The heat transfer processes in the heat exchange unit of combined photoenergy system

Keywords: heat exchanger unit, coolant, solar panels, combined photoenergy system

Abstract

Previously developed photoenergetic system based on silicon
multijunction solar cells with vertical diode cells or gallium arsenide
solar cells, which has a positioning and control facility,
which increases the amount of light energy that comes to the
surface of photoenergetic system has many advantages. Such
photoenergetic system will produce electricity and heat water, as
well. But significant weaknesses connected with a uniform cooling
of installed solar cells were detected and need a separate solution.
Based on aforesaid, the aim of this work was to make mathematical
modelling of the main parameters of heat transfer block
for such photoenergetic system based on heat transfer general
patterns for forced fluid circulation case.
Using theoretical study it was considered two options of construction:
construction with a large area of the heat exchanger,
and construction that has a large coefficient of heat transfer in
heat exchanger area that is close to heat receiving surface. Based
on carried calculations the basic construction of a flat heat exchanger
has been improved by the insertion of microchannels for
increasing heat transfer coefficient. Heat exchanger block is
designed as a finished unit with implementation turbulent flow in
it, which allows obtaining heat transfer coefficient of
18 kW/(m2×k).
Analysis of the received heat pictures allows concluding that at
the flowing liquid speed 0.3 m/s for the proposed construction of
the heat exchanger sufficient uniformity of cooling surface is
achieved. In this case, the maximum temperature does not exceed
43.5oC, which is sufficient for effective solar cell work without
reducing efficiency. Along with this, flowing liquid speed reducing
leads to loss of cooling uniformity and to significantly increasing
of the surface temperature more than 60oC, which is
unacceptable.
Flow analysis confirmed the turbulent regime of the flow, which
gives the maximum possible heat transfer coefficient.

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Published
2017-06-14
How to Cite
Zaitsev, R. (2017). The heat transfer processes in the heat exchange unit of combined photoenergy system. Renewable and Hydrogen Energy , (2 (49), 50-58. Retrieved from https://ve.org.ua/index.php/journal/article/view/59