Components.Partial.PartialHEXCrossflow
Partial base class for a moist-air cross-flow heat-exchanger element.
Defines the moist-air ports, the wall heat-port array, mass/energy/water-vapor balances and pressure-drop equation for an N-cell air stream. Extending components must declare N (the number of control volumes), supply the air-side heat-transfer coefficient htc[i] (typically via an initial binding to htc_nominal), the mass-transfer-driven condensation closure (mcond_flow[i]) and the fin efficiency eta_fin[i], plus the pressure-drop relation that defines p_loss. port_a is the upstream air port and port_b the downstream air port (m_flow > 0 means air enters port_a). medium_data must be a moist-air medium.
Usage
HVACComponents.Components.Partial.PartialHEXCrossflow(htc_nominal, CF_MassTransfer, CF_HeatTransfer, htc=missing, p_in_start, p_out_start, p_loss_start, m_air_flow_start, T_in_start, T_out_start, Xi_in_start, Xi_out_start, Q_start, eta_fin_start, h_in_start, h_out_start, mcond_flow_start, d_mean_start, Q_water_start, cp_mean_start, medium_data)
Parameters:
| Name | Description | Units | Default value |
|---|---|---|---|
N | Number of air-side control volumes | – | 1 |
N_Plus_1 | Number of cell faces (= N + 1) | – | N + 1 |
htc_nominal | Nominal air-side heat-transfer coefficient [W/(m^2.K)] | – | |
CF_MassTransfer | Correction factor on the Lewis-analogy mass-transfer coefficient [-] | – | |
CF_HeatTransfer | Correction factor on the air-side heat-transfer coefficient [-] | – | |
p_in_start | Initial air inlet pressure [Pa] | Pa | |
p_out_start | Initial air outlet pressure [Pa] | Pa | |
p_loss_start | Initial air-side pressure drop [Pa] | Pa | |
m_air_flow_start | Initial air mass flow rate [kg/s] | kg/s | |
T_in_start | Initial air inlet temperature [K] | K | |
T_out_start | Initial air outlet temperature [K] | K | |
Xi_in_start | Initial air inlet water-vapor mass fraction [-] | – | |
Xi_out_start | Initial air outlet water-vapor mass fraction [-] | – | |
Q_start | Initial air-side heat flow per element [W] | W | |
eta_fin_start | Initial fin efficiency [-] | – | |
h_in_start | Initial air inlet specific enthalpy [J/kg] | J/kg | |
h_out_start | Initial air outlet specific enthalpy [J/kg] | J/kg | |
mcond_flow_start | Initial condensate mass flow [kg/s] | kg/s | |
d_mean_start | Initial mean air density [kg/m^3] | – | |
Q_water_start | Initial heat flow carried by condensate [W] | W | |
cp_mean_start | Initial mean specific heat capacity of moist air [J/(kg.K)] | – | |
medium_data | Moist-air medium properties | – |
Connectors
port_a- (MoistAirFluidPort)port_b- (MoistAirFluidPort)heatPorts- This connector represents a thermal port with temperature and heat flow as the potential and flow variables, respectively. (HeatPort)
Variables
| Name | Description | Units |
|---|---|---|
p | Air-side pressure used internally (= medium_inflow.p = port_a.p) [Pa] | Pa |
T | Air temperature at each face [K] (length N+1) | K |
H_flow | Enthalpy flow at each face [W] (length N+1) | – |
mdot | Dry-and-vapor mass flow at each face [kg/s] (length N+1) | kg/s |
mXi_flow | Water-vapor mass flow at each face [kg/s] (length N+1) | – |
Q_flow | Sensible-plus-latent heat flow into each cell [W] (length N) | W |
mcond_flow | Condensate mass flow leaving each cell [kg/s] (length N) | – |
p_loss | Air-side pressure drop port_a - port_b [Pa] | Pa |
d_mean | Mean air density used in mass-transfer scaling [kg/m^3] | – |
Q_water | Heat flow carried out with the condensate [W] | W |
cp_mean | Mean specific heat capacity of moist air [J/(kg.K)] | – |
T_in | Air inlet temperature [K] (alias for medium_inflow.T at port_a) | K |
T_out | Air outlet temperature [K] (alias for medium_outflow.T at port_b) | K |
eta_fin | Fin efficiency per cell [-] (length N); extender supplies | – |