LOW COST INFRARED ARRAY AS A THERMAL COMFORT SENSOR

Energy in buildings has to be deployed in a more effective way, bearing in mind a comfortable indoor climate and full occupant satisfaction. Recent developments show that heating or cooling locally can improve both, the thermal comfort and energy effectiveness. Personalized conditioning systems are in principle able to satisfy the individual thermal comfort requirements, and at the same time they are conditioning only a small space around a single user and are thus more energy effective. However, personalized conditioning systems are still controlled only by direct user interaction, which can lead to problems such as temperature overshoots or energy wastes. For automation of the control process it is necessary to look into individual parameters that can predict thermal discomfort. It has been shown that the fingertip temperature is a good predictor of cold discomfort. Therefore, it has a potential to be used as a control signal for automatic personalized heating. For practical use it is necessary to develop a low cost sensor that can sense the fingertip temperature without direct interfering with the user. In this paper the initial tests of low cost infrared arrays are presented that can be used for this application. Two infrared arrays of resolution 4x4 and 16x4 pixels were tested in terms of their accur acy and feasibility for skin temperature measurement. The static tests proved these sensors to be adequate for the intended purpose. One of the infrared arrays was then combined with a visual camera allowing a real-time tracking of the hand movement. Development of this integrated visual and infrared sensor and their relation to thermal comfort are presented in this paper.