Computational Analysis of Internally Grooved Absorber Tubes of Parabolic Trough Solar Collector for Constant Mass Flow Rate of the Heat Transfer Fluid

2020 ◽  
pp. 1267-1279
Author(s):  
Suresh Vishwakarma ◽  
Prabina Kumar Meher ◽  
Biplab Kumar Debnath ◽  
Kishore Debnath
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Solar Collector ◽  
Computational Analysis ◽  
Heat Transfer Fluid ◽  
Constant Mass ◽  
Parabolic Trough ◽  
Parabolic Trough Solar Collector

Influence of Dimensionless Parameter on De-Ionized Water-alumina Nanofluid Based Parabolic Trough Solar Collector

2020 ◽  
Vol 13 (3) ◽  
pp. 206-221
Author(s):  
Vijayan Gopalsamy ◽  
Karunakaran Rajasekaran ◽  
Logesh Kamaraj ◽  
Siva Sivasaravanan ◽  
Metin Kok
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Efficiency ◽  
Solar Collector ◽  
Dimensionless Parameter ◽  
Parabolic Trough ◽  
Alumina Nanofluid ◽  
Parabolic Trough Solar Collector

Background: Aqueous-alumina nanofluid was prepared using magnetic stirrer and ultrasonication process. Then, the prepared nanofluid was subjected to flow through the unshielded receiver of the parabolic trough solar collector to investigate the performance of the nanofluid and the effects of the dimensionless parameter were determined. Methods: The experimental work has been divided into two sections. First, the nanofluid was prepared and tested for its morphology, dimensions, and sedimentation using X-Ray Diffraction and Raman shift method. Then, the nanofluids of various concentrations from 0 to 4.0% are used as heat transfer fluid in unshielded type collector. Finally, the effect of the dimensionless parameter on the performance was determined. Results: For the whole test period, depending upon the bulk mean temperature, the dimensionless parameters such as Re and Nu varied from 1098 to 4552 & 19.30 to 46.40 for air and 2150 to 7551 & 11.11 to 48.54 for nanofluid. The enhancement of thermal efficiency found for 0% and 4.0% nanoparticle concentrations was 32.84% for the mass flow rate of 0.02 kg/s and 13.26% for the mass flow rate of 0.06 kg/s. Conclusion: Re and Nu of air depend on air velocity and ambient temperature. Re increased with the mass flow rate and decreased with concentration. Heat loss occurred by convection mode of heat transfer. Heat transfer coefficient and global efficiency increased with increased mass flow rate and volume fraction. The thermal efficiency of both 0% and 4.0% concentrations became equal for increased mass flow rate. It has been proven that at high mass flow rates, the time available to absorb the heat energy from the receiver is insufficient.

Thermodynamic Analysis of an Integrated Solar-Based Cooling System in UAE

2014 ◽  
Author(s):  
Mohamed Gadalla ◽  
Amani Al Hammadi
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Solar Irradiance ◽  
Solar Collector ◽  
Cooling System ◽  
Constant Mass ◽  
Parabolic Trough ◽  
Energy And Exergy ◽  
Parabolic Trough Solar Collector

Renewable energy resource is considered by many developed and developing countries as a promising and a cost effective candidate to provide energy. The operation of cooling systems in the United Arab Emirates (UAE) have some operating problems especially in summer such as severe grid dependent, excessive energy consumption, high emissions and high costs. So, more economically and environmentally friendly HVAC systems are desired to provide the required electricity demands for cooling loads while saving energy and having low emissions to the environment. In this paper, a parabolic trough solar collector is integrated with a triple effect absorption cooling system for sustainable development. A computer code is developed using Engineering Equation Solver (EES) software to obtain all required thermodynamic properties of water-lithium bromide (H2O/LiBr) solution and to optimize all operating parameters and carry out all detailed energy and exergy analyses for a 10 kW cooling capacity. In addition, the parabolic trough solar collector (PTSC) is also designed for the required cooling load and its overall dynamic behavior is also investigated. The solar irradiance available in the UAE on a monthly basis is used in the analysis of a PTSC-based HVAC cooling system. Energetic and exergetic efficiencies of the PTSC for every month are also evaluated under different operating conditions. The Overall monthly energy and exergy efficiencies of the integrated PTSC-based HVAC system for a constant mass flow rate of Therminol-66 and concentration ratio are calculated. The dynamic variation of the coefficient of performance of the integrated system with the solar irradiance and mass flow rate of the oil are also evaluated. Results show that both energetic and exergetic COPs are decreased with increasing the solar irradiance for a constant mass flow rate of oil and constant concentration ratio. It is found that increasing the mass flow rate of the oil from 0.1 to 0.5 kg/s results in decreasing the energetic COP from 2.15 to 1.98 and the exergetic COP from 2.05 to 1.93.

Thermodynamic Performance Evaluation of a Solar Parabolic Dish Assisted Multigeneration System

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Muhammad Abid ◽  
Muhammad Sajid Khan ◽  
Tahir Abdul Hussain Ratlamwala
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Solar Collector ◽  
Integrated System ◽  
Heat Transfer Fluid ◽  
Outlet Temperature ◽  
Parabolic Dish ◽  
Single Effect

The concentration ratio of the parabolic dish solar collector (PDSC) is considered to be one of the highest among the concentrated solar power technologies (CSPs); therefore, such system is capable of generating more heat rate. The present paper focuses on the integration of the PDSC with the combined cycle (gas cycle as the toping cycle and steam cycle as the bottoming cycle) along with the utilization of waste heat from the power cycle to drive the single effect lithium bromide/water absorption cycle. Molten salt is used as a heat transfer fluid in the solar collector. The engineering equation solver (EES) is employed for the mathematical modeling and simulation of the solar integrated system. The various operating parameters (beam radiation, inlet and ambient temperatures of heat transfer fluid, mass flow rate of heat transfer fluid, evaporator temperature, and generator temperature) are varied to analyze their influence on the performance parameters (power output, overall energetic and exergetic efficiencies, outlet temperature of the receiver, and as coefficient of performance (COP) and exergy efficiencies) of the integrated system. The results show that the overall energy and exergy efficiencies are observed to be 39.9% and 42.95% at ambient temperature of 27 °C and solar irradiance of 1000 W/m2. The outlet temperature of the receiver is noticed to decrease from 1008 K to 528 K for an increase in the mass flow rate from 0.01 to 0.05 kg/s. The efficiency rate of the power plant is 38%, whereas COP of single effect absorption system is 0.84, and it will decrease from 0.87 to 0.79. However, the evaporator load is decreased to approximately 9.7% by increasing the generator temperature from 47 °C to 107 °C.

Exergy Optimization of a Novel Combination of a Liquid Air Energy Storage System and a Parabolic Trough Solar Collector Power Plant

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Shahram Derakhshan ◽  
Mohammadreza Khosravian
Keyword(s):  
Energy Storage ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Solar Collector ◽  
Design Parameters ◽  
Parabolic Trough ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Parabolic Trough Solar Collector

In this paper, a parabolic trough solar collector (PTSC) plant is combined with a liquid air energy storage (LAES) system. The genetic algorithm (GA) is used to optimize the proposed system for different air storage mass flow rates. The roundtrip exergy ratio is considered as the objective function and pressures of six points and mass flow rates of five points are considered as design parameters. The effects of some environmental and key parameters such as different radiation intensities, ambient temperatures, output pressures of the second compressor, and mass flow rates of the collectors fluid on the exergy ratio are investigated. The results revealed that the system could produce 17526.15 kJ/s (17.5 MW) power in high demands time and 2233.48 kJ/s (2.2 MW) power in low demands time and the system shows that a value of 15.13% round trip exergy ratio is achievable. Furthermore, the exergy ratio decreased by 5.1% when the air storage mass flow rate increased from 10 to 15 kg/s. Furthermore, the exergy ratio decreases by increasing the collectors inside fluid mass flow rate or by decreasing radiation intensity.

scholarly journals Computational analysis of transient turbulent flow and conjugate heat transfer characteristics in a solar collector panel with internal, rectangular fins and baffles

2010 ◽  
Vol 14 (1) ◽  
pp. 221-234 ◽  
Author(s):  
Rachid Saim ◽  
Said Abboudi ◽  
Boumédiene Benyoucef
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Turbulent Flow ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Solar Collector ◽  
Computational Analysis ◽  
Heat Transfer Characteristics ◽  
Thermal Exchange

The poor thermal exchange between the absorber and the fluid in the solar air flat plate collector, gives the bad performance and the mediocre thermal efficiency. The introduction of obstacles in the dynamic air vein of the solar collector in order to obtain a turbulent flow is a technique that improves the thermal exchange by convection between the air and the absorber. This article present a computational analysis on the turbulent flow and heat transfer in solar air collector with rectangular plate fins absorber and baffles which are arranged on the bottom and top channel walls in a periodically staggered way. To this end we solved numerically, by the finite volumes method, the conservation equations of mass, momentum and energy. The low Reynolds number k-? model was adopted for the taking into account of turbulence. The velocity and pressure terms of momentum equations are solved by the SIMPLE algorithm. The parameters studied include the entrance mass flow rate of air. The influence of the mass flow rate of air on the axial velocity and the efficiency of upward type baffled solar air heaters have been investigated numerically. The results show that the flow and the heat transfer characteristics are strongly dependent on mass-flow rate of air and the presence and/or the absence of the baffles and fins in the solar collector. It was observed that increasing the Reynolds number will increase the efficiency of the solar panel, as expected.

The Dynamic Behavior of Once-Through Direct Steam Generation Parabolic Trough Solar Collector Row Under Moving Shadow Conditions

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Su Guo ◽  
Yinghao Chu ◽  
Deyou Liu ◽  
Xingying Chen ◽  
Chang Xu ◽  
...  
Keyword(s):  
Mass Flow Rate ◽  
Dynamic Behavior ◽  
Mass Flow ◽  
Flow Rate ◽  
Solar Collector ◽  
Outlet Temperature ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Direct Steam ◽  
Parabolic Trough Solar Collector

Compared with recirculation and injection modes, once-through direct steam generation (DSG) parabolic troughs are simpler to construct and require the lowest investment. However, the heat transfer fluid (HTF) in once-through DSG parabolic trough systems has the most complicated dynamic behavior, particularly during periods of moving shadows caused by small clouds and jet contrails. In this paper, a nonlinear distributed parameter dynamic model (NDPDM) is proposed to model the dynamic behavior of once-through DSG parabolic trough solar collector row under moving shadow conditions. Compared with state-of-the-art models, the proposed NDPDM possesses three characteristics: (a) adopting real-time local values of the heat transfer and friction resistance coefficients, (b) simulating the whole collector row, including the boiler and the superheated sections, and (c) modeling the disturbance of direct normal irradiance (DNI) level on DSG parabolic trough solar collector row under moving shadow conditions. Validated using experimental data, the NDPDM accurately predicts the dynamic characteristics of HTF during periods of partial and moving DNI disturbance. The fundamental and specific dynamic process of fluid parameters for a DSG parabolic trough solar collector row is provided in this paper. The results show the following: (a) Moving shadows have a significant impact on the outlet temperature and mass flow rate, and the impact lasts up to 1000 s even after the shadows completely leave the collector row. (b) The time for outlet steam temperature to reach a steady-state value for the first time is independent of the shadow width, speed, and moving direction. (c) High-frequency chattering of the outlet mass flow rate can be observed under moving DNI disturbance and will have a longer duration if the shadow width is larger or the shadow speed is slower. Compared with cases in which the whole system is shaded, partially shading cases have shown a longer duration of high-frequency chattering. (d) Both wider widths and slower speeds of shadow will cause a larger amplitude of responses in the outlet temperature and mass flow rate. When the shadow speed is low, there is a longer delay time of response in the mass flow rate of the outlet fluid. (e) The amplitude of response in the outlet temperature does not depend on the direction of clouds movement. However, if the DNI disturbance starts at the inlet of the collector row, there will be significant delay times in both outlet temperature and mass flow rate, and a larger amplitude of response in outlet mass flow rate.

scholarly journals Contribution to the Parametric Study of the Performance of A Parabolic Trough Collector

2021 ◽  
Vol 321 ◽  
pp. 02016
Author(s):  
Belkacem Bouali ◽  
Hanane-Maria Regue
Keyword(s):  
Heat Transfer ◽  
Mass Flow ◽  
Flow Rate ◽  
Optimal Operation ◽  
Heat Transfer Fluid ◽  
Parabolic Trough ◽  
Parabolic Trough Collector ◽  
Heat Transfer Fluids ◽  
Ansys Cfx ◽  
Different Seasons

This paper presents an analysis of the performance of a parabolic trough collector (PTC) according to some key operating parameters. The effects of the secondary reflector, the length and thickness of the absorber tube (receiver tube) and the flow rate of the heat transfer fluid (HTF) are investigated. The main objective is to determine an optimal operation, which improves the performance of a traditional PTC. The target variables are the temperature at the outlet of the tube, the amount of energy collected by the HTF and the efficiency of the system. The solar flux data concern the city of LAGHOUAT located in the south of Algeria. Four days in different seasons are considered. The optical analysis of the system is performed by using the open source SolTrace code. The output of this analysis is used as a boundary condition for the CFD solver. The conjugate heat transfer and the fluid flow through the absorber tube are simulated by using ANSYS-CFX solver. Water is considered as heat transfer fluids. The obtained results show that the use of a curved secondary reflector significantly improves the performance of the traditional PTC. As the thickness of the tube increases, the heat storage in the material increases, which increases the temperature at the exit of the tube and therefore the efficiency of the system. However, the length of the tube depends on the mass flow of the HTF and vice versa. To keep the efficiency constant by choosing another length, it is necessary to choose a mass flow rate proportional to the flow rate corresponding to the initial length.

scholarly journals Effect of nanofluid properties and mass-flow rate on heat transfer of parabolic-trough concentrating solar system

2019 ◽  
Vol 16 (1) ◽  
pp. 33-44 ◽  
Author(s):  
M.K. Islam ◽  
Md. Hasanuzzaman ◽  
N.A. Rahim ◽  
A. Nahar
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Laminar Flow ◽  
Turbulent Flow ◽  
Transfer Coefficient ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Parabolic Trough ◽  
Concentrated Solar Energy

Sustainable power generation, energy security, and global warming are the big challenges to the world today. These issues may be addressed through the increased usage of renewable energy resources and concentrated solar energy can play a vital role in this regard. The performance of a parabolic-trough collector’s receiver is here investigated analytically and experimentally using water based and therminol-VP1based CuO, ZnO, Al2O3, TiO2, Cu, Al, and SiC nanofluids. The receiver size has been optimized by a simulation program written in MATLAB. Thus, numerical results have been validated by experimental outcomes under same conditions using the same nanofluids. Increased volumetric concentrations of nanoparticle is found to enhance heat transfer, with heat transfer coefficient the maximum in W-Cu and VP1-SiC, the minimum in W-TiO2 and VP1-ZnO at 0.8 kg/s flow rate. Changing the mass flow rate also affects heat transfer coefficient. It has been observed that heat transfer coefficient reaches its maximum of 23.30% with SiC-water and 23.51% with VP1-SiC when mass-flow rate is increased in laminar flow. Heat transfer enhancement drops during transitions of flow from laminar to turbulent. The maximum heat transfer enhancements of 9.49% and 10.14% were achieved with Cu-water and VP1-SiC nanofluids during turbulent flow. The heat transfer enhancements of nanofluids seem to remain constant when compared with base fluids during either laminar flow or turbulent flow.

Sign in / Sign up

Export Citation Format

Share Document