  For the thermal control of electronic components in aerospace, automotive or
server systems, the heat sink is often located far from the heat sources.
Therefore, heat transport systems are necessary to cool the electronic
components effectively. Loop heat pipes (LHPs) are such heat transport systems,
which use evaporation and condensation to reach a higher heat transfer
coefficient than with sole heat conduction. The operating temperature of the
LHP governs the temperature of the electronic components, but depends on the
amount of dissipated heat and the temperature of the heat sink. For this
reason, a control heater on the LHP provides the ability to control the
operating temperature at a fixed setpoint temperature. For the model-based
control design of the control heater controller, the current LHP state-space
model in the literature focuses on the setpoint response without modeling the
fluid's dynamics. However, the fluid's dynamics determine the disturbance
behavior of the LHP. Therefore, the fluid's dynamics are incorporated into a
new LHP state-space model, which is not only able to simulate the LHP behavior
under disturbance changes, but is also used for the model-based design of a
robust nonlinear controller, which achieves an improved control performance
compared to the nonlinear controller based on the previous LHP state-space
model.
