Author Contributions
Conceptualization, C.C.Y.; Methodology, C.C.Y.; Software, N.F.R.B.N.H.; Validation, N.F.R.B.N.H. and C.C.Y.; Formal analysis, N.F.R.B.N.H. and C.C.Y.; Investigation, N.F.R.B.N.H. and C.C.Y.; Resources, N.H.H.B.M.H. and A.F.I.; Data curation, N.F.R.B.N.H.; Writing—original draft preparation, N.F.R.B.N.H.; Writing—review and editing, C.C.Y., N.H.H.B.M.H., A.F.I. and H.-H.C.; Visualization, N.F.R.B.N.H.; Supervision, C.C.Y.; Project administration, C.C.Y.; Funding acquisition, N.H.H.B.M.H. All authors have read and agreed to the published version of the manuscript.
Figure 1.
Schematic diagram of the experimental setup to obtain the vibration data and RMS volt-age data.
Figure 1.
Schematic diagram of the experimental setup to obtain the vibration data and RMS volt-age data.
Figure 2.
Compressor unit (labeled 8) and service panel (labeled 10) locations at the air conditioning outdoor unit.
Figure 2.
Compressor unit (labeled 8) and service panel (labeled 10) locations at the air conditioning outdoor unit.
Figure 3.
(a). 6 placement points (A, B, C, D, E, and F) on the service panel enclosure directly adjacent to the compressor unit. (b). Air conditioning outdoor unit being anchored to the wall using “L” shaped wall support mounting with no anti-vibration support. (c). Vibration and Noise generated from the compressor system of the air conditioning outdoor unit in this experiment.
Figure 3.
(a). 6 placement points (A, B, C, D, E, and F) on the service panel enclosure directly adjacent to the compressor unit. (b). Air conditioning outdoor unit being anchored to the wall using “L” shaped wall support mounting with no anti-vibration support. (c). Vibration and Noise generated from the compressor system of the air conditioning outdoor unit in this experiment.
Figure 4.
Air Conditioning Indoor Unit.
Figure 4.
Air Conditioning Indoor Unit.
Figure 5.
3D printed and custom-made mounting for piezoelectric sensor.
Figure 5.
3D printed and custom-made mounting for piezoelectric sensor.
Figure 6.
Piezoelectric mounting at 9 o’clock orientation on the outdoor unit panel.
Figure 6.
Piezoelectric mounting at 9 o’clock orientation on the outdoor unit panel.
Figure 7.
Experimental setup to obtain vibration data.
Figure 7.
Experimental setup to obtain vibration data.
Figure 8.
Experimental setup for piezoelectric sensor.
Figure 8.
Experimental setup for piezoelectric sensor.
Figure 9.
Result of one factor ANOVA.
Figure 9.
Result of one factor ANOVA.
Figure 10.
Results of two factor ANOVA.
Figure 10.
Results of two factor ANOVA.
Figure 11.
Average vibration frequency (Hz) for point A, B, C at 20 °C.
Figure 11.
Average vibration frequency (Hz) for point A, B, C at 20 °C.
Figure 12.
Average vibration frequency (Hz) for point D, E, F at 20 °C.
Figure 12.
Average vibration frequency (Hz) for point D, E, F at 20 °C.
Figure 13.
Average vibration frequency (Hz) for point A, B, C at 22 °C.
Figure 13.
Average vibration frequency (Hz) for point A, B, C at 22 °C.
Figure 14.
Average vibration frequency (Hz) for point D, E, F at 22 °C.
Figure 14.
Average vibration frequency (Hz) for point D, E, F at 22 °C.
Figure 15.
Average vibration frequency (Hz) for point A, B, C at 24 °C.
Figure 15.
Average vibration frequency (Hz) for point A, B, C at 24 °C.
Figure 16.
Average vibration frequency (Hz) for point D, E, F at 24 °C.
Figure 16.
Average vibration frequency (Hz) for point D, E, F at 24 °C.
Figure 17.
Summary of highest average frequency of each placement.
Figure 17.
Summary of highest average frequency of each placement.
Figure 18.
Average RMS voltage (mV) for point A, B, C at 20 °C.
Figure 18.
Average RMS voltage (mV) for point A, B, C at 20 °C.
Figure 19.
Average RMS voltage (mV) for point D, E, F at 20 °C.
Figure 19.
Average RMS voltage (mV) for point D, E, F at 20 °C.
Figure 20.
Average RMS voltage (mV) for point A, B, C at 22 °C.
Figure 20.
Average RMS voltage (mV) for point A, B, C at 22 °C.
Figure 21.
Average RMS voltage (mV) for point D, E, F at 22 °C.
Figure 21.
Average RMS voltage (mV) for point D, E, F at 22 °C.
Figure 22.
Average RMS voltage (mV) for point A, B, C at 24 °C.
Figure 22.
Average RMS voltage (mV) for point A, B, C at 24 °C.
Figure 23.
Average RMS voltage (mV) for point D, E, F at 24 °C.
Figure 23.
Average RMS voltage (mV) for point D, E, F at 24 °C.
Figure 24.
Summary of highest RMS voltage (mV) for each placement.
Figure 24.
Summary of highest RMS voltage (mV) for each placement.
Table 1.
Data of the analysis tabulation.
Table 1.
Data of the analysis tabulation.
Source | Sum of Squares | Degree of Freedom | Mean Square | F | p-Value | F Crit |
---|
Between Groups (Factor) | SSF | VF | MSF | F | | |
Within Groups (Error) | SSE | VE | MSE | | | |
Total | SST | | | | | |
Table 2.
Data for two factor experimental design.
Table 2.
Data for two factor experimental design.
| Air Volume Flow Rates (Factor B) |
---|
Temperature (Factor A) | 1 (Low) | 2 (Medium) | 3 (High) |
---|
20 °C | y111, …, y11n | y121, …, y12n | y131, …, y13n |
22 °C | Y211, …, y21n | y221, …, y22n | y231, …, y23n |
24 °C | y311, …, y31n | y321, …, y32n | y331, …, y33n |
Table 3.
Result for a two-factor experimental design.
Table 3.
Result for a two-factor experimental design.
Source | Sum of Squares | Degree of Freedom | Mean Square | F | Fα,v1,v2 | Significant (Yes/No) |
---|
Factor A | SSA | vA | MSA | FA | Fα,vA,vE | |
Factor B | SSB | vB | MSB | FB | Fα,vB,vE | |
Factor AB | SSAB | vAB | MSAB | FAB | Fα,vAB,vE | |
Error | SSE | vE | MSE | | | |
Total | SST | | | | | |
Table 4.
Summary of the one factor analysis of variance (ANOVA) for vibration frequency data.
Table 4.
Summary of the one factor analysis of variance (ANOVA) for vibration frequency data.
| Significant? |
---|
Temperature | 20 °C | 22 °C | 24 °C |
---|
Point A | Yes | Yes | Yes |
Point B | Yes | Yes | Yes |
Point C | Yes | Yes | Yes |
Point D | Yes | Yes | No |
Point E | Yes | Yes | Yes |
Point F | Yes | Yes | Yes |
Table 5.
Summary of the two-way ANOVA analysis for vibration frequency.
Table 5.
Summary of the two-way ANOVA analysis for vibration frequency.
| Significant (Yes/No) |
---|
Placement | Factor A (Temperature) | Factor B (Air Volume Flow Rates) | Factor AB |
---|
A | Yes | Yes | No |
B | Yes | Yes | No |
C | Yes | Yes | No |
D | Yes | Yes | No |
E | Yes | Yes | No |
F | Yes | Yes | No |
Table 6.
Summary of the two-way ANOVA analysis for RMS voltage data.
Table 6.
Summary of the two-way ANOVA analysis for RMS voltage data.
| Significant (Yes/No) |
---|
Placement | Factor A | Factor B | Factor AB |
---|
A | No | Yes | No |
B | Yes | Yes | No |
C | Yes | Yes | No |
D | Yes | Yes | No |
E | Yes | Yes | No |
F | Yes | Yes | No |