Thermal sensation sensing technology in personalized ventilation systems

Abstract

Since people spend more than 80% of their lives in buildings or other indoor environments, and so comfortable conditions are essential in sustaining our quality of life and for saving energy. Personalized ventilation can control personal surroundings thermal conditions to provide comfort with minimal energy consumption. This is especially applicable in modern dense office buildings. However, one of the key issues in personalized ventilation is how to detect people’s comfort levels, and once this is determined, how to then automatically provide a comfortable environment. It requires an effective and easy-to-use tool to measure thermal sensation. According to previous researches, the metabolic rate that accounts for the heat generation rate of a human body is the most significant parameter of human thermal sensation. It is usually set as a constant because it is difficult to measure for free-moving humans. However, it is obvious that there are many elements affecting one’s metabolic rate, such as personal characteristics including age, gender, weight and height and environmental factors including air temperature and humidity. The existing methodologies to measure metabolic rate all have their limitations – inconvenience, low accuracy or lengthy measurement processes. In this study, thermal sensation sensing technology for use in the sensing and control of personalized ventilation in office buildings is developed. The metabolic rate is predicted by using heart rate, bio-impedance and heat loss based on the thermoregulation inside the human body. Then thermal comfort level is evaluated based on the predicted metabolic rate and the particular environment conditions. According to the thermal comfort level, the comfort temperature can be provided remotely for individuals from a central control system.

Date of Award	2017
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology