The effect of temperature and direction of airflow from the personalised ventilation on occupants' thermal sensations in office areas

• The influence of temperature and direction of PV was examined on thermal sensation.
• It is possible to increase temp. of indoor air without affecting the thermal sensation.
• In summer PV air's temperature has less influence on thermal sensation than direction.
• In winter do not confirmed the effect of airflow direction on the thermal sensation.
• Higher efficiency is obtained by supplying airflow for face.

Proper technical solutions used in the HVAC systems help to reduce cooling or heating load delivered to buildings. Potentially, personalised ventilation (PV) can serve as one of such solutions. The aim of the study was twofold: to determine proper airflow direction using PV and to define air parameters necessary to reduce energy consumption in office spaces without detriment to thermal comfort of office occupants. The focus of the study was the effect of PV on local thermal sensation and comfort of users.The tests were carried out with a participation of 20 volunteers. Two directions of airflow were used (at the face and ankle level). Simulated conditions corresponded to winter and summer temperatures. During each of a measurement session PV continued to supply a constant flow of fresh air in the amount of 20 l/s. Following the test, volunteers were requested to fill in a questionnaire on their subjective assessment of thermal sensation. The results of the survey showed a correlation between thermal sensation on particular body parts and a direction of supplied airflow. Change of the direction of supplied airflow was sensed with particular intensity on the face and the upper body parts.