This component transports two fluid streams between four ports, without storing mass or energy. It is similar to Buildings.Fluid.Interfaces.StaticTwoPortHeatMassExchanger, but it has four ports instead of two.
If dpN_nominal > Modelica.Constants.eps
,
where N
denotes the fluid 1 or 2,
then the model computes pressure drop due to flow friction in the
respective fluid stream. The pressure drop is defined by a
quadratic function that goes through the point
(mN_flow_nominal, dpN_nominal)
. At
|mN_flow| < deltaMN *
mN_flow_nominal
, the pressure drop vs. flow relation
is linearized. If the parameter
linearizeFlowResistanceN
is set to true, then
the whole pressure drop vs. flow resistance curve is
linearized.
This model uses inputs and constants that need to be set by
models that extend or instantiate this model. The following inputs
need to be assigned, where N
denotes
1
or 2
:
QN_flow
, which is the sensible and latent
heat flow rate added to the medium N.mWatN_flow
, which is the moisture mass flow
rate added to the medium N.Set the constant sensibleOnlyN=true
if the
model that extends or instantiates this model sets
mWatN_flow = 0
.
Note that the model does not implement 0 = Q1_flow +
Q2_flow
or 0 = mXi1_flow + mXi2_flow
. If there
is no heat or mass transfer with the environment, then a model that
extends this model needs to provide these equations.
homotopyInitialization
to a constant.Q1_flow
and
Q2_flow
include latent heat flow rate.sensibleOnly
in
bal1
and bal2
as this constant has been
removed in
Buildings.Fluid.Interfaces.StaticTwoPortHeatMassExchanger.homotopyInitialization
as it has been
removed in the base class.import Modelica.Constants;
statement.show_V_flow
.mXi_flow[Medium.nXi]
to a scalar
input connector mWat_flow
. The reason is that
mXi_flow
does not allow to compute the other
components in mX_flow
and therefore leads to an
ambiguous use of the model. By only requesting
mWat_flow
, the mass balance and species balance can be
implemented correctly.m_flow=0
.homotopy
operator.port_b
was multiplied with the mass flow rate at
port_a
. The old implementation led to small errors
that were proportional to the amount of moisture change. For
example, if the moisture added by the component was 0.005
kg/kg
, then the error was 0.5%
. Also, the
results for forward flow and reverse flow differed by this amount.
With the new implementation, the energy and moisture balance is
exact.sensibleOnly1
and
sensibleOnly2
to simplify species balance
equations.