Partial model of a heat exchanger without humidity condensation. This model transfers heat in the amount of
Q = Qmax ε
ε = f(NTU, Z, flowRegime),
where Qmax is the maximum heat that can be transferred, ε is the heat transfer effectiveness, NTU is the Number of Transfer Units, Z is the ratio of minimum to maximum capacity flow rate and flowRegime is the heat exchanger flow regime. such as parallel flow, cross flow or counter flow.
The flow regimes depend on the heat exchanger configuration. All configurations defined in BuildingSystems.Fluid.Types.HeatExchangerConfiguration are supported.
By default, the flow regime, such as counter flow or parallel flow,
is kept constant based on the parameter value configuration
.
If a flow reverses direction, it is not changed, e.g.,
a heat exchanger does not change from counter flow to parallel flow
if one flow changes direction.
To dynamically change the flow regime,
set the constant use_dynamicFlowRegime
to
true
.
However, use_dynamicFlowRegime=true
can cause slower simulation due to events.
Models that extend from this partial model need to provide an assignment
for UA
.
noEvent()
in the assertion function to avoid Optimica to not converge.flowRegime
to be equal to flowRegime_nominal
by default. Added an assertion warning to inform the user about how to change
this behaviour if the flow direction does need to change.sta2_default
.Z
that is not used.
This is for
issue 1328.
sta1_default
and sta2_default
to enable translation under OpenModelica.
Removed max=1
attribute for Z
. This is needed as near
zero flow, Z
can be larger than one due to the regularization.
As Z
is not used in this model other than for reporting, this bound
need not be enforced (and the calculation of eps
is fine at these small flow rates).
This is for
issue 490.
assert
statement to avoid comparing
enumeration with an integer, which triggers a warning
in Dymola 2015.
mWat_flow
in the base class.