Modeling and Design of Net ZEBs as Integrated Energy Systems - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 47

(2.22)
Subscript i indicates the node for which the energy balance is written and
j all nodes connected to node i , while p is the time interval; q i represents
a heat source at node i such as solar radiation or possible heat release in
PCMs.
Thetimestep(Δ t )isselectedbasedonthefollowingconditionfornumerical
stability:
(2.23)
for all nodes i ; the summation is performed for all nodes j connected to the
node i .
The explicit finite difference method is particularly suitable for modeling
of nonlinear heat diffusion problems such as the heat transfer through
phase change materials. It can easily accommodate nonlinear heat transfer
coefficients and control actions.