II - 9
Design of W-ECO MULTI SYSTEM
2
TD831077
1. Model Selecting and Capacity Calculation
1-5. Capacity correction graph according to refrigerant tubing length and elevation
difference (For R407C)
Elevation Total equivalent Cooling capacity Heating capacity
difference tubing length coefficient coefficient
Indoor unit 25: a 30 m 54.2 m 90.0 % 97.4 %
Indoor unit 12: b 30 m 60.8 m 89.0 % 97.1 %
Indoor unit 9: c 30 m 70.9 m 87.0 % 96.5 %
Indoor unit 18: d 34 m 61.8 m 88.0 % 97.0 %
Indoor unit 36: e 34 m 65.8 m 88.0 % 96.8 %
System example
1) Plus side of the elevation difference is when the outdoor unit is higher than the indoor unit.
2) Minus side of the elevation difference is when the outdoor unit is lower than the indoor unit.
3) The value of gas tube is used as equivalent length.
4) The capacity of each indoor unit is calculated by multiplying it with the capacity coefficient, as obtained from the total equivalent
lengths of main tubes and distribution branches which are directly connected to the indoor units.
5) Equivalent length conversion is not necessary for the optional distribution joint.
6) Total equivalent length is calculated by adding the straight equivalent length of joints to the actual length.
7) Model selection is done from the value calculated for total cooling and total heating.
NOTE
Reference tubing diameter (wide tubing) mm
ø12.7 ø15.88 ø19.05 ø22.22 ø25.4 ø28.58 ø31.75 ø38.1 ø41.28 ø44.45
Modified tubing diameter (wide tubing) mm
ø15.88 ø19.05 ø22.22 ø25.4 ø28.58 ø31.75 ø38.1 ø41.28 ø44.45 ø50.8
Equivalent coefficient of correction of tubing length
0.4 0.5 0.6 0.7
When increasing the tubing diameter on the gas side, calculate the equivalent length by the coefficient of correction as specified in Table 1.
Equivalent tubing length after increasing the diameter = Reference tubing length × equivalent coefficient of correction of tubing length
abecd
0
-10
-20
-30
10
20
30
40
50
Total equivalent tubing length (m)
Elevation Difference (m)
Heating capacity coefficient
10 20 30 40 50 60 70 80 90 100 110 120 125
97
100
%
96 95 94
98
99
1530_M_I
abecd
0
-10
-20
-30
10
20
30
40
50
Total equivalent tubing length (m)
Elevation Difference (m)
Cooling capacity coefficient
10 20 30 40 50 60 70 80 90 100 110 120 125
90
92
94
96
98
88 86 84 82 80 78
100
%
1529_M_I
To minimize the reduction in cooling capacity to be caused when an excessively long tubing is used, we recommended increasing the
diameter of the wide tubing as indicated in Table 1. Do not exceed the recommended total tubing length.
* Increase diameter of the gas tubing side only, as specified in Table 1. Caliculate the refrigerant additional charging volume appropri-
ate for the narrow tubing diameter and length.
Table 1: Equivalent coefficient of correction of tubing length to be applied when increasing the diameter of the gas tubing.
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