Experimental and numerical study on a freeze protection system for flat-plate solar collectors with silicone peroxide tubes

2018 ◽  
Vol 135 ◽  
pp. 446-453 ◽  
Author(s):  
J. Vera-Medina ◽  
I. Lillo-Bravo ◽  
J. Hernández ◽  
M. Larrañeta
Keyword(s):  
Flat Plate ◽  
Numerical Study ◽  
Protection System ◽  
Solar Collectors ◽  
Freeze Protection

scholarly journals Long-Term Performance of Anti-Freeze Protection System of a Solar Thermal System

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1286
Author(s):  
Sebastian Pater
Keyword(s):  
Winter Season ◽  
Heating System ◽  
Protection System ◽  
Solar Thermal ◽  
Long Term Results ◽  
Solar Collectors ◽  
Evacuated Tube Collectors ◽  
Term Performance ◽  
Freeze Protection

In a moderate, transitory climate, to prevent freezing of outdoor pipes and collectors in solar thermal systems, anti-freezing fluids are commonly used. There is little experience of using water without any additives as a solar thermal fluid in such a climate. Based on these findings, to fill the knowledge gap this article presents the long-term results of thermal performance and anti-freeze protection of a solar heating system with heat pipe evacuated tube collectors with water as a solar thermal fluid. The operation of this system under real conditions was analysed for five years in southern Poland. The annual value of solar insolation ranged from 839 to almost 1000 kWh/m2. The monthly efficiency of the solar collectors from March to October was usually higher than 25%, and the lowest was between November and January. The anti-freeze protection system consumed annually from 7 to 13% of the heat generated by the collectors in the installation. Supporting the operation of the central heating system in the building during the winter season highly improved the efficiency of the solar collectors. Results show that it is possible to use water without any additives as a solar thermal fluid in a moderate, transitory climate.

scholarly journals Numerical study of natural convection in an inclined enclosure: application to flat plate solar collectors

2017 ◽  
Vol 4 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Charaf-Eddine Bensaci ◽  
Adnane Labed ◽  
Miloud Zellouf ◽  
Abdelhafid Moummi
Keyword(s):  
Natural Convection ◽  
Flat Plate ◽  
Numerical Study ◽  
Solar Collectors ◽  
Inclined Enclosure

Numerical Study of Boundary Layers With Reverse Wedge Flows Over a Semi-Infinite Flat Plate

2009 ◽  
Vol 77 (2) ◽  
Author(s):  
R. Ahmad ◽  
K. Naeem ◽  
Waqar Ahmed Khan
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
Numerical Study ◽  
Boundary Layer Equation ◽  
Wedge Angle ◽  
Adverse Pressure Gradient ◽  
Problem Solution ◽  
Weighted Residual Method ◽  
Boundary Layer Problem ◽  
Layer Problem

This paper presents the classical approximation scheme to investigate the velocity profile associated with the Falkner–Skan boundary-layer problem. Solution of the boundary-layer equation is obtained for a model problem in which the flow field contains a substantial region of strongly reversed flow. The problem investigates the flow of a viscous liquid past a semi-infinite flat plate against an adverse pressure gradient. Optimized results for the dimensionless velocity profiles of reverse wedge flow are presented graphically for different values of wedge angle parameter β taken from 0≤β≤2.5. Weighted residual method (WRM) is used for determining the solution of nonlinear boundary-layer problem. Finally, for β=0 the results of WRM are compared with the results of homotopy perturbation method.

Thermal and mechanical performance of sealed, gas-filled, flat plate solar collectors

Solar Energy ◽  
2012 ◽  
Vol 86 (1) ◽  
pp. 13-25 ◽  
Author(s):  
Johan Vestlund ◽  
Jan-Olof Dalenbäck ◽  
Mats Rönnelid
Keyword(s):  
Flat Plate ◽  
Mechanical Performance ◽  
Solar Collectors
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