modelChiller

Base subsystem with heat recovery chiller

Extends from Buildings.Obsolete.BaseClasses.ObsoleteModel (Icon for classes that are obsolete and will be removed in later versions).

Information

This is a model for a chiller system with constant speed evaporator and condenser pumps, and mixing valves modulated to maintain a minimum condenser inlet temperature (resp. maximum evaporator inlet temperature).

The system is controlled based on the logic described in Buildings.Obsolete.DHC.ETS.Combined.Controls.Chiller. The pump flow rate is considered proportional to the pump speed under the assumption of a constant flow resistance for both the condenser and the evaporator loops. This assumption is justified by the connection of the loops to the buffer tanks, and the additional assumption that the bypass branch of the mixing valves is balanced with the direct branch.

Parameters

Type	Name	Default	Description
Buildings.Fluid.Chillers.Data.ElectricEIR.Generic	dat		Chiller performance data
Assumptions
Boolean	allowFlowReversal	false	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Nominal condition
Modelica.Units.SI.PressureDifference	dpCon_nominal		Nominal pressure drop accross condenser
Modelica.Units.SI.PressureDifference	dpEva_nominal		Nominal pressure drop accross evaporator
Modelica.Units.SI.Pressure	dpValCon_nominal	dpCon_nominal/2	Nominal pressure drop accross control valve on condenser side
Modelica.Units.SI.Pressure	dpValEva_nominal	dpEva_nominal/2	Nominal pressure drop accross control valve on evaporator side
Controls
Modelica.Units.SI.Temperature	TConWatEntMin	dat.TConEntMin	Minimum value of condenser water entering temperature
Modelica.Units.SI.Temperature	TEvaWatEntMax	dat.TEvaLvgMax - dat.QEva_flow_nominal/cp_default/dat.mEva_flow_nominal	Maximum value of evaporator water entering temperature

Connectors

Type	Name	Description
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput	uHea	Heating enable signal
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput	uCoo	Cooling enable signal
Buildings.Controls.OBC.CDL.Interfaces.RealInput	TChiWatSupSet	Chilled water supply temperature set point (may be reset down)
Modelica.Fluid.Interfaces.FluidPort_a	port_aChiWat	Fluid port for chilled water return
Modelica.Fluid.Interfaces.FluidPort_b	port_bChiWat	Fluid port for chilled water supply
Modelica.Fluid.Interfaces.FluidPort_a	port_aHeaWat	Fluid port for heating water return
Modelica.Fluid.Interfaces.FluidPort_b	port_bHeaWat	Fluid port for heating water supply
Buildings.Controls.OBC.CDL.Interfaces.RealOutput	PChi	Chiller power
Buildings.Controls.OBC.CDL.Interfaces.RealOutput	PPum	Pump power

Components

Type	Name	Description
Buildings.Fluid.Chillers.ElectricEIR	chi	Water cooled chiller (ports indexed 1 are on condenser side)
Buildings.DHC.ETS.BaseClasses.Pump_m_flow	pumCon	Condenser pump
Buildings.DHC.ETS.BaseClasses.Pump_m_flow	pumEva	Evaporator pump
Buildings.Obsolete.DHC.ETS.Combined.Controls.Chiller	con	Controller
Buildings.Fluid.Sensors.TemperatureTwoPort	senTConLvg	Condenser water leaving temperature
Buildings.Fluid.Sensors.TemperatureTwoPort	senTConEnt	Condenser water entering temperature
Buildings.Fluid.Sensors.TemperatureTwoPort	senTEvaEnt	Evaporator water entering temperature
Buildings.Fluid.Sensors.TemperatureTwoPort	senTEvaLvg	Evaporator water leaving temperature
Buildings.DHC.ETS.BaseClasses.Junction	splEva	Flow splitter for the evaporator water circuit
Buildings.DHC.ETS.BaseClasses.Junction	splConMix	Flow splitter
Buildings.Fluid.Actuators.Valves.ThreeWayEqualPercentageLinear	valEva	Control valve for maximum evaporator water entering temperature
Buildings.Fluid.Actuators.Valves.ThreeWayEqualPercentageLinear	valCon	Control valve for minimum condenser water entering temperature
Buildings.Controls.OBC.CDL.Conversions.BooleanToReal	booToRea	Constant speed primary pumps control signal
Buildings.Controls.OBC.CDL.Reals.Add	add2
Buildings.Controls.OBC.CDL.Reals.MultiplyByParameter	gai1	Scale to nominal mass flow rate
Buildings.Controls.OBC.CDL.Reals.MultiplyByParameter	gai2	Scale to nominal mass flow rate

Name	Description
Medium	Medium model

Revisions

November 3, 2025, by Michael Wetter:
Moved to Buildings.Obsolete.
This is for #4354.
March 27, 2024, by David Blum:
Update icon and fix port orientation to align with convention.
This is for issue #3606.
July 31, 2020, by Antoine Gautier:
First implementation.