Methodology for the Evaluation of Natural Ventilation in ... - Cham

Chapter 8.0Summary, Conclusions and Future Research Work8.1 SummaryNatural ventilation offers many benefits for the performance and comfort of office buildings.Among the advantages of passive ventilation are (Martin and Fitzsimmons 2002): Reduced operating costs Lower first (construction) costs Decreased impact on the environment Increased occupant comfort Improved indoor environmentHowever, before natural ventilation can be widely adopted as a passive cooling and ventilationstrategy, the underlying phenomena that govern the flow patterns and temperature distributionmust be understood. Though modeling tools are available, there has been limited validationbetween design phase and post-occupancy phase performance of these passive buildings. Thisresearch developed an innovative modeling methodology for evaluating natural ventilation in acommercial office building for a commonly used office plan. This was completed using a 1:12scale model and CFD simulations. This research also incorporated a novel means to assesswindow airflow through the creation of a bag device. Through monitoring, modeling andsimulation, the methodology was able to predict the temperature distribution and airflow patternsin the prototype naturally ventilated office building. Further research using additional site datawould be needed to fully validate the method. Monitoring methods currently in use forevaluating mechanically ventilated buildings were adapted for use in assessing a naturallyventilated commercial office building which was used as the prototype for validating thereduced-scale air model method. Numerical modeling techniques were refined and guidelinesdeveloped for the use of these methods in evaluating naturally ventilated buildings. Theguidelines are presented in this section.The main types of natural ventilation, buoyancy, wind, and combined wind-buoyancy, weredescribed and presented in chapter two along with simple analytical analyses. Designcharacteristics that often are incorporated into passively ventilated buildings, including atriumstacks to enhance buoyancy-driven flow and window locations, were identified as they pertain tothe prototype building and scaled model. Additionally, methods for evaluating buildingperformance, with a focus on those required for evaluating naturally ventilated buildings, werepresented. These methods were implemented in evaluating the prototype building described inchapter three. The monitoring and measuring methodology used and problems encountered inassessing a naturally ventilated building were identified, along with the resulting data from themonitoring period. The variation in performance due to seasonal conditions was described, andthe performance compared to existing benchmarks for typical and good practice naturallyventilated buildings. The challenge of determining an effective window opening area wasaddressed through the design and use of a device to measure the volume flow rate of air through161