Photovoltaic Pumping Research Articles

Efficient solar‐powered water pump with single‐input dual‐output DC–DC converter employing four‐phase SRM drive

The present work deals with the design of an efficient and inexpensive autonomous photovoltaic array-based water pumping system utilising a new configuration of a single-input balanced dual supply buck–boost DC–DC converter. A four-phase switched reluctance motor (SRM) drive is selected to pump the water effectively and to make the system reliable. The utilised DC–DC converter can provide two balanced outputs using a single solar power source. It offers continuous output supply with minimum ripple to the SRM pump. The new control logic is also discussed in this work to provide equal voltages for two capacitors of the split converter in both starting and steady-state conditions. An improved perturb and observer-based maximum power point tracking control is also utilised to enhance the solar output power at varying irradiance. Moreover, owing to the pulse-width modulation switching of a split converter, a reduction is achieved in the size of split DC-link capacitors. The MATLAB/Simulink-based simulation is done to validate the real-time implementation of a developed system. These obtained responses are again validated through test results obtained via the developed prototype.

The Energy Performance and Techno-Economic Analysis of Zero Energy Bill Homes

In the past 12 years, the United Kingdom (UK) has made significant progress in making domestic dwellings more efficient. Presently, the domestic sector is required to meet the UK’s net-zero target in new and renovated dwellings by 2050. As a measure in this on-going determination, the UK has constructed a number of Zero Energy Bill Homes (ZEBH) in Corby, Northamptonshire, which is currently a part of the European Union District of Future Project. For the effectiveness of a zero energy bill performance, a solar photovoltaic thermal-assisted heat pump (SPVTAH) was modelled, which represented building modelling, emphasising the essential outcomes through energy demand profiles (electricity, space heat, and domestic hot water), and occupant behaviour. To authenticate the building modelling, the baseline models were calibrated using the weekly electricity-use curve and validated using statistical indices. It is inferred that the evidence-based manual calibration technique has fairly validated the energy-use profiles of the chosen case studies and is found to be within acceptable tolerance levels. In addition, to verify the zero-energy bill status of the buildings, an economic analysis was extremely crucial. A feasibility assessment indicated that the ZEBH concept will be impractical if the UK government subsidies are withdrawn. Moreover, the Net Present Value analysis further signified that although SPVTAH seemingly generates revenues, the initial investment turned out to be the largest barrier to repay for the system. However, it was proven that the renewable energy technology operational in the domestic dwellings of the UK does offer major advantages, and reduction in costs appears to be the most significant one.

Solar Energy Application in Indian Irrigation System

The electricity deficit and high diesel costs influence the pumping needs of urban water supply and irrigation; hence, the use of solar power for water pumping is a viable alternative to traditional water pumping systems dependent on grid power and diesel. In recent decades, attention has been given to clean and renewable energies from the vast majority of countries’ priorities in the environmental and economic sectors. Agricultural sector is backbone of Indian economy as population increases demand of water also increases. Extract and transfer of water to agriculture and drinking is equals high-energy consumption. One of the best solutions is to use of an abundant and almost free solar energy to supply energy in all sectors, especially the irrigation sector. In the growth period of crops, when irrigation is often required, there are a high of solar radiation comes from the sun. This study shows that in India, like many other developing countries, the weakness of using this important source, the program of converting solar energy, and photovoltaic pumping systems use. This paper summarizes solar energy development and its application in the irrigation system and comparing them with the conventional diesel pumps. The expected results of this paper are to encourage the politicians, statesmen, and professionals to planning and policy-making the use of the green energy industry in the water sector that could pump water to the villages and agriculture and jump in the energy sector to the economic and Sustainable development.

Modelling and Design Methodology of an Improved Performance Photovoltaic Pumping System Employing Ferrite Magnet Synchronous Reluctance Motors

This paper proposes a novel photovoltaic water pumping system (PVWPS) with an improved performance and cost. This system doesn’t contain a DC-DC converter, batteries nor rare-earth motors. Removing the aforementioned components will reduce the whole cost and increase the reliability of the system. For enhancing the performance of the PVWPS, a ferrite magnet synchronous reluctance motor (FMSynRM) is employed. Besides, the motor inverter is utilized to drive the motor properly and to extract the maximum available power of the PV system. This is performed using a suggested control strategy that controls the motor inverter. Furthermore, to show the effectiveness of the proposed PVWPS, the performance of the proposed system is benchmarked with a PVWPS that is employing a pure SynRM. Moreover, the complete mathematical model of the system components and the control is reported. It is proved that the flow rate employing the proposed system is increased by about 29.5% at a low irradiation level (0.25 kW/m2) and 15% at a high irradiation level (1 kW/m2) compared to the conventional solar system using a pure synchronous reluctance motor (SynRM). An experimental laboratory test bench is built to validate the theoretical results presented in this research work. Good agreement between the theoretical and the experimental results is proved.

Energy efficiency improvement of water pumping system using synchronous reluctance motor fed by perovskite solar cells

Perovskite solar cells (PSCs) are in the forefront of third-generation of photovoltaics and gained a lot of attention as a very promising green technology toward direct solar energy conversion to electricity. PSCs are fabricated following solution-processed techniques at low temperature and they present high power conversion efficiency exceeding 25%, enabling them to be attractive alternative to the silicon-based devices. This research work proposes an efficient and cost-effective photovoltaic (PV) pumping system based on PSCs. For this purpose, lab-scale PSCs were fabricated and their characteristics were determined. In parallel, the geometry of a synchronous reluctance motor (SynRM) driving a 350 m(3)/day water pump was optimized for maximizing the output power, while minimizing the torque ripple simultaneously. In addition, a perovskite solar array feeding the SynRM via an inverter was designed and implemented. The inverter was properly regulated by a control system which optimized the maximum available power of the PSCs solar array and the SynRM characteristics. Finally, laboratory measurements were performed, including a power generator simulating the behavior of the PSCs array feeding the SynRM. The obtained results confirmed the experimental validation of the proposed approach.

Cooperative control of photovoltaic based water pumping system

In this study, novel control schemes are developed for cooperative control of stand-alone and grid-connected photovoltaic (PV) based water pumping system. Brushless DC motor is used as pumping motor due to its superior characteristics. The cooperative control effectively utilises the available resources. In stand-alone system, control scheme is developed for power sharing among PV pumping units. Assuming some of the PV units have battery, the charging/discharging controller is incorporated. In grid-connected system, flexible control scheme is proposed so that consumer can draw lesser power from grid by running the motor at lower speed instead of rated speed. In case of high PV power penetration into weak grid, the modified perturb and observe algorithm is proposed for sharing of de-loaded power among the PV units. Due to de-loading of PV power, motor speed reduces, hence, speed compensation mechanism is developed to bring back the speed at desired value. As a futuristic concept, consumer can buy power from neighbour instead of taking from grid. To establish above-mentioned concept, control scheme is developed for sharing the power among PV pumping units. The simulation and hardware results are carried out to test performance of the proposed control schemes.

A Comparative Economic Feasibility Study of Photovoltaic Heat Pump Systems for Industrial Space Heating and Cooling

The use of photovoltaic (PV) systems for powering heat pumps (HP) leads to an economic, energy efficient and environmentally friendly alternative for heating and cooling generation. A technical solution developed by the authors permits stand-alone configurations to operate without batteries, mitigating up to 75% of the solar power fluctuations resulting from cloud-passing. Once its technical feasibility has been demonstrated, the economic potential of this innovative solution should be assessed (avoiding a battery system is a significant advantage). This paper presents a comparative economic assessment of this autonomous (AU) solution and a self-consumption (SC) solution, that would substitute a grid-powered HP system for the space heating and cooling of two livestock farms located in Spain. Results show that PV-HP systems are economically feasible regardless of the technical solution: the Profitability Index (PI) is in the 2.23–2.97 €/€ range, the Internal Rate of Return (IRR) is in the 8.1–10.9% range, the Payback Period (PBP) is in the 9.2–11 years range and the savings in terms of the Levelized Cost of Energy (LCOE) are in the 57–70% range. The AU solution offers a higher economic profitability, because it permits larger savings in the electricity bill. The SC solution presents lower LCOEs because of its greater electricity production.

Technical paradigms in electricity supply for irrigation pumps: Case of Maharashtra, India

Solar photovoltaics are being promoted in various parts of the developing world for irrigation pumps as a clean energy source, for use in remote areas, to provide livelihood generation, and in India, additionally to address issues with grid supply. India has a well-developed system of electricity distribution for irrigation, but socio-political issues in this sector have led to a system with poor quality supply for farmers, and losses for distribution utilities. A technical solution is being sought through the following new paradigms: offgrid solar photovoltaic pumps, grid-connected solar photovoltaic pumps, agricultural solar feeders, and High Voltage Distribution Systems (HVDS). These paradigms have been evaluated in this work considering Maharashtra, a representative state with an agricultural distribution infrastructure similar to many states of India. We conduct a comparison of the ALCC (Annualized Life Cycle Costing) of the different technologies based on the seasonality of irrigation, sizes of pumps, and areal density of connections as reflected in the cost of infrastructure, by using marginal costs for supply of electricity. Energy consumption of five agricultural feeders representing four main agro-climatic zones of Maharashtra, has been considered to provide context. The study finds that offgrid solar photovoltaic pumps are more cost-effective than the current system when operated for more than 875 h annually. Other than that most systems are more likely to be economically suboptimal in comparison to upgrading the current distribution system. Other researchers have proposed that grid-connected solar photovoltaic pumps can be used to encourage farmers to reduce groundwater extraction through the use of feed-in tariffs. This study finds that the economics do not support this contention.

A comparative study between PI and cascaded sliding regulator based on rotor flux oriented control for photovoltaic pumping system and fuzzy MPPT optimization

In this paper, a comparative study between the PI and the cascaded sliding regulator is made, based on rotor flux oriented control for the photovoltaic pumping system. In order for the motor-pump to be always optimized and operate at the maximum power for each change of illumination or temperature, it is necessary to integrate the MPPT tracking system, we used the fuzzy MPPT technique. The three-phase converter is controlled by the technique of vector width modulation (SVPWM), characterized by low response time and oscillation. Simulations of the proposed structures are validated under Matlab/Simulink. The obtained results show the superiority of cascaded sliding mode control combined with fuzzy MPPT technique, they confirm the effectiveness of this control structure in terms of parametric robustness and ensure proper operation over the entire speed range.

Investigation of the use of photovoltaic solar water pump by occupants of residential buildings in Ile-Ife, Nigeria

The study examined the types of pumps used in supplying water to buildings, assessed the factors affecting the adoption and use of photovoltaic solar water pump and the perception of stakeholders on the use of the photovoltaic solar water pump in the study area. These were done to assess the effectiveness of the use of photovoltaic solar technology to improve the availability of water for the use of the building occupants. The study was carried out in Ile-Ife Region, Osun State, Nigeria. Stratified random sampling was used to categorize the selected residential buildings based on their distance limits to the locations of boreholes, 1-300m, 301-700m, and 711-100m respectively. Systematic sampling was further used in the selection of residential buildings and respondents in the study area. A total of 125 questionnaires were administered on the respondents and the data collected were analyzed using both descriptive and inferential statistical methods. The result shows that a very significant proportion of the respondents, 83.33% depended on wells and boreholes while 73.33% of the wells/boreholes used in the study area had pumping facility. A large proportion of the boreholes in the study area had photovoltaic facilities and were majorly (60%) donated by the government. The most significant factor that influenced the adoption and use of photovoltaic solar water pumps was the level of technical know-how (mean score of 4.1167) and the most ranked benefit had from the use of the facility was less time spent in collecting water (mean score of 4.3583). To foster the availability of quantitative and qualitative water for the use of the building occupants through the provision of photovoltaic water supply, efforts are direly needed to take advantage of the tropical environment of the study area, to ensure optimum performance and security of the facility to drastically reduce dependence on the national grid.

A novel fuzzy controller for photovoltaic pumping systems driven by general-purpose frequency converters

In this paper, a fuzzy logic based Mandani-type controller is applied to an industrial frequency converter to couple a photovoltaic generator to a conventional centrifugal pump for water pumping applications. The system operates in closed loop and the DC bus voltage regulation of the frequency converter is done indirectly by varying the speed of the pump according to the power provided by the photovoltaic generator. In order to decrease the number of series-connected modules, the working voltage of the photovoltaic generator (maximum power point voltage) must be as close as possible to the minimum voltage limit required by the frequency converter’s input. The proposed algorithm was embedded in a general-purpose microcontroller. Controller performance was evaluated through tests on an experimental bench that allows simulating different water heads. Experimental results shows that the speed of the proposed fuzzy controller allows the operation close to the lower DC voltage limit imposed by the frequency converter, making possible the use of photovoltaic generators with a reduced number of PV modules in series (in this work, 30% fewer modules). The fuzzy controller regulates the photovoltaic generator voltage throughout the day, avoiding frequency converter limitation due to undervoltage errors, even with sudden changes in irradiance.

Technical evaluation of a stand-alone photovoltaic heat pump system without batteries for cooling applications

The coupling of Photovoltaic (PV) and Heat Pump (HP) systems is an attractive alternative for reducing the energy consumption associated to cooling applications, as well as increasing the renewable share in the electric systems. This work presents the results of the technical validation of a stand-alone PV-HP system operating without batteries, for two different control algorithms implemented for the compressor of the HP unit: the Maximum Power Point Tracking control (MPPT) and the inverter control. Both algorithms include a routine for mitigating the solar power fluctuations due to passing clouds, which was able to resist 75% of the clouds registered during the carrying out of the tests. The values of the main Key Performance Indicators (KPIs) traditionally used for the characterization of PV and HP systems –Performance Ratio (PR), Energy Efficiency Ratio (EER) and Seasonal Performance factor (SPF)– were calculated, as well as some new KPIs proposed for PV-HP systems. These new KPIs are proposed to distinguish the loss of performance due to any bad quality of the PV-HP and to external factors such as user behavior or the cooling period. The results show a PR of between 0.17 and 0.5, an EER of between 2.51 and 3.06 and a SPF of between 2.51 and 3.01. The low PR value is explained by the utilization ratios of the system (UREF ranged from 0.27 to 0.77) due to the characteristics of this application, rather than any bad quality in the PV-HP system.

DIRECT CONNECTION PHOTOVOLTAIC SYSTEM IN MULTI-MOTOR APPLICATION FOR THE RURAL SECTOR

Photovoltaic pumping systems equipped with variable speed drive have been consolidated as an alternative for water supply in rural locations where energy services are unavailable. Such systems are of the direct connection type and, therefore, it is likely that their operation occurs in two situations: when energy is available and when the reservoir is full or the available energy is insufficient for pumping water. Thus, this study aimed to evaluate the shared use of a photovoltaic pumping system equipped with a variable speed drive and the motor load of the agricultural equipment (cassava grater). The tests were performed in the laboratory and subsequently in the field, where data of the grated cassava production was collected in periods when the solar radiation is insufficient to pump the water. The results indicate that water can be pumped at an irradiance higher than 375 W m-2, while the cassava grater can operate at an irradiance starting from 200 W m-2. Thus, we could conclude that the agricultural equipment can be used in a photovoltaic pumping system equipped with a variable speed drive in a complementary way such that, besides optimizing the use of energy, it adds a new functionality to the application through the use of agricultural equipment.

A study on the viability of an on-site combined heat- and power supply system with and without electricity storage for office building

The building sector in the European Union accounts for over 40% of the final energy use, where the usage of non-residential buildings may be up to 40% higher than the residential sector. Improving building energy efficiency across all categories of buildings is one key goal of the European energy policies, made prominent by the Climate and Energy package, Energy Performance of Building Directive and Energy Efficiency Directive. In this study, the profitability of an on-site combined heat and power supply system for an office building is investigated. A reference model utilizing solely district heating was constructed and used for validation purposes. Then, a photovoltaic assisted ground source heat pump model was developed and investigated with and without electrical storage to reveal the most cost-effective investment scenario in cold climate regions. The reference model was validated using consumption data provided by the facility owner, after which an investigation of the energy saving potential along with the economic viability of adapting a new heat- and power supply system was conducted. It was concluded that a ground source heat pump in combination with a standalone rooftop photovoltaic system, was successful in satisfying thermal requirements while lowering the building specific energy demand compared to utilizing a district heating system. The photovoltaic assisted ground source heat pump system including a battery bank is the most profitable when incentives are granted, a higher self-consumption of 93.1% is achieved with a battery capacity of 38.4 kWh.

The detection and correction of various faulty sensors in a photovoltaic thermal heat pump system

Accurate and reliable measurements collected from various physical sensors are of great importance to improve the energy utilization efficiency of solar energy systems. Sensor errors have various significant negative impacts on the automatic control and optimized operation. The current study used the virtual in-situ calibration (VIC) instead of traditional methods to spot possible systematic and random errors of temperature, pressure and mass flowrate sensors in a photovoltaic-thermal heat pump (PVT-HP) system. Seven working conditions were designed to check the robustness and accuracy of the proposed VIC technology. The effects of systematic and random errors on the sensor calibration process and performance estimation of a PVT-HP system were investigated. It’s shown that after calibration the systematic errors of all kinds of sensors were less than 2% and the random errors were also reduced by as much as 74%, significantly reducing the possibility of abnormal data and enhancing the reliability of sensor measurements. The VIC method is very effective to guarantee the thermal performance of PVT-HP system.

Adoption of renewable energy technologies (RETs) using a mixed-method approach

Purpose This paper aims to propose that the socio-technical perspective is under-represented when appraising the adoption potential of renewable energy technologies (RETs) in late-industrialising countries and that this results in under-adoption. It also aims to identify a methodological approach that allows the socio-technical perspective to be integrated into management decision-making, alongside the more typical economic appraisal methodology. Design/methodology/approach A case study and novel mixed-methodology approach is used, which applies the diffusion of innovations framework, innovation system (IS) framework and system dynamics modelling (SDM) alongside traditional economic modelling and appraisal techniques. This approach is used to assess the adoption potential of solar photovoltaic (PV) and diesel water pumping systems in the wildlife conservation sector and surrounding rural communities in Kenya. The case study approach tests the merits of the mixed-methodology approach. Findings The life-cycle costs of solar PV water pumping systems are lower in nearly all financing and utilisation scenarios; offer additional social, technical and environmental benefits; and the conditions exist for greater adoption. The use of an integrated diffusion of innovations and IS framework generates significant qualitative data that can support management decision-making. The use of SDM techniques aid conceptualisation of the community economic, water and institutional systems into which water pumps may be diffused and provide a starting point for formal SDM simulation. The results suggest that these techniques capture the socio-technical perspective well and, when used alongside traditional project appraisal approaches, produce more complete information with which to support management decision-making. Originality/value This mixed-methodology approach could be used by practitioners to increase the diffusion and adoption of RETs in more complex contexts in late-industrialising countries. The emergent theory built through the case-study approach should be tested further to assess the merits of applying these techniques to support RET management decision-making in other contexts and more broadly.

Optimisation of the distribution of power from a photovoltaic generator between two pumps working in parallel

In this work, a method for distributing the power generated in a photovoltaic pumping system equipped with two equal pumps, working in parallel is analysed.For this purpose, a system equipped with two pumping groups 0.75 kW each was investigated. Experimental tests at five different working frequencies (30 to 50 Hz), and at six pumping heads (18 to 48 m) were carried out.The main objective of this paper is to establish a strategy for the distribution of the generated power that maximises the flow rate from the set of two pumps. This distribution depends both on the available electric power and on the pumping head.The results show some differences between higher and lower pumping heads, but in both cases for lower power values, the strategy involves the operation of a single pump with the limitation that the power assigned to this pump cannot exceed the maximum value (Pmax). However, if the available power exceeds a certain value, referred to as Pe, it must then be distributed at 50% between the two pumps. Thus, there is no power distribution ratio other than 0 and 50% that maximises the flow rate, except that required to limit the power assigned to one of the pumps to Pmax.It was proven that the optimal distribution strategy for the available power depends on whether Pe > Pmax (for higher pumping heads) or Pe < Pmax (in case of lower heads). In practice, it is easy to determine which case applies using a simple pumping test.

Performance enhancement of a photovoltaic thermal (PVT) and ground-source heat pump system

A new system consisting of photovoltaic thermal-ground source heat pump (PV/T-GSHP) was proposed as a solution for electricity shortage and high electricity consumption in heating buildings in Jordan. The performances of the photovoltaic system and the ground source heat pump system were studied without coupling as in real life and with coupling in a hybrid system using TRNSYS software. The results show that this PV/T-GSHP hybrid system can reduce the photovoltaic panels' temperature by more than 20 °C, and improve the efficiency of electricity production by 9.5 %, simultaneously. And in heating season the average coefficient of performance of the heat pumps increased from 4.6 to 6.2 with a decreament in electricity consumption by 25.7 %. The life cycle cost of the hybrid system decreased by 3.9 % and the net present value inceased by 13.2 % compared to the two systems separated. The model of the PV/T-GSHP system was established using TRNSYS software, an optimmization was made to select the photovoltaic modules' temperature at which cooling starts, followed by technical and economical studies on both systems separated and coupled in a hybrid system. This hybrid system can provide guidance for future related project.

Adaptive neuro fuzzy selection of the most important factors for photovoltaic pumping system performance prediction

The main aim of the study was to perform a selection procedure to determine the most important factors for the photovoltaic pumping system performance prediction. As the input factors, photovoltaic modules loss, water control counter loss, pump loss and pipe system loss were used along. As the output factor performance ratio of the photovoltaic pumping system was used. The performance ratio of photovoltaic pumping system is an important parameter for quality measurement of the system. There is a need to analyze which factors have the most influence on the performance ratio in order to perform satiable calibration in order to reduce losses of the system. Adaptive neuro fuzzy inference system (ANFIS) was used to determine factors’ influence on the performance ration of the system. Root mean square error (RMSE) was used to assets the influences. Based on the RMSE values loss of photovoltaic modules has the strongest impact on the performance ratio of the system. The obtained results could be of practical usage for improving performance ration of the photovoltaic pumping system.

Multistage Bounded Evolutionary Algorithm to Optimize the Design of Sustainable Photovoltaic (PV) Pumping Irrigation Systems with Storage

Small off-grid photovoltaic (PV) pumping irrigation systems with storage tanks are an environmentally friendly, cost effective and efficient way of taking advantage of solar energy to irrigate crops, and they are increasingly being used today. However, finding the optimal design of this type of system is cumbersome since there are many possible designs. In this work, a new heuristic method based on the hybrid approach, which uses search space reduction, is developed and adapted to the optimal design for this type of PV irrigation system. At different stages, the proposed approach iteratively combines a bounding strategy based on the application of engineering rules with the aim of reducing the search space with a genetic algorithm to find the optimal design within this search space. The proposed methodology was applied to minimize the cost of a benchmark case study consisting of a real farm placed in the province of Almería (Spain). The proposed methodology was able to provide a faster and an accurate convergence due to the reduction of the search space. This fact led to a reduced total cost of the system. This study proved that the most sensitive variables were the number of modules and the type of pump, whereas the diameter of the pipe and volume of the storage tank remained more stable.