THESIS
2021
1 online resource (iv, vi, 184 pages) : illustrations (some color)
Abstract
Since people spend a lot of time indoors, it is important to assess and monitor indoor air quality (IAQ) for the wellbeing of its occupants. Computational fluid dynamics (CFD) is a powerful tool for performing indoor airflow analysis. CFD simulation has been used by previous studies for single rooms, but not for floors with multi-zone ventilation systems. Since it is often not possible to take measurements across an entire floor due to concerns of tenant privacy, few studies have used the limited obtainable field measurements to validate multi-zone CFD simulations. In addition, validation of multi-zone CFD model is sophisticated. To improve accuracy, boundary conditions need to be adjusted based on the sensitivity of the model to the influence factors, which few studies have been conduc...[
Read more ]
Since people spend a lot of time indoors, it is important to assess and monitor indoor air quality (IAQ) for the wellbeing of its occupants. Computational fluid dynamics (CFD) is a powerful tool for performing indoor airflow analysis. CFD simulation has been used by previous studies for single rooms, but not for floors with multi-zone ventilation systems. Since it is often not possible to take measurements across an entire floor due to concerns of tenant privacy, few studies have used the limited obtainable field measurements to validate multi-zone CFD simulations. In addition, validation of multi-zone CFD model is sophisticated. To improve accuracy, boundary conditions need to be adjusted based on the sensitivity of the model to the influence factors, which few studies have been conducted on. On the other hand, validation of CFD model requires field measurement results. Moreover, IoT (Internet of Things) sensor deployment provides real time data for IAQ monitoring and becomes more popular in recent years because of reduced cost. The accuracy of IoT sensors can be affected by sensor placement and therefore determining optimal placement is crucial for producing reliable results. However, existing research of optimizing IoT sensor placement in a non-laboratory environment is lacking. On the other hand, few studies consider IAQ when enhancing energy efficiency of mechanical ventilation and air conditioning (MVAC) systems, which are critical for maintaining satisfactory IAQ for occupants’ wellbeing. To tackle the limitations of existing research, this thesis aims to improve accuracy in IAQ assessment and monitoring, as well as to develop methodologies for optimizing IAQ sensor placement and MVAC system controls, by leveraging building information modeling (BIM) technology.
This research has three parts. The first part is background study on IAQ and literature review on IAQ assessment and monitoring using CFD simulation and IoT sensors, respectively. The second part applies BIM for IAQ assessment using multi-zone CFD simulation under limited information, including the following three studies: (1) CFD simulation of a single floor; (2) sensitivity analysis of a single floor; and (3) CFD simulations of multiple floors and connected fresh air shafts. The third part applies BIM to improve IAQ monitoring and control, including the following two studies: (1) temperature and CO
2 sensor placement optimization; and (2) MVAC system setting optimization for thermal Comfort, IAQ and energy consumption. These findings support building managers: (1) to better understand their managed multi-zone indoor environment by improving accuracy in airflow simulation and investigating how IAQ varies in different regions with different MVAC system settings and layouts; (2) to improve IAQ and MVAC system control based on IAQ sensor data and simulated results at a reduced energy cost.
To illustrate and evaluate the proposed methodologies, illustrative examples of an existing commercial building and an operating lecture theatre are used. For each illustrative example, the dimensions of building elements and properties of lamps and MVAC system of all studied rooms, floors are created based on CAD drawings, field observations and measurement. All CFD and energy models created in the studies are validated with measured results. By doing so, the advantages of all the developed methodologies of improving the IAQ assessment and monitoring of non-residential buildings can then be identified.
Post a Comment