Prototype development and performance analysis of latent heat thermal battery integrated with solar collector / Farhood Sarrafzadeh Javadi
Thermal battery is one of the challenging topics due to its low thermal storage capability and independency from the energy sources. This study aims designing, modeling and performing the experimental analysis of a standalone latent heat thermal battery (LHTB) integrated with a solar collector as...
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Format: | Thesis |
Published: |
2022
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Online Access: | http://studentsrepo.um.edu.my/14301/2/Farhood.pdf http://studentsrepo.um.edu.my/14301/1/Farhood.pdf http://studentsrepo.um.edu.my/14301/ |
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Summary: | Thermal battery is one of the challenging topics due to its low thermal storage
capability and independency from the energy sources. This study aims designing,
modeling and performing the experimental analysis of a standalone latent heat thermal
battery (LHTB) integrated with a solar collector as the main source of heat. The LHTB
consists of a plate-fin and tube heat exchanger located inside the battery casing and
paraffin wax which is used as a latent heat storage material. Solar thermal energy is
absorbed by solar collector and transferred to the LHTB using water as heat transfer fluid
(HTF). As a result, the paraffin transforms from the solid to liquid and the heat is stored
in the form of latent heat. Then, the heat can be released in a reverse process. The
significances of this design are the compatibility with different types of solar collectors
which makes it a cheaper solution compared to replacement of solar collector, adaption
with different kinds of heat source such as solar heat and industry heat waste, and mobility
which allows the user to recover the heat in a place other than charging location.
The charging and discharging tests have been conducted in three different operating
temperature of 68, 88, and 108 °C and each test was repeated for HTF flow rates of 30,
60 and 120 l/h. The highest amount of stored thermal energy was 13,210 kJ versus the
highest recovered amount of 5,825 kJ at maximum recovery efficiency of 35%. However,
the highest charging efficiency of 29% achieved in the test using 30 l/h of HTF at 108 °C
with stored thermal energy of 11,189 kJ. The recovery efficiency of the LHTB is varies
between 18% and 35%. It is highlighted that around two third of the paraffin remained at
the temperature above 58 °C at the end of the discharging tests. This is a considerable
amount of unused heat trapped inside the paraffin.
Thermodynamic analysis confirmed that the highest charging and recovery exergy
efficiency of 93.4% and 35.9% are achieved in the tests using 30 l/h of HTF at 68 °C and
120 l/h of HTF at operating temperature of 108 °C, respectively. However, the highest overall exergy efficiency of 25% achieved in the test using 120 l/h of HTF at operating
temperature of 68 °C. In the improved LHTB design, the best performance achieved by
absorbing 12,647 kJ thermal energy at efficiency of 11% using 120 l/h of HTF at 88 °C.
But, highest efficiency of 37% recorded in the test using 30 l/h of HTF.
The highest efficiency of 34%-42% in different tests was reported for the HPSC-LHS,
as the most advanced design in this field. The similar range of charging and recovery
efficiency of 34% and 37% were respectively calculated for the improved LHTB design.
The significant result shows that the charging rate advancement is from 2.07 MJ/h in
HPSC-LHS to 3.16 MJ/h in LHTB design. Therefore, an increase of 52.3% in charging
rate is proven.
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