modelReciprocatingCompressor

Model for a reciprocating compressor, based on Jin (2002)

Extends from AixLib.Fluid.HeatPumps.Compressors.BaseClasses.PartialCompressor.

Information

Model for a reciprocating processor, as detailed in Jin (2002). The rate of heat transferred to the evaporator is given by:

Q̇_Eva = ṁ_ref ( h_Vap(T_Eva) - h_Liq(T_Con) ).

The power consumed by the compressor is given by a linear efficiency relation:

P = P_Theoretical / η + P_{Loss,constant}.

Variable speed is acheived by multiplying the full load piston displacement by the normalized compressor speed. The power and heat transfer rates are forced to zero if the resulting heat pump state has higher evaporating pressure than condensing pressure.

Assumptions and limitations

The compression process is assumed isentropic. The thermal energy of superheating is ignored in the evaluation of the heat transferred to the refrigerant in the evaporator. There is no supercooling.

References

H. Jin. Parameter estimation based models of water source heat pumps. PhD Thesis. Oklahoma State University. Stillwater, Oklahoma, USA. 2002.

Parameters

Type	Name	Description
Modelica.Units.SI.VolumeFlowRate	pisDis	Piston displacement
Real	cleFac	Clearance factor
Modelica.Units.SI.Efficiency	etaEle	Electro-mechanical efficiency of the compressor
Modelica.Units.SI.Power	PLos	Constant part of the compressor power losses
Modelica.Units.SI.AbsolutePressure	pDro	Pressure drop at suction and discharge of the compressor
Modelica.Units.SI.TemperatureDifference	dTSup	Superheating at compressor suction

Components

Type	Name	Description
Modelica.Units.SI.MassFlowRate	m_flow	Refrigerant mass flow rate
Modelica.Units.SI.Power	PThe	Theoretical power consumed by the compressor
Modelica.Units.SI.Efficiency	COP	Heating COP of the compressor

Revisions

January 25, 2019, by Michael Wetter:
Added start value to avoid warning in JModelica.
May 30, 2017, by Filip Jorissen:
Removed pressure_error as this is replaced by AixLib.Fluid.HeatPumps.Compressors.BaseClasses.TemperatureProtection. See #769.
November 14, 2016, by Massimo Cimmino:
First implementation.