Three Dimensional CFD Simulation of Thermosyphon Flow in an Unglazed Solar Flat Plate Collector

Abstract

Thermosyphon unglazed solar flat plate collectors have been widely used all over the world to harness solar energy for generating hot water for various applications. This is mainly due to the passive nature of the system besides being simple in design. However, flat plate collectors are associated with higher heat losses from the surface leading to lower thermal performance. Hence, there is a dire need to optimize the thermal design aspects of the flat plate collector in order to achieve higher thermal performance. In this paper, the results of a full three dimensional CFD simulation of thermosyphon flow in an unglazed solar flat plate collector are presented. It is observed from the parametric study that there are interesting trends for the temperature distribution of the absorber plate and loop water for various simulated solar heat flux inputs. This analysis also brings out the effect of various simulated heat fluxes on the mass flow rates in the collector loop. The results of this CFD simulation study provide an insight into the behavior of the thermosyphon solar flat plate collector under various operating conditions and hence will be further helpful to undertake optimization for enhanced thermal performance of the collector.

Computation of Gold-Water Nanofluid Natural Convection in a Three-Dimensional Tilted Prismatic Solar Enclosure With Aspect Ratio and Volume Fraction Effects

“…Natural convection in three dimensional enclosures is also a major area of interest in solar engineering, in particular in the design of direct absorber solar collectors (DASCs). Sharma et al [5] employed the PHOENICS solver to investigate the threedimensional thermosyphon flow in an unglazed solar flat plate collector and computed mass flow rates in the collector loop for a range of solar heat flux inputs. Li et al [6] applied a multiple-relaxation-time model (MRT) and lattice Boltzmann method (LBM) solver to analyze the three-dimensional cubic natural convection for a solar cell at various Rayleigh numbers.…”