Design and Technical Manual

2. MODEL SELECTION
Fig 4
z
(X
1
, Y
1
)
(X
2
, Y
2
)
(X, Y)
x
y
i) Refer to 4. CAPACITY TABLE to nd Y
1
and Y
2
using X
1
and X
2
.
ii) Calculate capacity of outdoor unit using
following equation:
Y=(Y
2
-Y
1
) / (X
2
-X
1
)

(X-X1) + Y
1
Capacity ratio of indoor units to outdoor unit, X (%)
Capacity of outdoor unit, Y (kBtu/h )
Indoor unit
connecting
capacity (%)
Outdoor
temperature
Indoor temperature
DB WB
60°F DB 65°F DB 70°F DB 75°F DB 78°F DB
°F °F
TC IP TC IP TC IP TC IP TC IP
120
5 3 38.9 5.57 37.5 5.58 36.2 5.60 34.8 5.62 33.8 5.64
14 12 49.5 5.62 48.8 5.64 47.8 5.66 46.7 5.68 45.7 5.70
23 19 53.2 5.71 52.5 5.74 51.5 5.77 50.8 5.79 49.8 5.81
32 28 57.3 5.80 56.3 5.82 55.6 5.86 54.9 5.88 54.3 5.90
41 37 60.7 5.92 60.1 5.93 59.4 5.95 58.7 5.96 58.0 5.97
47 43 63.8 5.98 63.1 5.98 62.1 5.98 61.4 5.98 60.4 5.98
50 47 66.2 5.98 65.2 5.98 64.5 5.98 63.8 5.98 63.1 5.98
59 50 68.6 5.10 67.9 5.22 66.9 5.45 66.2 5.84 65.2 5.98
68 59 69.6 4.37 68.9 4.44 68.6 4.73 67.9 5.05 67.2 5.17
75 65 70.3 4.14 69.9 4.25 69.3 4.39 68.6 4.61 67.9 4.88
●●●
●●● ●●● ●●● ●●● ●●● ●●● ●●● ●●● ●●● ●●● ●●● ●●●
●●● ●●● ●●● ●●● ●●● ●●● ●●● ●●● ●●● ●●● ●●● ●●●
100
5 3 35.8 5.55 34.1 5.52 32.8 5.50 31.4 5.48 31.0 5.45
14 12 43.7 5.60 41.6 5.61 40.3 5.62 38.6 5.64 37.5 5.66
23 19 49.1 5.70 47.1 5.78 45.4 5.75 44.0 5.72 42.7 5.40
32 28 53.6 5.76 51.5 5.78 49.5 5.74 47.1 5.68 43.7 5.38
41 37 58.0 5.76 55.3 5.61 51.2 5.23 47. 8 4.92 45.0 4.79
47 43 63.1 5.70 59.4 5.35 54.0 4.89 49.5 4.55 46.1 4.46
50 47 63.5 5.56 59.7 5.25 54.6 4.80 50.2 4.53 46.7 4.37
59 50 64.1 5.19 60.1 4.80 56.0 4.61 51.2 4.33 47. 4 4.05
68 59 64.8 4.63 60.7 4.45 57.0 4.36 52.5 4.08 48.5 3.77
75 65 65.2 4.05 61.4 3.92 58.0 3.81 56.0 3.73 53.9 3.51
X
2
X
1
Y
2
Y
1
Capacity ratio of indoor units to outdoor unit X1 = 100 % X = 120 % X2 = 120 %
Capacity of outdoor units (kBtu/h) Y1 = 54.0 Y Y2 = 62.1
Y= (62.1-54.0) / (120-100)

(120-100) + 54.0 = 62.1 (kBtu/h)
- (02 - 12) -
MODEL SELECTION MODEL SELECTION