InteriorWall represents heat storage within walls. It links a
  variable number n of thermal resistances and capacities to a
  series connection. n thus defines the spatial discretization of
  thermal effects within the wall. All effects are considered as one-dimensional
  normal to the wall's surface. This model is thought for interior wall
  elements that only serve as heat storage elements. The RC-chain is defined via
  a vector of capacities CInt[n] and a vector of resistances
  RInt[n].
  Resistances and capacities are connected alternately, starting with the first
  resistance RInt[1], from heat port_a into the wall.
  
