Average Daily Performance Research Articles

The Impact of Ambient Weather Conditions and Energy Usage Patterns on the Performance of a Domestic Off-Grid Photovoltaic System

Solar photovoltaic (PV) systems are growing rapidly as a renewable energy source. Evaluating the performance of a PV system based on local weather conditions is crucial for its adoption and deployment. However, the current IEC 61724 standard, used for assessing PV system performance, is limited to grid-connected systems. This standard may not accurately reflect the performance of off-grid PV systems. This study aims to evaluate how ambient weather conditions and energy usage patterns affect the performance of an off-grid PV system. This study uses a 3.8 kWp building-integrated photovoltaic (BIPV) system located at SolarWatt Park, University of Fort Hare, Alice, as a case study. Meteorological and electrical data from August and November are analyzed to assess the winter and summer performance of the BIPV system using the IEC 61724 standard. The BIPV system generated 376.29 kWh in winter and 366.38 kWh in summer, with a total energy consumption of 209.50 kWh in winter and 236.65 kWh in summer. Solar irradiation during winter was 130.18 kWh/m2, while it was 210.24 kWh/m2 during summer. The average daily performance ratio (PR) was 44.01% in winter and 28.94% in summer. The observed decrease in PR during the summer month was attributed to the higher levels of solar irradiance experienced during this time, which outweighs the increased AC energy output. The low-performance ratio does not indicate technical issues but rather a mismatch between the load demand and PV generation. The results of this study highlight the need for a separate method to assess the performance of off-grid PV systems.

Analysis of Thermal Characteristics of a Solar Heat Supply System With Thermosiphon Circulation

In this paper, the characteristics of the vertical distribution of the thermosiphon in the conditions of the southern region of Kazakhstan are experimentally studied. The design was equipped with several thermocouples for measuring and collecting the provided data using a data logger. The collector temperature has reached 75 °C, and the time to reach the highest temperature is approximately 1.5 hours after the point of limiting the flow of solar radiation. During the sunny period, the temperature of the upper layer of water in the storage tank was 60 °C. This system was demonstrated during the winter days. The measured thermal characteristics of the alignment are in good agreement. At the maximum values of the temperature systems, the average daily efficiency of the system was 52% with the difference between the collector temperature and the ambient temperature. While on other days, the average daily performance of the system is about 50%. The initial temperature in the tank has an impressive effect on the daily return of the system. An increase in the temperature difference between the water temperature and the collector temperature will lead to an increase in the thermal power of the collectors. Compared to other days, the daily efficiency of the system can reach 60% at an initial temperature of 7°.

Experimental study of a novel solar multi-effect distillation unit using alternate storage tanks

Abstract In recent years, the use of solar energy has been growing exponentially and applied in a wider range of applications; one of the important applications for using solar energy is water desalination. The current work investigates the proof of concept experimental setup for a novel solar multi-effect distillation (MED) using alternate storage tanks. The experimental setup consists of a MED unit, two thermal storage tanks, and a solar collector. One storage tank is used as a charging tank while the other tank is used as a discharging tank. This unique dual-tank system stores the thermal energy to be used later in the MED unit, which improves the control of the water mass flow rate and water temperature throughout the MED process. The peak temperature achieved every day in the charging tank determines the MED production capacity. This system is designed for the tanks to alternate roles every 24 hours. The testing of this design was carried out during May 2019 in Saudi Arabia. The experimental results prove the novel concept design to work efficiently providing an average production rate of about 21 kg/day with total solar collector area of 2.7 m2 and average daily performance ratio of 2.5.

Performance and economic viability assessment of a 50 KWp rooftop solar photovoltaic system

Green energy is a global consensus to cope with increasing energy needs. Recognising this fact, the Government of India is expecting 40% of the demand to be fulfilled through rooftop solar plants by 2022. As a result, in many metropolitan regions, government and non-government organisations installed rooftop Solar Photovoltaic (SPV) systems and the energy produced is consumed for their usage. To contribute to this universal mission of energy conservation, The ICFAI University, Jaipur, had taken a significant step by installing a 50 kWp SPV system on its campus. This paper presents the performance assessment and economic feasibility of the SPV system which is monitored between January 2018 and June 2018. The energy production of the plant at 34,476.64 kWh recorded during the period. The array, final, and reference yields are perceived to vary from 2.7 to 5.04 kWh/kW/day, 2.45 to 4.73 kWh/kW/day, and 3.22 to 7.4 kWh/kW/day respectively. The monthly average daily performance ratio (PR) and capacity utilisation factor (CUF) measured amid 16.39-76.97% and 10.23-19.71 respectively. To investigate the pecuniary feasibility of the venture, the net present value (NPV), Profitability Index (PI), Internal Rate of Return (IRR) and Payback Period are used for different discount and subsidy rates.

Performance and economic viability assessment of a 50 KWp rooftop solar photovoltaic system

Green energy is a global consensus to cope with increasing energy needs. Recognising this fact, the Government of India is expecting 40% of the demand to be fulfilled through rooftop solar plants by 2022. As a result, in many metropolitan regions, government and non-government organisations installed rooftop Solar Photovoltaic (SPV) systems and the energy produced is consumed for their usage. To contribute to this universal mission of energy conservation, The ICFAI University, Jaipur, had taken a significant step by installing a 50 kWp SPV system on its campus. This paper presents the performance assessment and economic feasibility of the SPV system which is monitored between January 2018 and June 2018. The energy production of the plant at 34,476.64 kWh recorded during the period. The array, final, and reference yields are perceived to vary from 2.7 to 5.04 kWh/kW/day, 2.45 to 4.73 kWh/kW/day, and 3.22 to 7.4 kWh/kW/day respectively. The monthly average daily performance ratio (PR) and capacity utilisation factor (CUF) measured amid 16.39-76.97% and 10.23-19.71 respectively. To investigate the pecuniary feasibility of the venture, the net present value (NPV), Profitability Index (PI), Internal Rate of Return (IRR) and Payback Period are used for different discount and subsidy rates.

Premises of the creation of a digital traffic safety management system

Aim.The digital transformation of the traffic safety management system in JSC RZD involves top-level integration with the operating processes of all business units in terms of integral assessment of the risk of possible events and achievement of specified indicators. The result will be the merger of the traffic safety management system with the processes of all levels of the company’s management enabled by an integrated intelligent system for managing processes and services whose functionality includes real-time traffic safety management.Methods. The paper uses system analysis of existing approaches and methods of processing of large quantities of structured and unstructered data.Results. The paper examines the development stages of train traffic safety management, as well as automated information and control systems that enable traffic safety management. General trends in the creation of systems for collection and processing of information are analyzed. The applicability of such technologies as Big Data, Data Mining, Data Science as part of advanced control systems is shown. The paper examines the performance of the above technologies by analyzing the effect of various factors on the average daily performance of a locomotive, where, at the first level, such factors as average daily run of a locomotive, average trainload are taken into consideration; at the second level, the focus is on the service speed, locomotive turnover at station, etc.; at the sixth level, the focus is on the type of locomotive, its technical state, etc. It is shown that statistical methods of factor analysis and link analysis combined with such other methods of Data Mining as methods of simulation and prediction, the average daily performance of a locomotive can be planned proactively. The author proposes a procedure of migration towards a digital traffic safety management system that would be based on models of interaction of safety and dependability factors of all railway facilities at all railway levels of hierarchy, as well as in association with other factors that have no direct relation to dependability, yet affect the safety of the transportation process.Conclusions. The primary benefit of migration towards Big Data consists in the development of a dynamic model of traffic safety, the elimination of human factor in control systems. Most importantly, it enables the creation within the Russian Railways company (JSC RZD) of an integrated intelligent process and service management system that enables real-time traffic safety management. An extensive process of development and deployment within the company of the URRAN Single Corporate Platform (SCP) enabled executive decision support as regards risk-based functional dependability and safety of transportation facilities. Thus, the URRAN SCP sets the stage for the digital transformation of the traffic safety management system in JSC RZD.

A novel design for solar integrated multi-effect distillation driven by sensible heat and alternate storage tanks

This article presents a novel Multi-Effect Distillation (MED) system which utilizes indirect brine heating such that a medium fluid is circulated through the concentrating solar collectors and store the energy in a charging tank. Each “effect” of a MED unit is a chamber in which cool feedwater brine is sprayed onto heat exchangers, partially evaporating the brine. The vapors and heated brine serve to pass thermal energy to subsequent effects. One of the uniqueness of the design is that the heat exchanger in the first effect of the system receives a flow of hot medium fluid, such that sensible heat is passed to the incoming feedwater. The thermal storage system consists of two identical, insulated tanks, each with sufficient volume to supply the medium fluid for a full day. A dynamic mathematical model is developed and simulated with four MED stages (“effects”). The number of concentrated solar arrays are optimized to generate a peak of 2200 metric ton per day of distilled water, with indispensable total array area of 92,000 square meter. The average daily performance ratio is 2, and the average specific thermal energy consumption is 1140 kJ per kg.

The validation of a novel lumped parameter model for photovoltaic thermal hybrid solar collectors: a new TRNSYS type

Decarbonisation is one of the most important challenges facing researchers, and solar-assisted systems represent an important solution to reduce the energy consumption at the household-scale. The current work contributes to existing research by proposing and validating a novel lumped parameter simulation model for photovoltaic thermal hybrid solar collectors using field measurements carried out at an experimental facility. The modelling approach, which also considers the effect of the thermal capacitances of the elements composing the photovoltaic thermal collector, used an electrical analogy method to solve the transient heat transfer problem. The results of the simulations were compared with the experimental data collected during different weather conditions; the effects of the thermal capacitances of the collector were also investigated. The results were compared in terms of both average daily performance and instantaneous values of the variables characterizing the system. Although the differences were negligible, the results of the simulation analyses matched the measurements more precisely when the thermal capacitances were taken into consideration. Finally, the simulation model was implemented as a TYPE of Transient System Simulation (TRNSYS) software, and it is made freely available to facilitate future integrated computer simulations.

Performance evaluation of grid-connected photovoltaic systems based on two photovoltaic module technologies under tropical climate conditions

The aim of this paper is to evaluate grid-connected photovoltaic systems based on two kinds of photovoltaic module technologies. This study presents a one-year evaluation of four grid-connected photovoltaic systems installed at the National Institute of Advanced Industrial Science and Technology, in Tsukuba in the northern Kantō region of Japan. Two grid-connected systems based on multi-crystalline: mc-Si and two other ones based on thin film technology namely copper indium selenium: CIS modules. The monitoring data have been collected for one year to make an evaluation of all possible changes in climate environment. The goal of this study is to define the characteristics, the behavior and the sensitivity of the grid-connected PV system to the environmental parameters. Various parameters were used for the outdoor performance evaluation of the four grid-connected PV systems; including performance ratio, temperature losses, final yield, reference yield, AC energy generated and system efficiency. It was found that the grid-connected PV systems based on mc-Si technology perform much better than the systems based on CIS.The annual average daily performance ratios of the systems based on mc-Si modules were found to be about 5.53% higher compared to those of the systems based on CIS module, and an annual average daily AC energy production about 42.85% higher than CIS.

Performance evaluation of a rooftop solar photovoltaic power plant in Northern India

The rapid growth of electricity demand due to the increase in population has put the burden on the power stations of India to enhance their generation. With the serious drop in prices of solar photovoltaic (SPV) generated electricity and rising tariffs on conventional electricity have drawn attention to generate electricity through the solar photovoltaic plant. Therefore, it is important to assess accurately and precisely the annual and monthly yield of SPV plant to help in designing and installation of new plants. Performance analysis of a 5 kWp roof-top photovoltaic plant has carried out, and the effect of temperature analyzed. The annual average daily reference yield, array yield, and final yield found 5.23 kWh/kWp/day, 4.51 kWh/kWp/day and 3.99 kWh/kWp/day respectively. The annual average daily array efficiency, inverter efficiency and system efficiency found to be 11.34%, 88.38%, and 10.02% respectively. The annual average daily performance ratio and capacity utilization factor measured 76.97% and 16.39%. The annual energy yield of the plant recorded 7175.4 kWh. Results show that energy loss is maximum during May when the temperature is highest. The performance of the plant compared with PV plants installed all over in India and found comparable.

Traction capabilities of a dual-voltage electric locomotive 2EV120 on the West Siberian Railway

The paper discusses the traction parameters of an electric locomotive of a new generation. The existing schemes of sections served by electric locomotives and locomotive crews at the studied railway operating domain are presented. A comparison of the main parameters of DC and single-phase AC electric locomotives, the operation of which is currently organized at sections with trains of estimated weight in the long-term traction mode on the ground slopes with different steepness, is made. The scheme of the proposed organization of operation of dual-voltage electric locomotive and locomotive crews is presented. Traction parameters of a dual-mode electric locomotive are calculated, taking into account the plan and profile of the track at the proposed sections of operation, the specific basic resistance to the movement of the locomotive and the train at the estimated speed, the specific accelerating and decelerating forces of the train. When dual-mode electric locomotives are put into operation, it will be possible to reduce the fleet of locomotives in operation, the number of locomotive runs due to their lengthening, and the number of locomotive crew relief points, reduce the transit time of freight trains, increase technical and service speed, average daily mileage and average daily performance of the locomotive, reduce power consumption for traction. The operation of such electric locomotives contributes to the development of technologies for rail traffic management and the improvement of quantitative and qualitative indicators of various railway facilities.

Performance assessment of five different photovoltaic module technologies under outdoor conditions in Algeria

The aim of this paper is to establish a performance assessment of different kinds of photovoltaic (PV) module technologies installed in the city of Saida in Algeria. The modules are three thin film modules: copper indium selenide (CIS), mono-crystalline heterojunction with intrinsic thin layer (HIT) and tandem structure of amorphous silicon and microcrystalline silicon (a-Si_μc-Si) with two crystalline silicon modules: multi-crystalline and mono-crystalline back contact. The modules were characterised by measuring their I-V characteristics under the same outdoor conditions. Moreover, measurements of various meteorological parameters such as irradiance, temperature and humidity, using the weather station, were also performed. The monthly average daily performance parameters as performance ratio, energy yield and efficiency are given and analysed. It was found that the HIT and the a-Si_μc-Si performed much better than the other technologies. The annual average daily performance ratios of a-Si_μc-Si module was found to be about 1.55% higher compared to HIT module and 2.04% compared to CIS. The HIT module produce an annual average daily energy of 1.15 kWh more than double what the a-Si_μc-Si produce and an annual average daily efficiency more than double of the efficiency of a-Si_μc-Si.

Leverage for the Long Run - A Systematic Approach to Managing Risk and Magnifying Returns in Stocks

Using leverage to magnify performance is an idea that has enticed investors and traders throughout history. The critical question of when to employ leverage and when to reduce risk, though, is not often addressed. We establish that volatility is the enemy of leverage and that streaks in performance tend to be beneficial to using margin. The conditions under which higher returns would be achieved from using leverage, then, are low volatility environments that are more likely to experience consecutive positive returns. We find that Moving Averages are an effective way to identify such environments in a systematic fashion. When the broad U.S. equity market is above its Moving Average, stocks tend to exhibit lower than average volatility going forward, higher average daily performance, and longer streaks of positive returns. When below its Moving Average, the opposite tends to be true, as volatility often rises, average daily returns are lower, and streaks in positive returns become less frequent. Armed with this finding, we developed a strategy that employs leverage when the market is above its Moving Average and deleverages (moving to Treasury bills) when the market is below its Moving Average. This strategy shows better absolute and risk-adjusted returns than a comparable buy and hold unleveraged strategy as well as a constant leverage strategy. The results are robust to various leverage amounts, Moving Average time periods, and across multiple economic and financial market cycles.

Measured performance of a 1.72 kW rooftop grid connected photovoltaic system in Ireland

This paper presents results obtained from monitoring a 1.72 kW p photovoltaic system installed on a flat roof of a 12 m high building in Dublin, Ireland (latitude 53.4°N and longitude 6.3°E). The system was monitored between November 2008 and October 2009 and all the electricity generated was fed into the low voltage supply to the building. Monthly average daily and annual performance parameters of the PV system evaluated include: final yield, reference yield, array yield, system losses, array capture losses, cell temperature losses, PV module efficiency, system efficiency, inverter efficiency, performance ratio and capacity factor. The maximum solar radiation, ambient temperature and PV module temperature recorded were 1241 W/m 2 in March, 29.5 °C and 46.9 °C in June respectively. The annual total energy generated was 885.1 kW h/kW p while the annual average daily final yield, reference yield and array yield were 2.41 kW h/kW p/day, 2.85 kW h/kW p/day and 2.62 kW h/kW p/day respectively. The annual average daily PV module efficiency, system efficiency and inverter efficiency were 14.9%, 12.6% and 89.2% respectively while the annual average daily performance ratio and capacity factor were 81.5% and 10.1% respectively. The annual average daily system losses, capture losses and cell temperature losses were 0.23 h/day, 0.22 h/day and 0.00 h/day respectively. Comparison of this system with other systems in different locations showed that the system had the highest annual average daily PV module efficiency, system efficiency and performance ratio of 14.9%, 12.6% and 81.5% respectively. The PV system’s annual average daily final yield of 2.4 kW h/kW p/day is higher than those reported in Germany, Poland and Northern Ireland. It is comparable to results from some parts of Spain but it is lower than the reported yields in most parts of Italy and Spain. Despite low insolation levels, high average wind speeds and low ambient temperature improve Ireland’s suitability.

Fast Universalization of Investment Strategies

A universalization of a parameterized investment strategy is an online algorithm whose average daily performance approaches that of the strategy operating with the optimal parameters determined offline in hindsight. We present a general framework for universalizing investment strategies and discuss conditions under which investment strategies are universalizable. We present examples of common investment strategies that fit into our framework. The examples include both trading strategies that decide positions in individual stocks, and portfolio strategies that allocate wealth among multiple stocks. This work extends in a natural way Cover's universal portfolio work. We also discuss the runtime efficiency of universalization algorithms. While a straightforward implementation of our algorithms runs in time exponential in the number of parameters, we show that the efficient universal portfolio computation technique of Kalai and Vempala [Proceedings of the 41st Annual IEEE Symposium on Foundations of Computer Science, Redondo Beach, CA, 2000, pp. 486--491] involving the sampling of log-concave functions can be generalized to other classes of investment strategies, thus yielding provably good approximation algorithms in our framework.

A non-linear flat-plate collector model

The analysis of a non-linear flat-plate collector is presented in which the overall loss coefficient is assumed to be a linear function of the temperature difference between the fluid in the collector and the environment. The instantaneous performance of collectors calculated using linear and non-linear models is presented in terms of three dimensionless numbers. For an assumed parabolic solar radiation profile, the average daily performance for a constant fluid inlet temperature can be presented in terms of three further dimensionless numbers. The resulting expressions for both instantaneous and daily performance are shown graphically. A method of calculating linear collector performance characteristics from non-linear curve fitting to experimental results is shown so that the predicted daily performance from non-linear and linear curve fits can be compared. In most circumstances, a linear fit is adequate.