Title of article
Transient Thermal Behavior of a Vertical Solar Storage Tank with a Mantle Heat Exchanger during No-Flow Operation
Author/Authors
Barzegar، A. نويسنده , , Dehghan، A.A. نويسنده ,
Issue Information
ماهنامه با شماره پیاپی 3 سال 2009
Pages
15
From page
55
To page
69
Abstract
Transient thermal behavior of a vertical storage tank of a domestic solar heating system with a mantle heat exchanger has
been investigated numerically in the charging mode. It is assumed that the tank is initially filled with uniform cold water. At
an instant of time, the hot fluid from collector outlet is uniformly injected in the upper section of the mantle heat exchanger
and after heat transfer with the fluid inside the tank, withdrawn from the bottom part of the heat exchanger. The
conservation equations in the cylindrical coordinate and in axis-symmetric condition have been used according to the
geometry under investigation. Governing equations have been discretized by employing the finite volume method and the
SIMPLER algorithm has been used for coupling between momentum and pressure equations. The Low Reynolds Number
(LRN)
?
? k model is utilized for treating turbulence in the fluid. First, the transient thermal behavior of heat storage tank
and the process of formation of thermal stratification in the heat storage tank were investigated. Then, the influence of
Rayleigh number in the heat storage tank, Reynolds number in the mantle heat exchanger and vertical positioning of mantle
on the flow and thermal fields and the formation of the thermal stratification was investigated. It is found that for higher
values of Rayleigh number, a more suitable thermal stratification is established inside the tank. Also it is noticed that
increasing the incoming fluid velocity through the mantle heat exchanger causes a faster formation of the thermal
stratification. A superior thermal performance was achieved when the mantle heat exchanger is positioned at the middle
height of the storage tank.
Journal title
Journal of Applied Fluid Mechanics (JAFM)
Serial Year
2009
Journal title
Journal of Applied Fluid Mechanics (JAFM)
Record number
2398397
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