Performance Assessment of Parabolic Trough Collectors with Variable Mass Flow Rates

2022 ◽  
pp. 225-235
Author(s):  
Anshul Tewari ◽  
R. S. Mishra
Keyword(s):  
Performance Assessment ◽  
Mass Flow ◽  
Variable Mass ◽  
Parabolic Trough ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Variable Mass Flow

Comparative Study on Parabolic Trough Collector by using Different Heat Transfer Fluids

2019 ◽  
Vol 11 (4) ◽  
Author(s):  
Krishna Mounica ◽  
Y.V. Hanumantha Rao ◽  
Vinay Atgur ◽  
G. Manavendra ◽  
B. Srinivasa Rao
Keyword(s):  
Heat Transfer ◽  
Mass Flow ◽  
Thermal Model ◽  
Heat Transfer Fluid ◽  
Parabolic Trough ◽  
Flow Rates ◽  
Parabolic Trough Collector ◽  
Heat Transfer Fluids ◽  
Mass Flow Rates ◽  
Simulation Results

In this paper the use of Syltherm-800 and Therminol-55 thermal oils in parabolic trough collector (PTC) is investigated with inlet temperatures of 375.35 K, 424.15 K, 470.65 K and 523.85 K and for mass flow rates of 4, 4.5 and 5 kg/sec. Analysis has been carried out using a thermal model and validated using the simulation results. Therminol-55 gives better heat transfer coefficient compared to Syltherm-800. Since Therminol-55 has higher specific heat and viscosity when compared to Syltherm-800, the use of Syltherm-800 as a heat transfer fluid in PTC is preferred. Better results are observed for temperature of 375.35 K and mass flow rate of 4 kg/sec.

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 Net-exergetic, hydraulic and thermal optimization of coaxial heat exchangers using fixed flow conditions instead of fixed flow rates

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Tobias Blanke ◽  
Markus Hagenkamp ◽  
Bernd Döring ◽  
Joachim Göttsche ◽  
Vitali Reger ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Laminar Flow ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Circular Ring ◽  
Flow Conditions ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Pipe Radius

AbstractPrevious studies optimized the dimensions of coaxial heat exchangers using constant mass flow rates as a boundary condition. They show a thermal optimal circular ring width of nearly zero. Hydraulically optimal is an inner to outer pipe radius ratio of 0.65 for turbulent and 0.68 for laminar flow types. In contrast, in this study, flow conditions in the circular ring are kept constant (a set of fixed Reynolds numbers) during optimization. This approach ensures fixed flow conditions and prevents inappropriately high or low mass flow rates. The optimization is carried out for three objectives: Maximum energy gain, minimum hydraulic effort and eventually optimum net-exergy balance. The optimization changes the inner pipe radius and mass flow rate but not the Reynolds number of the circular ring. The thermal calculations base on Hellström’s borehole resistance and the hydraulic optimization on individually calculated linear loss of head coefficients. Increasing the inner pipe radius results in decreased hydraulic losses in the inner pipe but increased losses in the circular ring. The net-exergy difference is a key performance indicator and combines thermal and hydraulic calculations. It is the difference between thermal exergy flux and hydraulic effort. The Reynolds number in the circular ring is instead of the mass flow rate constant during all optimizations. The result from a thermal perspective is an optimal width of the circular ring of nearly zero. The hydraulically optimal inner pipe radius is 54% of the outer pipe radius for laminar flow and 60% for turbulent flow scenarios. Net-exergetic optimization shows a predominant influence of hydraulic losses, especially for small temperature gains. The exact result depends on the earth’s thermal properties and the flow type. Conclusively, coaxial geothermal probes’ design should focus on the hydraulic optimum and take the thermal optimum as a secondary criterion due to the dominating hydraulics.

Numerical Investigation of Local Cooling Enhancement Using Pin-Finned Channel With Incremental Impingement

2017 ◽  
Author(s):  
Susheel Singh ◽  
Sumanta Acharya ◽  
Forrest Ames
Keyword(s):  
Aspect Ratio ◽  
Mass Flow ◽  
Cross Flow ◽  
Surface Cooling ◽  
Local Cooling ◽  
Stagnation Region ◽  
Flow Rates ◽  
Pin Fins ◽  
Mass Flow Rates ◽  
The Impact

Flow and heat transfer in a low aspect ratio pin-finned channel, representative of an internally cooled turbine airfoil, is investigated using Large Eddy Simulations (LES). To achieve greater control of surface cooling distribution, a novel approach has been recently proposed in which coolant is injected incrementally through a series of holes located immediately behind a specially designed cutout region downstream of the pin-fins. Sheltering the coolant injection behind the pin-fins avoids the impact of the cross-flow buildup that deflects the impingement jet and isolates the surface from cooling. The longitudinal and transverse spacing of the pin-fins, arranged in a staggered fashion, is X/D = 1.046 and S/D = 1.625, respectively. The aspect ratio (H/D) of pin-fin channel is 0.5. Due to the presence of the sequential jets in the configuration, the local cooling rates can be controlled by controlling the jet-hole diameter which impacts the jet mass flow rate. Hence, four different hole diameters, denoted as Large (L), Medium (M) , Small (S), Petite (P) are tested for impingement holes, and their effects are studied. Several patterns of the hole-size distributions are studied. It is shown that the peak Nusselt number in the stagnation region below the jet correlates directly with the jet-velocity, while downstream the Nusselt numbers correlate with the total mass flow rates or the average channel velocity. The local cooling parameter defined as (Nu/Nu0)(1-ε) correlates with the jet/channel mass flow rates.

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