Components.Compressor
Positive-displacement compressor with no mass or energy storage.
port_a is the suction side and port_b the discharge side; m_flow > 0 means flow enters through port_a. input_speed is the commanded shaft speed in rev/s. Volumetric and shaft-power behaviour are set by the polynomial coefficient arrays c_vol (length 6) and c_pow (length 5); shaft power is capped at maxPower.
Usage
HVACComponents.Components.Compressor(medium_data, speed_start, m_flow_start, hDischarge_start, hSuction_start, p_a_start, p_b_start, dp_start, dSuction_start=HVACComponents.Density_ph(p_a_start, hSuction_start, medium_data), c_vol, c_pow, Vmax, Vrel, zFw_shell, maxPower, zFw, scP, scCF, scVdot, V=Vrel * Vmax)
Parameters:
| Name | Description | Units | Default value |
|---|---|---|---|
medium_data | Refrigerant medium properties | – | |
speed_start | Initial compressor speed [rev/s] (solver guess) | – | |
m_flow_start | Initial refrigerant mass flow [kg/s] (solver guess) | – | |
hDischarge_start | Initial discharge specific enthalpy [J/kg] (solver guess) | – | |
hSuction_start | Initial suction specific enthalpy [J/kg] (solver guess) | – | |
p_a_start | Initial suction-side pressure [Pa] (solver guess) | – | |
p_b_start | Initial discharge-side pressure [Pa] (solver guess) | – | |
dp_start | Initial pressure rise across the compressor [Pa] (solver guess) | – | |
dSuction_start | Initial suction density [kg/m^3] (derived from p_a_start, hSuction_start) | – | HVACComponents.Density_ph(p_a_start, hSuction_start, medium_data) |
c_vol | Volumetric efficiency polynomial coefficients (length 6) | – | |
c_pow | Shaft power polynomial coefficients (length 5) | – | |
Vmax | Maximum (geometric) displacement volume per revolution [m^3] | – | |
Vrel | Relative displacement fraction of Vmax used for the effective volume V | – | |
zFw_shell | Fraction of (shaftPower - refrigerantPortPower) lost as housing heat | – | |
maxPower | Upper bound on shaft power [W] | – | |
zFw | Thermal efficiency assigned to eta_therm | – | |
scP | Pressure scaling factor used in the polynomial correlations | – | |
scCF | Speed scaling factor used in the polynomial correlations | – | |
scVdot | Volumetric-flow scaling factor used in the polynomial correlations | – | |
V | Effective displacement volume per revolution [m^3] (= Vrel * Vmax) | – | Vrel * Vmax |
Connectors
input_speed- This connector represents a real signal as an input to a component (RealInput)port_a- (FluidPort)port_b- (FluidPort)
Variables
| Name | Description | Units |
|---|---|---|
speed | Compressor shaft speed [rev/s] (clamped at 1e-3 from below) | – |
m_flow_comp | Refrigerant mass flow through the compressor [kg/s] | – |
hDischarge | Discharge specific enthalpy at port_b [J/kg] | – |
eta_v | Volumetric efficiency [-] | – |
eta_therm | Thermal efficiency [-] | – |
dp | Pressure rise port_b - port_a [Pa] | – |
pRat | Pressure ratio port_b.p / port_a.p [-] | – |
dSuction | Suction-side refrigerant density [kg/m^3] | – |
H_flow_a | Enthalpy flow at port_a [W] | – |
H_flow_b | Enthalpy flow at port_b [W] | – |
hSuctionIs | Isentropic suction enthalpy [J/kg] (simplified: pass-through from port_b) | – |
hSuction | Suction specific enthalpy entering through port_a [J/kg] | – |
shaftPower | Shaft power [W] (clamped to [1e-3, maxPower]) | – |
refrigerantPortPower | Net power into the refrigerant at the ports [W] | – |
housingHeatLosses | Heat lost through the housing [W] (= zFw_shell * (shaftPower - refrigerantPortPower)) | – |
TDischarge | Discharge temperature at port_b [K] | – |
TSuction | Suction temperature at port_a [K] | – |
ps | Suction pressure alias for port_a.p [Pa] | – |
pd | Discharge pressure alias for port_b.p [Pa] | – |
vdot | Volumetric flow rate [m^3/s] (= eta_v * V * speed) | – |
ratPow | Rated power per unit suction-density flow used in the enthalpy rise equation | – |
CFSc | Scaled compressor speed (= scCF * speed) | – |
PDisSc | Scaled discharge pressure (= scP * pd) | – |
PSucSc | Scaled suction pressure (= scP * ps) | – |
deltaPSc | Scaled pressure difference (= PDisSc - PSucSc) | – |
PRatSc | Scaled pressure ratio (= PDisSc / PSucSc) | – |
VdotSc | Scaled volumetric flow rate (= scVdot * eta_v * V * CFSc) | – |
shaftPower1 | Speed-dependent term of the shaft-power polynomial | – |
shaftPower2 | Pressure/flow-dependent term of the shaft-power polynomial | – |