Center for the Built Environment

This paper reports the results of recently completed laboratory and field measurements investigating the thermal performance of an occupant-controlled desktop task conditioning system. The laboratory experiments were performed in a controlled environment chamber configured to resemble a modern office space with modular workstation furniture and partitions. Velocity and temperature distributions were measured throughout the test chamber for a range of test conditions to investigate the effects of supply volume and direction, supply outlet size, and heat load levels (both uniform and nonuniform) in the space. Comfort model predictions are presented to describe the degree of environmental control and range of occupant comfort levels produced in the workstations. Individual desktop units in side-by-side workstations having significantly different heat load levels could be adjusted to maintain close to comfortable conditions, demonstrating localized comfort control.

The field study was performed in a small demonstration office containing two permanent data acquisition systems capable of monitoring in detail the thermal and energy performance of the office, including four installed desktop task conditioning units. Portable measurement methods were also used to assess the thermal comfort of the workers occupying the office. Initial results from the field study demonstrate the occupant response and use patterns of the desktop system, typical energy use pattrns, and the effect of the desktop system on local air velocities and thermal comfort within the workstations.