy buildings varies in the range at 36% to 83% that is significantly higher than the ratio in conventional residential buildings which is in the range of 6% to 20%. The ratio of embodied energy to life-cycle energy in agricultural greenhouses, at 0.86% - 70.41%, varies significantly depending on many parameters. The importance of carbon emissions related to embodied energy in low-energy buildings, in net-zero energy buildings and in agricultural greenhouses is highlighted. Our work could be useful to policy makers who are willing to accelerate the green transition to a low carbon economy in the coming decades.

The kindergarten of Crosara by Sergio Los: reassessing a pioneering thermally efficient building

ABSTRACT Given the environmental and energy crises, European directives are targeting building energy efficiency. Architects must improve the thermal performance of their designs to approach Nearly-Zero Energy Building (NZEB) standards. Energy-efficient experimental buildings from the 1970s are often held up as inspiring examples of energy-conscious architectural design. However, the lack of quantitative data about their thermal performance, measured using current evaluation standards and units, makes their legacy difficult to interpret today. This study aims to verify the relevance of 1970s energy-efficient architecture by quantifying the thermal performance of an exemplary case: the kindergarten designed by Sergio Los in Crosara (Italy). The thermal performance of the building in its original configuration is re-assessed using energy simulation software and discussed relative to past and present standards, including carbon emissions. The results quantify the contributions of different energy-conscious strategies and show that the building’s pioneering performance results primarily from the architect’s bioclimatic design decisions. The study demonstrates how architects reduced building energy demands in the 1970s and explores the impact of their strategies relative to contemporary efficiency priorities.

Evaluation of a modular construction system in accordance with the Passivhaus standard for components

Passivhaus is an energy performance standard for buildings that has been deeply analyzed in the current scientific literature. However, the study of the Passivhaus standard for components and the use of certified components in the construction of new nearly-zero energy buildings have not been thoroughly discussed. Additionally, hygrothermal performance evaluations of components in accordance with this standard have not been fully presented to the scientific community. This paper addresses this topic and aims to evaluate the hygrothermal performance of a Spanish modular construction system of extruded aluminum, in accordance with the criteria for Passivhaus components, suitable for warm temperate climate. A three-part methodology was implemented, including hygrothermal performance simulations on fourteen connection details comprising wall, roof, window, and floor solutions. The initial outcomes reveal that only four connection details fully meet the Passivhaus criteria for components. Therefore, an optimization of the connection details is proposed to validate the Passivhaus suitability of the construction system. The connection details are redesigned to reduce thermal energy losses in the junctions and to eliminate the risk of interstitial condensation. Several simulation processes are then conducted and the new results are compared against the criteria for components, validating the Passivhaus suitability. The evaluation presented in this paper provided valuable data that enabled to later optimize and submit the construction system to the Passivhaus Institut to become the first lightweight metallic construction system for walls and roofs manufactured in Spain with a Passivhaus certification for warm temperate climate.

Optimizing heating operation via GA- and ANN-based model predictive control: Concept for a real nearly-zero energy building

Using a simulation- and optimization-based framework that leverages artificial neural networks for the model predictive control of space heating operation, machine learning techniques are explored to predict the energy performance of a real nearly zero energy building located in Benevento (Southern Italy, Mediterranean climate). The framework's goal is to minimize heating energy costs and thermal discomfort by providing optimal values of setpoint temperatures on a day-ahead planning horizon based on weather forecasts. To achieve this, a Pareto multi-objective approach is applied, which considers thermal comfort via the adaptive theory of ASHRAE 55, assessing a comfort penalty function. The optimization problem is solved using a genetic algorithm in the MATLAB® environment. Objective functions are evaluated using the coupling between MATLAB® and EnergyPlus, which is used as building performance simulation tool. Multi-criteria decision-making is performed to select an optimal solution from the Pareto front while setting a limit to the comfort penalty. To test the framework, EnergyPlus weather data is used to simulate weather forecasts for typical days of the winter season. Two different economic scenarios are simulated in order to be able to analyze both conditions and given the variability of the electricity price. For the different days tested, the best results in terms of savings achieved through the proposed solution are on Feb. 28, corresponding to the coldest day and the highest energy cost, with daily savings of 26% compared to a reference control with a fixed setpoint of 21 °C, while maintaining similar comfort performance. The results suggest that optimized control is a crucial aspect of sustainable building design, and the proposed framework can be virtually implemented or integrated into automation systems for real-time model predictive control.

Development of an optimization model for decision-making in building retrofit projects using RETROSIM

ABSTRACT Nearly-zero energy buildings are standard for new constructions in the European Union. The challenge for decarbonized cities is retrofitting the existing buildings. Retrofitting the existing buildings provides considerable opportunities for improving occupants’ comfort and reducing global energy consumption and greenhouse gas emissions. Building retrofit is being considered one of the main approaches to achieve sustainability in the built environment at relatively low-cost and high-uptake rates. Although a broad range of retrofit technologies are readily available, methods to ascertain the most suitable set of retrofit actions for specific projects are still a practical challenge. This article first aims to develop and present a simulation-based multi-objective optimization model, named RETROSIM, to quantitatively assess technology choices in a building retrofit project. RETROSIM is a combination of a building energy simulation model and RETROSIM proprietary optimization engine. Secondly, in this study, RETROSIM is used to evaluate a building retrofit project as a case study to show the functionality of the proposed method. The study initiates with the single optimization of objective functions focusing on the building’s characteristics and performance: primary energy consumption, global costs and thermal discomfort hours. Then this methodology is used to study the interaction between these conflicting objectives and evaluate their trade-offs.

Evaluating BIPV Façades in a Building Envelope in Hot Districts for Enhancing Sustainable Ranking: A Saudi Arabian Perspective

Enhancing contractual construction project documents with sustainability and green building requirements reflects growing concerns for the majority of organizations in hot zone districts. The aim is to provide a healthy, best functional performance, safe environment with occupant comfort, and an efficient building performance as an environmental-friendly building. This research study develops a holistic evaluation system for the façade composite of contractual documents. The aim of the current study was to enhance building energy performance under the sustainability rating system focusing on adapting active envelope energy applications. The research used technical evaluation with energy simulation based PVsyst V7.1.0 software and contractual status evaluation for an ongoing unique case study project in Saudi Arabia. Feasibility analysis was carried out for a sustainable active envelope using the adopted specifications of the Building Integrated Photovoltaics (BIPV) façade item instead of the contractual passive item in the Giftedness and Creativity Center project. The project was registered in the sustainability rating system called Leadership in Energy and Environmental Design (LEED). The results showed that using BIPV facades as an active renewable energy source enhances building energy performance over the project life cycle. Additionally, it generates 68% of energy demand as a nearly-zero energy project. Several other advantages include lower cost than tender cost without any contractual conflicts, energy savings per year, project upgrade to the platinum certificate, added value to the public investment, CO2 emission reduction, and barrels of oil saved.

Experimental study on performance of different local radiant cooling schemes

Energy consumption from building cooling is critical for the development of nearly-zero energy building. The indoor zone control of local cooling strategy has been proposed to address this problem. In this study, the application performance of different layout scheme of local radiant cooling was experimentally investigated to explore the optimum design strategy. A series of field experiments were conducted under eight layout schemes of the local radiant cooling considered height, horizontal installation zone, and area of the radiant terminal. The obtained results indicate that in the personnel activity zone (below 2.0 m), local radiant cooling can satisfy the thermal comfort requirements of the occupant. The installation zone has an obvious influence on the room thermal characteristics, whereas the influence from the area was limited. The thermal stability and uniformity of the indoor environment can be improved by modifying the layout of the low and outer zone for the radiant terminal. Increasing the area of the radiant panel is inefficient for the improvement of room thermal characteristics and indoor thermal comfort. The main ranges of the cooling capacity are 115–125 W/m2 for different layout forms of the local radiant terminal and the cooling capacity can be increased by 7%. The layout scheme for the radiant terminal with the outer and low zone can effectively improve the stability of the terminal cooling capacity. Results suggested that the layout scheme of both outer and low zone for the local radiant terminal is crucial to improve the thermal comfort and cooling efficient.

Co-optimization method research and comprehensive benefits analysis of regional integrated energy system

The nearly-zero energy community composed of contiguously nearly-zero energy buildings can effectively reduce the operational energy consumption of buildings by adopting appropriate active and passive technologies, which is the main development direction of future buildings. However, there are few studies on the collaborative optimization of nearly-zero energy community supply systems. Therefore, a nonlinear cooperative optimization model of the regional integrated energy system with multi-region energy sharing and multi-energy storage is constructed in this paper. A two-layer collaborative optimization method is proposed, which optimizes the upper layer's renewable energy and energy storage capacity and the operation dispatching in the underlayer. Finally, the overall benefit, typical daily energy scheduling, and the energy sharing and storage impact on renewable energy utilization of the system when it supplies energy to a nearly-zero energy community are studied. The research results show that compared with the isolated integrated energy system, the supply cost, primary energy consumption, carbon emission and interactive power per unit area of the regional integrated energy system are reduced by 3.45 CNY/m2, 3.95 kWh/m2, 1.35 kg/m2 and 1.66 kWh/m2, respectively. In addition, multi-region energy sharing and multi-energy storage can effectively improve the self-consumption/sufficiency ratio of photovoltaic and wind power generation and solar thermal collector heat collection. This study provides a feasible solution for applying nearly-zero energy communities in regional integrated energy systems.

A Tripartite Evolutionary Game on Promoting the Development of Nearly-Zero Energy Consumption Buildings in China

Nearly zero-energy-consumption buildings are the inevitable trend of future buildings. There have been a large number of studies on nearly zero building technology issues. However, there is no detailed study on how to effectively promote the development of nearly zero-energy consumption buildings according to China’s national conditions. Here, by establishing an evolutionary game model, this paper discusses the dynamic game scheme selection and stability strategy of three stakeholders, namely local government, real estate companies, and construction consumers, related to the development of nearly zero-energy-consumption buildings in the development process. The conditions required for evolutionary stabilization strategies were identified. Finally, Matlab data simulation analysis is used to further illustrate the stability and equilibrium strategies of each subject and the sensitivity analysis of the main influencing factors at various stages in the development process of nearly zero-energy-consuming buildings. The research results show that the government plays a leading role in the early stage of the development of nearly zero-energy consumption buildings, and as the market matures, government intervention gradually withdraws from the market; furthermore, if the cost of supervision is prohibitively high, the government’s willingness to supervise the market will be reduced. This will hinder consumers and developers from choosing nearly zero-energy-consuming buildings and if the penalties and subsidies are too low, it will be meaningless to the evolution of the optimal solution of the three parties. On this basis, targeted promotion programs are established to realize the rapid development of China’s nearly zero-energy-consumption building sector. Our research results can provide important scientific basis for the development of the nearly zero-energy building industry in China.

Net-Zero Climate Emissions Districts: Potentials and Constraints for Social Housing in Milan

Net-zero climate districts are gaining wide attention at the European and international levels. Urban regeneration competitions have been launched recently to stimulate development; nevertheless, the literature does not yet provide a shared scope definition (i.e., product system). Using the process-based life cycle assessment method, the authors evaluate the climate profile of a new district in Milan (14 buildings with 36,000 m2 of gross surface area in total) aiming to become the first net-zero social housing project in Italy. The authors show in the results section how climate neutrality is achieved on the part of the real estate operator by varying the scope. The most conservative scenario (including all the emission sources considered in the analysis) indicates that the net-zero climate target is reached only by purchasing voluntary carbon credits. The authors also highlight: (i) a district composed of nearly-zero energy buildings is far from the definition of a net-zero climate emissions district; (ii) a net-zero climate emissions district may not be a positive energy district and vice-versa; and (iii) constraints linked with the lack of space in a densely populated city due to insufficient area to install renewables on site.

Collaborative optimization method and energy-saving, carbon-abatement potential evaluation for nearly-zero energy community supply system with different scenarios

As a typical representative of a green and low-carbon community, a nearly-zero energy community is the main development direction of future building forms. Therefore, to improve the proportion of renewable energy and reduce primary energy consumption and carbon emissions, this paper constructed a nearly-zero energy community supply system, including the battery, heat storage tank, and cold storage tank. A multi-parameter collaborative optimization model considering system design and operation was established to improve the economy, energy-saving, and carbon-abatement potential of the system. This paper took a nearly-zero energy community to study the influence of different electric vehicle numbers on typical daily energy balance, energy-saving, and carbon-abatement potential of the nearly-zero energy community supply system. The results showed that when the number of electric vehicles increased from 0 to 600, the zero energy potential, primary energy saving rate, and carbon emission reduction rate of the nearly-zero energy community supply system decreased by 6.8%, 2.6%, and 1.8%, respectively. The cost per unit supply area increased by 7.8CNY/m2, and the annual cost saving rate increased by 29.7%. The system's optimization design method and energy-saving and carbon-abatement potential evaluation result provided a valuable reference for the integrated building and transportation sector development.

Building envelope-combined phase change material and thermal insulation for energy-effective buildings during harsh summer: Simulation-based analysis

Combined phase change material (PCM) and thermal insulation is a crucial practical opportunity to improve thermal inertia and resistance for energy-effective and nearly-zero energy buildings. To this aim, the current paper quantitatively investigated the role of traditional expanded polystyrene (EPS) thermal insulation of different thicknesses to improve the thermal performance of building envelope integrated PCM under harsh summer months. The improvement in indoor temperature was studied considering the maximum indoor temperature reduction (MITR), time lag (TL), average temperature fluctuation reduction (ATFR) and average operative temperature reduction (AOTR). Thereafter, the average heat gain reduction (AHGR) was introduced to quantify the thermal enhancement of envelope elements. Simulation results revealed that building envelope integrated with PCM-EPS demonstrated better thermal performance than incorporating PCM alone. Compared with the PCM room, the indoor temperature of PCM-EPS rooms was improved by a maximum of 143 %, 177.2 %, 35 % and 8.5 % in terms of MITR, TL, ATFR and AOTR, respectively, along with enhanced envelope resistance by up to 103.8 % concerning the AHGR. Increasing EPS layer thickness by up to 2 cm has increased the PCM room thermal performance during the daytime. However, the EPS thickness of 1 cm showed better performance considering the ATFR and AOTR during full thermal cycles.

Optimizing the energy transition of social housing to renewable nearly zero-energy community: The goal of sustainability

The decarbonization of the energy industry is essential to achieve a future net-zero energy system. To maximize the capacity of citizens to contribute to the clean energy transition, sustainable energy technologies are mandatory. Accordingly, the development of nearly-zero energy districts and communities is up-to-date, and, about it, the net-zero energy goal requires a challenging combination of building design and retrofit, renewable energy sources, energy storage systems. This manuscript investigates several alternative solutions for a shared energy system, to turn a 29-building social housing district in Naples, Southern Italy, in a nearly zero-energy community. The method is quite articulated, based on various numerical approaches, applied by the cycling use of many programs, namely: DesignBuilder® for the building modeling, EnergyPlus as simulation tool, and MATLAB® as optimization engine. A sustainability index based on emissions is introduced. A first optimization is carried out to maximize the sustainability index of the energy community, with a brute-force algorithm used to investigate several design variables, that address building envelopes, energy systems, renewables, electric storage, and operation strategies, resulting in 2,224,044 solutions explored. A second multi-objective optimization is then performed on a limited number of solutions, to evaluate not only the energy-environmental aspects but also the economic ones. The analyzed solutions have a minimum sustainability level equal to 85% and it shows a suitable combination of common buildings retrofit measures. Finally,in order to be able to achieve generalizable results, possible energy and economic targets are outlined: sustainability levels of 85%, 90%, and 95% with an investment budget of up to 150–200 €/m2.