Effects of humidification process on the thermal behavior of floor heating systems

Abstract

Since the outbreak of the Covid-19 pandemic, working from home has become the norm for millions of workers in the world. Indoor humidification and heating are essential for health and comfort in a dry and cold climate. In order to investigate the interaction between humidification process using a cool mist humidifier and the heating process using a floor heating system, a total of 4 experimental tests were carried out, which included three experimental groups with humidification process in the conditions of three relative humidity setpoints (45%, 55%, 65%), and one control group without humidification process. In the process of experiments, indoor relative humidity of the control group basically maintained around 30%. Therefore, the heated room would be dehumidified to about 30% before each experiment started. The indoor temperature was maintained at 25 ℃ by the floor heating system. Obtained results showed the floor heating system was stimulated to reheat the room due to the cooling effect of the humidifier and a new balance was established in the process of competition between the evaporative cooling and floor heating. When humidifying air to over 45%, it would lead to floor overheating. Furthermore, the humidification process improves the non- uniformity of air temperature distribution, but at the same time brings more uneven RH distribution. Besides, the energy consumption increases following with the rising of setpoints of RH, and the growth rate is 60%, 87% and 100% respectively for RH 45%, 55% and 65%. In conclusion, the optimal setpoint of the humidifier is RH 45% based on a comprehensive consideration of health, thermal comfort and energy consumption.