scholarly journals Optimization of operational parameters for a photovoltaic panel cooled by spray cooling

Author(s):  
Faruk Yesildal ◽  
Ahmet Numan Ozakin ◽  
Kenan Yakut
2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Mojtaba Nateqi ◽  
Mehran Rajabi Zargarabadi ◽  
Roohollah Rafee

AbstractIn this study, a spray cooling system is experimentally investigated to increase the photovoltaic panel efficiency. Cooling of photovoltaic panels is one of the important parameters that affects the PV panel performance. In this experiment the effects of spray angle, nozzles to PV panel distance, number of nozzles, and pulsating water spray on the PV panel performance are investigated. For this purpose, an experimental setup was made. The spray angles varied from 15° to 50°. The comparison between the spray angles shows that by decreasing the spray angle to 15° increases the electrical efficiency of PV panel to 19.78% and simultaneously the average PV panel temperature decreases from 64 (for non-cooled PV) to 24 °C. Also, nozzle to PV panel distance was changed from 10 to 50 cm. The best result was obtained for the lowest distance by 25.86% increase in power output. Study of various frequency also show that due to the surface evaporation and the intensity of the radiation, increasing the water spraying frequency can increase or decrease the electrical efficiency. The On–Off water spray system results show that the maximum increase in efficiency was obtained with frequency of 0.2 Hz which it was 16.84%. Water consumption also decreased to half.


Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1770
Author(s):  
Mariusz Woszczyński ◽  
Joanna Rogala-Rojek ◽  
Sławomir Bartoszek ◽  
Marian Gaiceanu ◽  
Krzysztof Filipowicz ◽  
...  

The dynamic development of photovoltaic systems in the world and in Poland is mainly related to the drop in prices of installation components. Currently, electricity from photovoltaics is one of the cheapest renewable energy sources. The basis for effective energy generation is, first of all, failure-free operation of the photovoltaic system over a long period of operation, up to 30 years. The paper presents the results of a study of a low-cost distributed system for monitoring and diagnosis of photovoltaic installations (SmartPV), capable of assessing the operating parameters of individual photovoltaic panels. The devices were tested by connecting them to an existing photovoltaic installation, allowing the measurement of operational parameters of individual photovoltaic panels as well as operating conditions such as illuminance and panel surface temperature. The data were recorded on a server using wireless Wi-Fi transmission. Interesting data were collected during the tests, confirming the usefulness of the suggested device for monitoring the photovoltaic installations. Differences in performance of the photovoltaic panel depending on solar radiation and surface temperature were recorded. The temperature coefficient of power was determined, allowing for increased accuracy in the prediction of generated power. The correct recording in different situation, i.e., shading, sensor damage or weather anomalies, was verified. Based on the collected data, rules will be defined for an expert application which, in combination with SmartPV devices, will ensure a quick response to any malfunctions of the photovoltaic system, both related to failures and those resulting from natural degradation during operation.


2019 ◽  
Vol 146 ◽  
pp. 85-91 ◽  
Author(s):  
Yixiao Ruan ◽  
Yu Hou ◽  
Rong Xue ◽  
Gaoqiao Luo ◽  
Kuizhang Zhu ◽  
...  

Author(s):  
David C Joy

The electron source is the most important component of the Scanning electron microscope (SEM) since it is this which will determine the overall performance of the machine. The gun performance can be described in terms of quantities such as its brightness, its source size, its energy spread, and its stability and, depending on the chosen application, any of these factors may be the most significant one. The task of the electron gun in an SEM is, in fact, particularly difficult because of the very wide range of operational parameters that may be required e.g a variation in probe size of from a few angstroms to a few microns, and a probe current which may go from less than a pico-amp to more than a microamp. This wide range of operating parameters makes the choice of the optimum source for scanning microscopy a difficult decision.Historically, the first step up from the sealed glass tube ‘cathode ray generator’ was the simple, diode, tungsten thermionic emitter.


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