Co-simulation of building energy simulation and computational fluid dynamics for whole-building heat, air and moisture engineering

Building performance simulation (BPS) is widely applied to analyse heat, air and moisture (HAM) related issues in the indoor environment such as energy consumption, thermal comfort, condensation and mould growth. The uncertainty associated with such simulations can be high, and incorrect simulation results can lead to a design with adverse effects on health, comfort and functionality of space. In recent years, the use of BPS tools to predict and analyse the HAM behaviour of the indoor environment has grown significantly. Among these tools, Building Energy Simulation (BES) and Computational Fluid Dynamics (CFD) are recognized as potential tools for assessing HAM behaviour of the indoor environment, such as interaction of the HVAC system with convective heat and mass transfer. These tools have strong capabilities, but also some particular deficiencies in terms of boundary conditions, physical models and resolution in space and time. BES is mainly used to assess the thermal performance of buildings throughout the entire year. It is a powerful tool, but when compared to CFD tools it includes simplified air flow, heat and moisture transfer modelling. Detailed HAM modelling of the building indoor environment is possible with CFD. In CFD, however, the implementation of meteorological boundary conditions, the whole HVAC system modelling etc. are significantly less advanced than in BES. In this thesis, it is hypothesized that if used correctly, the combination of BES and CFD tools will increase the accuracy of HAM simulations of the indoor environment. The thesis first presents approaches for domain integration, relevant physical phenomena, interface variables, and coupling requirements. Then, it introduces a newly developed prototype, which integrates BES and CFD for high resolution HAM simulation of the indoor environment. Next, it describes the verification of the prototype. This is followed by the validation study of the prototype, which shows that the accuracy of the HAM simulation is enhanced. Finally its usage potential is illustrated by discussion of the results of real applications in the building industry

Application of externally-coupled BES-CFD in HAM engineering of the indoor environment

The high importance of indoor environment performance aspects such as surface condensation, mold growth, thermal comfort, etc., is widely recognized. High-resolution simulation of heat, air and moisture (HAM) transfer can be used to enhance the prediction and analysis of these aspects. For this purpose, a coupling mechanism has been developed in order to perform run-time external coupling between Building Energy simulation (BES) and Computational Fluid Dynamics (CFD). This paper presents the results of indoor humidity calculation using the new coupled tool for the BESTEST case- 600. The results are compared with stand-alone BES results and the need and importance of coupled simulations is discussed

Validation of external BES-CFD coupling by inter-model comparison

Conflation of computational fluid dynamics (CFD) and building energy simulation (BES) has been used in recent years in order to improve the estimation of surface coefficients for studies on thermal comfort, mold growth and other performance aspects of a building. BES can provide more realistic boundary conditions for CFD, while CFD can provide higher resolution modelling of flow patterns within air volumes and convective heat transfer coefficients (CHTC) for BES. BES and CFD can be internally or externally coupled. Internal coupling is the traditional way of expanding software by which the code is expanded by adding new modules and it entails a lot of effort in terms of debugging, maintenance etc. On the other hand, by external coupling different existing numerical packages work together, using the latest advances already implemented in them.This paper focuses on the validation of a newly developed prototype performing the external coupling of BES and CFD. The validation procedure involves an inter-model comparison between a conjugate heat transfer model and the prototype

Validation of external BES-CFD coupling by inter-model comparison

Conflation of computational fluid dynamics (CFD) and building energy simulation (BES) has been used in recent years in order to improve the estimation of surface coefficients for studies on thermal comfort, mold growth and other performance aspects of a building. BES can provide more realistic boundary conditions for CFD, while CFD can provide higher resolution modelling of flow patterns within air volumes and convective heat transfer coefficients (CHTC) for BES. BES and CFD can be internally or externally coupled. Internal coupling is the traditional way of expanding software by which the code is expanded by adding new modules and it entails a lot of effort in terms of debugging, maintenance etc. On the other hand, by external coupling different existing numerical packages work together, using the latest advances already implemented in them.This paper focuses on the validation of a newly developed prototype performing the external coupling of BES and CFD. The validation procedure involves an inter-model comparison between a conjugate heat transfer model and the prototype

Towards the application of distributed simulation in HAM engineering

This paper presents ongoing research about an integrated approach to perform high resolution heat, air and moisture (HAM) simulation of whole buildings. There are several HAM modelling tools, with different space and time resolution. The integrated approach establishes run-time external coupling of existing tools (building envelope HAM, BES, CFD) and utilizes the capabilities of one tool in an attempt to compensate the deficiencies of the other. The paper presents the literature review of approaches for domain integration, the physical processes as dealt with by existing tools, coupling requirements and it addresses the importance of validation and coupling necessity decision procedures

Healthy environments from a broad perspective : an overview of research performed at the unit Building Physics and Systems of Eindhoven University of Technology

The design and realization of a healthy indoor environment is a challenge that is investigated from different perspectives at the unit Building Physics and Systems (BPS; Faculty of Architecture, Building and Planning) of Eindhoven University of Technology. Performance requirements (for instance, with respect to air quality, thermal comfort and lighting) and performance based assessment methods are the point-of-departure, focusing at computational techniques supporting the design process. Different specific application fields such as dwellings, offices, schools, but also, operating theatres, churches, musea and multifunctional stadiums, underline the applied approach that is part of the research within the unit. In the design of healthy environments, the performance based design assessment is crucial in arriving at innovative design solutions and optimized indoor and outdoor environments. In this assessment computational support tools and experimental verification play an important role. However, assessing the right indicators in an objective way, applying the correct tools and correct application of these tools is not yet well established. Alongside, developments are still ongoing. The work performed in the unit by the different researchers relates to the research questions that can be derived from this notice. The paper gives an introduction to the Unit BPS and presents a brief overview of recent and ongoing research. An extensive list of references is provided for further reading and supports the conclusion that healthy environments can and should be addressed from a wide angle

Healthy environments from a broad perspective : an overview of research performed at the unit Building Physics and Systems of Eindhoven University of Technology

The design and realization of a healthy indoor environment is a challenge that is investigated from different perspectives at the unit Building Physics and Systems (BPS; Faculty of Architecture, Building and Planning) of Eindhoven University of Technology. Performance requirements (for instance, with respect to air quality, thermal comfort and lighting) and performance based assessment methods are the point-of-departure, focusing at computational techniques supporting the design process. Different specific application fields such as dwellings, offices, schools, but also, operating theatres, churches, musea and multifunctional stadiums, underline the applied approach that is part of the research within the unit. In the design of healthy environments, the performance based design assessment is crucial in arriving at innovative design solutions and optimized indoor and outdoor environments. In this assessment computational support tools and experimental verification play an important role. However, assessing the right indicators in an objective way, applying the correct tools and correct application of these tools is not yet well established. Alongside, developments are still ongoing. The work performed in the unit by the different researchers relates to the research questions that can be derived from this notice. The paper gives an introduction to the Unit BPS and presents a brief overview of recent and ongoing research. An extensive list of references is provided for further reading and supports the conclusion that healthy environments can and should be addressed from a wide angle

Co-simulation of building energy simulation and computational fluid dynamics for whole-building heat, air and moisture engineering

Building performance simulation (BPS) is widely applied to analyse heat, air and moisture (HAM) related issues in the indoor environment such as energy consumption, thermal comfort, condensation and mould growth. The uncertainty associated with such simulations can be high, and incorrect simulation results can lead to a design with adverse effects on health, comfort and functionality of space. In recent years, the use of BPS tools to predict and analyse the HAM behaviour of the indoor environment has grown significantly. Among these tools, Building Energy Simulation (BES) and Computational Fluid Dynamics (CFD) are recognized as potential tools for assessing HAM behaviour of the indoor environment, such as interaction of the HVAC system with convective heat and mass transfer. These tools have strong capabilities, but also some particular deficiencies in terms of boundary conditions, physical models and resolution in space and time. BES is mainly used to assess the thermal performance of buildings throughout the entire year. It is a powerful tool, but when compared to CFD tools it includes simplified air flow, heat and moisture transfer modelling. Detailed HAM modelling of the building indoor environment is possible with CFD. In CFD, however, the implementation of meteorological boundary conditions, the whole HVAC system modelling etc. are significantly less advanced than in BES. In this thesis, it is hypothesized that if used correctly, the combination of BES and CFD tools will increase the accuracy of HAM simulations of the indoor environment. The thesis first presents approaches for domain integration, relevant physical phenomena, interface variables, and coupling requirements. Then, it introduces a newly developed prototype, which integrates BES and CFD for high resolution HAM simulation of the indoor environment. Next, it describes the verification of the prototype. This is followed by the validation study of the prototype, which shows that the accuracy of the HAM simulation is enhanced. Finally its usage potential is illustrated by discussion of the results of real applications in the building industry

Application of externally-coupled BES-CFD in ham engineering of the indoor environment

The high importance of indoor environment performance aspects such as surface condensation, mold growth, thermal comfort, etc., is widely recognized. High-resolution simulation of heat, air and moisture (HAM) transfer can be used to enhance the prediction and analysis of these aspects. For this purpose, a coupling mechanism has been developed in order to perform run-time external coupling between Building Energy simulation (BES) and Computational Fluid Dynamics (CFD). This paper presents the results of indoor humidity calculation using the new coupled tool for the BESTEST case600. The results are compared with stand-alone BES results and the need and importance of coupled simulations is discussed