Measuring Thermal Comfort with the use of Infrared Cameras

Abstract

Studies have shown that adjusting the mechanical cooling systems according to the thermal comfort needs of occupants will lead to huge energy savings and greater energy efficiency. Studies have also shown if the thermal environment is not within thermal comfort range of most people, it will lead to decrement in work performance and occupants might also experience symptoms of the Sick Building Syndrome (SBS).

Many existing thermal comfort studies collect various physiological data which usually requires subjects to wear or strap on the devices which might cause a physical or mental weight on the subjects. Infrared thermal imaging is unique for being a mode of non-invasive and contactless option for object temperature analysis. Hence, this study aims to assess the effectiveness of a thermal imaging camera as a tool to measure thermal comfort.

Temperatures of various facial regions were recorded and compared, and the forehead was determined to be most sensitive to the surrounding environment. The overall facial temperature was also compared against the environmental measurements. Results from the initial findings show that air temperature and mean radiant temperature had a positive correlation with the overall facial temperature, while relative humidity has a negative correlation and the air speed graphs showed that there was no correlation. However, based on the Multi-Linear Regression Analysis, only the average air temperature and the air speed is shown to have a significant influence on the overall facial temperature.

Thermal comfort survey was also done to analysis of the results of various thermal comfort scales and overall facial temperature. Thermal comfort scales included are the common scales used to determine the participant’s thermal sensation, comfort, preference, and acceptability. The results from the analysis show that overall facial temperature has a positive correlation with the thermal sensation and comfort scale, a negative correlation with the thermal preference scale, and no significant correlation for thermal acceptability scale.