Thermal Conditions in a Simulated Office Environment with Convective and Radiant Cooling Systems

The thermal conditions in a two person office room were measured with four air conditioning systems: chilled beam (CB), chilled beam with radiant panel (CBR), chilled ceiling with ceiling installed mixing ventilation (CCMV) and four desk partition mounted local radiant cooling panels with mixing ventilation (MVRC).

CB was based on convection cooling while the remaining three systems (CBR, CCMV and MVRC) on combined radiant and convective cooling. Measurements were performed in design (64 W/m2) and usual (38 W/m2) cooling conditions. Air temperature, operative temperature, radiant asymmetry, air velocity and turbulent intensity were measured and draft rate levels calculated in the room.

Manikin-based equivalent temperature (MBET) was determined by two thermal manikins to identify the impact of the local thermal conditions generated by the studied systems on occupants’ thermal comfort. The results revealed that the differences in thermal conditions between the four systems were not significant.

This result was contrary to the expectation that operative temperature would be lower in the CCMV case. The velocity levels in the occupied zone were slightly higher in both CB and CBR cases. However the highest measured values were located outside the workstations.