Photovoltaic Pumping Research Articles

Optimal control of a grid-connected photovoltaic agricultural water pumping system

Optimization of water pumping systems has been studied using various techniques which include classical, mathematical, and heuristics. Few studies have explored use of optimal controllers in agricultural water pumping applications. Some studies also ignore the interconnection between the water demand and energy used. Introduction of renewable energy sources such as photovoltaic (PV) necessitates different geographical studies as the intensity of the renewable energy varies widely with location. In this paper, an optimal controller for a batteryless grid-connected photovoltaic system to power water supply system for irrigation purposes was developed. The aim was to minimize the operational cost of grid energy by maximizing utilization of photovoltaic power and minimizing the utilization of grid power. A case study was done at a farm in Kajiado (−1.6033257^{circ } latitude and 36.7863352^{circ } longitude). The farm photovoltaic, grid power, water pumps (underground and booster pump), and storage tanks were modelled into a binary linear programming optimization problem and solved using intlinprog solver on MATLAB. Energy demand data was collected using a three-phase power logger, while water demand data was collected using onsite water meter and stopwatch timer. Photovoltaic power produced was estimated using Photovoltaic Geographical Information System (PVGIS). Simulation results obtained show that the use of an optimal controller results in reduced cost of energy by 44.4%. Better utilization of renewable photovoltaic energy by 24% was observed, and 3.6% more water was pumped.

Energy and Cost Analysis of an Integrated Photovoltaic and Heat Pump Domestic System Considering Heating and Cooling Demands

The integration of photovoltaic panels and heat pumps in domestic environments is a topic that has been studied extensively. Due to their electrical nature and the presence of elements that add thermal inertia to the system (water tanks and the building itself), the functioning of compression heat pumps can be manipulated to try to fulfill a certain objective. In this paper, following a rule-based control concept that has been identified in commercial solutions and whose objective is to improve the self-consumption of the system by actively modulating the heat pump compressor, a parametric analysis is presented. By making use of a lab-tested model, the performance of the implemented control algorithm is analyzed. The main objective of this analysis is to identify and quantify the effects of the main parameters in the performance of the system, namely the climate (conditioning both heating and cooling demands), the photovoltaic installation size, the thermal insulation of the building and the control activation criteria. A total of 168 yearly simulations have been carried out. The results show that the average improvement in self-consumption is around 13%, while the cost is reduced by 2.5%. On the other hand, the heat from the heat pump and the power consumed increase by 3.7% and 5.2%, respectively. Finally, a linear equation to estimate the performance of the controller is proposed.

Fault detection and calibration for building energy system using Bayesian inference and sparse autoencoder: A case study in photovoltaic thermal heat pump system

Fault detection and calibration for building energy system using Bayesian inference and sparse autoencoder: A case study in photovoltaic thermal heat pump system

Research on designated calibration method of fault sensor in photovoltaic thermal heat pump system based on fault detection and virtual calibration

With the increasingly serious global energy problem, clean energy sources such as solar energy have become the mainstream focus of development. Among these, solar Photovoltaic thermal (PVT) heat pump systems have promising prospects. However, incorrect data transmitted by sensors can significantly impact the operation and control of the entire heat pump system, leading to reduced efficiency. Given the specific nature of PVT heat pump systems, their internal sensors are prone to errors during operation. To address these challenges, the Autoencoder Virtual in-situ calibration (AE-VIC) is applied to PVT heat pump systems. Preliminary studies have shown that this method can effectively reduce systematic and random errors in sensors. However, the current AE-VIC method faces certain issues, including unclear calibration targets and inefficient calibration of multiple sensors simultaneously, making it difficult to implement in practical systems. In order to overcome the limitations, fault detection is integrated with AE-VIC. By combining the feature extraction capability of Autoencoder with a Softmax classifier, sensors with faults can be identified before the overall calibration process, making the calibration objective of the AE-VIC more targeted. Following fault detection, inputs of the AE model are optimized using the mRMR algorithm for the identified faulty sensors. This optimization alleviates the difficulty of calibration. Through validation with actual system, the improved method effectively diagnoses and locates faulty sensors, and subsequently calibrates them. After calibration, the sensor system error can be reduced by over 95%. The improved calibration method surpasses the original AE-VIC method in terms of both time and accuracy.

Quantifying the energetic cost tradeoffs of photovoltaic pumping systems for Sub-Saharan African smallholder farms

As solar technology has matured, irrigation using photovoltaic pumping systems (PVPSs) has gained popularity in developing markets as an effective means to alleviate poverty and increase food security. Yet, there remains a barrier to adoption; the upfront costs of PVPSs pose a financial burden for many low-income farmers. In a PVPS, the capital cost of the solar array contributes a large portion of upfront system costs. The solar pump is the largest energy consumer in the system, thus its efficiency directly impacts the size and cost of the solar array. There is a limited quantitative understanding of how solar pump efficiency affects the capital cost of the solar array. This study presents a technoeconomic framework to directly quantify the impact of solar pump efficiency on the cost of the solar array in a PVPS, for a range of hydraulic operating conditions. New empirical efficiency scaling laws were created by characterizing the efficiencies of 4-inch multistage centrifugal borehole pumps and induction motors. The utility of the technoeconomic framework is demonstrated through a case study comparing solar pump architectures with motors of different efficiencies. Results indicate that, despite the increased motor cost, the use of high-efficiency motors in solar pumps may lead to an overall cost reduction in a PVPS. Counter to the conventional capital cost-driven process, this work demonstrates that an efficiency-driven design process could improve low-cost, solar-powered system design. Engineers and system designers can leverage the presented framework during the design process to make informed decisions to achieve more cost-effective PVPSs.

A 600 W Photovoltaic Groundwater Pumping System Based on LLC Converter and Constant Voltage MPPT

The work consists of the development of a market-friendly 600 W photovoltaic battery-less water pumping system. The system is composed of four 280 Wp solar panels, an auxiliary 10 W solar panel, a three-phase converter and a ½ horsepower (hp) submersible water pump. The electronic stage involves a resonant DC-DC converter in series with a voltage source three-phase inverter. The novelties of this work are related to the use of a resonant DC-DC converter with fixed duty-cycle and frequency for water pumping application, the use of Silicon Carbide Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) for solving converter startup issues, and the use of a constant voltage maximum power tracking (MPPT) algorithm with auxiliary panels. The work displays the design of the converter, simulation and experimental results, discussions, and cost evaluation. The feasibility of the system is studied for the water requirements of a beef cattle farm in Brazil.

Evaluation of the performance of a FONN-based MPPT control for a photovoltaic watering system

This study aims to increase the effectiveness of photovoltaic pumping systems. A practical installation and cost-effective design are suggested. This paper examines the nonlinear behaviour of photovoltaic generators from a distinct perspective; where it repeatedly transitions between a constant current and a constant voltage source and shows how this affects the behaviour of the induction motors. A Fractional-order Neural Network (FONN) is suggested to forecast the harvested solar-energy. The results showed that FONN improved forecasting accuracy by effectively capturing the nonlinear behaviour of PV panels. A Fractional Order MPPT (FO-MPPT) control augmented with Gray Wolf, Anti-lion, and Whale metaheuristic optimizers is proposed and shows capacity to maximize the harvest power for the PV-driven Induction Motor-Pump. The proposed FO-MPPT is compared to conventional techniques using several performance metrics. According to the comparison study, the optimized FO-MPPT enhances the standard MPPT and shows superiority in managing the nonlinear and unpredictable dynamical loads.

Performance and Cost Comparison of Photovoltaic and Diesel Pumping Systems: In Central Rift Valley of Ethiopia

Diesel pumps have extensively used for irrigation water pumping. However, this causes challenges both in terms of economic factors (fuel costs) and environmental impacts (emits air pollution). An alternative solution is using renewable energy sources. In this regard, a battery less solar PV energy system was designed and evaluated was designed and evaluated for the geographic location and metrological data of Dugda woreda, representing the central rift valley of Ethiopia. Performance testing were conducted on sunny days of April month and with time intervals of from 9:00 am to 5:00 pm, again the respective solar radiation ranges between 385.8 to 862.2 W m^(-2) h^(-1). The solar photovoltaic pumping has been evaluated with the head levels of 10, 12, 15, and 18 m. Accordingly the result showed that, PV system size can irrigate a tomato field of 0.33-0.75 ha with a mean daily water use of 8.7 and 17.4 m^3 〖day〗^(-1) at head levels of 10 and 18 meters, respectively. After evaluation, the maximum water flow rate has been at the midday day from 12:00 am to 1:00 pm. Comparative economic evaluation of the solar-powered water pump system and diesel pump devices were done using cycle cost breakdown and the cost of water per unit volume. Thus the long term economics of water pumping using solar photovoltaic and diesel pumping systems showed a cost of 1.33 〖ETB m〗^(-3) and 3 ETB m^(-3), respectively. The result demonstrated that photovoltaic water pump systems are more affordable for the long-term services of small to medium-scale farms than gasoline water pumps.

Design and Management of a Photovoltaic Pumping System

Solar energy is recognized as one of the most important renewable alternatives to electricity, especially in remote areas where solar energy is not available due to high line costs. This innovative and sustainable solution is becoming increasingly popular in many parts of the world due to its environmental and economic benefits.
 The purpose of this research is to study water pumping using photovoltaic energy. Optimization algorithms are used to track the maximum power point and apply it to control step-ups in order to operate the photovoltaic system at maximum capacity and predict the impact of climate change on system performances. Powering the converter, powering the frequency converter and analysis of motor pump operation under the influence of climate change is presented and discussed however the control system credibility and effectiveness is proved by simulation results under MatLab/Simulink software.

An Efficient Design and Control Techniques of Photo-Voltaic Pumping System (PVPS)

In this paper, new methods for increasing the efficiency of photovoltaic pumping systems are presented (PVPS). A feasible implementation of battery-free PVPS, as well as a cost-effective design, has been proposed. The variation of the PV power causes its behaviour to transit permanently between the characteristics of constant current sources and constant voltage sources, which is studied in this paper from a new perspective. The inconsistency of PV generator behaviour reveals an unexpected phenomenon in the operation of induction motors (IM). To overcome the effects of fluctuating PV behaviour on IM operation, a modified fractional order MPPT controller (FO-MPPT) has been proposed. FO-MPPT has improved as a result of the use of several metaheuristics approaches, including the Grey Wolf (GWO), Anti-lion (ALO), and Whale Optimizer (WOA). A comparison of the proposed FO-MPPT and conventional MPPT techniques is carried out. The steady-state power, rise time, and efficiency are used as three measures to demonstrate the reliability of the proposed controller, demonstrating that the FO-MPPT outperforms traditional MPPT techniques. The optimal FO-ability MPPT’s to regulate nonlinear and unpredictable dynamic loads is demonstrated.

Hybrid PV/T Heat Pump System with PCM for Combined Heating, Cooling and Power Provision in Buildings

Hybrid photovoltaic-thermal heat pump (PV/T-HP) solar energy systems are promising since they can achieve a system total efficiency greater than 80%. By maximizing the output of a PV/T system for simultaneous heating and cooling, this strategy can meet over 60% of urban households’ heating needs and around 40% of their cooling needs. In this work, a novel PV/T evaporator was designed, fabricated, and an aluminium foil encapsulated hydrated salt (HS36) PCM was integrated with the PV/T evaporator of the PV/T direct expansion heat pump system (PV/T-DXHP). Energy analysis was carried out on the PV/T-DXHP system with PCM in tropical climate regions of India for achieving net zero energy buildings. The experimental study revealed that the average PV electricity efficiency was 14.17%, which is near the PV panel’s STC value. The average thermal efficiency of the system was 104.38%, and the PV/T system’s average overall efficiency was 117.58%. The heating and cooling COPs of the system were 5.73 and 4.62, respectively. It was concluded that net-zero energy buildings are possible with the help of photovoltaic heat pump systems that use PCM and solar energy to make electricity, cool spaces, and heat water.

Low-carbon city planning based on collaborative analysis of supply and demand scenarios

With the proposal of carbon reduction goals of countries around the world, "green and low-carbon" has become a new key to urban development and construction. However, in the existing urban planning system, the energy planning mapped by carbon emissions has received less attention, and the main goal is often to ensure safe supply. There is less research on carbon emissions. Therefore, it is necessary to take the energy planning in urban planning as the breakthrough point to carry out research on green and low-carbon development and construction at the urban level in the " Carbon Reduction " era. First, a city in China was taken as the research object to evaluate the resource endowment and development potential of the target city. Then, the carbon reduction paths of target cities in the three fields of construction, transportation and industry were studied, and the carbon reduction potential in different scenarios was quantified. After that, the influence of electric power carbon emission coefficient on different carbon saving scenarios was studied through sensitivity analysis. Finally, the government's low-carbon urban planning and decision-making suggestions were given. The results show that the relatively effective way is to carry out large-scale promotion of ultra-low energy consumption buildings and electric vehicles on the demand side, and to build distributed photovoltaic and heat pump systems on the supply side. On this basis, with the introduction of additional 30% of foreign green power, the per capita carbon emissions of cities would be reduced to 1.5tCO2 in 2035. In this way, the target city can achieve the goal of carbon neutrality in advance. Therefore, the results of this study have certain theoretical reference value for the study of low-carbon urban planning.

Decision Support Tool for the Optimal Sizing of Solar Irrigation Systems

Solar photovoltaic (PV) irrigation is increasingly used in agriculture, driven by its low operation cost and virtually zero emissions, providing electricity access in rural areas. However, the high investment cost requires an optimal design. The objective of this work was to develop a user-friendly tool to optimally size a PV generator that satisfies crop irrigation needs under local constrictions. The ODSIS (Optimal Design of Solar Irrigation System) tool, was organized in three calculation modules, preceded by two complements, which determine the daily crop irrigation needs and power demand of the pumping system. Then, the first module sizes the PV plant, considering a multiplication factor, and provides the PV production potential throughout each day of the season. The second and third modules evaluate the total investment cost and equivalent greenhouse gas emissions avoided by comparison with traditional energy sources. This tool was applied to a case study in Senegal for which a multiplication factor of 1.4 was obtained for the optimal PV plant size. Between 22% to 64% of the investment cost corresponded to the PV pumping system, depending on the irrigation technique. The use of PV energy in the case study would represent an annual economic saving for the farmer after 5 to 8 years of payback period, avoiding the emission of between 29.8 and 37.9 tCO2eq/year for the case study area.

Annual analysis of the photovoltaic direct-expansion heat pump assisted by double condensing equipment for secondary power generation

Thermoelectric generation (TEG) converts heat directly into electricity based on temperature difference. Many studies on combining TEG with photovoltaics to convert waste heat into electricity to increase overall power generation have been conducted. However, through previous research, if TEG was installed between the cooling and PV, it will hinder PV heat dissipation and cause electricity deterioration, which could not be compensated by TEG output. To ensure the PV cooling and meanwhile realize thermoelectric conversion, a photovoltaic direct-expansion double-condensing heat pump system based on TEG assisted by micro-channel heat pipes and water-cooling condenser is proposed. Experiments & mathematical model are carried out & verified. The regional weather conditions at different latitudes and altitudes are adopted to predict the system performance on a year basis. From the results, the electrical efficiency is improved due to the additional TEG power output. With a higher ambient temperature in Hongkong, the heating capacity is higher, but the compressor consumption also increases. With better irradiation and a lower ambient temperature, Garze has brilliant electrical performance, the COPPVT & NEER are the highest at 9.9 monthly & 8.0 annually. Furthermore, the operating costs and CO2emissions of this system are just 1/4–1/3 and 1/3–1/2 of gas boiler, indicating significant potential for energy-savings & emission reduction.

Fuzzy Control of a High-Performance Boost Converter in Discontinuous Conduction Mode and its Application to a Photovoltaic Pumping System

In this work, a fuzzy voltage controller design of a 1 kW high-gain, high-efficiency direct current converter operating in discontinuous conduction mode is developed. In this condition, the design of a conventional controller is more challenging. This converter is part of an autonomous photovoltaic pumping system without batteries consisting of four photovoltaic modules, a variable frequency inverter and an induction motor coupled to a pump. The boost converter is responsible for the voltage elevation of photovoltaic modules to a 311V direct current bus, which must not have oscillations for a good operation of an algorithm to track the maximum power point of the modules. The fuzzy controller was implemented in a digital signal processor device to control the boost converter, producing a response with an overshoot of 5.78%, settling time of 3.8s and zero error in steady state.

Aquifer conditions, not irradiance determine the potential of photovoltaic energy for groundwater pumping across Africa

Groundwater pumping using photovoltaic energy has the potential to transform water services in poorly served areas. Here we develop a numerical model that uses openly available data to simulate the abstraction capacities of photovoltaic water pumping systems across Africa. The first contribution of this article is the detailed design of the large-scale model to include realistic geological constraints on the depth of pumping and sub-hourly irradiance time series. The second one is the provision of results for the whole continent. We simulated results for three system sizes (100, 1000, 3000 Wp) and the daily pumped volumes were found to vary between 0.1 and 180 m3, depending on the size and location. We show that, for much of Africa, groundwater pumping using photovoltaic energy is constrained by aquifer conditions, rather than irradiance. Our results can help identify regions where photovoltaic pumping has the highest potential and help target large scale investments.

Photovoltaic pumping system optimization with improved DTC for irrigation: a comparative study

Photovoltaic pumping system optimization with improved DTC for irrigation: a comparative study

Monitoring of PV systems installed in an extremely hostile climate in southern Algeria: Performance evaluation extended to degradation assessment of various PV panel of single-crystalline technologies

Any photovoltaic (PV) system technology must have been experienced for at least a year to provide valuable information about its seasonal behavior, which requires knowledge of the effects of each component of the PV installation chain. An experimental bench of different PV pumping systems using different PV panels was tested, which these PV systems (PVSs) consist of many brands of single-crystalline silicon (sc-Si) based technologies, including three manufacturers: ET-M53675, Isofotón (I-75 and I-100). This paper used the SV (sophisticated verification) method of analyzing and evaluating PVS performances in detail, for which we have developed a process to achieve good accuracy calculation, intended to estimate their various losses. This method was applied to the databases collected between 2014 and 2020. The output of real energy relative to its installed energy for four PVS configurations is between 72.7 % and 93.6 %, and in some cases it goes down to 48.8 %. This experimental study was extended to assess the degradation rate (DR) of PV panels exposed for long periods in the Saharan environment. Results show that after 2.5 years of operation for the ET-M53675 panels that are newly installed keep the same peak power, while PV panels that have been in operation for between 8 and 10 years have lost between 14.2 % and 19.5 % of their initial power value for Isofotón I-100 and Isofotón I-75 modules, respectively. The installed power in the Isofotón I-100 modules that have operated for more than 14 years has degraded by 23.59 %. This study is an effort to check and assess the feasibility of PVSs and the defects in PV modules found in newer and older installations in a desert environment at real operating conditions to enrich the databases concerning the DR of the various PV panels in the various environments around the world.

Optimal Sizing of a Photovoltaic Pumping System Integrated with Water Storage Tank Considering Cost/Reliability Assessment Using Enhanced Artificial Rabbits Optimization: A Case Study

In this paper, optimal sizing of a photovoltaic (PV) pumping system with a water storage tank (WST) is developed to meet the water demand to minimize the life cycle cost (LCC) and satisfy the probability of interrupted water (pIW) constraint considering real region data. The component sizing, including the PV resources and the WST, is determined optimally based on LCC and pIW using a new meta-heuristic method named enhanced artificial rabbits optimization (EARO) via a nonlinear inertia weight reduction strategy to overcome the premature convergence of its conventional algorithm. The WST is sized optimally regarding the lack of irradiation and inaccessibility of the pumping system so that it is able to improve the water supply reliability. The LCC for water extraction heights of 5 and 10 m is obtained at 0.2955 M$ and 0.2993 M$, respectively, and the pIW in these two scenarios is calculated as zero, which means the complete and reliable supply of the water demand of the customers using the proposed methodology based on the EARO. Also, the results demonstrated the superior performance of EARO in comparison with artificial rabbits optimization (ARO) and particle swarm optimization (PSO); these methods have supplied customers’ water demands with higher costs and lower reliability than the proposed EARO method. Also, during the sensitivity analysis, the results showed that changes in the irradiance and height of the water extraction have a considerable effect on the cost and ability to meet customer demand.

Review on Solar Photovoltaic-Powered Pumping Systems

Water and energy are becoming more and more important in agriculture, urban areas and for the growing population worldwide, particularly in developing countries. To provide access to water it is necessary to use appropriate pumping systems and supply them with enough energy for operation. Pumps powered by solar photovoltaic energy are complex electromechanical systems that include hydraulic equipment, electrical machines, sensors, power converters, and control units. Therefore, solar photovoltaic pumping systems are associated with various fields of science and engineering. In remote, less-populated areas without electricity, where it is either challenging to connect to the grid or it is not possible, solar photovoltaic water pumping systems can play a significant role. To see whether solar photovoltaic pumping systems may be a practical, viable, and affordable method of pumping water it is necessary to study different aspects of their operation. The goal of this current article is to evaluate and outline recent research and advancement in the field of solar photovoltaic pumping systems. The major focus is on the standalone photovoltaic pumping system’s components, factors that affect system efficiency, performance evaluation, system optimization, and the potential for integration with modern control techniques. The main objective of this article is to give a broader overview of solar photovoltaic technologies for researchers, engineers, and decision-makers.