.Buildings.Fluid.HydronicConfigurations.UsersGuide.Overview

Information

The configurations are grouped together depending on the type of primary network they are compatible with. See Buildings.Fluid.HydronicConfigurations.UsersGuide.NomenclatureSymbols for the definitions of the different circuit types and the symbols used in the schematics below.

Example models using the configurations are provided in Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Examples and Buildings.Fluid.HydronicConfigurations.PassiveNetworks.Examples. It is recommended that the user read the documentation of each example model carefully to understand their implementation, demonstration intent, and observations.

Configurations for active networks

The following table presents the configurations compatible with such networks.

Designation	Schematic	Application
Decoupling circuit with self-acting Δp control valve		Used for variable flow primary and consumer circuits where the consumer circuit has the same supply temperature set point as the primary circuit. The fixed bypass prevents the primary pressure differential from being transmitted to the consumer circuit. This allows a proper operation of the terminal control valves when the primary pressure differential is either too low or too high or varying too much. The self-acting Δp control valve maintains a nearly constant bypass mass flow rate. See Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Decoupling for further details.
Decoupling circuit with ΔT control		This configuration is nearly similar to Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Decoupling except that an actuated control valve is used to control the ΔT between the secondary and primary return, ensuring a nearly constant fraction of flow recirculation in the bypass line. This configuration is not included in the package, see the example Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Examples.DecouplingTemperature for a justification.
Diversion circuit		Used for constant flow primary circuits and variable flow consumer circuits where the consumer circuit has the same supply temperature set point as the primary circuit. See Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Diversion for further details.
Injection circuit with three-way valve		Used for constant flow primary and consumer circuits where the consumer circuit has a different supply temperature set point, either at design conditions or varying during operation. Although this configuration may theoretically still be used if the primary and secondary design temperatures are equal, it loses its main advantage which is that the control valve can be sized for a lower flow rate and can therefore be smaller. The fixed bypass ensures a consumer circuit operation hydronically decoupled from the primary side and the control valve position. See Buildings.Fluid.HydronicConfigurations.ActiveNetworks.InjectionThreeWay for further details.
Injection circuit with two-way valve		Used for variable flow primary circuits and either constant flow or variable flow consumer circuits. The fixed bypass prevents the primary pressure differential from being transmitted to the consumer circuit. This allows a proper operation of the terminal control valves on the consumer side when the primary pressure differential is either too low or too high or varying too much. See Buildings.Fluid.HydronicConfigurations.ActiveNetworks.InjectionTwoWay for further details.
Injection circuit with two-way valve and check valve in bypass branch		This configuration is nearly similar to Buildings.Fluid.HydronicConfigurations.ActiveNetworks.InjectionTwoWay except for the check valve that is added into the bypass. If used in DHC systems and if the control valve is not properly sized to maintain the set point at all loads, the check valve prevents recirculation in the service line which degrades the ΔT in the distribution system. If used to connect a heating coil, the check valve reduces the risk of freezing in case of secondary pump failure. See Buildings.Fluid.HydronicConfigurations.ActiveNetworks.InjectionTwoWayCheckValve for further details.
Single mixing circuit		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 control valve should be sized with a pressure drop equal to the primary pressure differential. That pressure drop must be compensated for by the secondary pump which excludes the use of this configuration to applications with a high primary pressure differential. See Buildings.Fluid.HydronicConfigurations.ActiveNetworks.SingleMixing for further details.
Throttle circuit		Used for variable flow primary and consumer circuits that have the same supply temperature set point. See Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Throttle for further details.

Configurations for passive networks

The following table presents the configurations compatible with such networks.

Designation	Schematic	Application
Dual mixing circuit		Used instead of Buildings.Fluid.HydronicConfigurations.PassiveNetworks.SingleMixing when the primary and secondary circuits have a different design supply temperature. Contrary to the single mixing circuit, the use of this configuration is restricted to constant flow secondary circuits due to the constraint on the fixed bypass pressure differential that must remain sufficiently high. See Buildings.Fluid.HydronicConfigurations.PassiveNetworks.DualMixing for further details.
Single mixing circuit		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. See Buildings.Fluid.HydronicConfigurations.PassiveNetworks.SingleMixing for further details.