Cleaner Energy Systems最新文献

The dominant contributors to electricity consumption in existing buildings are air-conditioning and lighting systems. This study aims to optimize hybrid ventilation and daylight-linked dimming control in a subtropical high-rise office building. The objective is to reduce carbon emissions while ensuring thermal and visual comfort. These two strategies can be retrofitted in a typical curtain wall system with vertical windows without encountering any technical limitations. EnergyPlus is used to analyze the impact of these strategies on enhancing thermal comfort and illuminance while achieving electricity savings in the high-rise office building. Based on the typical meteorological year of Hong Kong, using natural ventilation in perimeter zones can reduce the energy use intensity (EUI) by 2.6 to 3.41 % for 30.09 to 34.97 % of total operating hours, depending on window-to-wall ratios (WWRs). Furthermore, daylight-linked dimming control in perimeter zones can reduce EUI by 18.91 % to 21.9 % in the HVAC portion and 8.09 % to 12.25 % in the lighting portion during 91.39 % to 98.28 % of total operating hours. Using daylighting with a high WWR helps reduce 6.31 to 9.21 % in total greenhouse gas emissions. The study also develops a logistic regression model using three climatic variables to predict the natural ventilation status. Overall, the use of daylighting greatly improves the percentage of acceptable predicted mean vote (PMV), with the greatest improvements observed in perimeter zones facing east and west on the middle floors. However, the combined application of both strategies results in a tempered improvement. The novelty of this study lies in providing guidance on suitable WWRs for implementing both strategies to achieve carbon reduction. Moreover, the significance lies in providing a quantitative assessment of how enhanced ventilation and lighting controls contribute to lower carbon emissions while improving thermal comfort.

The solar cooling system results in a variety of technologies. It is an alternative and economical technology to conventional cooling systems and is environmentally friendly. In this work, a design of a H₂O-LiBr absorption chiller driven by a double-acting collector was proposed and studied under thermo-economic, energetic, and exergetic aspects according to Bamako climatic conditions. Higher performance was reached when the generator was operated at 85 °C, a condensing temperature of 40 °C with 8 °C as the evaporation temperature of the working fluid. The annual cooling production of the system was 52.272 MWh and the annual solar energy received on the area of the double-acting collector was 138.778 MWh. The annual energy and exergy efficiencies of the system were 0.39 and 0.025, respectively. The investment cost of the system was 36.9 k€ and the cooling cost was 0.08 €/kWh. Additionally, the simple payback period is approximately 10.4 years.

The utilisation of solar water heaters (SWHs) even in sunny locations remains low. Most previous studies used assumptions or modelling and simulation software to assess the techno-economic performance of SWHs and unravel the reasons. In this study, real-life data on domestic thermosiphon SWHs, operating in the large solar resource city of Windhoek, Namibia, were used to assess the performance. A novel payback model, based on non-financial variables, was proposed. With this model, the impact on payback time of solar fraction (SF), temporal mismatch between energy supply and energy demand, and other operational factors was quantified. The results show that despite the good thermal performance, the energy savings of the SWHs were limited by the temporal mismatch between energy supply and demand.

The payback periods of the SWHs, obtained with the net-present-value (NPV) financial approach, ranged between 11.6 and 13.5 years. The predictions of the developed model agreed well with the payback periods obtained with the financial approach. Fully paid upfront SWHs provided high return on investment (8 - 11%) while loan financed SWHs had negative return on investment and their payback periods stretched beyond the lifetime of the systems.

The decision making process in the choice of domestic water heating option was also analysed. The results showed that the choice was governed by the initial cost, disadvantaging the pricey SWHs, despite their potential for high returns, but favouring the cheap to acquire yet costly to operate electric water heaters (EWHs). The preferability of SWHs increased notably when their purchase price dropped to the price which guarantees a payback time of five years.

To address the need for enhancing the efficiency and harnessing the full potential of solar energy systems, this research aims to investigate mitigating solar energy losses, thereby contributing to the global transition towards renewable energy. A major impediment to solar panel efficiency is soiling, a phenomenon that causes significant decline in performance. This review sheds light on the pronounced impact of soiling, particularly emphasizing the exacerbated effects in arid and semi-arid regions, where solar irradiance is abundant, and the untapped solar energy potential is immense. This review provides an extensive discussion on soiling by specifically building on the research gaps identified by previous reviews. The effect of soiling on the efficiency and the adoption of solar systems in conjunction with the state-of-the-art cleaning techniques that can help reduce or eliminate dirt deposition on the surface of solar panels were comprehensively discussed. This work establishes that incorporating advanced cleaning measures like electrodynamic screen into solar system design has huge potential to reduce soiling, but have high cost implications, potentially rendering these systems financially prohibitive for some individuals and contributing to the low rate of solar energy adoption. Therefore, there is a need to further research commercially viable and cost-effective solutions.

This study investigated the catalytic effect of acid activated empty palm fruit bunch ash (AAEPFBA) on the transesterification reaction of Africa pear seed oil (APSO), optimization of the process and sensitivity analysis. The AAEPFBA was synthesized from waste palm fruit bunch, and modified. The activation was best achieved by adding H₃PO₄ acid in a ratio of 1:2 (g/ml). The modification of the catalyst increased the alkaline properties and surface area and decreased the particle size and adsorption energy. The biodiesel produced was characterized and compared with standard properties for its application Comparing the three models prediction using response surface methodology (RSM), rsm-genetic algorithm (RSM-GA) and artificial neural network (ANN), the RSM-GA model values of the process variables at temperature of 61.21°C, reaction time of 3.3 h, 10.3:1 methanol/oil molar ratio, 3.16wt% catalyst concentration, and agitation speed of 320.51 rpm gave an experimental optimal yield of biodiesel of 90.1 %. In addition, the RSM, RSM-GA and ANN statistical percentage errors (SPE) are 0.64, 0.06, and 0.29, respectively with RSM-GA having the best prediction of biodiesel yield. The novel model analysis of the process variables connection weight values of MATLAB R2015a shows that the catalyst has the highest percentage (40.7 %) of relative impact on the yield of biodiesel while the methanol/oil ratio has the least percentage contribution less than 5 %. The overall result shows that the catalyst EPFBA activated with phosphoric acid presently has high potential over other catalysts in converting APSO to biodiesel, and the application of RSM-GA tool predict the require values of the variables for maximum yield of biodiesel.

A sizable amount of wastewater is produced every day. Wastewater treatment is required to safeguard the environment, human health, flora, and aquatic life. However, wastewater treatment is an expensive operation on one hand, but on the other hand, wastewater contains five to ten times the energy needed for treatment in the form of chemical energy. This energy is accessible via biological processes. Wastewater contains potential and kinetic energy in addition to chemical energy, and it can be harnessed to generate hydropower. Any country must have a central inventory of wastewater in order to harvest this energy. To harness renewable energy from wastewater sector, it is necessary to have a central database for wastewater generation with type of wastewater and its parameters. Unfortunately, Bangladesh lacks a reliable inventory of national wastewater generation, composition, and attributes that may be utilized for estimating wastewater's potential energy output. Therefore, the aim of this research is to estimate the annual total domestic and industrial wastewater output in Bangladesh and estimate its energy recovery potentials. To estimate domestic wastewater (DWW) and industrial wastewater (IWW), an income-based estimating technique and industry-based reports/literature, respectively have been used. Few novel technologies, such as up-flow anaerobic sludge blankets (UASB), anaerobic digestion (AD), and micro hydropower plants (MHP), and five scenarios using only half of the total wastewater (DWW & IWW) have been considered for estimating the energy recovery potential of wastewater. For the hydropower evaluation using MHP, the unit total head is assumed, whereas the average chemical oxygen demand (COD) has been considered for the energy potential assessment of the UASB and AD. Techno-economic analysis (TEA) steps have been also discussed. Results indicate that the expected annual output of DWW and IWW is 4874 million m³ /yr. and 452 million m³ /yr., respectively. In terms of energy potential, scenario 2 has the highest (1986 Giga watt-hour equivalent (GWh)/yr.)), followed by scenario 1 (1857 GWh/yr.), scenario 5 (1770 GWh/yr.), scenario 3 (1401 GWh/yr.), and scenario 4 (976 GWh/yr.). This rigorous research will open up new horizons by attracting the attention not only of Bangladeshi researchers, but also of the international community.

World energy consumption will grow by almost 50 % between 2018 and 2050, resulting in a 79 % increase in electricity generation over this period. In general, renewable energy has been an important source of electricity generation for several years due to its ability to produce unlimited energy. Among the renewable energies are the oceanic ones, which depend on the resources of the tidal waters and the oceans. Tides are a promising energy source, given their periodicity and predictability, using techniques of harmonic analysis or ocean modeling. The Amazon is a region with multiple sparsely distributed populations, with difficult access to energy. Renewable sources are an alternative to bring energy and development to these communities. This paper focuses on the assessment of the power of tidal currents in the Pará River Estuary (PRE, Brazilian Amazon) as an alternative source of electricity generation in the region. This estuary is characterized by particularities such as not having its own source, it has an extension of 300 km and a depth between 0 and 70 m. The methodology was based on the two-dimensional hydrodynamic model (2DH) of SisBahia. The results show the occurrence of five areas with potential for tidal energy exploitation. Power densities for these areas are in the range of 0.4–0.7 MWh/m² in a spring and neap tidal cycle. This article demonstrates the relevance of choosing parameterized quantities that do not depend on specific equipment, as well as the importance of an adequate characterization of the hydrodynamic patterns in the PRE, necessary to optimize the use of hydrokinetic energy.

Green economy has become the world's main goal of economic development in the twenty-first century. The new energy vehicle industry has developed rapidly in a green and low-carbon economy. The government has used subsidies to promote the healthy and efficient development of the new energy vehicle industry in its early development stage. However, due to information asymmetry and the correlation of interests between the government and firms, some new energy vehicle firms have fraudulent behavior to obtain government subsidies. In the face of this fraudulent phenomenon, how should the audit department take corresponding measures to avoid the audit risk of government subsidies for firms, and how can the government face the unknown nature of the development of the emerging industry? The study takes Suzhou Golden Dragon, a new energy automobile firm, as an example to analyze the impact of government subsidies on this automobile firm in recent years and explore the causes of its audit risk and corresponding countermeasures by analyzing the motive and means of its fraudulent behavior, which can play a role in improving the defects of China's government subsidy audit theory and strengthening the rigor of audit practice. By analyzing the fraudulent phenomenon, some reasonable suggestions can be given to the government to promote the healthy and benign development of China's new energy vehicle industry, which can also enrich the means of supporting the development of new industries in the early stage of the future.

In the modern era, every country work towards sustainable development with the help of effective utilization of renewable energy system. The design and planning of multi-renewable energy system networks for Hurawalhi, Maldives, with an approximate 450.09 KW load, is proposed in this study. The first resource assessment for solar radiation, wind velocity, and the tidal range is done through linear regression and decision tree-based data analysis. Design of the system is done through the HOMER software, where the electricity production (KWh/Year) through the solar and tidal systems are 1,401,086 and 197,509, respectively. The energy generation through the proposed system is 1593.6 kWh/day (Baseline) and 2424.25 (Scaled). Cost optimization is done through the Chaotic Particle Swarm Optimization and Cuckoo Optimization techniques. Further survival measurement is done through the logrank and probit analysis.

In the present scenario of renewable energy, there is growing interest in harnessing tidal energy resources in India. Converting the energy through the tidal range into electricity has the advantages of being predictable, yet the tidal range resources of India is largely unquantified. This paper shows possible tidal energy resources at Gulf of Kutch and Gulf of Khambhat. A detailed analysis to be done through the Logistic Regression, Linear Discriminant Analysis, K-Nearest Neighbor, Naïve Bayes, Support Vector Machine. Regression analysis is used to create the relationship between power generation and tidal range for different basin areas of different location. Other methods are used for the to identify the accuracy and validation of the results. In this paper the five potential locations of Gulf of Kutch are Okha, Sikka, Rozi, Kandla and Navlakhi, on the other hand five potential locations of Gulf of Khambhat are Daman, Hazira, Bhavnagar, Pipavav and Diu. In this analysis also identify possible power generation at all the location with probable basin areas. The possible basin areas at all the locations are 5 × 10⁶ m², 7 × 10⁶ m², 10×10⁶ m², 12×10⁶ m². It is find out, in the Gulf of Kutch the maximum tidal range at Okha, Sikka, Rozi, Kandla and Navlakhi are 8.88 m, 9.41 m, 7.97 m, 8.88 m and 8.07 m respectively. In the gulf of Khambhat the maximum tidal range at Daman, Hazira, Bhavnagar, Pipavav and Diu are 8.96 m, 13.14 m, 13.33 m, 13.41 m and 11.56 m respectively.