تجزیه و تحلیل حساسیت و کاربرد راهنمایی ها برای شبیه سازیCFD و انرژی ساختمان یکپارچه

Building energy simulation (ES) and computational fluid dynamics (CFD) programs provide complementary information essential to evaluating building thermal performance. Integration of the two programs eliminates many model assumptions in separate applications and thus improves the quality of simulation results. This paper discusses the potential building and environmental characteristics that may affect the necessity and effectiveness of applying an ES–CFD coupling simulation. These characteristics and the solution accuracy requirement determine whether a coupled simulation is needed for a specific building and which coupling method can provide the best solution with the compromise of both accuracy and efficiency. The study conducts a sensitivity analysis of the coupling simulation to the potential influential factors, based on which general suggestions on appropriate usage of the coupling simulation are provided.

Building energy simulation (ES) and computational fluid dynamics (CFD) programs provide plentiful and complementary information about building thermal performance, such as space cooling and heating load, distributions of indoor air velocity, temperature, and contaminant concentrations. This information is important to assessing thermal comfort, indoor air quality, and energy consumption of a building. Due to the complementary nature of results provided by the two programs, attempts to integrate these two programs receive increasing attention recently (e.g., [1], [2] and [3]. It has been envisioned as a potential approach to eliminating simplification assumptions in each model and providing more accurate prediction on building behaviors [4]. Zhai and Chen [4], [5] and [6] explored the principles, methodologies, strategies, implementation, and performance of the ES–CFD thermal coupling. Their study proved that a unique coupled solution exist in theory but different coupling methods may lead to different solution performance in terms of computing accuracy, stability and speed. It verified that the data coupling method, which transfers enclosure interior surface temperatures from ES to CFD and returns convective heat transfer coefficient and indoor air temperature gradients from CFD to ES, is the most straightforward, reliable and efficient coupling method. The study further proposed the staged coupling strategies to reduce the total computing time of a coupling simulation. A prototype of an integrated ES–CFD building simulation tool, implementing all the proposed coupling strategies, was developed. The performance of the program has been examined against experimental data and compared with no-coupling simulations. However, the previous studies did not provide answers to the questions that are most important to building designers and engineers who may think of using the coupling simulation: (1) Under which circumstance is an integrated ES–CFD simulation necessary? Or under which circumstance is a separate ES and CFD simulation sufficient? What is the improvement-cost-rate of coupling simulation? (2) Which coupling strategy should be used? (3) Which coupling frequency should be used? This paper addresses these questions with a sensitivity study of the coupling simulation to potential building and environmental influential factors. It will provide essential and practical knowledge of coupling simulation to developers and users of ES–CFD coupling programs.