scholarly journals Indoor Test Conditions of Thermal Collector Channel Using Water as a Working Fluid to Enhance the Electrical and Thermal Efficiency of the PV / T System

2021 ◽  
Vol 1 (2) ◽  
pp. 16
Author(s):  
Hazim A. Al-Zurfi ◽  
Hyder H. Balla ◽  
Ali N. Al-Shamani
Keyword(s):  
Thermal Efficiency ◽  
Working Fluid ◽  
Test Conditions ◽  
T System

Performance Study of Flowing-Over PV/T System with Different Working Fluid

2014 ◽  
Vol 488-489 ◽  
pp. 1173-1176 ◽  
Author(s):  
Li Qing Tang ◽  
Qun Zhi Zhu
Keyword(s):  
Thermal Efficiency ◽  
Experimental System ◽  
Experimental Results ◽  
Working Fluid ◽  
Performance Study ◽  
Electrical Efficiency ◽  
Overall Efficiency ◽  
T System

This paper studied the performance of a flowing-over PV/T system with water and Al2O3 nanofluid as the working fluid. The experimental system was built in the outdoors. The parameters of the experiment obtained for processing, analysis, accessing to the electrical efficiency and thermal efficiency. Experimental results show that the flowing-over PV/T system with Al2O3 nanofluid as working fluid has a higher overall efficiency than that with water.

scholarly journals Numerical Modelling of a Photovoltaic Thermal (PV/T) System Using Nanofluid With Parallel Flow Thermal Absorber

2021 ◽  
Vol 945 (1) ◽  
pp. 012013
Author(s):  
J. Kubenthiran ◽  
S. Baljit ◽  
A. S. Tijani ◽  
Z. A. K. Baharin ◽  
M.F. Remeli ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Energy Efficiency ◽  
Thermal Efficiency ◽  
Pure Water ◽  
Fluid Velocity ◽  
Parallel Flow ◽  
Working Fluid ◽  
Volume Percentage ◽  
Electrical Efficiency ◽  
T System

Abstract In the present study, a numerical model of photovoltaic thermal (PV/T) system using alumina (Al2O3) nanofluid, and pure water are used as working fluid. The proposed PV/T model consists of parallel riser tubes that are connected to two header tubes and it is attached to an absorber plate to simulate the conduction and convection heat transfer mechanism of a conventional PV/T system. The energy efficiency of the PV/T model is analyzed by varying the solar radiation (Heat Flux), inlet fluid velocity, and the volume percentage of the nanofluids. The numerical simulation is performed by using a conjugate heat transfer method with a computational fluid dynamics (CFD) software. According to the simulation data, the energy efficiency and the heat transfer coefficient of the PV/T system increased by increasing the inlet fluid velocity. In comparison with water, alumina nanofluid showed better thermal and electrical efficiency due to its high thermal conductivity. The thermal efficiency increased by 5.55% for alumina, compared to pure water and the electrical efficiency increased by 0.15% for alumina. Moreover, the effect of inlet fluid velocity ranging from 0.04m/s to 0.2m/s was also evaluated, and the results showed that the increase in thermal efficiency for pure water and alumina are 18.15% and 25.77%, respectively. Subsequently, the electrical efficiency increased by 0.52% and 0.56% for pure water and alumina using the new parallel flow thermal absorber, respectively.

scholarly journals Experimental and Theoretical Analysis of a Linear Focus CPV/T System for Cogeneration Purposes

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2960 ◽  
Author(s):  
Carlo Renno
Keyword(s):  
Focal Length ◽  
Concentration Field ◽  
Operating Conditions ◽  
Working Fluid ◽  
Fluid Temperature ◽  
Atmospheric Conditions ◽  
High Concentration ◽  
Environment Temperature ◽  
Temperature Levels ◽  
T System

The knowledge of the actual energy performances of a concentrating photovoltaic and thermal (CPV/T) system with a linear focus optics, allows to evaluate the possibility of adopting this type of system for cogeneration purposes. Hence, the main aim of this paper is the design, realization, setting and modeling of a linear focus CPV/T system in the high concentration field. An experimental linear focus CPV/T plant was created in order to determine its electrical and thermal performance under different working conditions in terms of environment temperature, sunny and cloudy conditions, focal length, etc. Moreover, a theoretical model of the linear focus CPV/T system was also studied. This model evaluates the temperatures of the working fluid that flows in the cooling circuit of the CPV/T system under several operating conditions. The temperatures of the triple junction (TJ) cells, experimentally evaluated referring to different solar radiation and atmospheric conditions, were considered as the input data for the model. The values of the fluid temperature, theoretically and experimentally determined, were thus compared with good agreement. The electrical production of the CPV/T system depends generally on the TJ cell characteristics and the concentration factor, while the thermal production is above all linked to the system configuration and the direct normal irradiance (DNI) values. Hence, in this paper the electric power obtained by the linear-focus CPV/T system was evaluated referring to the cogeneration applications, and it was verified if the TJ cell and the cooling fluid reach adequate temperature levels in this type of system, in order to match the electrical and the thermal loads of a user.

scholarly journals Applications of nanotechnology with hybrid Photovoltaic/Thermal systems

2020 ◽  
pp. 1-15
Author(s):  
Mohammed Alktranee
Keyword(s):  
Thermophysical Properties ◽  
Base Fluid ◽  
Volume Fraction ◽  
Working Fluid ◽  
Spectral Filter ◽  
Thermal Systems ◽  
Cooling Fluid ◽  
Numerical Studies ◽  
The Impact ◽  
T System

This paper appears potential of use nanofluids as a working fluid with the photovoltaic/thermal (PV/T) systems as an alternative of the conventional liquids in improves the efficiency of the hybrid PV/T system. The review highlights the impact of some parameters (base fluid, volume fraction, the concentration of nanoparticles, surfactants, shape, and size of nanoparticles) on nanofluids' thermophysical properties and their effect on the PV/T system's efficiencies. Hence, it discusses the PV/T behavior, which uses different nanofluids based on previous experimental, analytical, and numerical studies. The review concluded that using nanofluid as a cooling fluid or spectral filter contributes by enhancing the performance and increasing the PV/T system's efficiency. Thus, each type of nanofluids has certain features that contribute to removing the PV cells' excess heat by cooling it, contributing to its work's stability, and increasing its productivity. Nanofluids thermophysical properties play an intrinsic role by enhancing nanofluids' performance, thus positively reflecting on the PV/T system's performance. Despite the variation in the values of thermal and electrical efficiency, Most of the studies that used nanofluids have achieved encouraging results that appeared by improving the performance of PV/T systems.

Thermodynamic Analysis of a Novel Ammonia-Water Cogeneration System for Maritime Diesel Engines

2020 ◽  
Author(s):  
Ziyang Cheng ◽  
Yaxiong Wang ◽  
Qingxuan Sun ◽  
Jiangfeng Wang ◽  
Pan Zhao ◽  
...  
Keyword(s):  
Power Output ◽  
Thermal Efficiency ◽  
System Performance ◽  
Mass Fraction ◽  
Ammonia Concentration ◽  
Working Fluid ◽  
Fluid Temperature ◽  
Kalina Cycle ◽  
Ammonia Water ◽  
Cogeneration System

Abstract This paper proposes a novel cogeneration system based on Kalina cycle and absorption refrigeration system to meet the design requirements of China State Shipbuilding Corporation, which is efficiently satisfy the power and cooling demands of a maritime ship at the same time. Unlike most of the combined systems, this cogeneration system is highly coupled and realizes cogeneration without increasing the system complexity too much. The basic ammonia mass fraction of this novel system is increased, so that the ammonia concentration of ammonia-water steam from the separator can be higher, which contributes to lower refrigerating temperature and thus less heat loss in the distillation process. In addition, higher ammonia concentration solution makes overheating easier, which improves the thermal efficiency. Moreover, the system has two recuperators to make further improvement of the thermal efficiency. Thermodynamic models are developed to investigate the system performance and parametric analysis is conducted to figure out the effects of including working fluid temperature at the outlet of the evaporator, working fluid temperature at superheater outlet, mass fraction of ammonia in basic solution, turbine inlet pressure, temperature of cooling water at the inlet of condensers and the refrigeration evaporation temperature on the system performance. Furthermore, the cogeneration system is optimized with genetic algorithm to obtain the best performance, which achieves 333.00kW of net power output, 28.83 kW of cooling capacity and 21.81% of thermal efficiency. Finally, the performance of the proposed system is compared with an optimized recuperative organic Rankine cycle (ORC) system and an optimized Kalina cycle system 34 (KCS34) using the same heat source. The results show that the thermal efficiency and power output of the novel cogeneration system is 3.89% and 1.05% higher than that of the recuperative ORC system and KCS34 system respectively.

Experimental Study of Thermal Performance of Nanofluid-Filled and Nanoparticles-Coated Mesh Wick Heat Pipes

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Naveen Kumar Gupta ◽  
Arun Kumar Tiwari ◽  
Subrata Kumar Ghosh
Keyword(s):  
Thermal Resistance ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Physical Vapor Deposition ◽  
Power Input ◽  
Working Fluid ◽  
Physical Vapor Deposition Method ◽  
The Stability ◽  
Stability Issues ◽  
Time Of Operation

The enhancements in thermal performance of mesh wick heat pipe (HP) using TiO2/H2O nanofluid (0.5, 1.0, and 1.5 vol %) as working fluid for different (50, 100, and 150 W) power input were investigated. Results showed maximum 17.2% reduction in thermal resistance and maximum 13.4% enhancement in thermal efficiency of HP using 1.0 vol % nanofluid as compared to water. The wick surface of the HP was then coated with TiO2 nanoparticles by physical vapor deposition method. The experimental investigation had been also carried out on coated wick HP using water as working fluid. Results showed 12.1% reduction in thermal resistance and 11.9% enhancement in thermal efficiency of the HP as compared to uncoated wick HP using water. Temporal deteriorations in thermal performance during prolonged working (2, 4, and 6 months) of HP were also studied. Temporal deterioration in thermal performance of HP filled with nanofluid depends upon the deterioration in thermophysical properties of nanofluids. The deterioration is due to the agglomeration and sedimentation of nanoparticles with respect to the time. Comparative study shows that after a certain time of operation, thermal performance of HP with nanoparticle coated wick superseded that of the HP filled with nanofluid. Therefore, nanoparticle coating might be a good substitute for nanofluid to avoid the stability issues. The present paper provides incentives for further research to develop nanofluids that avoid the encountered sedimentation or agglomeration.

Optimization of Overcritical Organic Rankine Cycle

2016 ◽  
Vol 831 ◽  
pp. 306-315
Author(s):  
Qing Quan Wang ◽  
Sławomir Smoleń
Keyword(s):  
Numerical Method ◽  
Thermal Efficiency ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Independent Variables ◽  
Hot Temperature ◽  
Working Fluid Selection ◽  
Two Independent Variables

This paper explores the optimization cases for overcritical Organic Rankine Cycle (ORC) in various situations. First the ORC optimization in terms of working fluid selection is discussed. In this case, thermal efficiencies for 10 different working fluids have been calculated under certain temperature frames and the results are compared. Second, overcritical optimization case in terms of variation of hot temperature and evaporation pressure is presented. In this overcritical ORC case, the influence of evaporation pressure on ORC thermal efficiency is studied by conducting a case study of R234a, and first 1-D freedom optimization case is discussed within the variation of evaporation pressure. 2-D freedom optimization is also considered, in which the two independent variables, hot temperature and evaporation pressure, are both varied within certain boundaries. This study employs numerical method for this 2-D problem and it is also presented in detail in the case study.

A Study of Supercritical Carbon Dioxide Power Cycle for Concentrating Solar Power Applications Using an Isothermal Compressor

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Jin Young Heo ◽  
Jinsu Kwon ◽  
Jeong Ik Lee
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Thermal Efficiency ◽  
Solar Power ◽  
Working Fluid ◽  
Brayton Cycle ◽  
Concentrating Solar Power ◽  
Power Cycle ◽  
Compressor Inlet ◽  
Supercritical Carbon

For the concentrating solar power (CSP) applications, the supercritical carbon dioxide (s-CO2) power cycle is beneficial in many aspects, including high cycle efficiencies, reduced component sizing, and potential for the dry cooling option. More research is involved in improving this technology to realize the s-CO2 cycle as a candidate to replace the conventional power conversion systems for CSP applications. In this study, an isothermal compressor, a turbomachine which undergoes the compression process at constant temperature to minimize compression work, is applied to the s-CO2 power cycle layout. To investigate the cycle performance changes of adopting the novel technology, a framework for defining the efficiency of the isothermal compressor is revised and suggested. This study demonstrates how the compression work for the isothermal compressor is reduced, up to 50%, compared to that of the conventional compressor under varying compressor inlet conditions. Furthermore, the simple recuperated and recompression Brayton cycle layouts using s-CO2 as a working fluid are evaluated for the CSP applications. Results show that for compressor inlet temperatures (CIT) near the critical point, the recompression Brayton cycle using an isothermal compressor has 0.2–1.0% point higher cycle thermal efficiency compared to its reference cycle. For higher CIT values, the recompression cycle using an isothermal compressor can perform above 50% in thermal efficiency for a wider range of CIT than the reference cycle. Adopting an isothermal compressor in the s-CO2 layout can imply larger heat exchange area for the compressor which requires further development.

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