This study scrutinizes the reliability and validity of existing analyses that focus on the impact of various environmental factors on a photovoltaic (PV) system’s performance. For the first time, four environmental factors (the accumulation of dust, water droplets, birds’ droppings, and partial shading conditions) affecting system performance are investigated, simultaneously, in one study. The results obtained from this investigation demonstrate that the accumulation of dust, shading, and bird fouling has a significant effect on PV current and voltage, and consequently, the harvested PV energy. ‘Shading’ had the strongest influence on the efficiency of the PV modules. It was found that increasing the area of shading on a PV module surface by a quarter, half, and three quarters resulted in a power reduction of 33.7%, 45.1%, and 92.6%, respectively. However, results pertaining to the impact of water droplets on the PV panel had an inverse effect, decreasing the temperature of the PV panel, which led to an increase in the potential difference and improved the power output by at least 5.6%. Moreover, dust accumulation reduced the power output by 8.80% and the efficiency by 11.86%, while birds fouling the PV module surface was found to reduce the PV system performance by about 7.4%.

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Thermoelectric generation technology is considered to be one of the viable methods to convert waste heat energy directly into electricity. The utilization of this technology has been impeded due to low energy conversion efficiency. This paper aims to improve the energy conversion efficiency of the thermoelectric generator (TEG) model with a novel maximum power point tracking (MPPT) technique. A variable fractional order fuzzy logic controller (VFOFLC)-based MPPT technique is proposed in the present work in which the operating point of the TEG is moved quickly towards an optimal position to increase the energy harvesting. The fraction order term α, introduced in the MPPT algorithm, will expand or contract the input domain of the fuzzy logic controller (FLC to shorten the tracking time and maintain a steady-state output around the maximum power point (MPP). The performance of the proposed MPPT technique was verified with the TEG model by simulation using MATLAB /SIMULINK software. Then, the overall performance of the VFOFLC-based MPPT technique was analyzed and compared with Perturb and observe (P&O) and incremental resistance (INR)-based MPPT techniques. The obtained results confirm that the proposed MPPT technique can improve the energy conversion efficiency of the TEG by harvesting the maximum power within a shorter time and maintaining a steady-state output when compared to other techniques.

For an efficient energy harvesting by the PV/thermoelectric system, the maximum power point tracking (MPPT) principle is targeted, aiming to operate the system close to peak power point. Under a uniform distribution of the solar irradiance, there is only one maximum power point (MPP), which easily can be efficiently determined by any traditional MPPT method, such as the incremental conductance (INC). A different situation will occur for the non-uniform distribution of solar irradiance, where more than one MPP will exist on the power versus voltage plot of the PV/thermoelectric system. The determination of the global MPP cannot be achieved by conventional methods. To deal with this issue the application of soft computing techniques based on optimization algorithms is used. However, MPPT based on optimization algorithms is very tedious and time consuming, especially under normal conditions. To solve this dilemma, this research examines a hybrid MPPT method, consisting of an incremental conductance (INC) approach and a moth-flame optimizer (MFO), referred to as (INC-MFO) procedure, to reach high adaptability at different environmental conditions. In this way, the combination of the two different algorithms facilitates the utilization of the advantages of the two methods, thereby resulting in a faster speed tracking with uniform radiation distribution and a high accuracy in the case of a non-uniform distribution. It is very important to mention that the INC method is used to track the maximum power point under normal conditions, whereas the MFO optimizer is most relevant for the global search under partial shading. The obtained results revealed that the proposed strategy performed best in both of the dynamic and the steady-state conditions at uniform and non-uniform radiation.

Summary Integration of solar concentrators with photovoltaic (PV) systems reduces the required number of PV panels, which often account for the major costs of PV systems. The linear Fresnel reflector mirror is considered more effective because of its simplicity and effortless fabrication. An experimental test rig of a concentrated PV/thermal system that employs a linear configuration and horizontal absorber was built for evaluating its electrical and thermal performances. The considered concentrator consists of various widths of flat glass mirrors, which positioned with different angles, and with sun light focusing on the PV cells that fixed over an active cooling system. The experimental investigation of the proposed concentrated PV/thermal system shows that higher electrical and thermal efficiencies can be achieved at comparatively high temperature levels than that typically utilized in a nonconcentrated PV/thermal system. The characteristics of PV cells also indicate that the electrical efficiency values in case of no concentration and with concentration ratio of 6.0 are 9.6%, and 11%, respectively. The measured values for the inlet and outlet cooling water temperatures of the receiver showed that the maximum outlet temperature reached was 75°C with a flow rate of 0.025 L/min, and the product thermal efficiency was 62.3%. These obtained results illustrate an adequate and good thermal and electrical performance under the meteorological weather conditions of the province of Al‐Karak in Jordan.

The use of a concentrated photovoltaic (CPV) system significantly reduces the required solar cell area that often accounts for the major cost of a PV solar system. A comprehensive performance analysis of a multi-mirror solar concentrated hybrid PV thermal (CPVT) system was conducted. Among different concentrating systems, Linear Fresnel Reflector (LFR) systems are more effective due to their simplicity of operation and low fabrication cost. A mathematical model and the simulation of a CPVT system employing a linear configuration and horizontal absorber is developed here in order to evaluate its performance parameters, using a FORTRAN programing technique. The concentrator system consists of, different width of flat glass mirrors placed under various inclination angles, focusing sunlight on to the PV solar cells mounted along the active cooling system. The effect of focus distance on concentration ratio, collector width, and heat gained by the coolant fluid are investigated. All parameters of the linear Fresnel reflector solar concentrator system are determined and the effect of cooling mass flow rate and cooling inlet temperature upon the system performance is evaluated. With regards to simulation results obtained via the focus distances, the width of mirrors decreased by increasing the number of mirrors, and in turn by increasing the focus distances, this resulted in an increase in CR values. For the specific number of mirrors, concentration ratio increased simultaneously increasing the focus distance; furthermore, increasing the number of mirrors resulted in a reduction in both the width of the mirrors and their inclination angles, and an increase in CR values. The results further confirmed that the total (combined electrical-thermal) efficiency is higher than that of the individual electrical as well as thermal efficiency; reaching approximately 80% and showed no sensitivity to the rises in cooling water temperature for temperature cases under consideration.

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