By giving people individual control over the environmental conditions in their workplaces, designers and facility managers can help increase worker satisfaction and productivity. Task/ambient conditioning (TAC) systems allow occupants to control temperature, air flow, and in some cases lighting and sound to meet their individual needs. This technology has recently been gaining a foothold in the U.S. It is often implemented in conjunction with underfloor air distribution, which opens up opportunities for a number of efficiencies in building design and operation. In addition to improving worker satisfaction and productivity, this combined approach has the potential to improve thermal comfort and indoor air quality, reduce energy use and life-cycle building costs, and reduce floor-to-floor height in new construction. Guidelines and recommendations are presented based on recent field and laboratory research results that encourage the intelligent design, installation and operation of TAC systems using underfloor air distribution.

These user notes describe how to use a spreadsheet-based (Excel 2007) version of the ASHRAE method (Chen and Glicksman 2003) for calculating the amount of design cooling airflow required for a displacement ventilation (DV) system that is providing all sensible cooling for a conditioned space. The design tool has been developed by CBE and is available on the CBE Partner website: http://www.cbe.berkeley.edu/partners/downloads.php

This final report presents the results of research completed since June 1991 on PG&E's Advanced Office Systems Testbed (AOST) Project. The initial advanced office system selected for evaluation in the AOST office was the Personal Environmental Module (PEM), manufactured by Johnson Controls. The PEM represents one example of an emerging technology known as task conditioning, or localized thermal distribution (LTD). Workstation-based LTD systems that allow individuals a degree of control over their local environment have the potential to improve the energy efficiency of the building's air distribution system by enabling only the local workstation environments to be tightly controlled while relaxing the energy and comfort requirements in the less critical surrounding spaces.

Work was performed by UC Berkeley in the following task areas: (1) detailed field measurements of thermal comfort of the PG&E employees participating in the study, both before and after moving into the AOST office; (2) installation of a permanent data acquisition and information display system capable of recording and displaying the status of a selected number of performance parameters from the AOST office, including occupant use patterns from each of the eight workstations, supply and return conditions from the air distribution system serving the office, and average room air conditions; (3) analysis of the collected data; and (4) evaluation of the applied measurement methods. 

Underfloor air distribution (UFAD) is an innovative technology that uses the underfloor plenum below a raised floor system to deliver space conditioning in offices and other commercial buildings. The use of UFAD is increasing in North America because of the benefits that it offers over conventional ceiling-based air distribution.

This section provides full details of work performed in support of Task 2.3 (Underfloor Plenum Testing) and Task 2.5 (Underfloor Plenum Model Development). The ultimate goal of these tasks was to develop a model capable of calculating the thermal performance of underfloor air supply plenums, while at the same time suitable for implementation in EnergyPlus. A secondary goal was to conduct fundamental research that provides a sound theoretical and practical understanding of underfloor plenum energy performance in terms of heat transfer entering the plenum and the resulting airflow and temperature distributions. The technical approach used to accomplish this work included the following tasks:

• Full-scale experiments in CBE’s underfloor plenum test facility

• Development of computational fluid dynamics (CFD) model of underfloor plenum

• Validation of CFD plenum model by comparison with full-scale experimental database

• Use of the validated CFD plenum model to conduct simulations of a broader range of plenum design and operational parameters

• Development of simplified underfloor plenum model based on CFD database for implementation into EnergyPlus

• Comparison between EnergyPlus and CFD plenum model predictions

• Simplified heat balance modeling study of heat transfer pathways in UFAD systems