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System Design
6. Sound-proofing measures
D-28
Figure 5. Combined sound correction values
(4) Additional sound from reflections
●
Operating sound from outdoor units reflects from the walls of building and ground surfaces. These
reflections are received at the reception point, increasing the sound level of the system.
●
The sound received at the reception point is the sum of the sound propagated directly from the source plus
reflected sound.
The reflected sound level is obtained by establishing a virtual sound source (A'), and estimating the sound level
at B from A' (subtract the distance attenuation over the path A'-B). See the next paragraph on combining
sounds for a description of how to add direct and reflected sounds.
(5) Combining sounds
For multiple outdoor units, the sound level at the reception point is
determined by combining the sounds from each unit.
The combined sound from n units L
1
, L
2
, …L
n
is expressed by the
following formula.
If L = the combined sound level,
L = 10 log
10
(10
10
+ 10
10
+
・・・・・・
+ 10
10
)
For example, adding 61 phones and 62 phones gives
L = 10 log
10
(10
10
+ 10
10
) = 64.5 dB
This for of expression is applicable for any value of n.
Although sound level can be calculated this way, for simplicity, we have
prepared graphs to use instead.
<Calculation Example 1>
Calculate the combined sound level of L
1
= 62 [dB] and L
2
= 61 [dB]. L
1
– L
2
= 62 – 61 = 1 [dB], the correction value
from Figure 5 is 2.5 [dB], and 62 + 2.5 = 64.5 [dB], so the combined sound level is 64.5 [dB].
<Calculation Example 2>
To combine sound levels of 60, 64, 63 and 65 dB, first sort the values in order of magnitude.
65, 64, 63 and 60 dB
Then combine 65 and 64 dB to obtain the difference, 65 – 64 = 1 dB, which has a correction value of 2.5 dB, and
65 + 2.5 = 67.5 dB.
Next, combine 67.5 and 63 dB for a difference of 4.5 dB, for which the correction value is 1.3 dB, and 67.5 + 1.3 =
68.8 dB.
In the same way, combine 68.8 and 60 dB for level difference of 8.8 dB, for which the correction value is 0.5 dB.
And finally, 68.8 + 0.5 = 69.3 dB, which is the combined level of the four sounds.
65 64 63 60
Difference = 1
Correction value = 2.5
65+2.5=67.5
Difference = 4.5
Correction value = 1.3
67.5+1.3=68.8
Difference = 8.8
Correction value = 0.5
68.8 + 0.5 = 69.3 dB
B
○
●
●
A
’
●
●
●
’
Outdoor Unit
L1
L2 L3
62
61
Virtual sound source A'
Soun
d b
arri
er
Reception point
Sound source A
Reception point B
Reflected sound
(reflection surface)
Reception point B
Figure 7. Adding reflected sound
(ground surface)
Figure 6. Adding reflected sound (wall surface)
Summary of Contents for ECO G SGP-EW120M2G2W
Page 3: ...A 1 System Configuration Contents 1 Type Configuration 1 Outdoor unit A 2 ...
Page 12: ...Outdoor Unit 3 External Dimensions B 8 ...
Page 13: ...Outdoor Unit 4 Wiring Diagram B 9 ...
Page 14: ...Outdoor Unit 5 Performance Characteristics B 10 Cooling Heating SGP EW120M2G2W ...
Page 15: ...Outdoor Unit 5 Performance Characteristics B 11 Cooling Heating SGP EW150M2G2W ...
Page 16: ...Outdoor Unit 5 Performance Characteristics B 12 Cooling Heating SGP EW190M2G2W ...
Page 17: ...Outdoor Unit 5 Performance Characteristics B 13 Cooling Heating SGP EW240M2G2W ...
Page 18: ...Outdoor Unit 6 Operating Sound Level Characteristics B 14 1 Standard Mode ...
Page 19: ...Outdoor Unit 6 Operating Sound Level Characteristics B 15 ...
Page 20: ...Outdoor Unit 6 Operating Sound Level Characteristics B 16 ...
Page 21: ...Outdoor Unit 6 Operating Sound Level Characteristics B 17 ...
Page 22: ...Outdoor Unit 6 Operating Sound Level Characteristics B 18 2 Quiet Mode ...
Page 23: ...Outdoor Unit 6 Operating Sound Level Characteristics B 19 ...
Page 24: ...Outdoor Unit 6 Operating Sound Level Characteristics B 20 ...
Page 25: ...Outdoor Unit 6 Operating Sound Level Characteristics B 21 ...
Page 28: ...Control Related 1 System Block Diagram C 2 ...
Page 29: ...Control Related 2 Remote Control Warning List C 3 ...
Page 30: ...Control Related 2 Remote Control Warning List C 4 ...
Page 31: ...Control Related 2 Remote Control Warning List C 5 ...
Page 76: ...Installation Work 1 Points regarding refrigerant pipe work E 3 APR P680BG ...
Page 77: ...Installation Work 1 Points regarding refrigerant pipe work E 4 APR P1350BG ...
Page 78: ...Installation Work 1 Points regarding refrigerant pipe work E 5 APR CHP680BG APR CHP1350BG ...
Page 86: ...Installation Work 2 Points regarding electrical work outdoor unit E 13 ...
Page 87: ...Installation Work 3 Outdoor unit installation work E 14 ...
Page 88: ...Installation Work 3 Outdoor unit installation work E 15 ...
Page 89: ...Installation Work 3 Outdoor unit installation work E 16 ...
Page 90: ...Installation Work 3 Outdoor unit installation work E 17 ...
Page 91: ...Installation Work 3 Outdoor unit installation work E 18 ...
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