HVAC plant using a header with pressure, header with variable volumetric flow |
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Air heating coil 1 Flow 60 °C Return 40 °C Supply air 20 °C Outside air 10 °C Output 55 kW ∆pVR 34 kPa ∆ppiping 11 kPa Other plant data Pressure class PN 16 Control DC 0…10 V Operating voltage AC 24 V |
1 |
Determine the basic hydraulic circuit |
Injection circuit with 2-port valve |
2 |
Determine ΔpVR or ΔpMV |
With pressure and variable volumetric flow 🡪 ΔpVR ΔpVR = 34 kPa |
3 |
Determine ΔpV100 |
With pressure and variable volumetric flow 🡪 ΔpV100 = 17 kPa |
4 |
Determine the volumetric flow V100 |
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5 |
Determine the kvs value |
Flow chart Use the flow chart to determine the kvs value:
By way of calculation
kvs value ≥ 0.85 • 5.7 m3/h = 4.8 m3/h 🡪 kvs value = 5 m3/h or 6.3 m3/h
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6 |
Check the resulting differential pressure ΔpV100 |
First kvs value: Second kvs value: |
7 |
Select suitable line of valves |
🡪 1st selection: VVF53.25-5 2nd selection: VVF53.20-6.3 or VVF53.25-6.3 |
8 |
Check the valve authority PV (control stability) |
Check PV using the resulting differential pressure ΔpV100: First kvs value: Second kvs value: 🡪 Higher valve authority PV 🡪 kvs value = 5 m3/h |
9 |
Select the actuator |
Select actuator according to the following criteria:
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10 |
Check the working ranges |
Differential pressure Δpmax > ΔpV0 Closing pressure Δps > H0 |
11 |
Select valve and actuator |
Type of valve: VVF53.25-5 Type of actuator: According to the table |
