External coupling of building energy simulation and building element heat, air and moisture simulation

Abstract

The present challenge for the building industry is to provide buildings that are safe, comfortable, energy efficient and sustainable; creating a healthy and productive environment for users. Computational building performance simulation (CBPS) can play an important role to deal with this challenge, particularly for performance indicators related to the heat, air and moisture (HAM) at the whole-building scale. These indicators are currently assessed by a large number of programs with considerable uncertainty in their results, such as building energy simulation (BES) programs and building element heat, air and moisture (BEHAM) programs. This thesis poses the hypothesis that the lack of integration between these programs represents an important source of uncertainty in whole-building HAM simulation, which can compromise, in some circumstances, the accuracy of their results. In order to test this hypothesis, this thesis proposes, implements, verifies and validates protocols to integrate BES and BEHAM programs using external coupling. These protocols, which are based on literature review and theoretical analysis of the governing equations, are implemented in prototype computer programs using numerical simulation and inter-process communication routines. The prototypes are verified by a number of techniques developed in this thesis, such as the use of emulators, one-way coupling and self-coupling. Validation is carried out using analytical solutions, inter-model comparison and experimental results reported in the literature. Coupled BES-BEHAM simulations showed improvements in the accuracy when compared to stand-alone BES or BEHAM simulations. In order to identify cases where coupled BES-BEHAM simulations provide significant improvement in the results, the coupling necessity decision procedure (CNDP) is formulated. Capabilities of coupled BES-BEHAM simulations in combination with the CNDP are demonstrated by case studies, where some capabilities and deficiencies of stand-alone programs are also evaluated. This research concludes that coupled BES-BEHAM simulation provides a viable and reliable way to perform whole-building HAM simulation. A number of additional results are also provided in this thesis, such as the solution for several coupling features addressed in the coupling protocols, the verification techniques developed and the use of TCP/IP sockets for the communication between the programs.