This configuration (see schematic below) is used for variable flow primary circuits and either constant flow or variable flow secondary circuits that have a design supply temperature identical to the primary circuit but a varying set point during operation.
The following table presents the main characteristics of this configuration.
Primary circuit | Variable flow |
Secondary (consumer) circuit | Constant or variable flow |
Typical applications | Widely used in heating applications as it is very simple to achieve. |
Non-recommended applications | Low-temperature systems that would require the control valve to be operated on a limited opening range: use Buildings.Fluid.HydronicConfigurations.PassiveNetworks.DualMixing instead. |
Built-in valve control options | Supply temperature |
Control valve selection (See the nomenclature in the schematic.) |
β = ΔpA-AB /
(Δp1 + ΔpA-AB) The control valve is sized with a pressure drop equal to the maximum of Δp1 and 3e3 Pa. |
Balancing requirement | In most cases the bypass balancing valve is not needed. However, it may be needed to counter negative back pressure created by other served circuits, see Buildings.Fluid.HydronicConfigurations.PassiveNetworks.Examples.SingleMixingOpenLoop. |
Lumped flow resistance includes (With the setting use_lumFloRes=true .)
|
Control valve val and primary balancing valve res1
|
The parameter dp1_nominal
stands for the potential
primary back pressure and must be provided as an absolute value.
By default the secondary pump is parameterized with
a design pressure rise equal to
dp2_nominal + dpBal2_nominal +
max({val.dpValve_nominal + dp1_nominal, val.dp3Valve_nominal + dpBal3_nominal}
.