COMPUTATIONAL SIMULATION AND ANALYSIS OF MAJOR CONTROL PARAMETERS OF TIME-DEPENDENT PV/T COLLECTORS

2021 ◽  
pp. 1-25
Author(s):  
Jimeng Shi ◽  
Cheng-Xian Lin

Abstract In order to improve the transient performance of photovoltaic/thermal (or PV/T for simplicity) collectors, this paper firstly developed and validated a computational thermal model to investigate the effects of the major control parameters on the thermal performance of PV/T collectors, including inlet water temperature and inlet water flow rate. Secondly, a computational electrical model of PV/T system, coupled with the thermal model, was also introduced to elaborate the relationship of voltage, current and power of a PV module (MSX60 poly-crystalline solar cell) used in an experiment in the literature. The thermal and electrical models were solved simultaneously to predict the transient energy conversion efficiencies of the PV/T system. Simulation results were found to agree with the experimental data very well. The effects of the time-steps from 1 hour to 1 minute, which is closed to the real time, were also reported at various conditions. It was found that both thermal and electrical efficiencies are fluctuating with time. There is an optimal water flow rate at which the efficiencies are at the maximum. At last, several suggestions to improve the efficiency of PV/T system were discussed.

Author(s):  
Jimeng Shi ◽  
Cheng-Xian Lin

Abstract In order to improve performance of photovoltaic/thermal (or PV/T for simplicity) collectors, this paper firstly validated a previous computational thermal model and then introduced an improved computational thermal model to investigate the effects of the major control parameters on the thermal performance of PV/T collectors, including solar cell temperature, back surface temperature, and outlet water temperature. Besides, a computational electrical model of PV/T system was also introduced to elaborate the relationship of voltage, current and power of a PV module (MSX60 poly-crystalline solar cell) used in an experiment in the literature. Simulation results agree with the experimental data very well. The effects of the time-steps from 1 hour to minute, which is closed to the real time, were also reported. At last, several suggestions to improve the efficiency of PV/T system were illustrated.


2013 ◽  
Vol 448-453 ◽  
pp. 3386-3391
Author(s):  
Qian Wang ◽  
Qing Lin Meng

Room air conditioner is widely used in a single room or other enclosed spaces to increase the comfort of the environment. It adjusts the temperature and humidity to maintain the comfort for humans; dehumidification is a very important function of room air conditioner. This paper demonstrated the relationship among dehumidification capacity, entering air parameters, and evaporative temperature, presented the calculation method of maximum condensate water flow rate in certain condition, discussed the interaction of energy efficiency ratio and dehumidification capacity, and gave the relationship of condensate water flow rate and evaporative temperature using a specific compressor model. It is suggested that a balance should be made between dehumidification capacity and energy efficiency ratio for room air conditioner operating requirement.


Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 682
Author(s):  
Eko Surojo ◽  
Aziz Harya Gumilang ◽  
Triyono Triyono ◽  
Aditya Rio Prabowo ◽  
Eko Prasetya Budiana ◽  
...  

Underwater wet welding (UWW) combined with the shielded metal arc welding (SMAW) method has proven to be an effective way of permanently joining metals that can be performed in water. This research was conducted to determine the effect of water flow rate on the physical and mechanical properties (tensile, hardness, toughness, and bending effect) of underwater welded bead on A36 steel plate. The control variables used were a welding speed of 4 mm/s, a current of 120 A, electrode E7018 with a diameter of 4 mm, and freshwater. The results show that variations in water flow affected defects, microstructure, and mechanical properties of underwater welds. These defects include spatter, porosity, and undercut, which occur in all underwater welding results. The presence of flow and an increased flow rate causes differences in the microstructure, increased porosity on the weld metal, and undercut on the UWW specimen. An increase in water flow rate causes the acicular ferrite microstructure to appear greater, and the heat-affected zone (HAZ) will form finer grains. The best mechanical properties are achieved by welding with the highest flow rate, with a tensile strength of 534.1 MPa, 3.6% elongation, a Vickers microhardness in the HAZ area of 424 HV, and an impact strength of 1.47 J/mm2.


Author(s):  
Afshin Goharzadeh ◽  
Keegan Fernandes

This paper presents an experimental investigation on a modified airlift pump. Experiments were undertaken as a function of air-water flow rate for two submergence ratios (ε=0.58 and 0.74), and two different riser geometries (i) straight pipe with a constant inner diameter of 19 mm and (ii) enlarged pipe with a sudden expanded diameter of 19 to 32 mm. These transparent vertical pipes, of 1 m length, were submerged in a transparent rectangular tank (0.45×0.45×1.1 m3). The compressed air was injected into the vertical pipe to lift the water from the reservoir. The flow map regime is established for both configurations and compared with previous studies. The two phase air-water flow structure at the expansion region is experimentally characterized. Pipeline geometry is found to have a significant influence on the output water flow rate. Using high speed photography and electrical conductivity probes, new flow regimes, such as “slug to churn” and “annular to churn” flow, are observed and their influence on the output water flow rate and efficiency are discussed. These experimental results provide fundamental insights into the physics of modified airlift pump.


Energies ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 112 ◽  
Author(s):  
Yonghong Guo ◽  
Huimin Wei ◽  
Xiaoru Yang ◽  
Weijia Wang ◽  
Xiaoze Du ◽  
...  

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 167
Author(s):  
Hasan Alimoradi ◽  
Madjid Soltani ◽  
Pooriya Shahali ◽  
Farshad Moradi Kashkooli ◽  
Razieh Larizadeh ◽  
...  

In this study, a numerical and empirical scheme for increasing cooling tower performance is developed by combining the particle swarm optimization (PSO) algorithm with a neural network and considering the packing’s compaction as an effective factor for higher accuracies. An experimental setup is used to analyze the effects of packing compaction on the performance. The neural network is optimized by the PSO algorithm in order to predict the precise temperature difference, efficiency, and outlet temperature, which are functions of air flow rate, water flow rate, inlet water temperature, inlet air temperature, inlet air relative humidity, and packing compaction. The effects of water flow rate, air flow rate, inlet water temperature, and packing compaction on the performance are examined. A new empirical model for the cooling tower performance and efficiency is also developed. Finally, the optimized performance conditions of the cooling tower are obtained by the presented correlations. The results reveal that cooling tower efficiency is increased by increasing the air flow rate, water flow rate, and packing compaction.


Author(s):  
Mohammed El Hadi Attia ◽  
Abd Elnaby Kabeel ◽  
S. A. El-Agouz ◽  
El Mir Mabrouk Lassaad ◽  
Ravishankar Sathyamurthy ◽  
...  

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