Effect of Supply Air Temperature on Indoor Thermal Comfort in a Room with Radiant Heating and Mechanical Ventilation

The study presents the investigation of the effect of supply air temperature on thermal comfort in a room with floor heating (FH) or ceiling heating (CH) and mixing ventilation (MV) or displacement ventilation (DV). Vertical distributions of air temperature and velocity and globe temperature in the occupied zone were measured when supply air temperature varied from 15.0°C to 19.0°C. PMV-PPD, vertical air temperature difference and draught near the neck were calculated and compared for the four hybrid systems. The results showed that the PMV values were varied from 0.24 to 0.37 and from 0.11 to 0.27 for FH + MV and CH + MV and from 0.01 to 0.19 and from -0.41 to -0.12 for FH+DV and CH+DV. The vertical air temperature differences were less than 0.3°C with FH+MV or CH+MV, and from 1.9°C to 4.0°C and from 2.5°C to 4.2°C for FH+DV and CH+DV. The PPDs and draughts near the neck for the four systems were all less than 10%. The results in this paper can be used to facilitate the design and operation of a hybrid system with a radiant heating system and a mechanical ventilation system for both residential and commercial buildings.