Kvs calculator
Control valve selection
Valve parameters
Medium
Control theory
What is Kvs?
Kvs is the flow coefficient of a valve. It gives the water flow in m³/h through the fully open valve at a pressure drop of 1 bar (100 kPa).
Valve authority (a)
The ratio of the pressure drop across the fully open valve to the pressure drop across the whole controlled circuit.a = ΔP_valve / (ΔP_valve + ΔP_circuit)
Recommendations
- •For two-port valves, the optimal authority is 0.3 — 0.7.
- •For three-port valves (mixing), authority must be ≥ 0.5.
- •Low authority makes the valve behave like an on/off device and the temperature swing.