This paper deals with a numerical strategy for obtaining a stable numerical solution of combined heat, air and moisture transport in building envelope components. Based on an analysis of the coupling characteristics between the three transport processes, a conditionally stable algorithm is presented. The algorithm combines the explicit and relaxation schemes. The former is used for heat and moisture transport, and the later for air transport. Along with the algorithm, a criterion for a determination of the time step is developed to ensure numerical stability. The calculation time step is determined in terms of the stability criteria for heat and moisture transport, and a criterion for controlling latent heat release or absorption. The paper also presents two case studies to evaluate the prop osed numerical method.

• HAM: simplified models - simplification : on conditionally stable (sulotion) algorithm
• HAM: theory and modelling : a simple model

1. A numerically stable algorithm for simplified calculations of combined heat, air and moisture transport
2. An algorithm to accelerate simulations of simulataneous heat and gas transfer in gas-filled foams
3. Combined Heat, Air, and Moisture Transport in Loose-Filled Insulation - Experiment and Simulation
4. Heat and mass transfer in built structures: Numerical analyses
5. Measurements of volatile organic compound (VOC) emissions from wood stains using an electronic balance  

1. A numerically stable algorithm for simplified calculations of combined heat, air and moisture transport
2. An algorithm to accelerate simulations of simulataneous heat and gas transfer in gas-filled foams
3. An example of application of limit state approach for reliability analysis of moisture performance of a building component
4. Assessment method of numerical prediction models for combined heat, air and moisture transfer in building components: benchmarks for one-dimensional cases
5. Combined Heat, Air, and Moisture Transport in Loose-Filled Insulation - Experiment and Simulation
6. Durability control by means of hygrothermal history in building components
7. International building physics toolbox, general report
8. Moisture conditions in a north-facing wall with cellulos loose-fill insulation: construction with and without a vapor retarder and air leakage
9. Prediction of driving rain intensities using potential flows
10. Simulink modelling tool for HAM system analyses in building physics
11. The International Building Physics Toolbox in Simulink