scholarly journals NUMERICAL AND EXPERIMENTAL INVESTIGATION FOR HYBRID PHOTOVOLTAIC/THERMAL COLLECTOR SYSTEM IN DUHOK CITY

2020 ◽  
Vol 28 (4) ◽  
pp. 202-212
Author(s):  
Semyan Khaled ◽  
Omar Ali
Keyword(s):  
Solar Collector ◽  
Transfer Coefficients ◽  
One Dimensional ◽  
Heat Transfer Coefficients ◽  
Collector System ◽  
Solar Intensity ◽  
Implicit Finite Difference ◽  
Overall Efficiency ◽  
Water Mass Flow Rate ◽  
Thermo Physical Properties

The study deals with the experimental and numerical investigation of the hybrid Photovoltaic-thermal solar collector system in Duhok city during seven months and includes different measurements of temperatures, water mass flow rate, wind velocity, and solar intensity. A one-dimensional mathematical model is used to simulate the transient processes with constant thermo-physical properties and heat transfer coefficients. The energy conservation equations are solved using implicit finite difference method. The numerical and experimental results showed satisfactory agreement with an error (2.36%) between two thermal efficiencies. The results include the estimation of the electrical and thermal energy, thermal, electrical and overall efficiency. The highest overall efficiency of PV/T collector occurs in May 2019 with value (72.01%) and the lowest value in January 2019 is obtained as (63.1%). The cooling method leads to an increase in the electrical efficiency to about 3% as compared with PV solar collector system.

scholarly journals Performance Evaluation of Photovoltaic/Thermal (PV/T) System Using Different Design Configurations

2020 ◽  
Vol 12 (22) ◽  
pp. 9520
Author(s):  
M. Imtiaz Hussain ◽  
Jun-Tae Kim
Keyword(s):  
Heat Exchanger ◽  
Numerical Study ◽  
Balance Equations ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Pv Panel ◽  
Exchange Area ◽  
Energy And Exergy ◽  
Overall Efficiency ◽  
T System

This study summarizes the performance of a photovoltaic/thermal (PV/T) system integrated with a glass-to-PV backsheet (PVF film-based backsheet) and glass-to-glass photovoltaic (PV) cells protections. A dual-fluid heat exchanger is used to cool the PV cells in which water and air are operated simultaneously. The proposed PV/T design brings about a higher electric output while producing sufficient thermal energy. A detailed numerical study was performed by calculating real-time heat transfer coefficients. Energy balance equations across the dual-fluid PV/T system were solved using an ordinary differential equation (ODE) solver in MATLAB software. The hourly and annual energy and exergy variations for both configurations were evaluated for Cheonan City, Korea. In the case of a PV/T system with a glass-to-glass configuration, a larger heat exchange area causes the extraction of extra solar heat from the PV cells and thus improving the overall efficiency of the energy transfer. Results depict that the annual electrical and total thermal efficiencies with a glass-to-glass configuration were found to be 14.31% and 52.22%, respectively, and with a glass-to-PV backsheet configuration, the aforementioned values reduced to 13.92% and 48.25%, respectively. It is also observed that, with the application of a dual-fluid heat exchanger, the temperature gradient across the PV panel is surprisingly reduced.

Transient Considerations of Flat-Plate Solar Collectors

1974 ◽  
Vol 96 (2) ◽  
pp. 109-113 ◽  
Author(s):  
S. A. Klein ◽  
J. A. Duffie ◽  
W. A. Beckman
Keyword(s):  
Flat Plate ◽  
Solar Collector ◽  
Meteorological Data ◽  
Weather Conditions ◽  
Operating Conditions ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Thermal Capacitance ◽  
Flat Plate Solar Collector ◽  
Capacitance Effects

The effects of thermal capacitance in the modeling of the performance of a flat plate solar collector have often been neglected because of the computation involved. But because the solar collector is inherently exposed to continuously variable weather conditions, capacitance effects may be significant. To investigate these effects, three different models of flat-plate collectors have been investigated. The first, a quasi-steady-state model, simulates the performance of a collector of zero capacitance. The second model accounts for capacitance effects by assuming that a single value of thermal capacitance can be determined for the collector as a unit. The third model divides the collector into many isothermal segments, or nodes. For all three models the heat transfer coefficients are calculated as a function of operating conditions. The results show that, when hourly meteorological data are used, the zero-capacitance model is adequate.

Fluidized Bed Solar Collector

1988 ◽  
Vol 110 (4) ◽  
pp. 321-326 ◽  
Author(s):  
L. R. Glicksman ◽  
J. Azzola ◽  
J. Modlin
Keyword(s):  
Heat Transfer ◽  
Power Consumption ◽  
Fluidized Bed ◽  
Solar Collector ◽  
Effective Conductivity ◽  
Thermal Design ◽  
Low Density ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Order Of Magnitude

An air fluidized bed, contained in the wall cavity of an exterior building wall, forms the basis of a new solar collector design which is simpler than a water-cooled collector and has a thermal performance superior to that of an air-cooled collector. The fluidized bed serves as an intermediate heat transfer medium between a solar flux absorbed on the external building surface and a liquid thermal transfer loop. Fluidized beds yield heat-transfer coefficients an order of magnitude higher than single phase air flow. Low density particles are used in the bed to minimize power consumption. When defluidized, the bed acts as a good thermal insulator. Recent experimental results are presented for the heat-transfer coefficients of the immersed tubes, bounding walls, the effective conductivity of the bed, and the overall full-scale thermal design efficiency for various low density materials. Structural and power consumption performance is examined as well. An integrated fluidized bed solar collector design is proposed and compared with representative water and air collector designs.

Forced Convection Condensation on a Horizontal Tube: Influence of Turbulence in the Vapor and Liquid Phases

1999 ◽  
Vol 121 (4) ◽  
pp. 874-885 ◽  
Author(s):  
D. Homescu ◽  
P. K. Panday
Keyword(s):  
Turbulence Models ◽  
Horizontal Tube ◽  
Transfer Coefficients ◽  
Flow Equations ◽  
Heat Transfer Coefficients ◽  
Liquid Phases ◽  
Implicit Finite Difference Scheme ◽  
Implicit Finite Difference ◽  
Two Phases ◽  
Good Agreement

An implicit finite difference scheme is used to solve the problem of condensation of pure vapors flowing vertically downwards around a horizontal tube. The incompressible flow equations coupled at the interface for the liquid and vapor phases are solved. The pressure gradient, inertia, and enthalpy convection terms are retained in this analysis, and the influence of turbulence in the two phases is considered. The calculated results for laminar flow and those from different mixing length turbulence models are compared with experimental results for condensation of steam and R113. The results presented show that the average condensation heat transfer coefficients obtained using Kato’s turbulence model in the condensate film and Pletcher’s model in the vapor phase, are in good agreement with the experimental data.

scholarly journals A Numerical Well-Balanced Scheme for One-Dimensional Heat Transfer in Longitudinal Triangular Fins

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
I. Rusagara ◽  
C. Harley
Keyword(s):  
Heat Transfer ◽  
Differential Equation ◽  
Partial Differential Equation ◽  
Nonlinear Partial Differential Equation ◽  
Transfer Coefficients ◽  
Partial Differential ◽  
One Dimensional ◽  
Heat Transfer Coefficients ◽  
Highly Nonlinear ◽  
Triangular Fin

The temperature profile for fins with temperature-dependent thermal conductivity and heat transfer coefficients will be considered. Assuming such forms for these coefficients leads to a highly nonlinear partial differential equation (PDE) which cannot easily be solved analytically. We establish a numerical balance rule which can assist in getting a well-balanced numerical scheme. When coupled with the zero-flux condition, this scheme can be used to solve this nonlinear partial differential equation (PDE) modelling the temperature distribution in a one-dimensional longitudinal triangular fin without requiring any additional assumptions or simplifications of the fin profile.

Two-Dimensional Study of Heat Transfer and Fluid Flow in a Natural Convection Loop

1982 ◽  
Vol 104 (3) ◽  
pp. 508-514 ◽  
Author(s):  
A. Mertol ◽  
R. Greif ◽  
Y. Zvirin
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Natural Convection ◽  
A Priori ◽  
Two Dimensional ◽  
Transfer Coefficients ◽  
One Dimensional ◽  
Heat Transfer Coefficients ◽  
First Time ◽  
Good Agreement

A study has been made of the heat transfer and fluid flow in a natural convection loop. Previous studies of these systems have utilized a one-dimensional approach which requires a priori specifications of the friction and the heat-transfer coefficients. The present work carries out a two-dimensional analysis for the first time. The results yield the friction and the heat-transfer coefficients and give their variation along the loop with the Graetz number as a parameter. Comparison is also made with experimental data for the heat flux and good agreement is obtained.

scholarly journals Mixed Convection Flow over a Vertical Cone with an Applied Magnetic Field

2012 ◽  
Vol 11 (3) ◽  
pp. 105-112
Author(s):  
K R Jayakumar ◽  
A h Srinivasa ◽  
A T Eswara
Keyword(s):  
Magnetic Field ◽  
Mixed Convection ◽  
Applied Magnetic Field ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Transfer Coefficients ◽  
Vertical Cone ◽  
Heat Transfer Coefficients ◽  
Implicit Finite Difference Scheme ◽  
Implicit Finite Difference

An analysis is performed to investigate the mixed convection flow over a vertical cone with an applied magnetic field when the axis of the cone is in line with the flow. The results have been obtained for assisting and opposing flows. The partial differential equations governing the non-similar flow have been solved by an implicit finite difference scheme in combination with the quasilinearization technique. Numerical results are reported here to account the effects of magnetic field in presence of buoyancy parameter at different stream wise locations on skin friction and heat transfer coefficients.

Heat-Transfer Measurements in an Inexpensive Supersonic Wind Tunnel: 1—Apparatus and Results for a Laminar Boundary Layer Based on a Simple One-Dimensional Flow Model

1955 ◽  
Vol 22 (3) ◽  
pp. 289-296
Author(s):  
Joseph Kaye ◽  
J. H. Keenan ◽  
G. A. Brown ◽  
R. H. Shoulberg
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Reynolds Number ◽  
Laminar Boundary Layer ◽  
Flow Model ◽  
Transfer Coefficients ◽  
Supersonic Wind Tunnel ◽  
One Dimensional ◽  
Heat Transfer Coefficients ◽  
Dimensional Flow

Abstract Reliable experimental data, obtained at relatively low cost, are presented in the form of heat-transfer coefficients for air moving at supersonic speeds in a round tube. These data are analyzed, interpreted, and compared with available data in the literature. The experimental local heat-transfer coefficients are for laminar, transitional, and turbulent boundary layers. The data for a laminar boundary layer, comprising 17 runs, are discussed here for Mach numbers at tube inlet of 2.8 and 3.0. The range of values of diameter Reynolds number covered is from 20,000 to 100,000 for these laminar-flow tests, while the length Reynolds number extends to about 4,000,000. The computed quantities are obtained on the basis of a simple one-dimensional flow model, but a companion paper will analyze the same data in greater detail on the basis of a two-dimensional flow model.

Enhancing Productivity of V-Trough Solar Water Heater Incorporated Flat Plate Wick-Type Solar Water Distillation System

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
M. Murugan ◽  
A. Saravanan ◽  
G. Murali ◽  
Pramod Kumar ◽  
V. Siva Nagi Reddy
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Transfer Coefficients ◽  
Water Heater ◽  
Water Distillation ◽  
Solar Water ◽  
Heat Transfer Coefficients ◽  
Distillation System ◽  
Solar Intensity ◽  
The Comparative Study

Abstract This experimentation deals with the comparative study of a flat plate wick-based solar water distillation system (SWDS) with and without V-trough (VT) solar collector (SC) under the actual environmental conditions of Salem, Tamilnadu, India, as an attempt to enhance the productivity of the solar water distillation system. The influences of wick material, solar intensity, flow rate, and ambient temperature on productivity are also proposed. To ensure accuracy in the experimentation, the overall observation is divided into four spells with four different wick materials. The hourly productivity of the proposed still is compared with the standard theoretical equation, and the deviation between them is well accepted with ±10.14%. The maximum convective and evaporative heat transfer coefficients are observed during spell 3 as 2.488 W/m2K and 25.321 W/m2K, respectively. The prediction of Nusselt number and Sherwood number are also proposed to validate the heat transfer and mass transfer, respectively. Compared to polyester, terry cotton, and jute wick materials, fur fabric wick yielded maximum productivity of 4.40 l/day and 6.29 l/day for SWDS alone and SWDS with VT, respectively. The results revealed that the productivity of the SWDS coupled with V-trough SC is 30.12% greater than SWDS alone.

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