Stand-alone PV System Research Articles

Practical constraints for photovoltaic appliances in rural areas of developing countries: Lessons learnt from monitoring of stand-alone systems in remote health posts of North Gondar Zone, Ethiopia

Photovoltaic stand-alone systems are largely regarded as a viable option for decentralized rural electrification in developing countries. However, literature review reveals lack of documented experiences with installed PV systems such as Solar home systems as well as general problems with system maintenance and battery up keeping. This paper presents results from monitoring 31 stand-alone PV systems in remote health posts of North Gondar Zone in Ethiopia from installation until system failure; several systematic factors were found to have contributed to failure: lack of clear responsibility for the systems due to regular job rotation among health workers and lack of upfront, gender sensitive training, lack of equipment for maintenance work, very slow and unreliable chain of information in case of system failure and costly double tracking of energy supply. Nonfunctioning PV systems were found to threaten the technology'’s reputation by word of mouth. The results gained in this research provide important lessons for future programs of rural electrification by means of PV systems: they stress the importance of awareness building amongst funding agencies as well as the imperative of intense and sensitive training for users, especially women, and advocate for considering living conditions of users in system design.

Performance comparison investigation on solar photovoltaic-thermoelectric generation and solar photovoltaic-thermoelectric cooling hybrid systems under different conditions

ABSTRACTThe performance of solar photovoltaic-thermoelectric generation hybrid system (PV-TGS) and solar photovoltaic-thermoelectric cooling hybrid system (PV-TCS) under different conditions were theoretically analysed and compared. To test the practicality of these two hybrid systems, the performance of stand-alone PV system was also studied. The results show that PV-TGS and PV-TCS in most cases will result in the system with a better performance than stand-alone PV system. The advantage of PV-TGS is emphasised in total output power and conversion efficiency which is even poorer in PV-TCS than that in stand-alone PV system at the ambient wind speed uw being below 3 m/s. However, PV-TCS has obvious advantage on lowering the temperature of PV cell. There is an obvious increase in tendency on the performance of PV-TGS and PV-TCS when the cooling capacity of two hybrid systems varies from around 0.06 to 0.3 W/K. And it is also proved that not just a-Si in PV-TGS can produce a better performance than the stand-alone PV system alone at most cases.

Minimisation of energy consumption of a bioclimatic building based on heat balance study and stand-alone PV system sizing using LLP

ABSTRACTBioclimatic buildings are very comfortable habitats for significant savings in the consumption of daily energy. They help to protect the environment by preventing the emission of dust and pollutant gases into the atmosphere. In this paper, a sizing method is proposed that ensures a suitable internal climate with adequate comfort. First, a simple algorithm is used for the estimation of the heat balance and performance of a typical bioclimatic house in the region of Laghouat, Algeria. Second, the load demand is assured using an optimal stand-alone photovoltaic system sizing method based on the loss of load probability method (LLP) while ensuring the minimum cost of the system. The results show the effectiveness of the proposed method that can be used to develop an optimal building sizing project in all its dimensions, in particular to reduce the overall budget of the operation.

Critical analysis of power conversion topologies for stand-alone PV systems with super-capacitor

This study presents a Critical analysis of power conversion topologies used in conventional Photovoltaic stand-alone system. The analysis has been run for a range of parameters which are: Capacitance of Super-capacitor as storage unit, converter efficiency, and the load power. Moreover, the load power variation is related to the input mean power by a proportional constant k, and also for every single load, a wide range of capacitance values has been considered. However, the criterion of the comparison is the longest continuous load supply period without interruption for both topologies in changing weather. the study outcome will help choose the right topology for the right application. MATLAB software has been used to confirm the performance and effectiveness of each topology.

Performance of data acquisition system for monitoring PV system parameters

Abstract Data acquisition systems (DAQSs) are widely employed with PV plants for collecting all system data for evaluating plant performance and optimization purposes. The main objective of this work is to develop a cost effective DAQS based on Lab-VIEW. The proposed monitoring system has been employed for continuously collecting and displaying the electrical output parameters of stand-alone PV system. Such parameters include; PV generated voltage, current and power. Also it allows drawing of PV panel characteristics under real test conditions. In addition, the global solar radiation can be calculated via measuring the PV module short circuit current since it directly related to the solar concentration. The proposed system is considered as a good solution for collecting the system database to be ready for the analysis and optimization of PV plant’s performance. The configurations of software and hardware of the proposed system are presented and the performance of the proposed system is tested when integrated with small size PV system. Field testes demonstrated that the obtained monitoring data are very satisfactory. The online obtained data that displayed on PC screen is very informative. The developed DAQS was found to be very supportive for research and educational purposes.

Output Analysis of Stand-alone PV Systems: Modeling, Simulation and Control

A stand-alone PV system was studied, designed and simulated for an isolated mountain area in Romania. This PV system was developed for energy production, ensuring energy independence (electricity for lighting and supply of power for electric equipment with low consumption during a period of 70% from a year) of a house / chalet in an area where connection to the local grid is impossible or would require very high costs to developed electricity grid. A library of simple mathematical models for each element of such a stand-alone PV system, namely PV generator, battery, controller and load was established. The models of the PV system components are based on literature, but their implementation for analyses is developed using the MATLAB/Simulink software. It is discussed the interconnection of the subsystems and the performance of the PV system.

Development of coconut-based floating structure for stand-alone solar PV system in the tropics

The use of plastics and composite materials as the base structure for a floating solar photovoltaic system commonly known as floatovoltaic system can cause negative impact to the environment especially the aquatic life and human. Additive materials are infused to form the plastics by which giving adverse effect to our metabolism. Despite the fact that the plastics are durable, to create and recycle it will produce toxic materials of many kinds in addition to the higher expenses for floatovoltaic installation. The unique approach of floatovoltaic is further discussed withstanding the continuous constraint of limited and suitable land for solar PV farms. This paper presents field analysis of the development of coconut-trunk as the base structure for a floatovoltaic system with regards to the environmental impact. A framework based on the density and buoyancy of the coconut trunk material is considered for the design

Comparison of Mainsversus Standalone PV Electricity to Powera Residentialstandalone Solar Absorption Chillerin Australia

Abstract This study compares the cost of operating the auxiliary components of an optimised standalone hot water fired absorption chiller, using mains grid electricity and an optimised standalone photovoltaic system. The cheaper source was further compared with using mains electricity to operate a conventional reverse cycle air-air heat pump. Both types of air conditioners were sized to condition the same typical Australian house in three different Australian climate zones. The life-cycle cost of the electrical subsystem was determined for a house located in both a city and for a remote (grid-free) locations; the latter assumed the new connection could sustain the energy and power demands of the air conditioner. The operation and life-cycle costs are determined using TRNSYS 17. The results show that mains electricity attracts a lower cost than an optimised PV system for the chiller case; however, the standalone PV system offers a lower cost than mains, when operating a reverse cycle heat pump air conditioner. Finally, the paper shows that investing in a chiller system is better suited to houses in remote locations and in colder climate zones.

A hybrid PV/T collector using spectrally selective absorbing nanofluids

Nanotechnology is a rapidly developing field with a wide range of potential applications. One such application is using nanoparticles to selectively absorb and transmit light. By controlling the material, size and shape of nanoparticles it is possible to achieve spectrally selective optical properties. This phenomena can be exploited in solar energy applications where selective absorption of the solar spectrum enables high efficient hybrid photovoltaic/thermal (PV/T) collectors. In this study, we suspend core-shell Ag-SiO2 nanoparticles in water to filter out the ideal spectrum for creating electricity from Si PV cells. A detailed optical and heat transfer model for this approach was developed and validated using the electric and thermal outputs from a prototype system operating in real outdoor conditions. The results of this experimental work indicates that 12% more value (weighted energy output) can be achieved from this PV/T prototype compared with a stand-alone PV system under the same illumination. Since the proposed system inherently decouples the thermal receiver from the PV cells, it is possible to extend this technology to industrial combined heat and power applications.

Stand-alone PV systems for rural areas in Sabah, Malaysia: Review and case study application

Stand-alone PV systems for rural areas in Sabah, Malaysia: Review and case study application

Determination of Monthly Unit Cost of Energy for Standalone Photovoltaic System in Owerri, Imo State

In this paper, simulation approach is used for determination of the monthly unit cost of energy generated from standalone PV (SAPV) power system in Imo State. The meteorological data used in the study are compiled from National Aeronautics and Space Administration (NASA) worldwide meteorological database. The meteorological data include 22-year monthly and annual averaged insolation incident on a horizontal surface (kwh/m2/day) and 22-year monthly averaged air temperature. A hypothetical electric load demand data of 5000 kWh per day is used for the simulation. The PVsyst industrial PV system planning software solution was selected to model and simulate the entire PV system. PVSyst uses life cycle cost analysis approach to determine the investment cost and unit cost of energy generated from SAPV system. According to the results, the average total energy supplied to the user (load) in a year is 1751 kWh. The economic analysis result shows that the total annual cost of energy is 246760 Naira per year at a unit cost of 141 Naira per kWh. Also, the highest unit cost of energy of 168.6 Naira/ kWh occurred in August whereas the lowest unit cost of energy of 132.7 Naira/ kWh occurred in October. The idea presented in this paper is useful for smart grid, dynamic energy pricing and energy cost management system.

Novel Switch Adaptive Control to Improve the Efficiency of Boost Converter in Photovoltaic Systems

The efficiency of photovoltaic power generation is affected by the changeable weather conditions. This paper improves the efficiency of a standalone PV system over a wider range of operating conditions by employing novel switch adaptive control to an interleaved boost converter. With various loads, simulation and experimental results show that the interleaved boost converter with novel switch adaptive control offers better performance and higher conversion efficiency under changeable weather conditions.

Comparison of Turkey’s Geographical Regions in terms of Stand-Alone PV System Design and Cost Parameters

Stand-alone photovoltaic (SAPV) systems are widely used in rural areas where there is no national grid or as a precaution against power outages. In this study, technical and economic analysis of a SAPV system was carried out using meteorological data for 75 province centers in seven geographical regions of Turkey. Obtained results for each province center were separated by geographical area. The averages of the centers for each region are taken as output. A calculation algorithm based on MsExcel has been established for these operations. The analyses made with the developed algorithm are repeated for five different scenarios that they cover periods of time when a constant strong load is active for all seasons (winter, spring, summer, and autumn) and all year round. The developed algorithm calculates the life-cycle cost, the unit energy cost, the electrical capacity utilization rate, the amount of generated/excess energy per month, the initial investment/replacement, and operating and maintenance (O&M) costs of each element. As a result, geographical regions of Turkey are compared in terms of these outputs graphically. Further investigations may include the sale of excess energy generated, small-scale PV system cost factors parallel to the grid, and the effects of government incentives.

Performance analysis of a soil-based thermal energy storage system using solar-driven air-source heat pump for Danish buildings sector

Denmark has set an ambitious long-term future energy goal to become independent of fossil fuel by 2050, depending completely on renewable and alternative resources in the energy and transport sectors. Solar energy is one of the most favourable alternative resources in terms of cleanness, safety and the economic and environmental aspects. However, the intermittent nature of solar energy and the lack of high solar radiation intensities in various climates favour the use of various energy storage techniques to eliminate the discrepancy between energy supply and demand. The current work presents an analysis and evaluation of the performance of an underground soil-based thermal energy storage system for solar energy storage, coupled with a combined heat and power generation system. A combined PV-Air Source Heat Pump (ASHP) system is utilized to fulfil heating and electricity needs of a housing project in Odense, Denmark, in addition to charging the soil storage medium in summer months when excess electric power is generated. The stored heat is discharged in December and January to provide the space heating and domestic hot water demands of the residential project without the utilization of an external heating source. Employing a PV system of 30kW capacity, it was found that a storage medium of 900m3 of soil is capable of providing the heating needs for a housing project of 1000m2 internal floor area. The year round transient behaviour of the thermal energy storage medium is reported in addition to the heat losses and the surrounding soil temperature variation throughout the year. It was found that the overall system heating coefficient of performance is around 4.76, where the reported energetic efficiency is 5.88% for the standalone PV system, 19.1% for the combined PV-ASHP system, and 22.2% for the combined PV-ASHP system employing a seasonal underground thermal energy storage block.

An optimal control strategy for standalone PV system with Battery-Supercapacitor Hybrid Energy Storage System

Abstract This paper proposes an optimal control strategy for a standalone PV system with Battery-Supercapacitor Hybrid Energy Storage System to prolong battery lifespan by reducing the dynamic stress and peak current demand of the battery. Unlike the conventional methods which only use either filtration based controller (FBC) or fuzzy logic controller (FLC), the proposed control strategy comprises of a low-pass filter (LPF) and FLC. Firstly, LPF removes the high dynamic components from the battery demand. FLC minimizes the battery peak current demand while constantly considering the state-of-charge of the supercapacitor. Particle swarm optimization (PSO) algorithm optimizes the membership functions of the FLC to achieve optimal battery peak current reduction. The proposed system is compared to the conventional system with battery-only storage and the systems with conventional control strategies (Rule Based Controller and FBC). The proposed system reduces the battery peak current, battery peak power, maximum absolute value of the rate of change of power and average absolute value of the rate of change of power by 16.05%, 15.19%, 77.01%, and 95.59%, respectively as compared to the conventional system with battery-only storage. Moreover, he proposed system increases the level of supercapacitor utilization up to 687.122% in comparison to the conventional control strategies.

Evaluation of Solar Energy Potential in Malaysia

Most developing countries are facing the same problem of increasing population and pollution. This has led to the increase of energy consumption that forces them to seek for alternative energy other than depleting fossil fuel such renewable energy namely solar. Located in South East Asia, Malaysia is confronting with the same situation. In this study, the evaluation of potential of solar energy for three locations in Malaysia including Pontian, Kerteh and Teluk Intan is performed using HOMER software. Based on the results, Pontian generates the highest annual solar electricity generation of 543,509 kWh year-1 due to the large size of 400 kWPV panel of the system. However, the cost of energy or also known as COE produced is expensive. On the other hand, with the highest solar radiation received in Kerteh, the PV stand-alone system requires lower size of 350 kW PV panel but at the same time is able to fulfil the demand with the lowest COE of $0,442 kWh-1 among other locations.

Review and design of a standalone PV system performance

Global interest in solar power has reached new highest with continues efforts by governments and organizations to establish a stance against fossil fuel dependence and the high percentage of carbon dioxide emitted by the industrialized world. Employing ren...

Design, simulation and economic analysis of standalone roof top solar PV system in India

The process of acquiring photovoltaic power involves designing, selecting and determining specifications depending on a variety of factors, such as geographical location, weather condition, solar irradiance, and load consumption. In this paper a detailed design of a standalone rooftop solar PV system to provide uninterrupted power supply for a hostel building is presented. It outlines the detailed procedure for specifying each component of the stand-alone rooftop solar PV system and its performance analysis using simulation software. Detailed cost analysis including installation and maintenance of a rooftop solar PV system during its life span has also been carried out. The cost of PV generation and environmental benefit are also highlighted.

Architectures for scalable integrated photo driven catalytic devices-A concept study

Architectures with various degrees of integration are investigated for water splitting devices using the energy of light for fuel production. The many approaches presented in literature for such ‘photo driven catalytic (PDC) devices’ are reviewed and discussed in perspective of their scalability to large area. Then, back-of-the-envelope type techno-economic considerations for such systems are presented. Compared to the benchmark, consisting of large electrolyzers coupled to the grid, it was found that PDC devices could be competetive in places with high irradiation, given the assumption that no compromises on system stability have to be made compared to stand-alone PV-systems for electricity generation. In agreement with literature, it was found that the cost of the PV part dominate the hydrogen generation costs, based on today's technology. Thus, device architectures that allow low cost PV (by e.g. avoiding use of costly materials or introducing further inherent loss mechanisms) are considered the most promising ones.

Performance Analyzing of Stand-Alone PV Hybrid Mini-Grid System with PV at DC and AC Coupling

Stand-alone PV system has been originally developed to feed solar energy produced by PV modules into the system by using solar charger controller at DC bus called “DC Coupling” for long time. In Late 1990 there is a new concept of feeding solar energy to the PV system at AC bus called “AC Coupling”. The AC coupling system uses grid connected inverter to convert energy produced by PV modules and synchronize output to AC distribution line. In mini grid system the common AC output of Bi-directional inverters or diesel generators performs as grid forming device to supply distribution line. Since 1990 there are stand-alone PV systems designed by using DC coupling or AC coupling which each type of PV coupling system highlight their advantage over the other. The work in this document presents a comparison of the efficiency of DC coupling and AC coupling PV system design in a hybrid mini-grid and finally proposes the alternative PV system design by using the “Dual DC and AC coupling” PV system in a hybrid mini-grid design. The HOMER Pro micro-grid analysis tool which can simulate DC and AC coupling PV system is used to compare leverage cost of energy (LCOE) of different type of PV hybrid mini-grid system. The simulation software which can do performance analyzing metric according to IEC 61724 and IEA-PVPS T2 is created in this study in order to simulate system operation and performance using DC, AC and dual DC and AC coupling PV system. The conclusion can clearly identify the best PV system in hybrid mini-grid in terms of LCOE and system performance.