PolyU Carbon Neutrality Project
Layman Summary
The Hong Kong Polytechnic University (PolyU) campus is a complex of multiple buildings, housing different types of facilities such as offices, classrooms, lectures, canteens, libraries, laboratories, and sports centers. With a dynamic occupancy profile, the campus relies heavily on electricity, leading to inevitable carbon emissions. According to the EMSD’s report on Hong Kong Energy End-use, over 50% of energy consumption in the education sector is attributed to air conditioning. The PolyU campus, located in the heart of the urban area, has the potential to become a pioneering prototype of a built environment socioecological system for achieving carbon neutrality in the near future.
With extensive research expertise in indoor environmental quality (IEQ), our research team aims to adopt a user-centric approach and take the campus indoor space as a threshold to achieve three primary objectives: (1) examine the nexus between occupant behavior and preferences, indoor environment quality, and energy management; (2) propose a cost-effective intervention strategy from both “supply side” and “demand side” perspectives to facilitate carbon emission reduction; and (3) utilize our research finding to transform the PolyU campus into a living lab for future carbon neutrality research.
To achieve those objectives, a campus-wide environmental survey will be conducted to collect relevant IEQ data in air-conditioned spaces in PolyU, occupancy profiles in open areas, and MVAC energy usage data. The comprehensive survey program will take 24 months to complete for adequate data collection, analysis, and preparation of a detailed report. The ultimate goal of this campaign is to develop a baseline indoor environmental quality database to identify the most optimal environmental conditions concerning occupant comfort and health, safeguarding building users while reducing energy wastage to achieve carbon reduction.
The proposed project holds significant academic value, as it aims to contribute to the ongoing research on carbon emission reduction in building environment. By utilizing a user-centric approach, the study will provide insights into the interdependence between occupant behavior and preferences, indoor environment quality, and energy management. The proposed intervention strategy will also provide cost-effective solutions to facilitate carbon emission reduction, further contributing to the academic discourse on carbon neutrality. Finally, by utilizing the PolyU campus as a living lab, this study will offer an innovative approach to future carbon neutrality research, providing practical insights into the implementation of carbon reduction strategies in building environments.
Research Activities
Indoor Environmental Quality (IEQ) monitoring campaign
Setting Up an Indoor Environmental Quality Sensor Grid for PolyU Campus
The proposed exercise required establishing an in-depth environmental monitoring program in the PolyU campus covering various types of facilities. Compared to traditional environmental monitoring method through periodic survey, Internet-of-Things (IoT)-based sensing networks can capture instantaneous environmental variation induced by human activities or extreme weather. It also provides spatial characterization and temporal understandings of an environment, which aid the identification of resources of discomfort and mitigation strategies. The sensor grid will measure indoor air temperature, radiant temperature, relative humidity, air velocity, carbon dioxide (CO2) level, particulate matter (PM10 and PM2.5) level, total volatile organic compound (TVOC), horizontal illuminance level and sound pressure level, which are representative surrogate indicators for thermal comfort, indoor air quality (IAQ), aural and visual comfort. Data will be transmitted wirelessly through the Wi-Fi network and stored in the backend cloud server that PolyU maintains. The server will automatically compute the acceptance to each IEQ aspect and the overall IEQ acceptance predicted by an open probabilistic IEQ acceptance model developed by our research team. The level of environmental quality will be presented as various levels of a 5-star IEQ benchmark and displayed on a designated user interactive web-based/mobile App platform. Building occupants can also view real-time environmental data and vote for their subjective comfort sensations and acceptance towards the thermal environment and IAQ.
IEQ measurement in classrooms and lecture theaters
Outdoor Wind Measurement
The present study aims to investigate the viability of utilizing natural ventilation in classrooms to enhance ventilation performance during the winter months while also saving energy. In addition, the study seeks to evaluate the impact of outdoor prevailing wind on air pollutant distribution and indoor air quality in both naturally-ventilated classrooms and the PolyU campus. The research will involve assessing the ventilation performance of each room through tracer gas decay under unoccupied conditions, identifying the potential natural ventilation rate for classrooms with openable windows, conducting field measurements of the prevailing wind in the PolyU campus, and conducting two stages of wind measurement and tracer gas dispersion experiments. The findings of this research will offer valuable insights into the potential of natural ventilation to enhance ventilation performance in classrooms for energy-saving purposes during the winter, as well as improve our understanding of the effects of outdoor prevailing wind on air pollutant distribution and indoor air quality in naturally-ventilated classrooms and the PolyU campus.