Assembling thermal circuits

The workflow for thermal analysis by using dm4bem module is presented in Figure 1:

• Model:

  • given data on walls (type and data on surfaces), thermal circuits and the assembling lists or matrix;

  • obtain the matrices and vectors of the thermal circuit \(A, G, C, b, f, y\):

    • convert a folder containing the files characterizing the building into a disassambled thermal circuit (function bldg2TCd());

    • assemble the thermal circuits (functions assemble_TCd_matrix() and assemble_lists2matrix());

  • transform the thermal circuit into state-space representation \(A_s, B_s, C_s, D_s, u_s\) (function tc2ss()).

• Inputs:

  • given the Typical Meteorological Years (TMY) in EnergyPlus format .epw;

  • read weather data: outdoor temperature, \(T_o,\) and solar radiation (direct, \(E_{dir},\) and diffuse, \(E_{diff}\)) with function read_epw() and calculate the solar radiation on tilted surfaces with function sol_rad_tilt_surf();

  • determine the weather sources outdoor temperarure, \(T_o,\) and solar radiation absorbed by the outdoor wall, \(\Phi_o,\) the indoor wall, \(\Phi_o,\) and the glass, \(\Phi_a.\)

  • define the other inputs, such as indoor temperature set points, \(T_{i,sp},\) auxiliary flow-rates, \(\dot Q_a.\)

• Simulation:

  • prepare the inputs from input description of the state-space, \(u_s,\) and the input data set with function inputs_in_time();

  • integrate in time by using Euler explicit and/or implicit methods.

Figure 1. Workflow for building simulation by using dm4bem module (see an example).