Why does a robust man sweat, while a slender woman shivers from the cold even indoors? In office spaces in particular, the temperature has often been adjusted in accordance with how men, who are more muscular than women, sense the temperature, so it is no wonder women feel cold. The unique solution developed by VTT Technical Research Centre of Finland adjusts the room temperature automatically as close to the ideal level for those spending time in the room in accordance with how they sense the temperature. The solution is particularly well suited for offices, hospitals, hotels and retirement homes, which require individual conditions.
"People in the western world spend more than 90% of the day indoors. The thermal comfort also significantly affects work efficiency. If the indoor room temperature in a building is adjusted by 1 to 3 degrees, the productivity of work improves by 4 to 7%. And, according to recent reports, if the indoor conditions are good, the value and utilisation rate of a building can increase by 10%," says Pekka Tuomaala, Principal Scientist at VTT.
In its IoT (Internet of Things)-based solutions, VTT Technical Research Centre of Finland uses both printed and ordinary sensors. Using printed conductors, information can be transferred from these sensors through structures over even quite extended distances to data transfer units, which then wirelessly relay the data to a cloud service. In the cloud service, the thermal model developed by VTT, the Human Thermal Model (HTM), based on body composition, clothing and level of activity, calculates the optimal adjustments for the building automation system.
"Sensors measure the temperature, relative humidity and human presence in the space where adjustment is needed, and send the data to the cloud via the internet. The VTT thermal model then calculates the room temperature setting for the room-specific control connected to the property's building automation system. On this basis, the heating system either increases or reduces heating or cooling on the premises," Senior Scientist Kalevi Piira explains.
The difference between people may be as great as 5 degrees, depending on their muscularity, body fat percentage, weight, age, clothing and level of activity. If they have the same level of activity and similar clothing, the difference between a muscular man and a person in advanced old age is up to 6 degrees.
Reductions also in the property's energy costs
Temperature adjustment according to need would primarily bring benefits in terms of comfort and enhanced work efficiency, but it would also result in energy savings, when only those rooms where people are present would be heated in winter and cooled in summer.
As regard building service systems, room-specific ventilation-based heating is quick to react to desired changes. However, the temperature can also be adjusted in advance on the basis of individual preferences, before the person enters the room.
In the same regard, VTT has been testing wireless humidity sensors, which can be used, for example, in the monitoring of building conditions or in other applications, such as monitoring the state of house plants.
VTT has been testing the system and is now seeking partners to commercialise the IoT solution. The solution would, for example, benefit the real estate sector, companies developing and using sensors based on printed electronics and IoT, and companies providing and developing cloud service applications.