MediaModels.BaseProperties_Refrigerant
Refrigerant property model using (p, h) as independent states.
Exposes density T, internal energy, the density derivatives needed by the distributed-volume momentum balance (dddh_p, dddp_h, dhdd_p, dhdp_d), and the two-phase vapor quality xq. Saturated-liquid and saturated-vapor states at the current pressure are also available on the liq and vap sub-components. medium_data must be a refrigerant medium.
Usage
HVACComponents.MediaModels.BaseProperties_Refrigerant(medium_data, p_start, h_start, p_crit=HVACComponents.critical_pressure_Pa(medium_data), h_liq_start=HVACComponents.BubbleEnthalpy_p(p_start, medium_data), h_vap_start=HVACComponents.DewEnthalpy_p(p_start, medium_data), d_start=HVACComponents.Density_ph(p_start, h_start, medium_data), T_start=HVACComponents.Temperature_ph(p_start, h_start, medium_data), e_start=h_start - (p_start / d_start), dddh_p_start=HVACComponents.dddh_p_f(p_start, h_start, medium_data), dddp_h_start=HVACComponents.dddp_h_f(p_start, h_start, medium_data), dhdd_p_start=1.0 / dddh_p_start, dhdp_d_start=-dddp_h_start * dhdd_p_start, xq_start=HVACComponents.splice_function(max(0.0, min(1.0, (h_start - h_liq_start) / max(h_vap_start - h_liq_start, 1e-6))), 1.0, 1.0 - p_start / p_crit, 0.01))
Parameters:
| Name | Description | Units | Default value |
|---|---|---|---|
medium_data | Refrigerant medium properties | – | |
p_start | Initial pressure [Pa] (solver guess for p) | Pa | |
h_start | Initial specific enthalpy [J/kg] (solver guess for h) | J/kg | |
p_crit | Critical pressure of the medium [Pa] (looked up from medium_data) | – | HVACComponents.critical_pressure_Pa(medium_data) |
h_liq_start | Initial saturated-liquid enthalpy at p_start [J/kg] | – | HVACComponents.BubbleEnthalpy_p(p_start, medium_data) |
h_vap_start | Initial saturated-vapor enthalpy at p_start [J/kg] | – | HVACComponents.DewEnthalpy_p(p_start, medium_data) |
d_start | Initial density [kg/m^3] (derived from p_start, h_start) | – | HVACComponents.Density_ph(p_start, h_start, medium_data) |
T_start | Initial temperature [K] (derived from p_start, h_start) | – | HVACComponents.Temperature_ph(p_start, h_start, medium_data) |
e_start | Initial specific internal energy [J/kg] (= h_start - p_start / d_start) | – | h_start - (p_start / d_start) |
dddh_p_start | Initial dd/dh at constant p [(kg/m^3)/(J/kg)] (derived from p_start, h_start) | – | HVACComponents.dddh_p_f(p_start, h_start, medium_data) |
dddp_h_start | Initial dd/dp at constant h [(kg/m^3)/Pa] (derived from p_start, h_start) | – | HVACComponents.dddp_h_f(p_start, h_start, medium_data) |
dhdd_p_start | Initial dh/dd at constant p (= 1 / dddh_p_start) | – | 1 / dddh_p_start |
dhdp_d_start | Initial dh/dp at constant d (= -dddp_h_start * dhdd_p_start) | – | -dddp_h_start * dhdd_p_start |
xq_start | Initial vapor quality [-] (smoothly clamped to [0, 1] off-saturation) | – | HVACComponents.splice_function(max(0, min(1, (h_start - h_liq_start) / max(h_vap_start - h_liq_start, 0.000001))), 1, 1 - p_start / p_crit, 0.01) |
Variables
| Name | Description | Units |
|---|---|---|
p | Pressure [Pa] | – |
h | Specific enthalpy [J/kg] | – |
d | Density [kg/m^3] | – |
T | Temperature [K] | – |
e | Specific internal energy [J/kg] (= h - p / d) | – |
dddh_p | Density derivative dd/dh at constant p [(kg/m^3)/(J/kg)] | – |
dddp_h | Density derivative dd/dp at constant h [(kg/m^3)/Pa] | – |
dhdp_d | Enthalpy derivative dh/dp at constant d | – |
dhdd_p | Enthalpy derivative dh/dd at constant p | – |
xq | Vapor quality [-] (smoothly clamped to [0, 1] off-saturation) | – |