The application on the usage of natural fibers as noise absorbers
The Heat Ventilation Air Conditioning System (HVAC) is one of the ducting systems that are commonly found to make occupants in the building comfortable by controlling the temperature and air flow. However, noise is produced in the system and reaches the occupants inside the building, thus causing...
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| Format: | Thesis |
| Language: | English English English |
| Published: |
2013
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| Subjects: | |
| Online Access: | http://eprints.uthm.edu.my/6692/1/24p%20MOHD%20AMRAN%20MADLAN.pdf http://eprints.uthm.edu.my/6692/2/MOHD%20AMRAN%20MADLAN%20COPYRIGHT%20DECLARATION.pdf http://eprints.uthm.edu.my/6692/3/MOHD%20AMRAN%20MADLAN%20WATERMARK.pdf http://eprints.uthm.edu.my/6692/ |
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| Summary: | The Heat Ventilation Air Conditioning System (HVAC) is one of the ducting
systems that are commonly found to make occupants in the building comfortable by
controlling the temperature and air flow. However, noise is produced in the system
and reaches the occupants inside the building, thus causing distraction, discomfort
and uneasiness. There are HVAC silencers in the market, however the typical sound
absorbing material used is mineral wool types. This research focuses on the ducting
silencer with the sound absorbing material that made from Coconut fiber, Arenga
Pinnata (Ijuk), Kenaf, Cotton and Rockwool. The compositions of these materials
have been tested to identify its performance. The objective of this research is to
compare the insertion loss in the HVAC by using various configurations. The
materials have been tested separately at various frequencies to determine the effects
of the forward airflow in the HVAC system in the transmission loss and to analyse
the affect of the insertion loss on the straight and bend in the HVAC duct system.
The experiment that was carried out follows the standard ASTM E477. In this
experiment, the sound absorbing material of Coconut fiber with different
configuration has been investigated, followed by other types of sound absorptive
materials such as Arenga Pinnata (Ijuk), Kenaf, Cotton and Rockwool. From the
overall result and comparison, all the materials that tested on straight and bend
ducting showed the same performance trends where at below frequency of 500 Hz
the insertion loss was high at certain frequency only. The insertion loss increases
steadily from 500 Hz until 6300 Hz and maintained until frequency 10000 Hz at
around 6 dB to 40 dB. The insertion loss increase as the numbers of sound absorptive
materials in the silencer increase but the 4 pieces configuration has been chosen as
the best configuration because the air flow was higher around 60% compared to
configuration of 5 pieces. The insertion loss of 30g Rockwool combined with 30g
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Cotton was higher compared to other materials which are averagely 44.8% higher
than Rockwool alone, 44.1% higher than Cotton alone, 35% higher than Kenaf alone,
81.4% higher than combination of Arenga Pinnata and Kenaf, 65.1% higher than
Coconut fiber alone, and 118.9% higher than Arenga Pinnata alone. The insertion
loss at straight and bend ducting that was analysed showed that the bend ducting
gave more insertion loss at an average of 47% than the straight ducting. |
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