SAMIRA: Balancing accuracy and cost in hygrothermal simulations

Abstract

This paper presents a 12-step decision framework for input and model parameters in Heat Air and Moisture simulations (HAM simulations) which goes well beyond the existing standards and guidelines. The proposed framework has significant practical implications for building designers, engineers, and researchers who rely on HAM-simulations to evaluate building performance. The complex process of creating a HAM case is broken down into 12 comprehensive steps. The steps cover the scope of the simulation, the prediction of deterioration and performance assessment, boundary conditions, the computational domain, material characterization, initial conditions, selection of appropriate outputs, and a review of the simulation result. Each step consists of a structured approach for the input parameter selection, with its corresponding model parameters, using three strategic levels with different complexity and granularity. The three levels are referred to as the Superior, Advanced, and Minimum Requirement Approach (SAMiRA). While increasing the parameter level from minimum toward superior, the model accuracy and reliability of the simulation will increase but at a higher computational and financial expense. The framework can be applied to a wide range of building components, different climates, and their projections, and helps practitioners to optimize the energy efficiency, comfort, and moisture control in buildings. The results are made publicly available in a webtool called HAMalyser where the user is guided through the 12 steps, with additional information and examples with some critical points. Next to that, the webtool includes a post-processing tool which can calculate the state-of-the-art degradation models based on uploaded simulation outputs. Concluding, the aim of this paper and complementary webtool is to help engineers and scientists to take critical decisions on the inputs of HAM-simulations, the simulation approach itself, and the processing of the output with its interpretation in a systematic way.