A Shared Ventilation System for Individuals’ Preferences

Description

Conventional room ventilation principles aim to provide a uniform thermalenvironment, which implies that all room occupants are treated as standard persons. Thisis inefficient as significant differences exist between occupants with regards to preferredindoor environment. On the other hand, purposely designed non-uniformity of the indoorenvironment could benefit energy efficiency of air conditioning (cooling) systems, e.g.allowing for significantly higher temperature in the unoccupied zone. Therefore, there is aneed for a paradigm shift from uniform collective environments to environments thatentertain preferences of individual occupants as well as energy efficiency. How to providesuch environments cost effectively, both environmentally and economically, is a seriouschallenge to current air distribution research. Personalized ventilation represents anexisting 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 undesirablecoupling effects, besides the difficulty of connecting multiple air supplies in the occupiedzones.In recent years, there has been a new development in mathematical-modellingtechniques that can help to solve the coupling effects of multiple air supplies. Thisoptimization-based technique can entertain preferences by multiple individuals. Once thepreferences of occupants at multiple locations are specified, this model caninstantaneously determine where, when and how much air at what temperature should besupplied. Furthermore, for better controllability, systems with fast response are preferredfor this ventilation solution. Because of its fast response, stratum ventilation will be thefirst air distribution system to be tested together with the model, followed by displacementventilation and mixing ventilation. A wireless sensor and human-machine interfacenetwork 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 formultiple individuals’ preferences (VIP). By supplying air directly to the most relevantbody parts for cooling - the head, neck and chest from the front and/or side directions, thesuggested solution could provide thermal comfort to the occupants while the rest of theroom is kept warm. Air will be directly delivered to the breathing zone to improve inhaledair quality. Other than the locations of the air supplies, the equipment will be almost thesame as conventional systems, which minimizes the technological risk. The new systemrequires less cooling capacity due to better energy efficiency. Hence, the system willoccupy 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 whichconveniently allows the scenarios of offices and classrooms to be tested. Objectivemeasurements will be collected through wireless sensors. Simultaneously, humansubjective responses on thermal sensation and comfort will be input via the human-machineinterface network. Both the objective measurements and subjective inputs will beused by the optimization model to control the system. The system design will be improvediteratively. Finally, a set of design guidelines for the application of VIP technology will bedeveloped. Partly evident in 33 SCI refereed journal articles, the advantages of this novelair 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 realizedwith conventional ventilation devices; and6. 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.