The selection of the fan must be made as follows:
| a) | Estimate the calorific value in the unit. |  |
| b) | Determine the temperature rise value in the unit. | |
| c) | Calculate the needed air quantity. | |
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Q = 50 × Ha H : Calorific value (kW) |
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| d) | Estimate the system impedance in the unit. | |
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△P = KQn(Pa) △P : Reduced pressure (m3/min) |
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K : Constant measured in each unit. Q : Air quantity N : Determined by the air flow in the unit. n = 1 for steady flow, n = 2 for turbulent flow. n = 2 may be generally used. |
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| e) | Select the fan by the P-Q characteristics in the fan catalog. | |
| f) | Mount it on the equipment to measure the temperature rise. | |
Example: When setting the temperature rise value T = 10deg.C at calorific value 300W
Q =
50 × 0.3
10
= 1.5 (m3/min)
Estimate the system impedance, select the fan, conduct the actual operation, measure the temperature rise and investigate the fan.