study of solar water heaters based on exergy analysis - YMCA ...

Proceedings <strong>of</strong> the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University <strong>of</strong> Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
Assuming the temperature distribution in the storage tank is linear (∆T α ∆L), where L is the height <strong>of</strong> the storage
tank), we get;
Where T x , T L and T 0 are the temperature <strong>of</strong> <strong>water</strong> at position X, L and O from the bottom <strong>of</strong> the storage tank. Then
we obtain the exergy from storage tank to users ( ) by use the following equation:
(6)
6. Conclusion
The <strong>study</strong> <strong>of</strong> <strong>solar</strong> <strong>water</strong> heater <strong>based</strong> on exergy analysis is done in this paper. the conversion <strong>of</strong> <strong>solar</strong> radiation in
the evaluation <strong>of</strong> direct-<strong>solar</strong> systems leads to extremely high exergy losses in the direct <strong>solar</strong> systems.
Subsequently, the optimisation <strong>of</strong> these systems should be oriented so as to reduce the magnitude <strong>of</strong> exergy losses in
the conversion device. Exergy efficiency <strong>of</strong> <strong>solar</strong> systems is highly dependent on the daily <strong>solar</strong> radiation and
radiation intensity. To improve the exergy efficiency, we must select the material and design the number layer <strong>of</strong>
transparent cover and a judicious choice <strong>of</strong> the length <strong>of</strong> pipe is necessary. It is a good way to find out to design a
new style <strong>of</strong> storage tank, because large exergy losses in the storage tank.
7. Suggestions for Future work
• In this <strong>study</strong>, the flat plate collector is considered for analysis and it would be a good initiative to explore the
impact <strong>of</strong> other types <strong>of</strong> <strong>solar</strong> collector such as an evacuated tube or a concentrated collector.
• In this paper, only two components <strong>of</strong> the <strong>solar</strong> <strong>water</strong> heater are analyzed. Other components such as pump and
piping system could also be considered. Analysis <strong>of</strong> other components would help in calculation <strong>of</strong> pressure
drop across the system in order to select the pump and optimize the piping size.
References
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