Abstract

Accurate solution to the nonlinear parameters of solar energy mathematical model has a great influence on the accuracy of solar cell output power calculation, but it is difficult to obtain. Moreover, these parameters will also change as the environment or battery life changes. A method is proposed to accurately solve the nonlinear parameters of photovoltaic cells based on Newton-Raphson method with limit constraints. This method uses Newton-Raphson method to iteratively solve the exact solution of the nonlinear parameters. The limit constraints are used to effectively solve the problem that the stiffness of the Jacobian matrix is not converged due to the improper selection of the initial value, which makes convergence faster and can realize the real-time online exact calculation of the nonlinear parameters for the currently operating photovoltaic cell. A single-diode four-parameter mathematical model is built, and the fourth-order Jacobian matrix is deduced, and the limit constraint is given. Finally, the feasibility and validity of the proposed method are demonstrated by two example experiments.

Abstract

The startup and shutdown simulation of a micro gas turbine (MGT) is concerned. In order to build an accurate dynamic model, the general models of core components are presented first. Then, two dynamic parameters that influence rotating speed and temperature dynamics are put forward for further identification. The identification is accomplished by a reinforcement learning algorithm. The comparison between the simulation and experimental data show that this learning method leads to high-accuracy MGT startup and shutdown simulation.

Abstract

The multi-column parallel zinc oxide arrester has the characteristics of strong absorption capacity on overvoltage and low residual voltage, so it is widely used in high-voltage, extra-high voltage and ultra-high voltage transmission systems. But when the arrester is subjected to normal line voltage, there is a slight leakage current, and the core has a certain temperature rise, which causes the aging of the zinc oxide resistor valve. The degree of aging depends on the temperature distribution and the temperature rise rate. Therefore, when studying on the DC arrester time-varying temperature field distribution is of great significance. In this paper, YH20WDB1-188 multi-column parallel DC zinc oxide arrester is used as the model. According to the heat transfer differential equation and the supplementary equations, the time-varying temperature field simulation calculation is carried out, and the temperature distribution and temperature rise rate of the single core and the whole arrester are compared and analyzed. The simulation results contribute to structural optimization of multi-column parallel arrester and analysis of valve aging characteristics

Abstract

In world’s context the energy consumption for air conditioning and cold is rising year by year. Solar cooling is one of the most promising solutions to the worsening energy and climate issues. It can provide a sustainable active air-conditioning possibility due to reduce greenhouse gas emission as well as electricity consumption. This paper discusses current development and future aspects of solar cooling technology. The selection of adsorbent-adsorbate materials and solar collector are important to improve the solar cooling system. It is revealed in review that coefficient of performance (COP) of solar flat plate collector technology are still insignificant in range as well as systems are not economically viable. The use of highly efficient integrated solar concentrator systems able to achieve temperature up-to 180C can increase the COP by a significant amount and can pave a path to the future of this technology.

Abstract

Alongside the acceleration of building digitalization, making intelligent use of building energy consumption data attains more and more attention. As appliance-level energy consumption data is not generally available, the Non-Intrusive Load Monitoring (NILM) provides novel waysto disaggregate total energy consumption data into appliance-level while ensures privacy of customers. This work focuses on NILM algorithm that is applicable to common appliances and widespread smart metering infrastructure. The NILM energy consumption data of an office was collected with 1-min resolution and used for analysis. In the work, fuzzy c-means clustering NILM algorithm and inter-cluster entropy were used to classify and verify the categories of office appliances. The algorithm was proven to be able to disaggregate and classify office appliance energy consumption data with a satisfactory accuracy.

Abstract

The wrong application of laterite is one of the major causes of road failure in Nigeria, some road infrastructures in Nigeria are not sustainable and durable owing to the fact that the lateritic materials used as backfill material were not adequate enough to sustain the road over a considerable period of time, this, therefore, affects the durability of the road. In this study, the author has analyzed lateritic soil obtained from Awgu local government area in Enugu state, South East Nigeria, using basic prominent geotechnical laboratory tests. According to the results obtained, the sample in consideration had less than 35% by weight of sample passing through sieve 85,120,150,170 and 240. The sample had a liquid limit of 60%, plastic limit of 44.15%, plasticity index of 15.85%, a specific gravity of 2.49 and average moisture content of 12%. The California bearing ratio ranged from 29% to 77%. All the results above were analyzed according to the Federal Ministry of works specifications. This study has shown that the soil in consideration here is a good backfill material for sub-base and base material for highway construction, however, it is recommended that little improvement should be made on the soil in other to upgrade its ability to remain sustainable and durable over a considerable period of time.

Abstract

The objective of the present work is co-production of bio-fuels and magnetic activated carbon (MAC) materials via fast pyrolysis of lignin and ferrous salts mixtures and steam activation of pyrolysis char. Specifically, the effect of the addition of the ferrous salts on the quality of biofuels including bio-gas and bio-oil is investigated. The effect of the addition of the ferrous salts on the mass loss rate of bio-chars during the steam activation process is also investigated. Results show that for the fast pyrolysis process, the addition of ferrous salts leads to a hydrogen rich bio-gas and non-guaiacols containing bio-oil production. The cracking effect of irons for the fast pyrolysis vapors is believed to be the dominated reason. For the steam activation process, the addition of the ferrous salts causes a relatively low mass loss rate of biochars, because steam can oxidize iron to form magnetite.

Abstract

One of the major concerns leading to reduction in delivery of power and hence loss of revenue from solar photovoltaic (PV) plants is the deposition of dust on the panel surface. Solution to this problem lies in cleaning the panels frequently. Both events dust accumulation and cleaning entail cost which become significant as the size of the plant becomes large. Plant management often encounters a question as to what must be the periodicity of cleaning the panels that ensures maximum delivery of power to the grid. This study answers this question by determining optimum cleaning periodicity on the basis of maximum net energy delivered. The methodology is illustrated by an example of a 40 MWp PV plant. It is demonstrated that the optimum periodicity of cleaning for a 40 MWp PV plant comes out to be 7 days at which the annual energy delivered by the plant will be maximum at 60.53 GWh /year. The proposed methodology is simple, accurate, has a general applicability with no dependence on the capacity of the plant. However, the methodology requires experimental data on the rate of degradation in the output due to dust and dirt accumulation on the panels at the plant site.

Abstract

The molten slag discharged at high temperature between 1450°C~1450°C from the metallurgical industries, which is a kind of high-quality waste heat resource with extremely high utilization value. The various technologies of waste heat recovery of high temperature slags at home and abroad were summarized and compared in the paper. Through the technical comparison and analysis of the packed bed, fluidized bed and moving bed waste heat recovery scheme, it is concluded that the moving bed has significant technical advantages in recovering the waste heat of high temperature slags. The moving bed is the best solution to recover the waste heat from the high temperature slag.

Abstract

The climate responsive skin can adapt to changing climates by using intelligent or non-intelligent, active or passive strategies building envelop. This paper reviews the climate responsive skin design cases in modern buildings, and classifies them basing on environment performance and operation mode. The main aim of this paper is to present state-of-the-art of various kinds of climate responsive skin designs and analysis the current status. It is expected that the study helps to provide the reference for the design and application of climate responsive skin in buildings.