ZEMCH 2019 International Conference Proceedings April.2020 | Page 140
Design 1
12
Design 2
10
8
6
4
2
0
1
2
3
Velocity level (m/s)
4
Figure 8: Maximum temperature drop at air different level of air velocity 1, 2, 3 and 4 m/s for single
(Design #1) and series PCM enclosures (Design #2).
Figure 9. Total net heat reduction by implementing the PCM‐ based pre‐cooling unit in the duct
system for design#1 and design #2 at a velocity rate of 4,3,2,and 1 m/s .
Figure 10. AC cooling system capacity reduction by integrating the PCM in the pre‐cooling system for
design #1 and #2 at a velocity rate of 4, 3, 2 and 1 m/s in the UAE hot condition.
4. Discussion
4.1. Experimental Analysis
Fig. 4 shows that the inlet air temperature subjected to the AC duct system started with and
without the proposed pre‐cooling unit. The inlet air temperature starts at 29 °C and rise up as the solar
radiation increases reaching the maximum temperature of 45 °C at the noon time (1‐3) pm. Inclusion of
PCM as the latent heat storage system in the AC duct system cools the outlet air temperature and
reduced the peak air temperature achieving a temperature drop of 4.3 °C as maximum and 3.6 °C as an
average.
The total calculated heat released to indoor space by without and with employing PCM‐based pre‐
cooling system for three consecutive days applying UAE weather data is shown in Fig. 5A, and Fig.5 B
shows the corresponding reduction in the released heat by percentage. From the result, integrating
PCM‐based pre‐cooling system cooled the inlet air temperature and reduced the total heat from average
of 1000KW to around 650KW offering a daily reduction of 16% and day‐time reduction of 14%.
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ZEMCH 2019 International Conference l Seoul, Korea