Trane GEH 006 Manual page 43

ISO Heating Data Calculations
Examples for heating calculations in reference to ARI-ISO 13256-1 is listed below. This step-by-step example, utilizes the
unit information as shown in SP-5, to verify the ISO calculations found in SP-6.
SP-5: Unit information
Unit Information
Total Unit Watts
Air Flow, CFM
Static Pressure at the unit (in. wg)
GPM
Total Pressure Drop across water side (Ft. of water)
Air Side Capacity
Total Heating Capacity before adjustment (Btuh)
Explanation of Heating Calculations
STEP 1:
To calculate the fan power adjustment, refer to SP2 on Page
41 for the procedure on how to calculate the fan power
adjustment factor.
In this example:
CFM = 629
SP = 0.14
Fan Power Adjustment
=(CFM x 0.472) x (SP x 249) / 300
=(629 x 0.472) x (0.14 x 249) / 300
=34 Watts
STEP 2:
To calculate pump penalty, refer to SP1 on Page 41 for the
procedure on how to calculate the pump penalty.
In this example:
GPM = 5.02
FtHd = 2.08
Pump Penalty
=(GPM x 0.0631) x (PressDrop x 2990) / 300
=(5.02 x 0.0631) x (2.08 x 2990) / 300
=7 Watts
STEP 3:
To calculate capacity adjustment, multiply 3.413 times the
Fan Power Adjustment factor rounded to the nearest inte-
ger.
In this example:
Capacity adjustment = Fan Power Adjustment x 3.413
Result:
=34 x 3.413
=116 Btuh
WSHP-PRC001-EN
Selection
Procedure
1592
629
0.14
5.02
2.08
25118
STEP 4:
To calculate the ARI-ISO 13256-1 Heating Capacity Rating, sub-
tract the Heating Capacity Adjustment (Btuh) from the Total
Heating Capacity.
In this example:
ARI-ISO 13256-1 Heating Capacity Rating = 25118 - 116
Result:
ARI-ISO 13256-1 Heating Capacity Rating = 25002
STEP 5:
To calculate ARI-ISO 13256-1 Ratings Power Input (watts), add
the actual total measured watts to the pump penalty, then sub-
tract the Fan Power adjustment watts.
In this example:
Power Input = 1592 + 7 - 34
Result:
Power Input = 1565
STEP 6:
To calculate the Coefficient of Performance, divide the ARI-ISO
Heating Capacity by (ARI-ISO Power Input watts x 3.413).
In this example:
Energy Efficiency Ratio = 25002 / (1565 x 3.413)
Result:
Energy Efficiency Ratio = 4.68
SP-6: ISO calculations
ISO Calculations
ARI-ISO Power Adjustment
Fan Power (watts)
Pump Penalty (watts)
ARI-ISO Capacity Adjustment
Fan Power (Btuh)
ARI-ISO Ratings
Heating Capacity (Btuh)
Power Input (watts)
Coefficient of Performance (COP)
34
7
116
25002
1565
4.68
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