Kind Of Renewable Energy Research Articles

Experimental performance of a small solar system for adsorption cooling in summer and heating in winter

Solar energy is a kind of renewable energy with abundant resources and enormous reserves. Meanwhile, adsorption cooling technology can utilize natural refrigerants, thus also making this technology environmentally friendly. If solar energy can be effectively collected and utilized for heating in winter, then the environmental pollution caused by electricity and fossil energy consumption can be reduced. More importantly, considering engineering, the same solar device could provide cooling in the summer and heating in the winter. This study used parabolic trough and glass–metal vacuum heat collectors to conduct solar adsorption cooling and solar air heating experiments in summer and winter, respectively, to facilitate the complete and appropriate use of solar energy. Experimental results of solar adsorption cooling with silica gel as the adsorbent revealed that the coefficient of performance of the system reached 0.329. In addition, the influences of air flow rates and heat storage medium on the performance of the solar air heating system were investigated. Results revealed that the average and instantaneous efficiencies of the system considerably increased with the heat storage medium (i.e., water) filling in the annular cavity of the evacuated tube. The extended heating time also markedly increased by up to 170 min and was therefore of considerable practical value.

Design of hybrid heat and power co-generation system

The energy revolution considering renewable power is indispensable and inevitable in the development of modern power industry, yet has been restricted by many practical problems. The instability of renewable energy makes the whole power generation system unable to maintain stable output, which causes fluctuations in the power grid system, and ultimately affects the user side. Also, there are few researches on hybrid heat and power co-generation system and when applied to the regional power supply, current systems converse electric energy to thermal energy to meet the heating demand of users, which reduces the energy quality. Hybrid two or more kinds of renewable energy is a way to eliminate instability of renewable energy power generation system. In this paper, a hybrid heat and power co-generation system is designed to reach both heat and power demands of users, a solar-geothermal power generation system was simulated on ASPEN PLUS platform. The output power, entropy and energy efficiency are analyzed to optimize the system. Based on the solar-geothermal power generation system, exergy analysis shows that the parallel heating and power generating system is much more efficient than the original system.

Research on Hydraulic Conversion Technology of Small Ocean Current Turbines for Low-Flow Current Energy Generation

Ocean energy is a kind of renewable energy contained in seawater, which has the characteristics of large total reserves, sustainable use, and its being green and clean. Influenced by rising oil prices and global climate change, an increasing number of countries are attaching great importance to the strategic position of ocean energy in the future energy sector, and are formulating national ocean energy development roadmaps and conducting research and development on ocean energy technologies. Ocean current energy is a widely existing kind of ocean energy with abundant reserves. However, due to the low current velocity in most of the deep sea, low current energy has not been effectively exploited. In this paper, the Blade element momentum (BEM) theory based on Vortex column theory is used to design a special airfoil for low current energy applications, and a prototype turbine with rotor diameter of 4.46 m and tip speed ratio (TSR) of 6 is fabricated. In order to achieve stable electric power output, this paper designs a hydraulic conversion power generation control system with flexible control, and the hydraulic system working pressure designed to 21 MPa. In this paper, we conducted towing experiments on the prototype of an ocean current energy turbine, with hydraulic transmission and a control power generation system applied to the low flow rate, and achieved the target of hydraulic motor speed in the range of 14.7~15.9 r/min and steady-state speed accuracy in the range of ±1%. The research conducted in this paper can provide a research basis for the efficient exploitation of low-flow ocean current energy.

Using Y-source network as a connector between turbine and network in the structure of variable speed wind turbine

Environmental factors such as air pollution and increase in global warming by using polluting fuels are the most important reasons of using renewable and clean energy that runs in global community. Wind energy is one of the most suitable and widely used kind of renewable energy which had been in consideration so well. This paper introduces an electric power generation<br />system of wind based on Y-source and improved Y-source inverter to deliver optimal electrical power to the network. This new converter is from impedance source converters family. This presented converter has more degrees of freedom to adjust voltage gain and modulation. Also, by limiting the range of simultaneous control (shooting through) while it maintains the<br />highest power of maximizer, it can operate in higher modulation range. This causes the reduce of stress in switching and thus it will improve the quality of output. Recommended system had been simulated in MATLAB/Simulink and shown results indicate accurate functionality.

Influences of Geometrical Parameters of Upstream Deflector on Performance of a H-Type Vertical Axis Marine Current Turbine

Marine current power is a kind of renewable energy that has attracted increasing attention because of its abundant reserves, high predictability, and consistency. A marine current turbine is a large rotating device that converts the kinetic energy of the marine current into mechanical energy. As a straight-bladed vertical axis marine current turbine (VAMCT) has a square or rectangular cross-section, it can thus have a larger swept area than that of horizontal axis marine current turbines (HAMCT) for a given diameter, and also have good adaptability in shallow water where the turbine size is limited by both width and depth of a channel. However, the low energy utilization efficiency of the VAMCT is the main bottleneck that restricts its application. In this paper, two-dimensional numerical simulations were performed to investigate the effectiveness of an upstream deflector on improving performance of the straight-bladed (H-type) marine current turbine. The effects of various key geometrical parameters of the deflector including position, length, and installation angle on the hydrodynamic characteristics of the VAMCT were then systematically analyzed in order to explore the mechanism underlying the interaction between the deflector and rotor of a VAMCT. As a result, the optimal combination of geometrical parameters of the deflector by which the maximum energy utilization efficiency was achieved was a 13.37% increment compared to that of the original VAMCT. The results of this work show the feasibility of the deflector as a potential choice for improving the energy harvesting performance of a VAMCT with simple structure and easy implementation.

Cracking of waste cooking oil in the presence of copper slag

Waste cooking oil (WCO) as a kind of renewable energy has yet to be fully developed and utilized. Base on the elemental composition, WCO belongs to macromolecular organic substance composed of C, H, and O, which would be cracked into reducing gas at high temperature. Using WCO as a green reductant is a meaningful attempt, and has a broad application prospect. In present, WCO was applied as a reductant for copper slag cleaning, and the WCO cracking in the presence of copper slag was studied in detail. The results showed that higher temperature was beneficial to the cracking of WCO, and iron and zinc oxide in the slag could promote cracking of WCO. The metal oxides in the slag reacted with the deposited C, leading to an increasing of CO and CO2, which improved the gas yield of WCO cracking.

Design and Simulation of a Boost-Microinverter for Optimized Photovoltaic System Performancec

Renewable energy sources are the most important type of energy since they are clean and do not affect the environment. Solar energy is a kind of renewable energy that is more popular than other sources. Photovoltaic (PV) systems use solar energy as a source of electricity. The main parts of any PV system are: PV panel, DC-DC converter with maximum power point tracking and a DC-AC inverter with an adequate control. The Photovoltaic system for this study comprises a boost converter, a full-bridge inverter and an LCL filter. The boost converter is controlled using the Maximum power point Tracking (MPPT) algorithm, while the inverter is controlled through a Sinusoidal Pulse Width Modulator (SPWM).This paper provides a comparison performance between perturbation and observation [P&O] and particle swarm optimization [PSO] algorithms to get MPP for PV system. When the irradiance changes, the micro-inverter adapts under partial conditions. The micro-inverter is designed by MATLAB / Simulink/2020a software. The input maximum voltage from the PV is 80V direct current (DC) while alternating current [Ac] output voltage is 110 Vrms. The output voltage and current total harmonic distortion (THD) ratios are 2.58% and 2.76% respectively when the P&O algorithm is used , while that when using the PSO algorithm are 2.45% and 2.58%.The PV system efficiency achieved by using P&O, PSO are 95.7%, 96.8%.

A new view on the trend of solar radiation in mainland China — based on the optimized empirical model

As a kind of renewable energy, the development and utilization of solar energy are valued by many countries. To accurately provide a basis for the use of solar energy in mainland China, the optimized empirical model is adopted to analyze the variation trends and spatial patterns in solar radiation (SR) during 1961–2016 based on the data of 31 SR sites and 500 sunshine duration (SD) stations. The results indicate that there are obvious discrepancies in the variation trends of annual SR and SD during 1961–2016, with trend conversion occurring in 1992 (SR) and 1980 (SD), respectively. Overall, annual SR decreases at the rate of −3.68 MJ/m2·a in China. Notably, SR declines at the rate of −16.95 MJ/m2·a during 1961–1989 (“dimming” stage), while it increases at the rate of 5.34 MJ/m2·a for 1990–2016 (“brightening” period). In addition, all seasons show a tendency of dimming first and then brightening except for autumn. Compared with SD, SR is more sensitive to changes in pollution, leading to a marked recovery with the reduction of pollution after the 1990s. This study provides a new perspective for the trend difference between SR and SD after the 1990s.

Reliability Measures and Profit Exploration of Windmill Water-Pumping Systems Incorporating Warranty and Two Types of Repair

Wind energy is a kind of renewable energy that plays a significant role in remote areas for pumping water. The windmill is also used to generate electricity. The windmill is also known as a wind pump when it is used for pumping water. In this work, the authors proposed a complex hybrid model of an example of combined system (windmill, rechargeable battery and pumping system) to evaluate the system’s performance. System performance was affected by system degradation due to system failure. These factors also affected the profit of the user. Two types of repair facilities for continuous and satisfactory performance of the system were assumed. To illustrate the system modeling using the Gumbel–Hougaard family of the copula, numerical examples were used for the exploration of Markov results of the reliability measures and the profit of the system with the warranty period, with this also being demonstrated graphically.

Unraveling the adsorption and diffusion properties of hexamethyldisiloxane on zeolites by static gravimetric analysis

Utilization of biogas from wastewater treatment plants (WWTPs) as a kind of renewable energy can effectively alleviate the escalating energy crisis. However, volatile methylsiloxanes (VMS) exist in biogas as impurities and hinder its efficient use. Adsorption is the main technology to achieve high-efficiency purification of VMS currently, yet studies on the adsorption processes and mechanisms are quite insufficient. Here, we use the static vapor adsorption method to investigate the adsorption performances and mechanisms of four typical zeolite adsorbents (Hbeta, SBA-15, MOR and MCM-41) towards hexamethyldisiloxane (L2), which is a representative of VMS. Results suggest the adsorption interaction of L2 and zeolite is closely related to the pore size of zeolite and follows the order of Hbeta > MCM-41 > SBA-15 > MOR. The adsorption rate constants of L2 on MCM-41 are larger than the others in the most relative pressure ranges. Besides, cyclic adsorption/desorption performances of L2 on MCM-41, SBA-15 and Hbeta show their super recycling properties. These studies would provide important information on designing an effective zeolite-L2 adsorption system, and are helpful to understand the deeper adsorption mechanisms of VMS on zeolites.

Prediksi Energi Listrik Kincir Angin Berdasarkan Data Kecepatan Angin Menggunakan LSTM

Fossil energy is well known as the most energy resource consumed by humans. However, the exploitation leads to damage both in the process of taking raw materials and in the use of those. Furthermore, the amount has become decreasing nowadays. Renewable energy could solve the energy crisis. One kind of renewable energy that has been successfully used by a human is by utilizing wind turbines. However, there are still many problems in its implementation and usage. One of the problems is the unstable generated electricity that is caused by instability of the wind speed. Inappropriate plans for utilizing wind turbines in such areas with varying wind speed could harm renewable energy investment. Therefore, forecasting the wind speed is necessary to anticipate the stability and embrace optimal produced energy. This study proposes the Long Short Term Memory (LSTM) algorithm to predict the generated energy by using the wind speed dataset. Thus, wind turbines can be utilized effectively and efficiently in the right area with sufficient average wind speed.

Simulation and validation model of cooling greenhouse by solar energy (P V) integrated with painting its cover and its effect on the cucumber production

Solar energy as a kind of renewable energy is used to power evaporative cooling system to decrease high temperatures that pose a highly negative effect on agricultural production. Greenhouses can be used to avoid the impact of high temperatures. The main objective here is to study the effect of a solar-assisted evaporative cooling in a cucumber greenhouse integrated with painting the greenhouse cover on the environmental factors to improve production. The study was divided into two experiments (preliminary and field experiment). The preliminary study was a mathematical model by MATLAB program developed to predict the value of environmental factors inside the cooled greenhouse. The field experiment was to validate the solar panel (PV), cooling systems, model results and their effect on cucumber yield and water consumption. Good agreement was found between predicted and measured values. Evaporative cooling which consumed about 8.32 MJ day−1 obtained from solar energy (PV) alongside painting the greenhouse cover decreased the temperature about 10°. The evaporative efficiency was 74%. This system has been applied in the climatic conditions of Egypt and can be used for cooling within most facilities with high efficiency in areas of similar environmental conditions.

Imbalance Fault Classification Based on VMD Denoising and S-LDA for Variable-Speed Marine Current Turbine

Marine current energy as a kind of renewable energy has gradually attracted more and more attention from many countries. However, the blade imbalance fault of marine current turbines (MCTs) will have an effect on the power production efficiency and cause damage to the MCT system. It is hard to classify the severity of an MCT blade imbalance fault under the condition of the current instability and seafloor noise. This paper proposes a fault classification method based on the combination of variational mode decomposition denoising (VMD denoising) and screening linear discriminant analysis (S-LDA). The proposed method consists of three parts. Firstly, phase demodulation of the collected stator current signal is performed by the Hilbert transform (HT) method. Then, the obtained demodulation signal is denoised by variational mode decomposition denoising (VMD denoising), and the denoised signal is analyzed by power spectral density (PSD). Finally, S-LDA is employed on the power signal to determine the severities of fault classification. The effectiveness of the proposed method is verified by experimental results under different severities of blade imbalance fault. The stator current signatures of experiments with different severities of blade imbalance fault are used to validate the effectiveness of the proposed method. The fault classification accuracy is 92.04% based on the proposed method. Moreover, the experimental results verify that the influence of velocity fluctuation on fault classification can be eliminated.

Research on maximum power point tracking control of acoustic energy harvest system

As a kind of renewable energy, acoustic energy can be converted into electrical energy to supply energy for micro-electronic devices, which is a meaningful research topic. In order to keep working at the maximum power point all the time, an acoustic energy harvest system based on the maximum power point tracking (MPPT) control method is proposed. The system is composed of a Helmholtz resonator, a piezoelectric transducer, and an interface circuit, and the interface circuit is composed of a rectifier circuit and a buck-boost circuit. When the acoustic wave enters the cavity, the acousto-electric conversion is carried out through the piezoelectric transducer, and then the DC power is output through the interface circuit. Finally, through the MPPT control program, the system always works at the maximum power point. The theoretical and simulation analysis of the interface circuit is carried out, and the performance of the system is studied and verified by experiments. When the load is constant and the SPL (Sound Pressure Level) increases, the optimal duty cycle fluctuates between 0.1 and 0.3, and the voltage and power of the load increase with the increase of the SPL. When the SPL is 110 dB and the duty cycle is 0.15, the maximum power of the load is 115.2 µW. When the SPL is 110 dB, the optimal duty cycle fluctuates between 0.1 and 0.2. When the load resistance is 30 kΩ, 50 kΩ, 70 kΩ, 90 kΩ, and 110 kΩ, the maximum power of the load is 110.45 µW, 115.2 µW, 104.14 µW, 106.78 µW, and 105.1 µW, respectively.

Performance and emission characteristics of biodiesel-blend in diesel engine: A review

Many researchers delve for an alternative fuel to overcome the fossil fuel crisis. Developed countries have embarked focus on renewable energy like wind energy, geothermal, biofuel, ocean energy and solar energy. Biodiesel is considered to be one of the most felicitous one kinds of renewable energy with similar properties of diesel fuel. Biodiesel is gaining prominence due to the global fossil fuel crisis and emission control challenges. Biodiesel blends are formulated in numerous proportion with diesel to run the diesel engine and it has significantly reduced the harmful pollutants from contaminating the environment. This review paper summarizes the outcome of biodiesel blends on properties, performance and emission-quality of a diesel engine under different operating conditions. Results from the literature provide a comparative data between conventional diesel and diesel-biodiesel blend which indicates that the diesel-biodiesel blend provides shorter ignition delay and lesser heat release rate as well as slightly higher efficiency. The emissions like CO, HC and particulate matter are reduced while choosing biodiesel blends. Biodiesel blend with additives such as alcohol can be the appropriate solution for the fuel crisis. Finally, the review concludes the advantages and future scope of biodiesel as a better competent for diesel fuel.

A Novel Scenario Generation Framework Based on the Knowledge of Existing Wind Power Plants

As a kind of renewable energy with economic and environmental friendliness, wind energy is widely used, although the high uncertainty of wind speed has significant impact on the operation and planning of wind power systems. Thus, scenario generation of wind speed is the primary step to obtain optimal decisions. However, as to the wind power plants to be newly-built or expanded, adequate wind data may not be available, or even the wind data are missing or invalid, which may lead to the inaccuracy of data-driven scenario generation. In this paper, considering that multiple wind plants in neighboring areas may have similar wind patterns, a novel scenario generation framework is proposed to transfer the knowledge extracted from existing data-rich plants to help establish the uncertainty model of newly-built plant. Transfer component analysis (TCA) is used to minimize the distribution gap between multiple source plants and target plant, and the results of maximum mean discrepancy (MMD) can be obtained to construct the mixture distribution model of target wind speed. Experimental results show that the scenarios generated by transferring the knowledge of existing wind plants can better reflect the real characteristics of the target wind speed in the case of insufficient historical data.

Biomass Renewable Energy Environmental Protection Low Carbon City Power Generation and Heating Device

Biomass energy is a kind of renewable energy. The development and utilization of biomass energy can alleviate the pressure of energy shortage, reduce environmental pollution, and improve the future energy structure. This article aims to achieve eco-friendly, low-carbon, intelligent, modern, smoke-free, energy-cyclable and renewable energy through the research on biomass renewable energy and environmental protection low-carbon city power generation and heating devices. This paper proposes a modern utility model biomass renewable energy environmental protection low-carbon city power generation and heating device, and the feasibility of the device has been verified through experiments. It is concluded that the change in raw material consumption has little effect on the gas components and calorific value in biogas. The power generation and heating device has good adaptability to the amount of raw materials, and its comprehensive pollutant emissions are compared with traditional coal and petroleum. Power generation and heating facilities are reduced by 99%. The research in this paper helps to alleviate the shortage of energy supply in my country, develop a circular economy, and promote the sustainable development of social economy.

An Economic and Technology Analysis of a New High-Efficiency Biomass Cogeneration System: A Case Study in DC County, China

Biomass is the fourth largest energy source in the world; it is easy to store and can be converted into various kinds of renewable energies. The biomass cogeneration system is an important way to utilize biomass energy, especially in northern China. At present, there are many problems in biomass power plants in China, such as high latent heat loss of chimney and cooling towers, low power generation efficiency, and thermal efficiency. In order to solve this problem, this paper introduces low vacuum circulating water heating technology in the biomass cogeneration system, and expounds the differences between China and Western countries in biomass power plants. Based on this background, the technology is redesigned and reformed to make it more suitable for the biomass fuel varieties in the power plant location, and realize the localization of technology and the expansion of scale. The application of this improved technology in China’s biomass cogeneration project is analyzed. Based on the biomass cogeneration project in the DC County of China, the analysis confirms that the designed low vacuum circulating water heating technology is suitable for biomass power generation projects with agricultural and forestry wastes as raw materials, and its application can greatly improve the heat utilization efficiency of the whole cogeneration system. At the same time, in order to estimate the possibility of profitable investment when the key financial parameters change, the financial risk is analyzed. The results show that the probability of 90% net present value (NPV) in 15 years is between 355.28 million RMB and 623.96 million RMB, and the internal rate of return can reach 17.7%.

Realization of Building Energy Saving and Solar Heating in Cold Areas based on Computer Technology

The climate of cold area is cold in winter (the average temperature of the coldest month is 0 ∼ - 10 °C and < - 10 °C), the outer envelope of the building bears the interference of low temperature, wind and snow, hot in summer, and the outer envelope of the building bears the interference of high temperature, solar radiation and rain. Therefore, the design of buildings should meet the requirements of winter heat preservation, cold prevention and antifreeze. At present, 95% of the new buildings built every year in China are still high energy consumption buildings. The heating energy consumption per unit building area is about three times of that in countries with similar climate. The building energy consumption in China accounts for nearly 30% of the national energy consumption. With the development of building technology, the improvement of people’s awareness of energy and the attention of government departments, China should vigorously develop building energy saving, which is urgent. The demand of solar energy is increasing day by day, and the situation of energy utilization is tense. However, the large-scale use of conventional energy will have a negative impact on the environment. As a kind of renewable energy, solar energy is inexhaustible and will not increase the environmental load. It will become an important part of the future energy structure. In the building energy consumption, the energy consumption of domestic hot water and heating accounts for a considerable proportion. Using solar energy to meet the requirements of low-grade energy consumption, such as domestic hot water and heating, has great energy-saving benefits. Therefore, solar energy heating technology has been paid more and more attention. At the same time, with the development and maturity of computer technology, it also provides more support for solar heating technology. This paper analyzes the realization of building energy saving and solar heating in cold areas by using computer technology.

Photoassisted salt-concentration-biased electricity generation using cation-selective porphyrin-based nanochannels membrane

Abstract Natural sunlight is one kind of renewable energy that is considered likely to be ubiquitous at the river-sea junction. Ingeniously engineering a photoassisted enhanced electricity capture facility based on an artificial nano-porous membrane, is a necessity. Herein, a proof-of-concept system is constructed, wherein cation-selective photoresponsive porphyrin/alumina nanochannels are entrusted with cationic selectivity and extraordinary photoelectric response, thus it is available to synergistically convert salinity gradient and solar energy into high electric energy. Depending solely on excellent cationic selectivity of nanochannels, the salinity-gradient-driven membrane system can capture high power output of 2.16 W/m2. And harvested power of the generator with the help of photo is elevated to 4.56 W/m2. Resulted total transmembrane ionic current (Itotal) is traceable to a smooth cooperative effort of diffusion current (Idiff) and photo-induced ionic current (Iphoto). Benefiting from the accumulation characters of ionic current, the electricity generator with the modulation of concentration gradient and varying-intensity photo stimulus can achieve a multivalued conduction including current and power increase. The general nanofluidic system paves the way for other multi-functional membranes that simultaneously utilize various clean sources to potentially improve entire electricity output.