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M. Rößler:
"Studies on the Thermodynamical Behaviour of a Machine Tool and its Environment";
Poster: ASIM-TCSE Workshop 2012, TU Wien; 13.02.2012 - 14.02.2012; in: "ARGESIM Report", S. Tauböck, F. Breitenecker (Hrg.); Argesim / Asim, 37 (2012), S. 9 - 10.

ntroduction
Energy optimization is a very fascinating topic. For this reason, the research project INFO
1
, which
is supported by the FFG, the Austrian Research Promotion Agency, tries to make a comprehensive simulation of a
production plant, including micro- and macroscopic aspects, like machines, processes, the building envelope and so
on, to be able to make qualified predictions about the impact of certain energy-saving measures. In this context, the
issue of coupling different model-parts is of very high interest. This work focuses on two parts of the simulation,
a simple machine tool, namely a linear guiding device, and the environment surrounding it. The chosen modelling
approach is physical modelling, a block-based, acausal and object-oriented approach to model physical systems.
The Modelica Corp. provides a standard to describe physical systems and also provides a standard-library, where
common blocks are defined. By choosing the same approach for both model parts, the coupling of the two will be
less difficult than having to merge completely different models.
Machine tool
The linear guiding device is a very simple part of the machine tool. It consists of a permanent
magnet DC motor that is connected to a thread bar via a gear belt. The thread bar moves a cart, where the sliding
mass is attached. For the coupling the dissipative elements of the system have to be considered. In this case,
these are the electric motor, the bearing friction and the friction between the thread bar and the cart. The heat
emmission of these components is calculated in the respective blocks and can then be used as a heating source for
the environment model. For the validation of this partial model there is an actual test setup, where measurements
can be taken.
Environment
For the model of the environment a compartment-model is chosen. There are several assumptions made for the model:
. Each compartment has its own thermal mass, which depends on its volume and the specific heat capacity of
the air
. For the heat transfer into adjacent compartments only thermal conductance is considered
. The thermal properties of the air are assumed to be constant over the simulation run.
. The walls of the room are assumed to be perfectly isolated, so there is no heat exchange between the com-
partments and the adjacent walls and therefor no energy is lost in the system.
Under those assumptions a rather easy model of the environment can be made. The advantage of this model is,
that it can easily be refined if a higher resolution should be necessary.
For the coupling of the two partial models the heat emission of the dissipative parts of the machine tool can easily be considered the heat sources of the environment-model.