PartialOpaque

Conduction through the layers of a construction split into sublayers, a node at each sublayer boundary: the temperatures of the layer boundaries are T, the same states in FastSmoothBuildings and FastSmoothBuildingsMPC (a state copied from one library into the other by its name stays at its place), those of the nodes inside the layers TSub

FastSmoothBuildings.Envelope.PartialOpaque, partial model (source)

Extends PartialSurface.

Purpose

Conduction through the layers of an opaque construction (Data.Construction), from side a (outside) to side b (room). Layer l is split into nSta[l] sublayers of equal thickness, with a node at each sublayer boundary: nSub = nNod sublayers between nSub + 1 nodes, outside first.

Equations

Sublayer j of layer l = lay[j] has the thickness x_j = x_l/nSta_l, the conductance G_j = A k_j/x_j, and gives half of its capacity to each of its two nodes:

C_i = A (x_i−1 d_i−1 c_i−1 + x_i d_i c_i)/2,

the terms of a sublayer that does not exist left out at the surfaces. The heat into node i is

Q_i = G_i−1 (T_i−1 − T_i) − G_i (T_i − T_i+1),

with Q_a, the heat into the outer surface from the outside, in place of the first term at node 1, and Q_b, the heat into the inner surface from the room, in place of the second term at the last node. Each node inside a layer, sub[m], has the state TSub[m]: C dTSub[m]/dt = Q.

Extending classes

They declare the temperatures T of the layer boundaries (nodes nod[b]), with C dT/dt = Q at each node whose temperature is free, and give Q_a and Q_b from the exchanges at the two faces. T and TSub keep their names and places whatever the number of sublayers: with one sublayer a layer (the model for optimal control) there is no TSub (see Conventions).

Parameters

• stateAtSurface_a: true when the outer surface has a capacity and a state; BoundaryWall, whose outer surface is held at a temperature, sets it to false.

Relation to Buildings

The layers are split into the sublayers Buildings gives them (nSta of Buildings.HeatTransfer.Data.OpaqueConstructions.Generic), at most three a layer in the closed-loop model.

Parameters

Parameter	Type	Unit	Default	Description
constructionType	Data.Construction			Construction, layers from the outside
stateAtSurface_a	Boolean		true	Capacity at the outer surface (false: it is held at a temperature)

Revisions

• October 2026: moved from trano's FastModel.Envelope.