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[en] Highlights: • A FEM was developed to estimate the techno-economic performance of the BIPB. • The mean absolute percentage error of the FEM_4_-_n_o_d_eBIPB was determined to be 4.54%. • In implementing the BIPB with the GC_i_n_c_l_._S_R_E_C plan, it was superior to the others. • Users can understand the operating mechanism of the proposed model (FEM_4_-_n_o_d_eBIPB). • The proposed model can be extended to any other country in the global environment. - Abstract: This study aims to develop the four-node-based finite element model for estimating the techno-economic performance of the building-integrated photovoltaic blind (FEM_4_-_n_o_d_eBIPB), which can be used by decision-maker in the early design phase. In developing the proposed model, this study uses various research methodologies such as energy simulation, finite element method, life cycle cost analysis, policy analysis, and visual basic application. Compared to the simulation results, the mean absolute percentage error of the proposed model was determined to be 4.54%, showing that the prediction accuracy of the proposed model was found to be excellent. Furthermore, the practical application was conducted for the ‘S’ elementary school facility in South Korea, which allows potential readers to easily and clearly understand the operating mechanism of the proposed model as well as its usability and extendability. The proposed model can be used to conduct the detailed analysis of the techno-economic performance of the BIPB by the type of utilization plan and to determine the optimal strategy for maximizing the value of the investment. Furthermore, the proposed research framework can be extended to any other technology, industry, and country in the global environment.
[en] Highlights: • Effects of dust pollution on PV panels mounted on building roofs were investigated by CFD. • The dust deposition rates first increased and then decreased with the increase of dust size. • The gravity has different influences on dust deposition rates of large and small dusts. • The influence of released dust number on dust deposition rate is less than 8%. • A simple model was developed to estimate the PV efficiency reduction ratio by dust pollution. - Abstract: Dust deposition on a solar photovoltaic (PV) system mounted on the windward roof of an isolated building was investigated by CFD simulation. The SST k-ω turbulence model with UDF inlet profiles and the discrete particle model (DPM) were adopted to simulate the wind flow fields and the dust deposition behavior, respectively. The CFD wind flow velocity profiles around the building were in good agreement with experimental results reported in the literature. The effects of various dust particle sizes, differing quantities of released dust particles, and the force of gravity on the rates of dust deposition upon the PV panels were investigated in detail. It was found that the dust deposition rate first rose and then declined with the increase of dust particle size. The maximum deposition rate was about 0.28% for 10 μm dust, and the minimum deposition rate was about 0.13% for 50 μm dust. Gravity also had a significant effect on the rate of dust deposition for large-particle dust (d_p > 5 μm), and the rate could reach 75% for 50 μm dust. However, the effect of gravity on dust deposition was less than 5% for small-particle dust (d_p < 5 μm). The effect of releasing differing quantities of dust particles on the dust deposition rate was less than 8%. Moreover, the mechanisms by which dust was deposited on the PV roof were analyzed and discussed. Finally, a simple empirical model was developed to estimate the PV efficiency reduction ratios in relation to exposure time, as based on this study’s CFD results and the experimental data reported in the literature.
[en] The distribution of the photovoltaic systems is faced with technological and economic problems, and the businesses and corporations feel burdened by the photovoltaic system's dubious economic value and high construction costs. Thus, not too many enterprises or private citizens have been participating in the business of installing photovoltaic systems. Moreover, because of lack of skills in integrating engineering and architectural design, they are experiencing difficulties even in using the technologies that have already been developed and available for application. To provide the basic information and specific data required for making the guidelines for developing photovoltaic technologies, this paper evaluates the system types, the actual state of operation, and performance of the two photovoltaic systems that are installed in Kiemyung University's Osan Building and Dongho Elementary School in Daegu Metropolitan City
[en] Highlights: • We proposed a method for predicting the performance of a partly shaded PV cell. • Even a small shadow can significantly affect the performance of a PV/T system. • A parallel circuit is better than a series circuit in addressing partial shadows. • The total output of a series circuit within a day/year is higher than that of a parallel circuit. - Abstract: Most photovoltaic/thermal (PV/T) systems have an air layer between the glass cover and the cells to minimize heat loss and to improve overall efficiency. This feature is not found in typical PV systems. The frame border that supports the glass cover casts a shadow over the cells near the frame when sunlight is slanted. This design is common in PV/T systems. The objective of this study is to determine the effects of a frame shadow on PV/T systems. A mathematical model of a PV module in a PV/T system is established. An experimental research on a partly shaded single cell is then conducted. Based on the module model and the results of the experiment, a single cell model that simulates the performance of partly shaded cells is developed and integrated into an existing system model. The new model can be applied to simulate frame shadow in a PV/T system. Results show that the performance of a partly shaded single cell can be calculated as the cell operates below the average irradiation intensity of the shaded and unshaded parts. In the worst-case scenario, the frame shadow can cause a 39.3% decrease in photoelectric efficiency. Although the parallel circuit performs better than the series circuit in minimizing loss caused by the frame shadow, the latter has a higher total output
[en] Highlights: • An INC-MPPT technique is improved for PV plant. • Dynamic efficiency of the basic INC under a gradual irradiance profile is improved. • Energy conversion efficiency is increased by approximately 5%. • Stringent irradiance profile with different shapes is selected as in EN50530. • A robust tracker is proposed for variable irradiance, temperature and load. - Abstract: Perturb and Observe (P&O) and Incremental Conductance (INC) are widely used as Maximum Power Point Tracking (MPPT) techniques in Photovoltaic (PV) systems. But, they fail under rapidly varying of sunlight levels. This paper proposes a new MPPT technique, which can make a distinction between perturbation in the reference voltage and sudden-changing of sunlight and thus optimize the PV system efficiency. This method consists on a modified INC algorithm, which is used to fine-tune the duty cycle of the DC/DC converter in order to avoid divergences of the maximum power point (MPP) when using basic INC under fast varying of luminosity levels. The proposed PV-MPPT system, which is composed by a step-up converter as the interface to feed the load, is tested by simulation within the Matlab/Simulink software by taking into account the luminosity, the temperature and the load variation. The simulation results are satisfactory and demonstrate that the improved INC technique can track the PV maximum power at diverse operating conditions with the most excellent performance, the energy conversion efficiency is increased by approximately 5%.
[en] Highlights: ► We develop online prediction models for solar photovoltaic system performance. ► The proposed prediction models are simple but with reasonable accuracy. ► The maximum monthly average minutely efficiency varies 10.81–12.63%. ► The average efficiency tends to be slightly higher in winter months. - Abstract: This paper develops new real time prediction models for output power and energy efficiency of solar photovoltaic (PV) systems. These models were validated using measured data of a grid-connected solar PV system in Macau. Both time frames based on yearly average and monthly average are considered. It is shown that the prediction model for the yearly/monthly average of the minutely output power fits the measured data very well with high value of R2. The online prediction model for system efficiency is based on the ratio of the predicted output power to the predicted solar irradiance. This ratio model is shown to be able to fit the intermediate phase (9 am to 4 pm) very well but not accurate for the growth and decay phases where the system efficiency is near zero. However, it can still serve as a useful purpose for practitioners as most PV systems work in the most efficient manner over this period. It is shown that the maximum monthly average minutely efficiency varies over a small range of 10.81% to 12.63% in different months with slightly higher efficiency in winter months.
[en] Application of a simplified PV model to large-scale PV installations neglects the current distortion, potential rise and losses in the system as consequence of the capacitive coupling inside the dc electric circuit. These capacitive couplings represent a leakage impedance loop for the capacitive currents imposed by the high frequency switching performance of power converters. This paper proposes a suitable method to reproduce these harmonic currents injected not only into the grid, but also into the dc circuit of the PV installation. The capacitive coupling proposed of PV modules with ground is modeled as a parallel resistance and capacitor arrangement which leads to an accurate approximation to the real operation response of the PV installation. Results obtained are compared with those of simplified models of PV installations used in literature. An experimental validation of the proposed model was performed with field measurements obtained from an existing 1 MW PV installation. Simulation results are presented together with solutions based on the proposed model to minimize the capacitive ground current in this PV installation for meeting typical power quality regulations concerning to the harmonic distortion and safety conditions and to optimize the efficiency of the installation.
[en] Highlights: • A design approach of PV-coupled solar water heating system (SWHS) is presented. • Two different designs of PV modules are proposed and investigated. • A comparative test rig of PV-coupled SWHS and traditional SWHS is set up. • A flow rate increasing with solar irradiation is recommended. - Abstract: Simple and reliable, PV direct-coupled DC pumps are promising in solar water heating systems (SWHS). However, there is limited experimental data on the performance comparison of PV-coupled SWHS with traditional SWHS. Hence in this study, a comparative test rig is set up to measure and analyze the performance of the PV-coupled SWHS and the traditional system under the same conditions. The experimental results show that on sunny days the PV-coupled SWHS has similar daily thermal efficiency as the traditional SWHS, and slightly higher efficiency after improving the design of the PV module. Under low irradiation, the PV-coupled SWHS gains much more heat than the traditional SWHS, which indicates the potential of the PV-coupled SWHS having much higher efficiency than the traditional SWHS on cloudy days. In order to improve the performance of the PV-coupled SWHS, two different designs of PV module are proposed, and their influence on the pump startup characteristics, the flow rate profile, and the thermal efficiency of the system is investigated. It is found that the modified design of the PV module can reduce the requirement of PV cells and increase the efficiency of the system
[en] Highlights: • A novel heat-recirculating combustor for TPV power conversion is suggested. • The combustor consists of multi injectors, an emitter a shield and a recuperator. • The combustor with closer injectors shows an extended stable-burning regime. • The SiC emitter shows higher spectral emissive power density than the SUS emitter. • The suggested combustor is acceptable for practical TPV applications. - Abstract: A novel configuration of a heat-recirculating combustor with multiple injectors for 10–30 W power-generating thermophotovoltaic (TPV) systems is suggested. For the combustor as a heat source the combustion stability limits of premixed butane-air flames, the temperature distribution on the outer wall surface and the spectral emissive power density onto photovoltaic cells are measured to evaluate the combustion and radiation performance. Results show that the combustor can sustain stable burning and effective and uniform heat transfer for a wide operating range, due to the heat-recirculation using a cylindrical emitter with a quartz shield and a recuperator. Two distinct combustion stability limits, i.e., flashback and blowout limits, are observed, and a somewhat extended stable-burning regime is found for the combustor with a finned recuperator and closer injectors. The recuperator and injector geometry also affects the temperature distribution on the emitter wall surface. A silicon carbide (SiC) emitter shows higher spectral emissive power density than the stainless steel emitter, due to higher surface temperature and emissivity, and the emissive power density is further enhanced by applying the photonic crystal structure on the SiC emitter surface, due to the optical resonance effects. Thus, the present combustor configuration can be used in practical TPV power systems.
[en] Highlights: • The dynamics of the hybrid PV/TEG system operating in outer space is studied. • A generalized thermodynamic model of the hybrid PV/TEG system is given. • This model is then simplified to consider the outer space scenario. • The design of the hybrid PV/TEG system is optimized using the NSGA-II algorithm. • The optimized hybrid system is more efficient than its monolithic counterparts. - Abstract: The thermoelectric generator (TEG) has been widely considered as an electrical power source in many ground applications because of its clean and noiseless characteristics. Moreover, the hybrid photovoltaic cell and TEG (PV/TEG) system has also received wide attention due to its improved power conversion efficiency over its monolithic counterparts. This paper presents a study of the dynamics and the operation of the hybrid PV/TEG system in an outer space environment where a unified thermodynamic model of this system is presented. Moreover, the multi-objective NSGA-II genetic algorithm is utilized to optimize the design of the TEG both in terms of optimal output power and in terms of mass. Specifically, the design of the single stage and the two stage variant of the aforementioned TEG are considered. Simulation results indicate that the optimized PV/TEG system does indeed achieve better efficiencies than that of the monolithic counterparts. Furthermore, it is shown that the single stage TEG is more beneficial than the two stage TEG in terms of achieving optimal performance.