Annual Energy Consumption Research Articles

Application of Non-Parametric and Forecasting Models for the Sustainable Development of Energy Resources in Brazil

To achieve Sustainable Development Goal 7 (SDG7) and improve energy management efficiency, it is essential to develop models and methods to forecast and enhance the process accurately. These tools are crucial in shaping the national policymakers’ strategies and planning decisions. This study utilizes data envelopment analysis (DEA) and bootstrap computational methods to evaluate Brazil’s energy efficiency from 2004 to 2023. Additionally, it compares seasonal autoregressive integrated moving average (SARIMA) models and autoregressive integrated moving average (ARIMA) forecasting models to predict the variables’ trends for 2030. One significant contribution of this study is the development of a methodology to assess Brazil’s energy efficiency, considering environmental and economic factors to formulate results. These results can help create policies to make SDG7 a reality and advance Brazil’s energy strategies. According to the study results, the annual energy consumption rate is projected to increase by an average of 2.1% by 2030, which is accompanied by a trend of GDP growth. By utilizing existing technologies in the country, it is possible to reduce electricity consumption costs by an average of 30.58% while still maintaining the same GDP value. This demonstrates that sustainable development and adopting alternatives to minimize the increase in energy consumption can substantially impact Brazil’s energy sector, improving process efficiency and the profitability of the Brazilian industry.

The design and control of heat-integrated EDWC processes for the separation of THF/IPA/water

Extractive dividing wall columns (EDWC) and heat integration are effective process intensification strategies for separating azeotropes. In this study, the steady-state and dynamic control for the separation of tetrahydrofuran/isopropanol/water using a combination of EDWC and heat integration with intermediate reboilers are systematically investigated. The feasibility of the extractive distillation process is evaluated by analyzing the thermodynamic characteristics of the mixture through phase diagrams, and the three-column extractive distillation (TCED) process is established as the basic process. To enhance the energy and economic efficiencies, as well as environmental sustainability, three improved processes are proposed. Compared with TCED, the optimal process (E-EDWC-HI2) reduces the total annual costs, energy consumption, and CO2 emissions by 22.35 %, 41.77 %, and 26.28 %, respectively. In addition, a dynamic control structure is proposed for the E-EDWC-HI2, which exhibits robustness against disturbances in the feed flow rate and composition. This study provides guidance for the design and dynamic control of complex distillation processes.

Investigating the Heterogeneity Effects of Urban Morphology on Building Energy Consumption from a Spatio-Temporal Perspective Using Old Residential Buildings on a University Campus

The significant increase in building energy consumption poses a major challenge to environmental sustainability. In this process, urban morphology plays a pivotal role in shaping building energy consumption. However, its impact may exhibit latent heterogeneity due to differences in temporal resolution and spatial scales. For urban energy planning and energy consumption modeling, it is crucial to pinpoint when and where urban morphology parameters matter, an overlooked aspect in prior research. This study quantitatively explores this heterogeneity, utilizing a detailed dataset from old residential buildings within a university campus. Spatial lag models were employed for cross-modeling across various temporal and spatial dimensions. The results show that annual and seasonal spatial regression models perform best within a 150 m buffer zone. However, not all significant indicators fall within this range, suggesting that blindly applying the same range to all indicators may lead to inaccurate conclusions. Moreover, significant urban morphology indicators vary in quantity, category, and directionality. The green space ratio exhibits correlations with energy consumption in annual, summer, and winter periods within buffer zones of 150 m, 50~100 m, and 100 m, respectively. It notably displays a negative correlation with annual energy consumption but a positive correlation with winter energy consumption. To address this heterogeneity, this study proposes a three-tiered framework—macro-level project decomposition, establishing a key indicator library, and energy consumption comparisons, facilitating more targeted urban energy model and energy management decisions.

Multiple machine learning models for predicting annual energy consumption and demand of office buildings in subtropical monsoon climate

Multiple machine learning models for predicting annual energy consumption and demand of office buildings in subtropical monsoon climate

Numerical analysis of rack-based data center cooling with rear door heat exchanger (RDHx): Interrelationship between thermal performance and energy efficiency

This study presents a comprehensive numerical analysis of thermal performance and energy efficiency, IT operating environment, and thermal performance of the RDHx system, a rack-based cooling solution for high-density IT power using air-cooled equipment. A 150 kW IT module and RDHx cooling system were designed and evaluated, and CFD numerical analysis confirmed that RDHx maintains a stable IT environment within ASHRAE standards at a supply air temperature of 24 °C. Additionally, the chilled water supply temperature for the secondary CDU can be increased to 14 °C, and for the primary chiller to 12 °C. A central chilled water system for a 30 MW reference data center was designed and analyzed, showing increased efficiency with a 12 °C supply temperature and varying condenser water return temperatures in winter, resulting in an annual PUEcooling range of 1.25–1.33, with an average of 1.27. The annual energy consumption distribution for rack-based cooling is approximately 46 % from chillers, 21 % from fans, and 33 % from pumps. These results provide crucial insights into data center cooling and support the application of the RDHx system in high-density data centers, with future validation involving a field mock-up test of a 150 kW IT module.

Comparative analysis of direct coupling and MPPT control in standalone PV systems for solar energy optimization to meet sustainable building energy demands

Solar energy, a prominent renewable source, has reached an installed capacity of 71.78 GW in India. This research explored the load demands of the computer center at an engineering college in Tanjore, Tamil Nadu, India. The computer center at the engineering college has an annual energy requirement of 260,552 kWh/Year. Consequently, the research focused on the planning and implementation of a standalone photovoltaic (SAPV) system, assessing it against the institution's total annual energy consumption. The performance ratio and losses of the SAPV system with both direct coupling and an MPPT charge controller was compared. This comparative analysis aimed to evaluate the efficacy of two solar photovoltaic control methods—SAPV direct coupling and Maximum Power Point Tracking control—in optimizing energy harvesting from solar panels.

Evaluating the performance of six 1970s off-gas deep retrofit bungalows

This paper presents the energy and environmental performance of whole house energy systems implemented in six 1970s bungalows in South Wales, owned by Swansea Council. The objective was to reduce energy demand and carbon emissions, maximise renewable supply whilst ensuring a comfortable and affordable home for the residents. The whole house energy system for each home involved the installation of a combination of passive and active low carbon solutions. Detailed monitoring was carried out for a year before and for more than 2 years after the work, annual figures have been validated and normalised for weather. Analysis of monitored data confirms that Standard Assessment Performance ratings improved from 12 to 95. The average annual energy consumption across the six bungalows was reduced from 16,117 to 4560 kWh. 2418 kWh was provided by the PV panels and battery, with 1963 kWh of excess electricity that could be sold back to the grid. Real-life average Ground Source Heat Pump CoP was monitored at 3.3. Embodied carbon for retrofitting each house is estimated at 22,980 KgCO2e +/−20%, approximately 5-years carbon payback. Indoor conditions have been improved with internal temperature and relative humidity achieving standards with residents reporting levels of improved comfort satisfaction. Practical Application A whole house energy system demonstrates the benefits of a holistic, fabric and systems retrofit approach. The work informs how gathering data using appropriate methods assists modelling predictions and decisions throughout the retrofit stages. The study demonstrates extensive monitoring as a vital tool to evaluate the performance of the individual components and the whole system within the home, as used by the residents. Performance evaluation is critical in identifying issues, allowing resolutions to be made both immediately on-site as well for longer term, follow on retrofit programmes. Real-life performance evaluation and visualisation methods are transferable across global building industry.

A comparative analysis of the carbon footprint in green building materials: a case study of Norway.

This paper critically examines the carbon cycle and environmental impacts associated with building materials, encompassing diverse impact categories for both midpoint and endpoint scenarios. The research encompasses a comparative analysis of five distinct scenarios, contrasting the environmental performance of green against conventional counterparts. Notably, previous research endeavors did not investigate the effects of varying percentages with and without phase change materials (PCM). The primary objective is to assess the impact of integrating phase change materials (PCM) with varying percentages of fly ash (20% and 35%) on energy consumption and carbon emissions, particularly in cold climates like Norway. The study employs the ReCiPe2016 Midpoint (E) method, which offers a robust life cycle assessment (LCA) framework aligned with European standards, making it particularly suitable for this context. Energy Plus, within the Design Builder software, was used to simulate and calculate the impact of PCM on energy efficiency. The findings underscore those environmental impacts attributed to green buildings amount to 9.79 × 104 kg of CO2 equivalent, while conventional buildings account for 1.04 × 105 kg of CO2 equivalent. Furthermore, among the cases studied, the optimal scenario pertains to a green building utilizing 35% wind ash cement and PCM, resulting in the equivalent of 9.68 × 104 kg of CO2 emissions. Remarkably, the best-case scenario involves a green building boasting a robust steel interior structure and aluminum windows, whereas the worst-case scenario entails a typical building devoid of PCM implementation. Furthermore, energy consumption analysis indicates that scenario 5, which utilizes PCM and 35% fly ash, achieves a 15% reduction in cooling energy and a 6.9% reduction in heating energy compared to scenario 3, resulting in an annual energy consumption of 97,453.09 kWh.

Performance of Geopolymer Insulation Bricks Synthesized from Industrial Waste

In the current work, aluminum dross from the aluminum industry and fired-clay brick waste (Homra) were combined with alkaline activators (Na2SiO3/NaOH) with varying molarities of NaOH to create insulating geopolymer bricks. An alkaline activator with an (S/L) ratio of 3/1 was combined with Homra to replace it partly. The mixture was then molded into 50 × 50 × 50 mm3 stainless steel molds. Water absorption, compressive strength, bulk density, and apparent porosity of the produced geopolymer were measured at various curing durations and NaOH molarities. The findings showed that adding more aluminum dross waste replacement leads to a decrease in bulk density and compressive strength and an increase in the creation of pores that improve the produced bricks’ ability to insulate against heat. Using 8 M of NaOH after 28 days, the findings revealed that 3% aluminum dross waste replacement has a compressive strength of about 8.6 MPa, water absorption of 14.6%, bulk density of 1.307 g/cm3, and thermal conductivity of 0.32 W/m·K. The Egyptian standard, ASTM C62, satisfies these outcomes. Using DesignBuilder energy simulation software version 6.1.06, the constructed insulating brick under ideal circumstances was utilized to calculate its contribution performance in energy consumption. The annual energy consumption was reduced by about 21% compared to traditional hollow cement bricks.

Energy Efficiency and Sustainability in Food Retail Buildings: Introducing a Novel Assessment Framework

One of the primary global objectives is to decrease building energy consumption to promote energy efficiency and environmental sustainability. The large-scale food retail trade sector accounts for over 15% of total primary energy consumption in Europe, posing a significant challenge to the transition towards green energy. This study proposes a simple method for energy efficiency, environmental sustainability, and cost-saving assessment and improvement in large-scale food retail trade buildings. It aims to analyze the energy and environmental performance of building–plant systems, establishing an interactive network to assess intervention potential for the energy transition. The investigation focuses on the proper selection and analysis of the benefits of retrofit solution implementation, emphasizing potential energy savings in current and future climate change scenarios. Dynamic simulation with the Building Energy Model (BEM) was used to evaluate the impacts of building–plant system retrofit solutions, such as high thermal insulation, photovoltaic (PV) panels, Light Emitting Diode (LED) installation, waste heat recovery, and improvement in refrigeration units. The results show a reduction in annual energy consumption for the PV panel installation by up to 29% and lighting systems with high-quality LED to 60%. Additionally, CO2 emissions can be decreased by up to 41% by combining these two strategies.

The effect of window proportions in low-rise residential buildings on annual energy consumption in humid temperate climate (case study: Rasht city in Iran)

The effect of window proportions in low-rise residential buildings on annual energy consumption in humid temperate climate (case study: Rasht city in Iran)

BIM and orthogonal test methods to optimize the energy consumption of green buildings

The construction industry’s rapid growth significantly impacts energy consumption and environmental health. It is crucial to develop optimization strategies to enhance green building energy efficiency and encompass comprehensive analysis methods. This study aims to introduce and validate a novel framework for optimizing energy efficiency design in green buildings by integrating Building Information Modeling (BIM) technology, Life Cycle Cost (LCC) analysis, and orthogonal testing methods, focusing on enhancing energy efficiency and reducing life cycle costs. The optimization parameters for the building envelope are identified by analyzing energy consumption components and key green building factors. The orthogonal testing method was applied to streamline design options. Building Energy Consumption Simulation (BECS) software and LCC analysis tools were employed to calculate each optimized option’s total annual energy consumption and the current life cycle costs. Using the efficiency coefficient method, each optimization scheme’s energy consumption and economic indicators were thoroughly analyzed. The framework’s validity and applicability were confirmed through an empirical analysis of a campus green building case in Fujian Province, demonstrating that the optimized framework could reduce energy consumption by 4.85 kWh/m2 per year and lower costs by 38.89 Yuan/m2 compared to the reference building. The case study highlights the framework’s significant benefits in enhancing environmental performance and economic gains. The results provide critical parameter selection and offer scientific and technological support for the design of building energy efficiency, promoting optimization techniques and sustainable development within the construction industry.

Evaluating energy retrofit strategies in enhancing operational performance of mosques: A case study of Al-Imam Al-Hussein Mosque

Mosques are unique in terms of architectural design and operational efficiency. Architectural Design, building envelope characteristics, intermittent operating schedules, and occupancy patterns all impact the performance. Managing these factors poses challenges regarding reducing energy consumption and simultaneously achieving the occupants' thermal and visual comfort, especially in hot, arid climatic conditions. Also, the potential benefits of daylighting in reducing energy consumption in mosque buildings need to be addressed. Accordingly, this study evaluates the impact of various retrofit strategies on the operational performance of Al-Imam Al-Hussein Mosque, one of the large historic mosques in Cairo, considering the energy performance, thermal comfort, and daylighting performance. The current performance of the mosque has been analyzed using energy simulation software to determine the areas that affect its performance. Hence, five retrofitting strategies have been studied to assess their impact on improving the performance of the mosque. When changes are applied to the building envelope only by changing the glazing type, the visual discomfort is improved while sufficient daylighting is maintained inside the prayer area. By adding a cooling system and applying changes to the building envelope, thermal comfort was improved, and the visual discomfort decreased. However, this has led to an increase in energy consumption. Combining different strategies (as in strategy 5) by changing the glazing type, changing the operation scheme, adding LED lamps with dimmers, and adding a cooling system has improved the defined performance metrics. It has achieved a 23% decrease in the annual energy consumption, decreasing the visual discomfort by 30% while maintaining sufficient daylighting conditions inside the space, and enhancing occupants’ thermal comfort by 65%. The proposed approach aids in evaluating the retrofit strategies of mosque buildings, considering different criteria, including daylighting performance, to be energy efficient, sustainable, and maintain occupants’ visual and thermal comfort.

Evaluating Synergies between Electric Vehicles and Photovoltaics: A Comparative Study of Urban Environments

Electric vehicles (EVs) and photovoltaics (PVs) are expected to be broadly adopted in future power systems. However, the temporal variability of EV load and PV production presents challenges for integrating them into the power grid. This study evaluates and assesses the synergies between EVs and PV systems to maximize solar energy utilization for EV load coverage. The configurations studied include EV charging via the national grid as a reference case (Case 1) and two solar energy harvesting options: EVs powered directly by vehicle-mounted PVs (Case 2) and EV chargers connected to residential PV installations (Case 3). These cases are evaluated across different urban environments with large EV fleets and dissimilar weather conditions: Berlin and Los Angeles. A customized operation profile based on the worldwide harmonized light-duty test cycle (WLTC) and a charge-right-away (CRA) strategy is used. Energy performance analysis is conducted through dynamic simulations using the Modelica language, with environmental and economic indices derived. Key findings highlight the superior performance of residential PV systems in both cities compared to current solar EV technologies, with both solutions offering significant benefits over the reference case. Cases 2 and 3 result in a 44% and 59% reduction in annual energy consumption, greenhouse gas emissions, and charging costs in Berlin, while in Los Angeles, the reductions are 67% and 98%. The average daily solar driving range reaches 20.3% in Berlin and 30.4% in Los Angeles.

Heat-integrated extractive distillation for separating tetrahydrofuran/methanol/water with ionic liquid-based mixed entrainer: Molecular mechanism and process integration

Tetrahydrofuran (THF) and methanol (MeOH) are commonly used raw materials and reagents in the chemical industry, but the azeotropic phenomenon between the two components makes it challenging to achieve high-purity separation. This study separated THF/MeOH/H2O mixtures by heat-integrated extractive distillation using an ionic liquid-based mixed entrainer (ILME). The dimethyl sulfoxide (DMSO) was determined by relative volatility analysis, and IL [EMIM][AC] was screened from 240 ionic liquids according to the COSMOtherm 2021 software. The separation mechanism was investigated at the molecular level (i.e., IGM analysis, polarisation charge density (σ-profile), electrostatic potential (ESP), interaction energy, and quantum chemical theory), which demonstrated that the rationality and strength of the interaction between the entrainer and the separated system were conducive for the separation to proceed. Single DMSO, ILME indirect extractive distillation (IED) and direct extractive distillation (DED) were designed and optimized, and further heat-integrated optimization (HI-DED) was performed on the ILME direct extractive distillation process. The results showed that HI-DED reduced the average annual total energy consumption, energy utilization and CO2 emissions by 23.23%, 26.24% and 26.24%, respectively, compared to the conventional direct extraction distillation process. The HI-DED process using ILME significantly reduces economic, energy consumption and CO2 emissions compared to conventional extractive distillation and has great potential for industrial applications.

Impact of control strategies on energy consumption in cold storage facilities

The fast development of global cold chains has led to a rapid increase in cold storage facilities capacity, in which consumes substantial amounts of energy. However, limited research has been conducted on the energy consumed by cold storage facilities, and the time and economic costs of obtaining long-term measurements of annual energy consumption of cold storage facilities are high. Therefore, in this study, short-term field tests and simulations were combined to establish a transient thermal network model for cold storage, using a specific cold storage case study for validation. The model considers the structure of the hall, which strongly impacts the cooling load. The refrigeration system performance was analyzed on the measured data. Literature and field research have shown temperature range control to be the baseline control strategy used in cold storage refrigeration systems, which ensures that the cold storage temperature remains within the set temperature range at all times. In addition, some researchers have proposed a control strategy based on time-of-use tariff that provides cooling almost throughout the valley period. These two control strategies were applied to frozen and chilled rooms, separately; the results indicated that for both frozen and chilled rooms, the latter control strategy consumes slightly less energy than the former strategy. However, the electricity bill for the latter control strategy are 0.35 and 0.5 times lower than those for the former strategy for frozen rooms and chilled rooms, respectively.

Supervised learning based iterative learning control platform for optimal HVAC start-stop in a real building context

In comparison to commonly employed iterative learning controls and reinforced learning techniques in model predictive controls for buildings, a supervised learning based iterative learning control platform that is more suitable and computationally efficient for real-world applications is proposed. The proposed control system relies on a data-driven model and utilizes the Random Forest algorithm to develop an HVAC start-stop model; this model considers only a limited system history period that can influence the current state, thus avoiding prolonged learning periods and time-consuming exploration. Specifically, within the current timeframe, the HVAC start-stop model learns from daily errors, and start and stop times “labeled as adjusted” accordingly.The proposed platform was validated against the TRNSYS baseline of a research facility, which was meticulously calibrated with actual measurements. In comparison with the convention, the proposed approach yielded significant energy savings of 6.5–7.6 % in HVAC annual energy consumption, while maintaining temperature comfort for approximately 97–98 % of the annual operating days. Notably, by implementing supply air volume ramp-up in conjunction with HVAC optimal start control, temperature comfort for up to 99 % of the annual operating days was achieved, along with a notable 9.7 % reduction in HVAC annual energy consumption.

A comprehensive review of biofuel utilization for household cooking in developing countries: Economic and environmental impacts

The global energy consumption for household cooking is substantial, comprising approximately 90 % of total household energy usage worldwide. Research indicates that in 2002, food-related energy consumption averaged 340 million BTU (approximately 359 million J) per person. With the current global population exceeding 7 billion, this translates to an estimated annual energy consumption for cooking of 2.380×1018 BTU (2.519 ×1021 J). A significant portion of this energy is derived from the combustion of firewood, contributing to deforestation, CO2 emissions, and the release of toxic gases, which in turn, exacerbates environmental pollution and poses health risks. Household cooking, heating, and lighting activities in developing countries account for about 58 % of the black carbon emissions globally. Recognizing clean cooking as a crucial solution to mitigate climate change, there is growing interest in utilizing biomass as a source for biofuels and bioenergy. The comparative diminishing in greenhouse gas emissions from renewable fuels compared to conventional fossil fuels, along with the sustainable nature of these technological advancements, has spurred increased research into biofuel technology. To address energy poverty, achieve the Sustainable Development Goals, and align with the goals of the Paris Agreement, comprehensive and expedited efforts are needed to expand and enhance access to clean cooking solutions. Consequently, this article explores the potential of biofuels as viable alternatives to conventional fossil fuels for household cooking, focusing on their economic and environmental implications.

A PM2.5 pollution-level adaptive air filtration system based on elastic filters for reducing energy consumption

Exacerbated by human activities and natural events, air pollution poses severe health risks, requiring effective control measures to ensure healthy living environments. Traditional filtration systems that employ high-efficiency particulate air (HEPA) filters are capable of effectively removing particulate matter (PM) in indoor environments. However, these systems often work without considering the fluctuations in air pollution levels, leading to high energy consumption. This study proposed a novel PM2.5 pollution-level adaptive air filtration system that combined elastic thermoplastic polyurethane (TPU) filters and an Internet of Things (IoT) system. The developed system can effectively adjust its filtration performance (i.e., pressure drop and PM2.5 filtration efficiency) in response to real-time air quality conditions by mechanically altering the structures of TPU filters. Furthermore, while operating in varied pollution conditions, the proposed system demonstrated remarkable reductions in pressure drop without notably compromising the pollution control capability. Finally, the energy consumption of the pollution-level adaptive air filtration system was estimated when applied in mechanical ventilation systems in different cities (Hong Kong, Beijing, and Xi’an) with various pollution conditions. The results revealed that, compared to a traditional fixed system, the annual energy consumption could be reduced by up to ∼26.4 % in Hong Kong.

Achieving zero-bill for the grid-connected PV systems in Saudi Arabia governmental schools: a techno-economic analysis

Governmental schools are characterized as ideal places for installing grid-connected PV systems due to the availability of large spaces on their roofs. Schools are also characterized by their good annual load profile, in which most of the loads occur during the day, and there are no loads on nights or weekends or during summer and vacations. Moreover, in the winter, the loads drop dramatically due to the lack of air conditioning. This special annual load profile provides a relative property to government schools with regard to exporting the energy generated during off days to the general electricity grid. The main objective of this research is to attempt to design a grid-connected PV system that can balance imported and exported energy to the grid to achieve an annual zero bill based on the energy exchange tariff in Saudi Arabia. Three different schools in Buraidah City were selected for investigation. The annual energy consumption was estimated from energy bills for 3 years and compared with actual installed loads. The performance analysis was done by applying three widely used indicators: yield factor, capacity factor, and performance ratio. Also, the economic analysis was done using the life cycle analysis methodology based on the local market prices to find the levelized cost of energy (LCOE) and the payback time. The results of economic and performance analysis revealed the professionality of installing grid-connected PV systems in government schools.