A Shared Ventilation System for Individuals’ Preferences

Project: ResearchGRF

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Conventional room ventilation principles aim to provide a uniform thermal environment, which implies that all room occupants are treated as standard persons. This is inefficient as significant differences exist between occupants with regards to preferred indoor environment. On the other hand, purposely designed non-uniformity of the indoor environment could benefit energy efficiency of air conditioning (cooling) systems, e.g. allowing for significantly higher temperature in the unoccupied zone. Therefore, there is a need for a paradigm shift from uniform collective environments to environments that entertain preferences of individual occupants as well as energy efficiency. How to provide such environments cost effectively, both environmentally and economically, is a serious challenge to current air distribution research. Personalized ventilation represents an existing solution in this direction. However, in densely occupied rooms, e.g. classrooms, the intended individual air jets can be very close to one another, resulting in undesirable coupling effects, besides the difficulty of connecting multiple air supplies in the occupied zones. In recent years, there has been a new development in mathematical-modelling techniques that can help to solve the coupling effects of multiple air supplies. This optimization-based technique can entertain preferences by multiple individuals. Once the preferences of occupants at multiple locations are specified, this model can instantaneously determine where, when and how much air at what temperature should be supplied. Furthermore, for better controllability, systems with fast response are preferred for this ventilation solution. Because of its fast response, stratum ventilation will be the first air distribution system to be tested together with the model, followed by displacement ventilation and mixing ventilation. A wireless sensor and human-machine interface network will be constructed to bridge the air distribution system and optimization model. This is the first research proposal to build and test a shared ventilation system for multiple individuals’ preferences (VIP). By supplying air directly to the most relevant body parts for cooling - the head, neck and chest from the front and/or side directions, the suggested solution could provide thermal comfort to the occupants while the rest of the room is kept warm. Air will be directly delivered to the breathing zone to improve inhaled air quality. Other than the locations of the air supplies, the equipment will be almost the same as conventional systems, which minimizes the technological risk. The new system requires less cooling capacity due to better energy efficiency. Hence, the system will occupy less indoor space and the initial cost is also expected to be lower. The proposed study will be carried out in our unique environmental chamber which conveniently allows the scenarios of offices and classrooms to be tested. Objective measurements will be collected through wireless sensors. Simultaneously, human subjective responses on thermal sensation and comfort will be input via the human-machine interface network. Both the objective measurements and subjective inputs will be used by the optimization model to control the system. The system design will be improved iteratively. Finally, a set of design guidelines for the application of VIP technology will be developed. Partly evident in 33 SCI refereed journal articles, the advantages of this novel air distribution method are demonstrated in the following aspects: 1. Better thermal comfort ─ individual preferences will be accommodated; 2. Better indoor air quality ─ horizontal air supply at the head level; 3. Better energy efficiency ─ 20% to 40% less year-round energy consumption; 4. More environmentally friendly ─ smaller carbon footprint throughout life cycle; 5. Lower risk in research and development ─ the innovative technology can be realized with conventional ventilation devices; and 6. Safer installation ─ no scaffolding is needed for installation. Note: Only the essential information of the project is presented in this proposal due to the limit in length.


Effective start/end date1/01/18 → …