Heat capacitor in which the capacity is scaled based on the input signal u.
This model is similar to
Modelica.Thermal.HeatTransfer.Components.HeatCapacitor.
However, it has, depending on the parameterization, either
one or two heat capacities. Depending on the input signal ySha,
the size of one of the capacity is decreased, and the size of the other capacity
is increased.
This model is used to add a state variable on the room-facing surface of a window.
The window implementation in the Buildings library is such that
there are two parts of a window, one for the unshaded part, and one for the
shaded part.
This model allows adding heat capacity to such a window with variable
areas, while conserving energy when one area shrinks and the other expands
accordingly.