Headnote
ABSTRACT
Objective: The objective of this study is to investigate the contrivution of computational optimization tools to energy studies applied to single-family residential buildings located in Rio de Janeiro.
Theoretical Framework: The article was based on a bibliographic survey carried out in the Scopus database of the main computational tools and their optimization tools used in thermo-energetic studies of buildings.
Method: The study evaluated the energy performance of a single-family residential building using computer simulation with the EnergyPlus tools and the JEPlus optimization interface. The construction guidelines that varied were: wall material, internal and external roof material, percentage of opening of transparent elements, solar absorptance and orientation.
Results and Discussion: The JEPlus interface made it possible to simulate 1,080 building models simultaneously. The data enabled a stratified analysis of each of the construction guidelines in terms of their influence on the building's energy consumption. The variation in parameters resulted in an impact of between 0.5% and 20% on annual energy consumption.
Research Implications: The computational tools selected resulted in reliable data, quickly and free of charge, with a sample of results significantly superior to other studies.
Originality/Value: This research has a direct impact on the construction sector by highlighting multi-platforms that can be used in studies aimed at achieving energy-efficient buildings.
Keywords: EnergyPlus, JEPlus, Energy Consumption, Efficient Buildings, Computer Simulation.
RESUMO
Objetivo: O objetivo deste estudo é investigar a contribuição de ferramentas computacionais de otimização para estudos energéticos aplicados a edificações residenciais unifamiliar localizadas no Rio de Janeiro.
Referencial Teórico: O artigo foi fundamentado em um levantamento bibliográfico realizado no banco de dados Scopus das principais ferramentas computacionais e suas ferramentas de otimização utilizadas em estudos termoenergéticos de edificações.
Método: O estudo avaliou o desempenho energético de uma edificação residencial unifamiliar pelo método de simulação computacional com as ferramentas EnergyPlus e a interface de otimização JEPlus. Foi realizado a variação das seguintes diretrizes construtivas: material da parede, material dos fechamentos internos e externos da cobertura, percentual de abertura dos elementos transparentes, absortáncia solar e orientação.
Resultados e Discussão: A interface JEPlus permitiu realizar a simulação de 1.080 modelos construtivos de forma simultánea. Os dados possibilitaram uma análise estratificada de cada uma das diretrizes construtivas quanto a sua influência no consumo de energia da edificação. A variação dos parámetros resultou em um impacto de 0,5% a 20% no consumo energético anual.
Implicações da Pesquisa: As ferramentas computacionais selecionadas resultaram em dados confiáveis, de forma ágil e gratuita, com uma amostra de resultados significativamente superior a outros estudos.
Originalidade/Valor: Esta pesquisa impacta diretamente no setor da construção civil ao evidenciar multiplataformas que podem ser utilizadas em estudos que visam alcançar edificações eficientes energeticamente.
Palavras-chave: EnergyPlus, JEPlus, Consumo de Energia, Edificações Eficientes, Simulação Computacional.
RESUMEN
Objetivo: El objetivo de este estudio es investigar la contribución de las herramientas computacionales de optimización a los estudios energéticos aplicados a edificios residenciales unifamiliares situados en Río de Janeiro.
Marco Teórico: El artículo se basó en un estudio bibliográfico realizado en la base de datos Scopus de las principales herramientas computacionales y sus herramientas de optimización utilizadas en estudios termoenergéticos de edificios.
Método: El estudio evaluó el comportamiento energético de un edificio residencial unifamiliar utilizando el método de simulación computacional con las herramientas EnergyPlus y la interfaz de optimización JEPlus. Las pautas constructivas que se variaron fueron: material de las paredes, material de la cubierta interior y exterior, porcentaje de apertura de los elementos transparentes, absorbancia solar y orientación.
Resultados y Discusión: La interfaz JEPlus permitió simular simultáneamente 1.080 modelos de edificios. Los datos permitieron realizar un análisis estratificado de cada una de las pautas constructivas en función de su influencia en el consumo energético del edificio. La variación de los parámetros se tradujo en un impacto de entre el 0,5% y el 20% en el consumo anual de energía.
Implicaciones de la investigación: Las herramientas computacionales seleccionadas permitieron obtener datos fiables, de forma rápida y gratuita, con una muestra de resultados significativamente superior a la de otros estudios.
Originalidad/Valor: Esta investigación tiene una repercusión directa en el sector de la construcción al poner de relieve las múltiples plataformas que pueden utilizarse en los estudios encaminados a conseguir edificios energéticamente eficientes.
Palabras clave: EnergyPlus, JEPlus, Consumo de Energía, Edificios Eficientes, Simulación Computacionale.
1 INTRODUCTION
Buildings are currently one of the main energy consumers, accounting for 30% of global final energy consumption and 26% of global greenhouse gas emissions (IEA, 2023). In Brazil, in 2023, energy consumption related to buildings was around 26%, 11% of which was direct and 15% was indirect, for the generation of electricity and heat (EPE, 2024). The definition of the building envelope is among the main factors that influence the energy consumption of a building (Yoshino et al ., 2017) and national and international regulations that deal with lowenergy buildings, such as ISO 52.000-1:2017 and NBR 15220-3:2005, have highlighted the importance of analyzing the building envelope in terms of the choice of materials and the use of bioclimatic strategies.
Calculation methods based on computer simulations have been developed and used in several environmental certifications. For example, Leadership in Energy and Environmental Design (LEED), the Brazilian Building Labeling Program Seal - PBE Edifica, the French certification applied to the Brazilian territory AQUA-HQE, and several others (Procel, 2006; Vanzolini, 2022) consider envelope simulation in their methodologies.
Computer simulation is superior to simplified methods (Marra et al., 2020) because it considers thermal interactions between rooms, or zones, of the same building, allowing for more refined studies. Thus, as described by Meester ef al. (2013), this method results in greater precision and agility when compared to others. This is why the simulation method remains the most recommended for energy certification studies (Silva et al ., 2013; Zara et al. , 2018).
In the study by Pacheco (2013), 49 simulations were carried out in three stages for two typical cities aiming at reducing energy consumption. Brasileiro et al. (2023) analyzed, through 16 parametric combinations, the thermal influence of frames on the envelope of a hypothetical building in the INI-R classification. Souza et al. (2022) evaluated the implementation of thermal insulation on the roof of a single-family building in São Paulo, in a total of 62 simulations, varying the type and absorptance of the roof, based on the guidelines of NBR 15.575: 2021.
In comparing the studies and assessing the range of results, some questions were raised: What is the importance of computational optimization tools in energy studies of buildings? What programs have been used in recent years for professional and academic energy studies? What is the relevance of the results obtained by these tools? With this resource, is it possible to perform an individualized assessment of the construction guidelines of a building envelope?
The main objective of this work is to answer the questions raised by identifying the main computational tools available for thermoenergetic studies of buildings in an optimized way, using computational simulation to analyze the energy performance of a single-family residential building, focusing on the construction guidelines of the building envelope.
2 THEORETICAL FRAMEWORK
2.1 COMPUTATIONAL TOOLS FOR ENERGY STUDIES
The survey of the main analysis tools was carried out through a systematic review of the existing literature. The research was carried out in the Scopus database , due to its large number of publications related to the topic. The research was carried out on 03/29/2025, delimited by the combination of the following search terms: "simulation tools", "energy building" and "construction materials".
The sample resulted in 158 publications from 2020 to 2025. The publications ranged from scientific journal articles, conference papers, books, and book chapters. The abstracts of all documents were read to identify the tools currently being used. In 79 of the 158 abstracts read, computational tools were not directly mentioned, as their texts focused on concepts rather than specific tools, were other bibliographic reviews, or simply did not mention the computational program used. In the remaining documents, one or more tools were identified and all computational programs used were scored and are presented in Table 1.
Several computational tools have been developed over the years by companies and research laboratories. However, despite the large number of programs available, it is possible to observe that some tools are more commonly used.
The main programs mentioned, EnergyPlus , DesignBuilder , TRNSYS (TRaNsient SYstem Simulation, in English), eQUEST, Green Building Studio , stood out for being programs that differ in modeling visualization, report generation and interoperability with other interfaces, but all perform energy analyses for buildings (DOE2, 2018; TRNSYS, 2019; Pimentel et al ., 2020; Magni et al ., 2021).
Similar to the classification presented in this research, other academic studies have identified that EnergyPlus , developed by the National Renewable Energy Laboratory (NREL), is the most widely used energy simulation tool in building energy studies. It allows the evaluation of energy consumption considering thermal loads, lighting, materials, among other parameters (Rodrigues and Carlo, 2017; Bender et al ., 2019).
EnergyPlus ' authority in the energy sector, this program presents a challenge for its users: simulations are run individually and, when it is necessary to modify some characteristic of the building, new simulation rounds are performed manually. Due to this, in order to enable the evaluation of several scenarios with simulations occurring simultaneously, the JEPLus interface was developed. This energy simulation parameterization tool allows the selection of different design variables that, when combined, result in several models, allowing the evaluator to define the best solution for their analysis (Zhang, 2012, Leitzke et al ., 2020).
National and international research has already used this combination of tools. Therefore, this study will use the EnergyPlus program in combination with the JEPlus interface to carry out a case study focused on the parameterization of building envelope materials (Quevedo et al ., 2020; Es-sakali et al ., 2025).
3 METHODOLOGY
The evaluation carried out in the article consisted of seven stages: (1) selection of computational tools to be applied in this study; (2) definition and modeling of the building in the computational environment; (3) parameterization of the envelope components; (4) computational simulations; (5) stratified analysis of the adopted parameters; (6) construction guidelines for reducing the consumption of thermal loads within the adopted premises; and (7) final considerations with limitations and generalities obtained with this study.
3.1 DEFINITION OF THE OBJECT OF STUDY
The case study was carried out using a standard single-family residential building plan, according to the area defined by NBR 12721:2006, shown in the images in Figure 1. The building was modeled in 3D in the SketchUp 2017 program, with the Euclid 0.9.3 plugin. The file with the .idf extension was exported and used for the thermoenergetic parameterization performed in the EnergyPlus 8.7 program.
The building was simulated and located in the city of Rio de Janeiro/RJ, a city representative of bioclimatic zone 4A of NBR 15.220: 2024. The climate file used was in TRY format, a version compiled and updated in 2005 by the Laboratory of Energy Efficiency of Buildings (LabEEE) and made available on its website (LabEEE, 2005).
3.2 CHARACTERIZATION OF THE STUDY OBJECT
This study surveyed the main materials and construction systems used in this construction topology in the national market, with the aim of associating them with bioclimatic strategies, aiming to reduce energy consumption through the combination of materials and strategies. Currently in Brazil, the most commonly used materials for walls are concrete blocks and ceramic blocks (Santa Odila, 2024), while roofs are made of different types of tiles: ceramic, fiber cement, and metal (Calil and Molina, 2010). For internal ceiling closures, the most common materials are exposed slabs that are only treated with paint, or the use of plaster, wood, and polyvinyl chloride (PVC) linings (Diedrich, 2018). Table 2 shows the materials used in the simulation scenarios, indicating their main thermal properties.
Technical manuals and Brazilian standards indicate geometric guidelines for reference models according to the corresponding bioclimatic zone, such as ranges of percentages of openings of transparent elements and solar absorptance (ABNT, 2021; LabEEE, 2022) . The recommended ranges were considered and the percentage of transparent elements between 17 and 23% was used, varying every 3%. For solar absorptance, the range between 0.2 and 0.6 was considered, corresponding to light colors (white, ivory...) and darker colors (red, blue...). The orientation of the building was evaluated for the four directions, positioning the building at 0°, 90°, 180° and 270° from the North. The modeling used the occupancy patterns of the environments and the internal loads similar to those defined in NBR 15.575:2021 .
3.3 ENERGY SIMULATION
The specifications were entered into the Energy Plus idf file and the definition of the best envelope compositions, in terms of electrical energy, was carried out with the aid of the JEPlus program . The combinatorial analysis of all the defined parameters was carried out in the JEPlus program . The configurations made in the program according to each parameter are presented in Table 3. The thermal energy model of the building was parameterized in order to include the use of ideal thermal load in the simulation. The output variables of JEPlus were: annual consumption of electrical energy for cooling and heating.
4 RESULTS AND DISCUSSIONS
4.1 ENERGY CONSUMPTION OF SIMULATED COMBINATIONS
The simulations considered the thermal loads for cooling and heating of extended stay environments (APP). According to NBR 15.575:2021, the calculation for thermal load must consider the condition of the environment without the use of natural ventilation, with a setpoint temperature of 23°C for cooling and 21°C for heating, with activation associated with the occupation of APPs.
Figure 2 shows the results of the simulations with the thermal loads resulting from the 1080 scenarios developed by combining the construction systems and strategies. The annual thermal load showed a difference of almost 30% between the minimum and maximum results, indicating that the different construction guidelines applied to this study are relevant for defining the energy consumption of residential buildings in Rio de Janeiro. In order to understand the parameters that had the greatest influence on the annual thermal load, a stratified analysis of the simulation variables was performed.
4.2 STRATIFIED ANALYSIS OF BUILDING PARAMETERS
The study of the influence of the selected construction parameters (type of wall, roof, window openings, etc.) may raise some questions, such as: are there parameters that interfere more in the energy demand and should be highlighted in the design phase, while other parameters have a lesser influence on the final result? Is the individual selection of these construction guidelines advantageous or do they only have low energy consumption when implemented together? In order to answer these and other questions, an analysis by set of parameters is presented below. The evaluation divided the total of 1,080 combinations into groups. Each group is identified by a different color in the graphs and the results are presented in Figure 3.
Two wall models were selected for parameterization: ceramic and concrete blocks. With these four variables, two groups of 540 construction models each were obtained. In Figure 3(a), it is possible to see that the change in wall material had little impact on the different cities. On average, the values varied by 0.2%, showing the proximity of the energy performance of these construction systems to the city of Rio de Janeiro.
The evaluation of roof tiles also showed little variation, as can be seen in Figure 3(b) because, in relative values, the models with ceramic tiles were approximately 0.05% lower than those with fiber cement. The models with metal tiles, which had an average variation of 0.50% in relation to the ceramic tile, generally had higher consumption, but in some cases lower consumption than ceramic.
The modification of elements for the internal closure of the roofs presented a significant variation in the thermal load, as can be seen in Figure 3(c). The models with low-conductivity and thinner materials (wood, PVC and plaster linings) presented an average variation of 2% between them, but when compared with the material with the highest thermal conductivity (the concrete slab), the difference reached 20%. The sensitivity of the choice of the internal closure element is proven in the research by Bavaresco ef al. (2022), in which the absence of these elements in bioclimatic zones with higher temperatures, as in the case of bioclimatic zone 8, resulted in an increase in thermal load of more than 110% in relation to a reference model.
As shown in Figure 3(d), the typology using the lowest percentage of window openings in relation to the floor area of the APPs showed the lowest consumption in thermal load. And the energy gain from the models with the lowest to the highest percentage of openings was on average 3%. This same fact also occurred in other studies that highlighted that this strategy should be considered carefully, as reducing the number of windows can reduce energy consumption, but contribute to a reduction in ventilation and natural lighting inside the building. These items should then be evaluated in future studies (Quevedo ef al ., 2020).
As seen in Figure 3(e), the models with the lowest solar absorptance value, i.e., surfaces in lighter colors, presented a lower consumption of thermal loads, with a reduction of approximately 15% in annual consumption compared to those with darker colors. This value is consistent with other studies, such as that of Cruz ef al. (2020), which evaluated the construction performance of buildings located in bioclimatic zone 8 in terms of wall and roof materials. And the modification of the absorptance reduced more than 30% of the thermal load and also the maximum operating temperature. These data indicate the relevance of choosing the solar absorptance.
The assessment of the building orientation shown in Figure 3(f) identified a variation in results of 3 to 10% in energy consumption. The orientation with the lowest consumption was the orientation at 90° North and the one with the highest consumption was 180° North. Benincá et al. (2023) emphasize that for the southern hemisphere, the west facade may demand a greater thermal load for cooling, especially in the bedrooms, which are the environments occupied in the late afternoon and at night. This assessment is consistent with the present case study, since the configuration with the highest consumption was the one in which the two bedrooms and the living room face the west facade. While the one with the lowest consumption is facing the south facade, which receives less heat throughout the day. The objective of the study was not to evaluate changes in the distribution of environments defined by the architecture. However, it is possible to identify that this architectural configuration is relevant and changes in the distribution of environments have a strong impact on the thermal load demand of the room.
4.3 BUILDING WITH LOWER ENERGY CONSUMPTION IN THERMAL COMFORT
This analysis made it possible to see the potential of the construction elements for Rio de Janeiro. The groups that presented the lowest values of thermal load for cooling and heating were in agreement with the lowest consumption models in the global analysis.
The stratified assessment, already used in other studies such as Quevedo et al . (2020), allows for the individual identification of the weight of variations in the selected construction components. As demonstrated, some parameters presented irrelevant variations, being less than 1%, as in the case of walls and tiles. Other construction modifications, such as the orientation and the percentage of openings for transparent elements, presented an intermediate influence, varying from 3 to 10% of the thermal load value required for user comfort. However, the consideration of other items, such as the absorptivity of the materials and the selection of the internal roof closure material, presented a greater interference, with values of 15 and 20%, respectively.
In view of this, it 1s possible to identify that there are elements of the building envelope that can have a more relevant impact on the energy consumption of a building located in Rio de Janeiro, such as absorptance and internal roof closure. However, other parameters evaluated, such as the percentage of openings and orientation, require an analysis correlated with other parameters to ensure their application.
Considering that, according to NBR 15.220-3:2024, Rio de Janeiro is categorized as a city representative of its bioclimatic zone, it is possible to state that cities belonging to zone 4A must make use of these strategies that reduce heat gain and favor the cooling of the environment.
In summary, as perceived in the stratified analysis and in the result of the global assessment, the composition of the building envelope suggested as having the best energy performance due to being the lowest consumption model is shown in Table 4.
Based on the results obtained, it is possible to state that computational tools applied to energy studies have significant impacts, since when parameterized according to technical references, they allow replicating construction patterns and simulating behaviors that approximate reality.
Several programs have been developed and refined in recent years. This work demonstrated the application of the EnergyPlus and JEPlus tools. The combination of both presented relevant results through a significant sample of data that can be used to guide the characterization of a building in the design phase, especially in the definition of the envelope of a building that aims to reduce energy consumption.
5 CONCLUSIONS
This study focused on the use of computational simulation tools, a methodology consolidated by current regulations and calculation methods for sustainable building certifications. The selected platforms were EnergyPlus and JEPlus. EnergyPlus was used to dimension energy generation consumption, while JEP/us was used to optimize the analyses.
The sample obtained in the results allowed us to attest to the relevance of these tools, especially for evaluating the performance of a building's construction guidelines. The JEPlus tool allowed us to perform a large number of combinations - 1,080 simultaneous combinations - Without the need to create individual models for data collection. This tool allows the execution ofup to 10,000 simulations in parallel; however, this limitation was not an obstacle for this case study, since the number of combinations simulated simultaneously was lower than that.
Thus, the study was able to prove some generic premises, such as that the use of low thermal conductivity roof coverings, light-colored materials that have low solar absorptivity values, and orientation that avoids direct solar radiation in environments where prolonged periods of time are spent in the afternoon are relevant strategies for single-family buildings located in Rio de Janeiro. However, other aspects raised, such as the percentage of openings in transparent elements and the choice of roofing materials, should be evaluated in conjunction with other guidelines that can enhance or nullify their results.
The assessment of user thermal comfort was performed only for cooling and heating thermal loads. This study did not evaluate how the suggested interferences affect the use of ventilation and natural lighting, since the focus was on energy consumption with mechanical air conditioning. However, in future studies, these conditions can be evaluated. In addition, other strategies recommended in bibliographic references, such as the insertion of shading devices and modification of glass type, can be included in future research.
The data presented were evaluated for Rio de Janeiro/RJ, a city with a typical tropical climate. Because of this, the results can only be generalized to cities with similar climatic characteristics. Due to this, despite identifying possibilities for evolution in energy studies, this research concludes by showing that the current tools and regulations available are capable of generating efficient buildings with materials available in the Brazilian construction market.
ACKNOWLEDGMENTS
The study was supported by the Rio de Janeiro Research Foundation (FAPERJ), under the Basic Research Assistance Program (APQ1). The authors would like to thank FAPERJ and UFF for their support throughout the development of this research.
References
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