5th exercice class: step-by-step resolution
This package allows the user to build a basic heat pump
system by following a step-by-step procedure. The complete heat
pump model is composed by the following components: a compressor
(scroll-type), two plate heat exchangers one liquid receiver, a
valve and two pressure drop model.
-
Step1 We start by modeling the condensation of the
working fluid with the following components:
- Flow1Dim:
It represents the flow of the working fluid
- Source_T:
it represents the temperature source --> it allows the
condensation of the fluid
- SinkP:
pressure sink. It imposes the pressure to the system
-
SourceMdot: Mass flow source. It imposes mass flow and inlet
temperature to the system
-
Step2 We replace the Flow1Dim component with an heat
exchanger component where the secondary fluid is considered
incompressible --> Hx1DInc.
- Choose StandardWater as working fluid for the secondary
fluid
- Choose upwind-AllowFlowReversal as discretization
scheme
- Impose constant heat transfer coefficient in the working
fluid side
- Impose an heat transfer coefficient depending on mass flow
in the secondary fluid side
-
Step3 Add the Liquid
receiver after the condenser. The pressure is imposed by the
pressure sink connected to the liquid receiver.
-
Step4 Change the pressure sink after the liquid
receiver with a volumetric flow sink. In this way the pressure will
be imposed by the tank system.
-
Step5 Add the Valve
component after the liquid receiver
-
Step6 Add the evaporator after the valve considering
the secondary fluid as an incompressible fluid --> Hx1DInc.
- Choose Air as working fluid for the secondary
fluid
- Choose upwind-AllowFlowReversal as discretization
scheme
- Impose constant heat transfer coefficient in the working
fluid side
- Impose an heat transfer coefficient depending on mass flow
in the secondary fluid side
-
Step7 Add the
Compressor compoennt and the
Electric drive component which will allow to control the
rotational speed fof the compressor. Add finally a constant source
from the Modelica library (Constant source)
to impose a constant rotational speed to the system.
-
Step8 Close the cycle and simulate over 100
seconds
-
Step9 Add pressure drop that are considered lumped in
the lowest vapor density regions of both low and high pressure
lines. Simulate over 100 seconds
-
Step10 In order to evaluate the dynamic performance of
the system impose a variation in the compressor rotational speed at
50s and a variation in the aperture of the valve at 75s.
In order to get a better visualization of the results the
authors suggest the use of the ThermoCycle viewer which can be
easly downloaded from http://www.thermocycle.net/.
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