scholarly journals Analisa Energi pada Alat Desalinasi Air Laut Tenaga Surya Model Lereng Tunggal

2021 ◽  
Vol 12 (1) ◽  
pp. 193
Author(s):  
Munawar Alfansury Siregar ◽  
Wawan Septiawan Damanik ◽  
Sudirman Lubis
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Radiation Heat Transfer ◽  
Aluminum Foil ◽  
Solar Desalination ◽  
Human Need ◽  
Solar Intensity ◽  
Evaporative Heat Transfer ◽  
Renewable Technology

<p class="Abstract">The use of solar energy every day is increasing due to the greater human need for energy. the application of solar desalination equipment is classified as a renewable technology that is very profitable because the energy used is obtained for free and does not cause damage to the environment. This study examines the performance of the solar desalination device with a single slope model with a passive system. It is hoped that greater energy absorption is expected to accelerate the process of evaporation of seawater in the evaporator so as to produce lots of clean water. The desalination tool on the surface of the wall is insulated using aluminum foil with a thickness of 20 mm. The highest solar intensity was obtained on the fifth day of testing, namely 420.85 W/m<sup>2</sup> with the radiation heat transfer coefficient of 18.44 W/m<sup>2 o</sup>C, and the lowest solar intensity on the second day, namely 96.89 W/m<sup>2</sup> with the lowest total outside heat transfer coefficient of 25.57 W/m<sup>2 o</sup>C. The highest evaporative heat transfer coefficient is 10.54 W/m<sup>2 o</sup>C and the lowest is 4.42 W/m<sup>2</sup> <sup>o</sup>C. the lowest energy absorbed by the evaporator on the second day was 1.37 kWh. And the highest efficiency on the fifth day reached 58.89% and the lowest energy efficiency on the second day, namely 34.05%.</p>

Meshless Local Petrov-Galerkin Method for Heat Transfer Analysis

2013 ◽  
Author(s):  
Singiresu S. Rao
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Boundary Conditions ◽  
Transfer Coefficient ◽  
Transfer Problem ◽  
Radiation Heat Transfer ◽  
Heat Transfer Problem ◽  
Radiation Heat ◽  
Mlpg Method ◽  
Transfer Problems

A meshless local Petrov-Galerkin (MLPG) method is proposed to obtain the numerical solution of nonlinear heat transfer problems. The moving least squares scheme is generalized, to construct the field variable and its derivative continuously over the entire domain. The essential boundary conditions are enforced by the direct scheme. The radiation heat transfer coefficient is defined, and the nonlinear boundary value problem is solved as a sequence of linear problems each time updating the radiation heat transfer coefficient. The matrix formulation is used to drive the equations for a 3 dimensional nonlinear coupled radiation heat transfer problem. By using the MPLG method, along with the linearization of the nonlinear radiation problem, a new numerical approach is proposed to find the solution of the coupled heat transfer problem. A numerical study of the dimensionless size parameters for the quadrature and support domains is conducted to find the most appropriate values to ensure convergence of the nodal temperatures to the correct values quickly. Numerical examples are presented to illustrate the applicability and effectiveness of the proposed methodology for the solution of heat transfer problems involving radiation with different types of boundary conditions. In each case, the results obtained using the MLPG method are compared with those given by the FEM method for validation of the results.

scholarly journals FORCED CONVECTION DRYING OF INDIAN GROUNDNUT: AN EXPERIMENTAL STUDY

2017 ◽  
Vol 15 (3) ◽  
pp. 467
Author(s):  
Ravinder Kumar Sahdev ◽  
Mahesh Kumar ◽  
Ashwani Kumar Dhingra
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Forced Convection ◽  
Experimental Error ◽  
Linear Regression Analysis ◽  
Convective Heat Transfer Coefficient ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Evaporative Heat Transfer

In this paper, convective and evaporative heat transfer coefficients of the Indian groundnut were computed under indoor forced convection drying (IFCD) mode. The groundnuts were dried as a single thin layer with the help of a laboratory dryer till the optimum safe moisture storage level of 8 – 10%. The experimental data were used to determine the values of experimental constants C and n in the Nusselt number expression by a simple linear regression analysis and consequently, the convective heat transfer coefficient (CHTC) was determined. The values of CHTC were used to calculate the evaporative heat transfer coefficient (EHTC). The average values of CHTC and EHTC were found to be 2.48 W/m2 oC and 35.08 W/m2 oC, respectively. The experimental error in terms of percent uncertainty was also estimated. The experimental error in terms of percent uncertainty was found to be 42.55%. The error bars for convective and evaporative heat transfer coefficients are also shown for the groundnut drying under IFCD condition.

Evaporative Heat Transfer Analysis of a Heat Pipe With Hybrid Axial Groove

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Lizhan Bai ◽  
Guiping Lin ◽  
G. P. Peterson
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Liquid Film ◽  
Transfer Coefficient ◽  
Flow Resistance ◽  
Heat Pipes ◽  
Low Flow ◽  
Circular Channel ◽  
Evaporative Heat Transfer ◽  
Evaporative Heat Transfer Coefficient

Through the application of thin film evaporation theory and the fundamental operating principles of heat pipes, a hybrid axial groove has been developed that can greatly enhance the performance characteristics of conventional heat pipes. This hybrid axial groove is composed of a V-shaped channel connected with a circular channel through a very narrow longitudinal slot. During the operation, the V-shaped channel can provide high capillary pressure to drive the fluid flow and still maintain a large evaporative heat transfer coefficient. The large circular channel serves as the main path for the condensate return from the condenser to the evaporator and results in a very low flow resistance. The combination of a high evaporative heat transfer coefficient and a low flow resistance results in considerable enhancement in the heat transport capability of conventional heat pipes. In the present work, a detailed mathematical model for the evaporative heat transfer of a single groove has been established based on the conservation principles for mass, momentum and energy, and the modeling results quantitatively verify that this particular configuration has an enhanced evaporative heat transfer performance compared with that of conventional rectangular groove, due to the considerable reduction in the liquid film thickness and a corresponding increase in the evaporative heat transfer area in both the evaporating liquid film region and the meniscus region.

Calculations of Combined Radiation and Convection Heat Transfer in Rod Bundles Under Emergency Cooling Conditions

1976 ◽  
Vol 98 (3) ◽  
pp. 414-420 ◽  
Author(s):  
K. H. Sun ◽  
J. M. Gonzalez-Santalo ◽  
C. L. Tien
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Cooling System ◽  
Radiation Heat Transfer ◽  
Convection Heat Transfer ◽  
Transfer Coefficients ◽  
Operation Conditions ◽  
Water Reactors ◽  
Core Cooling

A model has been developed to calculate the heat transfer coefficients from the fuel rods to the steam-droplet mixture typical of Boiling Water Reactors under Emergency Core Cooling System (ECCS) operation conditions during a postulated loss-of-coolant accident. The model includes the heat transfer by convection to the vapor, the radiation from the surfaces to both the water droplets and the vapor, and the effects of droplet evaporation. The combined convection and radiation heat transfer coefficient can be evaluated with respect to the characteristic droplet size. Calculations of the heat transfer coefficient based on the droplet sizes obtained from the existing literature are consistent with those determined empirically from the Full-Length-Emergency-Cooling-Heat-Transfer (FLECHT) program. The present model can also be used to assess the effects of geometrical distortions (or deviations from nominal dimensions) on the heat transfer to the cooling medium in a rod bundle.

Meshless Local Petrov-Galerkin Method for Three-Dimensional Heat Transfer Analysis

2012 ◽  
Vol 134 (11) ◽  
Author(s):  
Jun Tian ◽  
Singiresu S. Rao
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Boundary Conditions ◽  
Transfer Coefficient ◽  
Transfer Problem ◽  
Radiation Heat Transfer ◽  
Three Dimensional ◽  
Radiation Heat ◽  
Mlpg Method ◽  
Transfer Problems

A meshless local Petrov-Galerkin (MLPG) method is proposed to obtain the numerical solution of nonlinear heat transfer problems. The moving least squares scheme is generalized to construct the field variable and its derivatives continuously over the entire domain. The essential boundary conditions are enforced by the direct scheme. By defining a radiation heat transfer coefficient, the nonlinear boundary value problem is solved as a sequence of linear problems each time updating the radiation heat transfer coefficient. The matrix formulation is used to drive the equations for a three dimensional nonlinear coupled radiation heat transfer problem. By using the MPLG method, along with the linearization of the nonlinear radiation problem, a new numerical approach is proposed to find the solution of the coupled heat transfer problem. A numerical study of the dimensionless size parameters for the quadrature and support domains is conducted to find the most appropriate values to ensure convergence of the nodal temperatures to the correct values quickly. Numerical examples are presented to illustrate the applicability and effectiveness of the proposed methodology for the solution of one-, two-, and three-dimensional heat transfer problems involving radiation with different types of boundary conditions. In each case, the results obtained using the MLPG method are compared with those given by the finite element method (FEM) method for validating the results.

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