Solution and algorithm optimization of coupled heat and moisture transfer model for porous media based on TDMA.

To improve the solution efficiency of coupled heat and moisture transfer model for porous media, the tridiagonal matrix algorithm (TDMA) was adopted to solve the model, and the comparisons between the TDMA and the iteration method were conducted. The sensitivity analysis between the TDMA calculation error and the time increment was conducted. Based on the sensitivity analysis results, a variable time increment TDMA optimization algorithm was proposed. The numerical results show that for cases with variable properties, the calculation accuracy of TDMA decreases while the accuracy of the iterative method remains unchanged with the increase of time increment. For the cellulose insulation, the effects of time increment on the calculation accuracy of TDMA can be ignored when the temperature and the relative humidity variations in two successive time steps are less than 0.1 °C and 0.24%, respectively. Compared with TDMA, the variable time increment TDMA algorithm is insensitive to time increment, showing a higher calculation accuracy. Compared with the iteration method, the variable time increment TDMA algorithm has the same calculation accuracy, but the calculation time is shorter, which is reduced by 67 %. [ABSTRACT FROM AUTHOR]