Fast Cooling of Occupants in Transitional Spaces for Better Environmental Quality and Energy Efficiency

Description

In urban areas with a subtropical climate, such as Hong Kong, people frequently enter an air-conditioned environment from a hot and humid outdoor environment. The sudden drop in temperature causes the blood vessels in the body to tighten, lessens the amount of heat released through the skin and helps the body stay warm. However, drastic blood vessel constriction causes elevated blood pressure, puts more strain on the heart and raises the risks of angina pectoris, myocardial infarction, asthma attacks and even death. From a thermal comfort and heat stress standpoint, a buffer should be provided for individuals when they migrate from outdoors to air-conditioned spaces to avoid abrupt temperature drops and give the human body some buffer time to adjust to a new thermal equilibrium. Transitional spaces, such as corridors and entrances, are often public passages and conjunctions to the outdoor environment, with great potential to perform as a buffer for individuals to adjust their thermal equilibrium. At the same time, there are concerns about the health implications because of the exposure to respirable indoor air pollutants such as VOCs and PM2.5. The pollutants emission and resuspension from the floor and infiltration from outdoors bring the indoor air quality problem to transitional spaces. The COVID-19 pandemic once again underlines indoor ventilation in public places. In addition, because the environment of the transitional space can be complex and diverse, optimal and intelligent ventilation control for transitional spaces is necessary for thermal comfort, indoor air quality and energy efficiency. The critical issue is determining the cooling needs and buffer time for people in transitional spaces, according to the following steps: 1. Experiments will be carried out to establish a transient thermal comfort model in the case of abrupt cold change as a reference to an appropriate thermal environment in transitional space for fast cooling.2. The influence of different air distributions on thermal comfort, air quality and energy efficiency of the transitional space will be investigated.3. A multi-objective optimization combined with predictive control will be applied to determine the operating parameters and control algorithms for optimal environmental quality and energy efficiency for the transitional spaces.