Use Of Energy Systems Research Articles

Liquid flow glazing contributes to energy-efficient buildings: A review

This work gives a precise review of the researches completed on the energy conservation characteristics of liquid flow glazing. Its energy saving and environmental benefits under various design and operation conditions, contributions with renewable energy utilization, as well as application in zero energy buildings are timely explored and summarized. Its advantages lie in the reduction of thermal transmission between the indoor and outdoor environments, the beneficial thermal collection, and the tactful utilization of renewable energy. The optical and thermal properties, as well as the energy performance of liquid flow glazing were found much affected by the glazing and fluid properties, the window configuration, and the operating conditions. These are consequently linked to the degree of electricity saving, the decrease in atmospheric CO2 emission, and the shortened life cycle payback time. The integrated use of solar and geothermal energy in liquid flow glazing systems is also addressed. This leads to more practical studies on the applications in zero energy buildings, such as control, real-time monitoring, and energy management strategies of liquid flow glazing system. In essence, the development of an evaluation platform or database, with systemic classification of liquid flow glazing categories plus the corresponding graded energy saving characteristics, is deemed helpful to the building professionals in meeting the zero energy buildings development targets.

From field to table through the long way. Analyzing the global supply chain of Spanish tomato

Modern food chains are energy intensive processes, which implies environmental impacts and a dependence on non-renewable resources. Nevertheless, some studies tend to underestimate the energy use of transport by assuming some simplifications in their models or by not considering aggregate levels of analysis. Tomatoes are a key agricultural commodity, and Spain is the second largest tomato producer and exporter in Europe. This paper comparatively analyses the embodied energy associated with consumption products of the tomato food chain in Spain including the products consumed in the country and those exported to third countries, taking into account energy consumption from production to household distribution. We estimate the fluxes of raw materials and products of the whole chain combining official databases and business reports to reconstruct the location and interconnection between international, national and provincial nodes of production, processing and consumption. On the one hand, agrarian specialization concentrates production in provinces with greenhouse off-season production, which contributes significantly to the overall energy requirement. In addition, manufactured products have a high level of embodied energy, particularly in Spain's product consumption mix, which is the key factor in the chain, both in exports and in national food consumption. On the other hand, provincial productive and export specialization determines the existence of decoupling between agricultural, manufacturing and exporting clusters throughout the chain, significantly increasing energy use per unit consumed or exported by implying recirculation transport flows between provinces, which is particularly evident in exporting provinces supplying European countries. This process is neglected in previous LCA studies, leading to an underestimation of the energy cost. As a general conclusion, recirculation due to geographical specialization of different stages of the food chain has been shown to be a major contributor to energy use in the Spanish tomato chain and should be further studied in food chains of other products and countries. Additionally, approaches to lower food system energy use should not only focus on specific measures on separated phases of the food chain, but on reconfiguring its territorial organization and its modes of production and processing.

Techno-economic analysis of optimal hybrid renewable energy systems – A case study for a campus microgrid

People are becoming more aware of the benefits of renewable energy. In recent years, a lot of research deals with the use of energy systems during on-grid or off-grid conditions, however, grid-connected systems may cause a power crisis to the grid. With the addition of renewable components, it is hard for the grid to keep balance. In hybrid systems, contradiction between net present cost (NPC) and excess electricity, unmet load, and capacity shortage always appears. Excess electricity, unmet load, and capacity shortage appear when the demand and supply are unbalanced, indicating the underutilization of energy. In this paper, we aim to overcome the aforementioned contradiction by conducting a case study for the first time on the implementation of a Hybrid Renewable Energy System (HRES) for a university campus in Selangor, Malaysia. Four different designs of HRES are proposed and compared. They are the Wind-Biogas-Battery System (Design A), Wind-Biogas-PV-Battery System (Design B), Wind-Biogas-Hydrogen Module-Battery System (Design C), Wind-Biogas-Diesel Generator-Battery System (Design D). The most optimal system will be selected based on the evaluation of three main criteria, i.e., cost analysis, electricity production analysis, and gas emission analysis.

Tillage practices and mulching affect system productivity, profitability and energy use in Sesbania alley based food - fodder systems under rainfed agro-ecosystems of semi-arid tropics

Context or problemThe low soil moisture availability in post rainy season is a major constraint for double cropping in rainfed agro-ecosystems. There are also trade-offs for use of crop residue as fodder and mulching material. Objective or research questionThe objective of the study to assess the crop productivity, profitability, forage quality and energy use in Sesbania alley based food-fodder systems. We hypothesized that soil tillage practices with Sesbania mulching would increase the system productivity, profitability and forage quality in rainfed agro-ecosystems. MethodsA four-years field experiment was conducted with Sesbania alley based food-fodder systems and three tillage practices with and without mulch. ResultsThe study revealed that Sesbania + (sorghum-mustard) and Sesbania + (sorghum-barley) cropping systems being at par, recorded significantly higher system productivity (59.4 t ha–1 and 58.7 t ha–1 respectively) and economic returns (US$ 504 ha–1) compared to Sesbania + (sorghum-chickpea) system (52.3 t ha–1). All the tillage practices, viz., conventional tillage in both the season (64.1 t ha−1); minimum tillage in rainy followed by zero tillage in winter season (63.5 t ha−1); and conventional tillage in rainy followed by zero tillage in winter season (60.1 t ha−1) with Sesbania mulching (SM), being at par, recorded significantly higher system productivity than their respective treatments without mulching. Sesbania mulching with all the above three tillage systems recorded 14.5%, 12.6% and 5.9% more net returns over their respective tillage practices without mulch, respectively. Among cropping systems, Sesbania + (sorghum-barley) was found most energy efficient which is at par with Sesbania + (sorghum-barley) but 28.2% higher over Sesbania + (sorghum-chickpea). The crude protein content of sorghum was 5–8% higher in Sesbania + (sorghum – chickpea) in comparison to other two cropping systems. ConclusionsOverall, innovative Sesbania alley based rainfed food-fodder system under reduced tillage and mulching improved system productivity, profitability, forage quality and energy use. Implications or significanceThe double cropping can be possible without compromising fodder needs if farmers used proper tillage and mulching practice in Sesbania alley based cropping systems.

Bayesian Optimization-Based LSTM for Short-Term Heating Load Forecasting

With the increase in population and the progress of industrialization, the rational use of energy in heating systems has become a research topic for many scholars. The accurate prediction of heat load in heating systems provides us with a scientific solution. Due to the complexity and difficulty of heat load forecasting in heating systems, this paper proposes a short-term heat load forecasting method based on a Bayesian algorithm-optimized long- and short-term memory network (BO-LSTM). The moving average data smoothing method is used to eliminate noise from the data. Pearson’s correlation analysis is used to determine the inputs to the model. Finally, the outdoor temperature and heat load of the previous period are selected as inputs to the model. The root mean square error (RMSE) is used as the main evaluation index, and the mean absolute error (MAE), mean bias error (MBE), and coefficient of determination (R2) are used as auxiliary evaluation indexes. It was found that the RMSE of the asynchronous length model decreased, proving the general practicability of the method. In conclusion, the proposed prediction method is simple and universal.

From assessment to a decision: a global framework for the management of energy use in wastewater systems

A global framework to assess the energy use and efficiency in wastewater systems is presented, focusing on the development of a portfolio of energy use improvement measures specifically tailored to these systems. The framework includes a performance assessment system for energy efficiency in wastewater systems and an energy balance scheme. The development and analysis of the portfolio of measures included the following steps: (i) an extensive review and compilation of existing energy improvement measures on the urban water cycle, (ii) a tailored survey addressed to multidisciplinary teams of wastewater utilities, (iii) the consolidation of the portfolio of measures for wastewater systems with the identification of main benefits and drawbacks of each measure and (iv) the discussion of the application of the improvement measures. Results from the survey for the different assessed dimensions (e.g., priority, importance) of each measure are presented together with a specific analysis of wastewater utilities. The final portfolio is instrumental for utilities to select measures, decide on the priority ones and prepare an implementation plan.

Multi-objective optimal control of multi-zone VAV systems for adaptive switching between normal and pandemic modes

The recent COVID-19 pandemic has highlighted the need to adapt the control of building HVAC systems to limit disease transmission in indoor environments. However, such operational adjustments may significantly increase energy use, creating a complex trade-off problem between infection risk mitigation and energy efficiency. Moreover, practical constraints, such as maintaining comfortable temperature and humidity levels for occupants and limited system equipment capacity, can limit the flexibility of operational adjustments, further exacerbating the challenge of finding optimal operational solutions. This paper therefore proposes an optimal control strategy for multi-zone VAV systems that adapts to switching between normal and pandemic modes. The strategy considers dual optimization objectives: minimizing system energy use and disease transmission risk, while also considering all practical constraints. Optimal operational parameters can be determined to achieve the best trade-off between these objectives based on pandemic conditions. Additionally, a new metric called “effective fresh air factor” is proposed to quantify the impact of multi-zone VAV systems on disease transmission in building zones. The effectiveness of the proposed strategy is evaluated in a simulated building and air-conditioning environment. Results show that the VAV system has superior ability to reduce transmission risk through operational adjustments, achieving a decrease in disease transmission risk by 25%–75% compared to normal operation.

Thermoeconomic and life cycle assessments for a trigeneration system: A case study

ABSTRACT The current need to diversify the global energy matrix implies introducing renewable energy sources and evaluating commercially available solutions. This study assesses a trigeneration system from thermoeconomic and environmental viewpoints, employing the Theory of Exergy Cost and Life Cycle Assessment. The location of the theoretical study case is the state of Pernambuco, Northeast Brazil. The trigeneration system operates on biogas and is comprised of four subsystems: biogas purification, molted carbon fuel cell, combined cycle, and absorption refrigeration system. The energy services produced are electricity, heat (hot water), and cooling. The results of the thermoeconomic analysis revealed that the energy system requires an electricity tariff of at least US$ 106.76/MWh to generate revenue due to the high costs associated with the purchase of biogas and capital costs of the equipment for biogas purification and fuel cell. The life cycle assessment identified that the biogas purification step presented the highest environmental impacts due to the material composition of the absorption and regeneration columns, which is interesting as this is the most critical step of the process. LCA results indicate that although methane is a vital energy vector for energy transition, further studies are required on the technical and environmental aspects of its use in energy systems.

SqueezeNet for the forecasting of the energy demand using a combined version of the sewing training-based optimization algorithm

With the introduction of various loads and dispersed production units to the system in recent years, the significance of precise forecasting for short, long, and medium loads have already been recognized. It is important to analyze the power system’s performance in real-time and the appropriate response to changes in the electric load to make the best use of energy systems. Electric load forecasting for a long period in the time domain enables energy producers to increase grid stability, reduce equipment failures and production unit outages, and guarantee the dependability of electricity output. In this study, SqueezeNet is first used to obtain the required power demand forecast at the user end. The structure of the SqueezeNet is then enhanced using a customized version of the Sewing Training-Based Optimizer. A comparison between the results of the suggested method and those of some other published techniques is then implemented after the method has been applied to a typical case study with three different types of demands-short, long, and medium-term. A time window has been set up to collect the objective and input data from the customer at intervals of 20 min, allowing for highly effective neural network training. The results showed that the proposed method with 0.48, 0.49, and 0.53 MSE for Forecasting the short-term, medium-term, and long-term electricity provided the best results with the highest accuracy. The outcomes show that employing the suggested technique is a viable option for energy consumption forecasting.

Energy recovery in a commercial building using pico-hydropower turbines: An Australian case study

Optimising energy use in systems and buildings is crucial to reduce climate change. This paper aims to address the gap in knowledge for pico-hydropower (<5 kW) that has been identified as an area of untapped potential in the water industries. A literature review and multivariate analysis are used to find a suitable pico-hydro turbine to install into a coral reef aquarium system in a government owned facility. Key findings from the literature review are untapped potential, gaps in knowledge and global quantification of small hydropower for energy recovery, and lack of enabling data contributing to slow uptake of small hydropower. The study showed a propeller pico-hydropower turbine could be used to recover approximately 10% of the energy used for pumping water through a filtration system. At 2.3 m available head, and 90 L/s water flow, power output up to 1.124 kW was achieved. The project was economically viable with financial and non-financial benefits for the life cycle of the product. There remain sparse case studies for energy recovery using small hydropower in the scientific literature. A growing number of authors see the potential of this renewable energy technology to reduce global greenhouse gas emissions and contribute to the UN Sustainable Development Goals to provide affordable clean energy and address climate change. This study helps to shine a light on opportunities to find value from waste using a novel application of hydropower in a water industry.

Energy Balance Assessment in Agricultural Systems; An Approach to Diversification

The energy in agricultural systems is two-fold: transformation and utilization. The assessment and proper use of energy in agricultural systems is important to achieve economic benefits and overall sustainability. Therefore, this study was conducted to evaluate the energy balance of crop and livestock production, net energy ratio (NER), and water use efficiency (WUE) of crops of a selected farm in Sri Lanka using the life cycle assessment (LCA) approach. In order to assess the diversification, 18 crops and 5 livestock types were used. The data were obtained from farm records, personal contacts, and previously published literature. Accordingly, the energy balance in crop production and livestock production was −316.87 GJ ha−1 Year−1 and 758.73 GJ Year−1, respectively. The energy related WUE of crop production was 31.35 MJ m−3. The total energy balance of the farm was 736.2 GJ Year−1. The results show a negative energy balance in crop production indicating an efficient production system, while a comparatively higher energy loss was shown from the livestock sector. The procedure followed in this study can be used to assess the energy balance of diversified agricultural systems, which is important for agricultural sustainability. This can be further developed to assess the carbon footprint in agricultural systems.

Energy use and energy efficiency in cruise ship hotel systems in a Nordic climate

In light of climate change, the shipping industry is committed to reducing its greenhouse gas emissions. When transitioning from fossil fuels to low-carbon fuels, it is crucial to also reduce the ships' energy need. For cruise ships, the hotel system is a major energy consumer and the focus of this paper. This study aims to investigate the energy use of an existing fossil-fuelled cruise ship operating in a Nordic climate, and evaluate the effectiveness of various passive and active energy-saving measures. For this purpose, a dynamic energy model of the hotel system was developed in the building simulation tool IDA Indoor Climate and Energy (IDA ICE), including a customised weather file. Validation of the model was achieved through comparison with literature and some operational data from the actual cruise ship. Simulation results showed a total annual energy use of 55 MWh/passenger, with the hotel system accounting for 20%. The passive measures, such as increased insulation and improved windows, each resulted in less than a 1% reduction in the hotel's annual energy use. Larger energy savings were achieved by using heat pumps (38%), improved ventilation system (8–24%), and heating setback in port and during the night (5%). A hot water storage tank, charged with the engines' waste heat during sea operation, could reduce the use of auxiliary boilers, especially in port. A hot water tank of 600 m3 could cover 97% of the heating demand in port, thereby minimising the use of fuel-fired boilers.

Cutting time & height improve carbon and energy use efficiency of the forage–food dual-purpose ratoon rice cropping

Forage–food dual-purpose ratoon rice cropping (FFRR) is used to balance forage demands with ratoon rice grain yields, that is whole plant (stem and sheath, panicles) cuttings in the main season are used as forage, and rice in the regeneration season is used as food. In this study, the local ratoon rice production system as the control, we were carried out the field experiment of cultivation practices (cutting time and cutting height), and investigated the system productivity, economic benefits, carbon footprints and energy use efficiency. The energy use efficiency, energy productivity and energy profitability increased with cutting time delay, and cutting height decreased. Significant differences of these index were observed among the treatments for cutting time and cutting height (p < 0.05). Carbon efficiency and carbon sustainability index was increase with cutting time delay, and there was significant difference among the treatment of cutting time in 2018 (p < 0.05), the minimum carbon footprint of FFRR was 78.6 kgCO2 t−1 averagely at the cutting time of 30 days after the flowering stage. In 2018, the maximum net income of FFRR was 30,577 CNY hm−2 at a cutting time of 30 days after the flowering stage while the stubble height was 10 cm, and dependent on the forage yield of the main crop; in 2019, the maximum net income of FFRR was 27,326 CNY hm−2 at a cutting time of 10 days after the flowering stage while the stubble height was 10 cm, and dependent on the grain yield of the ratoon crop. Therefore, the optimal cultivation practice of the FFRR (cutting at 30 days after the flowering stage and with a stubble height of 10 cm) showed higher carbon and energy use efficiency, economic benefits of the FFRR were fluctuated with the price of forage of the main crop and rice grain of the ratoon crop.

Effect of Viral Infection on the Ultrastructural Organization of Black Currant Leaf Tissue Cells

Effect of Viral Infection on the Ultrastructural Organization of Black Currant Leaf Tissue Cells

Evaluation of Electric Ships and Considered New Design Marine Cabin Combined with Solar Power

Demands for energy saving and emission reduction, and due to the restrictions imposed by the authorities, as well as most of new designs in the maritime field is oriented towards renewable energy sources. Solar energy and energy storage systems may a solution to the pollution problems, reducing CO2, SOX and NOX emissions and improving the ship's energy efficiency. Battery technologies emerge as a promising method to increase it. In this study, the recent electric ship markets have been examined with these respects. &#x0D; Furthermore, this study has aimed presentation of considered new design Electric Battery Sea Cab which is under aware of the requirements in practical applications. We believe that the sea cab as a public transportation or barge ship with the use of renewable energy sources will save emission of the harmful gases from the sea vehicles and the amount of energy consumed. In this project, the considered cab is 14,95 meters long and 4 meters wide. Considering the average resistance value for 16 knots speed, it has examined that the motor to be used should provide approximately 200 HP power. Studies obtained the possibility to produce a public transportation vehicle that is both environmentally friendly and less costly by using renewable energy systems for sea cab. Our evaluations provide that it is inevitable that the use of photovoltaic (PV) panels with 30 times less carbon footprint compared to fuel will become wide spread and be preferred to energies that can be consumed over time. Consequently, the results of this study also service that alternative in ship technology information on the use of energy systems is provided. In addition, the new considered cab which represents showing that battery electrical ship can be achieved shall be interesting to the future focuses of the representatives of the maritime sector.

Study on the combined use of solar and water energy in power supply systems

This article discusses the development of a system for the combined use of solar and water energy based on a systematic approach to power supply. An improved physical model has been developed based on a model for predicting the production of electricity, taking into account the power and time of solar radiation, the amount and speed of water flow. At the same time, the share of electricity in the use of solar and water energy was determined simultaneously, depending on the conditions for the uninterrupted supply of consumers with the daily necessary electricity. The assessment of indicators of the combined use of solar and water energy and the definition of energy efficiency were developed by the authors on the basis of an increase in the share of electricity obtained from renewable energy sources in the electricity supply, which is explained by the coincidence of theoretical and experimental results.

Regulatory and economic challenges in the production of geothermal brine from a mature oil field

ABSTRACT The paper analyzes the technical solutions, economic feasibility and institutional aspects of geothermal energy use in a district heating system by retrofitting wells on a mature oil field based on the case study. The objective is to describe institutional procedures for brine production from the mature oil field. The research methodology includes the well data and the condition of the existing oil infrastructure analysis, to evaluate the brine production possibility. The methodology also analyzes existing hydrocarbon contracts. Institutional steps to obtain a geothermal concession on the brownfields are proposed. The hypothesis assumes that, with the legislation change, a vertical distribution of concessions for simultaneous production of oil and brine is achievable. The conclusion brings the novelty of this paper as the provision of guidelines for the development of the projects and the start of the production of brine from a mature oil field for the investors and the legal authorities.

Carbon peaks of water systems in Chinese cities under varying water demand dynamics and energy transition pathways

Decarbonization of urban water systems has been increasingly important for addressing the target of climate change mitigation. Yet, little insight has been derived regarding how water use and energy transition policies jointly alter climate impact of water systems in cities. In this study, using 21 cities in Guangdong Province (China) as a case study, we account for the carbon dioxide emissions related to energy use in urban water systems (UWSs) over 2006–2035. By constructing a city-scale water-carbon nexus model, we project future trajectories of electricity-related CO2 emissions in UWSs by considering dynamics of water demand and varying pathways of energy transition. We show that increasing need of tap water purification is a main contributor to electricity-related CO2 emissions, followed by tap water distribution and wastewater treatment. The electricity-related CO2 emissions in most cities could peak before 2030 under a fast-decarbonization energy transition pathway, despite the rise of urban water demand. Fast-urbanizing cities like Foshan, Shantou and Qingyuan may witness a 4–23% increase of emissions between 2020 and 2035. With a more rapid increase of proportion of cleaner energies in electricity mix, the fast-decarbonization pathway could end up with 21% more reduction of emissions on average during 2020–2035, compared to currently-planned energy transition pathway. Under the stringent climate goal of China, cities should foster a joint mechanism between water system and grid companies that leads to a more effective low-carbon governance of water systems.

Comparison of two hybrid renewable energy systems for a residential building based on sustainability assessment and emergy analysis

High energy consumption along with the diversity of its species in the building section is one of the most important challenges for sustainable development. The use of solar energy in multi-generation systems is a new solution that has been considered by researchers. In this study, an integrated multi-generation solar energy system with the aim of supplying the demands of fresh water, electricity and heating of a building, as a case study, in the city of St. Petersburg has been suggested. The proposed system has PVT and PTC collectors, hot water storage tanks, heat exchangers, an electrolyzer, a hydrogen storage tank and a hydrogen engine for the purpose of production, storage and consumption of hydrogen. To evaluate the environmental and economic performance of the proposed system, initially, the performance of this system was evaluated and compared based on emergy analysis in two scenarios with and without desalination unit during one year. The difference between the two scenarios is the existence of a thermal water purification system in one scenario with the aim of supplying fresh water to the building and electrolyzer. In the first step of the study, the results showed that the system in scenario of without desalination unit has better performance in the viewpoint sustainability with higher environmental sustainability index (ESI) value, more dependence on environmental resources and lower investment costs. Also, in the second step, the stability performance of the system from emergy viewpoint for scenario without desalination unit in the climatic conditions of the four cities of St. Petersburg, Khabarovsk, Yakutsk and Moscow were evaluated. The results showed that the integrated energy system in the scenario without desalination unit with environmental sustainability index of 1.13 in the climatic conditions of the city of Khabarovsk is environmentally and economically sustainable.

Performance evaluation and multi-criteria decision analysis of thermal energy storage integrated geothermal district heating system

Geothermal energy use in district heating systems has been prevalent and familiar in areas with rich sources for many years. In conventional geothermal district heating systems (GDHS), the geothermal fluid is transported to a heat center to give its heat energy to the secondary fluid. Then, this secondary fluid is circulated in the city network to give its heat energy to the heating circuit by the heat exchangers in the substations. Finally, the geothermal fluid is re-injected to handle the continuity of the resources. This current system works under the designed conditions of a heating system with significant electricity consumption and enormous heat waste. In this study, a thermal energy storage (TES) system was integrated into substations instead of heat exchangers to prevent the waste of heat and overconsumption of electricity by obtaining just-in-time working conditions. In this regard, a shell and tube latent heat TES system was designed for residential use for peak loads and integrated into the heating circuit of GDHS, preserving the current main structure. A number of 37 available cases were formed parametrically to evaluate the system's performance. These cases were analyzed thermodynamically by energy and exergy methods. The net present value (NPV) method was used to evaluate the cases' economics. Finally, an efficiency analysis technique with output satisficing (EATWOS) was conducted to determine the most efficient design from the viewpoints of exergy efficiency, NPV, and CO2 emissions.