247
PERFORMANCE DATA (cont)
COOLING CAPACITIES, UNITS WITH HOT GAS REHEAT OPTION (cont)
LEGEND
NOTES:
1. Direct interpolation is permissible. Do not extrapolate.
2. The following formulas may be used:
tlwb = Wet-bulb temperature corresponding to enthalpy of air leaving evapo-
rator coil (hlwb)
Where: hewb = Enthalpy of air entering evaporator coil
3. The SHC is based on 80 F edb temperature of air entering evaporator coil.
Below 80 F edb, subtract (corr factor x cfm) from SHC.
Above 80 F edb, add (corr factor x cfm) to SHC.
Interpolation is permissible.
Correction Factor = 1.10 x (1 – BF) x (edb – 80).
581A240 (20 TONS) UNIT WITH HOT GAS REHEAT — A IN REHEAT, B AND C OFF
Temp (F )
Air Entering
Condenser
(Edb)
Evaporator Air Quantity — Cfm/BF
6000/0.04 7000/0.05 8000/0.06 9000/0.07 10,000/0.08
Evaporator Air — Relative Humidity (%)
50 55 60 50 55 60 50 55 60 50 55 60 50 55 60
65 TC 73 75 77 73 76 78 74 76 79 75 77 79 75 78 80
SHC 45 42 40 47 44 42 49 47 44 51 48 46 53 50 48
kW 6.1 6.1 6.1 6.1 6.1 6.1 6.1 6.1 6.1 6.1 6.1 6.1 6.1 6.1 6.1
75 TC 55 57 59 56 58 60 56 58 60 57 59 61 57 59 61
SHC 29 25 22 31 27 24 33 30 26 35 31 28 37 33 30
kW 6.6 6.6 6.6 6.6 6.6 6.6 6.6 6.6 6.6 6.6 6.6 6.6 6.6 6.6 6.6
85 TC 38 40 41 38 40 42 39 40 42 39 41 42 39 41 43
SHC 138 41510 7 1713 9 191410211612
kW 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2
95 TC 20 22 23 21 22 24 21 22 24 21 23 24 21 23 24
SHC –4 –9 –14 –1 –7 –11 1 –4 –9 3 –3 –7 5 –1 –6
kW 7.7 7.7 7.7 7.7 7.7 7.7 7.7 7.7 7.7 7.7 7.7 7.7 7.7 7.7 7.7
581A240 (20 TONS) UNIT WITH HOT GAS REHEAT — A AND B IN REHEAT, C OFF
Temp (F )
Air Entering
Condenser
(Edb)
Evaporator Air Quantity — Cfm/BF
6000/0.04 7000/0.05 8000/0.06 9000/0.07 10,000/0.08
Evaporator Air — Relative Humidity (%)
50 55 60 50 55 60 50 55 60 50 55 60 50 55 60
65 TC 106 110 113 10 8 111 114 109 113 116 11 0 114 117 111 115 11 8
SHC 45 42 39 47 44 41 49 46 44 51 48 46 53 50 47
kW 10.7 10.7 10.8 10.7 10.7 10.8 10.7 10.7 10.8 10.7 10.7 10.8 10.7 10.7 10.8
75 TC 81 84 87 82 85 88 83 86 89 83 87 89 84 87 90
SHC 29 25 21 31 27 24 34 29 26 36 31 28 37 33 30
kW 11.6 11.6 11 .6 11.6 11. 6 11.6 11.6 11 .6 11.6 11.6 11 .6 11.6 11. 6 11.6 11.6
85 TC 56 58 61 56 59 61 56 59 61 57 59 62 57 60 62
SHC 138 31610 6 1813 8 201510221612
kW 12.6 12.7 12.7 12.6 12.7 12.7 12.6 12.7 12.7 12.6 12.7 12.7 12.6 12.7 12.7
95 TC 30 33 34 30 32 34 30 32 34 30 32 34 30 32 34
SHC –3 –9 –14 0 –6 –12 2 –4 –10 4 –2 –8 6 0 –6
kW 13.6 13.6 13.6 13.6 13.6 13.6 13.6 13.6 13.6 13.6 13.6 13.6 13.6 13.6 13.6
581A240 (20 TONS) UNIT WITH HOT GAS REHEAT — A AND B IN REHEAT, C ON
Temp (F )
Air Entering
Condenser
(Edb)
Evaporator Air Quantity — Cfm/BF
6000/0.04 7000/0.05 8000/0.06 9000/0.07 10,000/0.08
Evaporator Air — Relative Humidity (%)
50 55 60 50 55 60 50 55 60 50 55 60 50 55 60
65 TC 177 185 191 177 185 192 178 186 192 178 186 193 178 186 193
SHC 98 92 86 100 94 88 101 95 90 103 97 92 104 98 93
kW 14.5 14.6 14.7 14.5 14.6 14.7 14.5 14.6 14.7 14.5 14.6 14.7 14.5 14.6 14.7
75 TC 154 161 168 154 162 169 155 162 169 155 163 169 155 163 170
SHC 81 73 66 83 75 69 85 78 71 87 80 73 89 81 75
kW 16.1 16.1 16.1 16.1 16.1 16.1 16.1 16.1 16.1 16.1 16.1 16.1 16.1 16.1 16.1
85 TC 131 138 145 131 139 145 131 139 146 132 139 146 132 140 146
SHC 63 54 46 66 57 49 69 60 52 71 62 54 73 64 56
kW 17.7 17.7 17.8 17.7 17.7 17.8 17.7 17.7 17.8 17.7 17.7 17.8 17.7 17.7 17.8
95 TC 107 115 122 108 115 122 108 116 122 108 116 123 109 116 123
SHC 46 35 25 50 39 29 53 42 32 55 45 35 58 47 38
kW 19.3 19.3 19.3 19.3 19.3 19.3 19.3 19.3 19.3 19.3 19.3 19.3 19.3 19.3 19.3
BF — Bypass Factor
Edb — Entering Dry-Bulb
Ewb — Entering Wet-Bulb
kW — Compressor Motor Power Input
ldb — Leaving Dry-Bulb
lwb — Leaving Wet-Bulb
SHC — Sensible Heat Capacity (1000 Btuh) Gross
TC — Total Capacity (1000 Btuh) Gross
tldb = tedb – sensible capacity (Btuh)
1.10 x cfm
hlwb = hewb – total capacity (Btuh)
4.5 x cfm
BYPASS
FACTOR
(BF)
ENTERING AIR DRY-BULB TEMP (F)
79 78 77 76 75 under 75
81 82 83 84 85 over 85
Correction Factor
.05 1.04 2.07 3.11 4.14 5.18 Use formula
shown below.
.10 .98 1.96 2.94 3.92 4.90
.20 .87 1.74 2.62 3.49 4.36
.30 .76 1.53 2.29 3.05 3.82
581A155-300