HNVR-Calculator · Handy natural ventilation rate calculator based on computational fluid dynamics

Handy natural ventilation rate calculator based on computational fluid dynamics

A well-controlled ventilation rate is essential to provide animals and plants with a good environment while minimizing climatic stresses and saving energy use as well as to assess the environmental impact from livestock buildings and greenhouses. Therefore, quantification of ventilation rate is crucial in terms of control of the thermal comfort zone, energy saving and emission of pollutants. Especially in naturally-ventilated (NV) buildings, measuring ventilation rate is more elusive because of dynamic and complex air flow patterns induced by natural wind and buoyancy effects driven by temperature differences. Opposite to mechanically ventilated buildings, there is no reliable low-cost measuring technique available for measuring ventilation rate through NV buildings. Computational fluid dynamics (CFD) simulation has been considered as a good method to quantify ventilation rate in NV buildings for design purposes because of its outstanding potential for analysing complex air flows. The concept of this project is to provide the users with access to an easy-to-use CFD simulation to get information about ventilation rate through their building. The more specific purpose of this research is to develop an automated simulation tool to predict the ventilation rate of naturally ventilated agricultural buildings considering building and ventilating configurations and outdoor wind conditions, aiming for farmers and non-CFD experts to easily use aerodynamic simulation results. To achieve the objective, the research produced research results according to five work phase (WP) as previously scheduled. The first WP involved a thorough review of the state-of-the-art knowledge about NV buildings and computational methodologies. In the second WP, three building structures were selected to be applied to the simulation tool. Their structure were modelled and vectorised in three dimensions (3D). Several discretisation schemes, mesh scales, turbulence models and numerical techniques that are practically available were determined in this phase. The automated simulation tool, named SYS (Simulate YourSelf), was developed in the third WP. It has user-friendly graphical-user-interfaces (GUI) and 3D interactive visualisation module. All CFD processes are automated, and the quality of each process is controlled. The biggest advantage is that the SYS was developed by a freely available open-source code, while many CFD packages are commercialised and has the burden of the expensive licence cost. In the fourth WP, the CFD simulation tool was validated by wind tunnel experiments. Air velocity predicted by the simulation tool showed a good agreement to the measurements obtained by three wind tunnel experiments. The effects of various mesh sizes and turbulence models on the simulation result were tested because the mesh size and the turbulence model were the most significant factors to keep a balance between the simulation accuracy and the computational cost. The fifth WP is an ongoing phase to disseminate the results. Its goal is to obtain feedback on the SYS from real world users. The SYS program and its documentation are available from the project website http://NatVent-CFD.com. The research results were presented at the international conference and in the seminars with outstanding European research groups. Two research papers are also in preparation to be published in leading international journals. All work phases of the project have concluded successfully. The developed program, SYS, is a handy CFD simulator to analyse air flow patterns and ventilation rates in NV agricultural buildings. Using the SYS, it is expected that general users, such as consultant, researcher and company, can easily work towards quick and practical solutions for ventilation performance. Highly accurate computing solutions are also available for scientific purposes in university. The detailed and technical results are shown in the attached report. The primary impact of this project is the proposal of the new simulation idea for encouraging people to benefit from CFD technique. While the CFD is still a highly technical method, the developed program enables non-CFD experts to use aerodynamic knowledge to their business and research. As the program is distributed through the project website, feedback on the program will enhance the usability of the program. The idea of this project can be applied to different disciplinary fields of research because the CFD is being used in a wide range of engineering fields. Besides, Dr. Hong is preparing a business model that is combined with SME to develop a web-based CFD service using the developed SYS program. The research results of HNVR-Calculator also inspired new research projects aimed at enhancing animal-rearing conditions against the hot climate problem while reducing energy costs, and predicting the infectious spread of bioterrorism between buildings and within cities. As unpredictable circumstances are significantly considered, such as climate change and threat of bioterrorism or massive CBRN exposure, the use of CFD simulation will be more indispensable for predicting such problems. The proposals are in preparation. Another important impact of this project is the training of the fellow. The project raised Dr. Hong’s international profile and provided the means to be involved in the EU network and to share his experience with others. During the project period, Dr. Hong was invited to give a lecture by five outstanding research groups and gave three oral presentations at well-known international conferences. He became involved in an EU scientific community that exchange knowledge and expertise on CFD and the natural ventilation of agricultural buildings. He is also participated in a working group to generate an EU project on developing a low-cost sensor to measure ventilation rates in NV livestock buildings. Dr. Hong also tried to transfer his knowledge to the hosting research group (M3-BIORES). As a member of the M3-BIORES, he gave three presentations and seminars to improve members’ in-depth understandings of CFD simulation and to promote collaborative research. He has collaborated with colleagues to blend different disciplines and made the published paper (Romanini et al., 2015) and one in preparation. He also served as a supervisor of an MSc student from University of São Paulo (internship program). Overall, this project was a unique opportunity to establish his scientific independence and gain professional maturity. It is expected to be a valuable asset to his future academic career. Project website: http://www.NatVent-CFD.com, Hosting group: http://www.m3-biores.com

Data: CORDIS, © European Union