scholarly journals A thermal model for open-rack mounted photovoltaic modules based on empirical correlations for natural and forced convection

2019 ◽  
Vol 23 (6 Part A) ◽  
pp. 3551-3566
Author(s):  
Bojan Perovic ◽  
Dardan Klimenta ◽  
Miroljub Jevtic ◽  
Milos Milovanovic

This paper proposes a thermal model for calculating the temperature of open-rack mounted photovoltaic (PV) modules taking into account the meteorological conditions, position (i. e. the inclination of one PV module and the angle between its surface and wind direction) and technical characteristics of the PV modules. The present model is valid for the steady-state operation and is based on the energy balance equation in which the forced convection is modelled by the new empirical correlations. The possibility of occurrence of the flow separation along the surfaces of the PV modules is included in these correlations. The effect of the angle between the wind direction and the PV module plane, which is usually ignored in the modelling of forced convection, is also taken into consideration. In this manner, it is possible to estimate the temperature of PV modules more precisely, as well as to determine the power and efficiency which depend on the temperature. For four particular PV modules, it is found that the temperatures, obtained using the proposed thermal model, are in good agreement with the corresponding measured temperatures. Compared with the other models commonly used for thermal analysis of PV modules (SNL and NOCT-based correlations), this model yielded better results. The deviation of the PV module temperature calculated using the proposed thermal model from the measured one is up to 2?C, and the deviations of the PV module temperatures calculated using the SNL and NOCT-based correlations from the measured ones amount up to 5?C and 20?C, respectively, depending on the PV module type and ambient conditions.

Author(s):  
Kamil Jadu Ali ◽  
Ahmed Hasan Mohammad ◽  
Ghanim Thiab Hasan

<p><span>In this paper, the effect of the ambient temperature on the PV modules for different angles of inclinations and different intensities of the solar radiation on the surface of the PV module is considered by using empirical correlations for natural convection. An analytical model based on the energy balance equilibrium between the PV module and the environment conditions has been used. Also an expression for calculating the electric power of silicon PV modules in a function of the ambient temperature, the intensity of the solar radiation, the incident angle of the solar radiation to the surface of the PV module and the efficiency of the PV modules at STC conditions have been used. By comparing the obtained both results, it can be seen that the largest deviation between the power values obtained by the analytical model and expression is about (5 %). The results obtained indicates that in the case of a small number of PV modules corresponding to the required number for an average household, it is more economical to invest additional resources in increasing the PV module's surface area than in case of the PV module with sun tracking system. </span></p>


2013 ◽  
Vol 448-453 ◽  
pp. 1559-1564
Author(s):  
Yu Zhang ◽  
Jian Bo Bai ◽  
Sheng Liu

The paper presents the thermoelectric coupling model for a photovoltaic (PV) module. Firstly, the five-parameter electrical model and the thermal model of the PV module are investigated. In order to evaluate the effectiveness of the model, the numerical computation and experimental values under certain environmental conditions are compared. The experimental results demonstrate the model has reasonable accuracy. Furthermore, to investigate the PV modules performance under different ambient temperature, irradiance and wind speed, the model is used to simulate the thermoelectric characteristics of the PV module. The simulation results can provide meaningful method to predict power generation of the PV module under various conditions.


Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2776
Author(s):  
Tekai Eddine Khalil Zidane ◽  
Mohd Rafi Adzman ◽  
Mohammad Faridun Naim Tajuddin ◽  
Samila Mat Zali ◽  
Ali Durusu ◽  
...  

Considering the recent drop (up to 86%) in photovoltaic (PV) module prices from 2010 to 2017, many countries have shown interest in investing in PV plants to meet their energy demand. In this study, a detailed design methodology is presented to achieve high benefits with low installation, maintenance and operation costs of PV plants. This procedure includes in detail the semi-hourly average time meteorological data from the location to maximise the accuracy and detailed characteristics of different PV modules and inverters. The minimum levelised cost of energy (LCOE) and maximum annual energy are the objective functions in this proposed procedure, whereas the design variables are the number of series and parallel PV modules, the number of PV module lines per row, tilt angle and orientation, inter-row space, PV module type, and inverter structure. The design problem was solved using a recent hybrid algorithm, namely, the grey wolf optimiser-sine cosine algorithm. The high performance for LCOE-based design optimisation in economic terms with lower installation, maintenance and operation costs than that resulting from the use of maximum annual energy objective function by 12%. Moreover, sensitivity analysis showed that the PV plant performance can be improved by decreasing the PV module annual reduction coefficient.


2020 ◽  
Vol 10 (3) ◽  
pp. 914 ◽  
Author(s):  
Joseph Appelbaum ◽  
Tamir Maor

The operating temperature of photovoltaic (PV) modules affects the photovoltaic conversion process. The operating temperature depends on various environmental conditions and on material-dependent properties of the PV modules. Many expressions for the operating temperature have been proposed in the literatures, some are simplified working Equation as NOCT (Nominal Operating Cell Temperature), and others are more complex, being based on a combination of the energy balance Equation and NOCT. The present study offers a new approach (model) for determining the PV module temperature based on the energy balance Equation and on the solar spectrum irradiance. While using the new model, the operating temperature has been determined for four module technologies: c-Si, a-Si/ μ c-Si, CdTe, and CIGS and it shows that the operating temperatures for the different cell types are close to the manufacturers’ NOCT data-sheet temperatures. For c-Si technology, for example, the simulation resulted in 43.2° and 46° for the spectrum and NOCT models, respectively. The proposed new model offers a new approach for determining the operating temperature of PV modules.


2018 ◽  
Vol 12 (2) ◽  
pp. 98 ◽  
Author(s):  
Jalaluddin . ◽  
Baharuddin Mire

Actual performance of photovoltaic module with solar tracking is presented. Solar radiation can be converted into electrical energy using photovoltaic (PV) modules. Performance of polycristalline silicon PV modules with and without solar tracking are investigated experimentally. The PV module with dimension 698 x 518 x 25 mm has maximum power and voltage is 45 Watt and 18 Volt respectively. Based on the experiment data, it is concluded that the performance of PV module with solar tracking increases in the morning and afternoon compared with that of fixed PV module. It increases about 18 % in the morning from 10:00 to 12:00 and in the afternoon from 13:30 to 14:00 (local time). This study also shows the daily performance characteristic of the two PV modules. Using PV module with solar tracking provides a better performance than fixed PV module. 


Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2308
Author(s):  
Kamran Ali Khan Niazi ◽  
Yongheng Yang ◽  
Tamas Kerekes ◽  
Dezso Sera

Partial shading affects the energy harvested from photovoltaic (PV) modules, leading to a mismatch in PV systems and causing energy losses. For this purpose, differential power processing (DPP) converters are the emerging power electronic-based topologies used to address the mismatch issues. Normally, PV modules are connected in series and DPP converters are used to extract the power from these PV modules by only processing the fraction of power called mismatched power. In this work, a switched-capacitor-inductor (SCL)-based DPP converter is presented, which mitigates the non-ideal conditions in solar PV systems. A proposed SCL-based DPP technique utilizes a simple control strategy to extract the maximum power from the partially shaded PV modules by only processing a fraction of the power. Furthermore, an operational principle and loss analysis for the proposed converter is presented. The proposed topology is examined and compared with the traditional bypass diode technique through simulations and experimental tests. The efficiency of the proposed DPP is validated by the experiment and simulation. The results demonstrate the performance in terms of higher energy yield without bypassing the low-producing PV module by using a simple control. The results indicate that achieved efficiency is higher than 98% under severe mismatch (higher than 50%).


Author(s):  
Heangwoo Lee ◽  
Xiaolong Zhao ◽  
Janghoo Seo

Recent studies on light shelves found that building energy efficiency could be maximized by applying photovoltaic (PV) modules to light shelf reflectors. Although PV modules generate a substantial amount of heat and change the consumption of indoor heating and cooling energy, performance evaluations carried out thus far have not considered these factors. This study validated the effectiveness of PV module light shelves and determined optimal specifications while considering heating and cooling energy savings. A full-scale testbed was built to evaluate performance according to light shelf variables. The uniformity ratio was found to improve according to the light shelf angle value and decreased as the PV module installation area increased. It was determined that PV modules should be considered in the design of light shelves as their daylighting and concentration efficiency change according to their angles. PV modules installed on light shelves were also found to change the indoor cooling and heating environment; the degree of such change increased as the area of the PV module increased. Lastly, light shelf specifications for reducing building energy, including heating and cooling energy, were not found to apply to PV modules since PV modules on light shelf reflectors increase building energy consumption.


2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
Vandana Jha ◽  
Uday Shankar Triar

This paper proposes an improved generalized method for evaluation of parameters, modeling, and simulation of photovoltaic modules. A new concept “Level of Improvement” has been proposed for evaluating unknown parameters of the nonlinear I-V equation of the single-diode model of PV module at any environmental condition, taking the manufacturer-specified data at Standard Test Conditions as inputs. The main contribution of the new concept is the improvement in the accuracy of values of evaluated parameters up to various levels and is based on mathematical equations of PV modules. The proposed evaluating method is implemented by MATLAB programming and, for demonstration, by using the values of parameters of the I-V equation obtained from programming results, a PV module model is build with MATLAB. The parameters evaluated by the proposed technique are validated with the datasheet values of six different commercially available PV modules (thin film, monocrystalline, and polycrystalline) at Standard Test Conditions and Nominal Operating Cell Temperature Conditions. The module output characteristics generated by the proposed method are validated with experimental data of FS-270 PV module. The effects of variation of ideality factor and resistances on output characteristics are also studied. The superiority of the proposed technique is proved.


2021 ◽  
Vol 13 (9) ◽  
pp. 5027
Author(s):  
Wenjie Zhang ◽  
Tongdan Gong ◽  
Shengbing Ma ◽  
Jianwei Zhou ◽  
Yingbo Zhao

In building integrated photovoltaics (PV), it is important to solve the heat dissipation problem of PV modules. In this paper, the computational fluid dynamics (CFD) method is used to simulate the flow field around the open-joint photovoltaic ventilated double-skin façades (OJ-PV-DSF) to study the influence of the mounting dimensions (MD) of a PV array on the module temperature. The typical summer afternoon meteorological parameters, such as the total radiation (715.4 W/m2), the outdoor temperature (33.1 °C), and the wind speed (2.0 m/s), etc., are taken as input parameters. With the DO (discrete ordinates) model and the RNG (renormalization-group) k − ε model, a steady state calculation is carried out to simulate the flow of air in and around the cavity under the coupling of hot pressure and wind pressure, thereby obtaining the temperature distribution of the PV array and the wall. In addition, the simulation results are compared with the onsite experimental data and thermal imaging to verify the accuracy of the CFD model. Then three MD of the open joints are discussed. The results show that when the a value (represents the distance between PV modules and wall) changes from 0.05 to 0.15, the temperature drop of the PV module is the most obvious, reaching 2.0 K. When the b value (representing the distance between two adjacent PV modules in the vertical direction) changes from 0 to 0.1, the temperature drop of the PV module is most obvious, reaching 1 K. When the c value (represents the distance between two adjacent PV modules in the horizontal direction) changes from 0 to 0.1, the temperature of the PV module is lowered by 0.8 K. Thus, a = 0.1–0.15, b = 0.1 and c = 0.1 are recommended for engineering applications to effectively reduce the module temperature.


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