Occupant controlled HVAC systems offer inhabitants of open office spaces some degree of control over their immediate microclimate typically by control of air supplied at floor or desk top level. Productivity gains have been attributed to these systems but it is unclear whether these systems will use less energy than conventional HV AC systems. It is also not clear what the controlling parameters will be. To study energy consumption, a simplified model of the thermal environment was created for an occupant controlled system.
This paper reviews the development of performance indices for fabric thermal storage from the original BRE office research data to the two mixed mode design options currently available, each having different design priorities, namely naturally ventilated or mechanically ventilated. Naturally ventilated mixed mode designs appear to be less suitable for UK locations and also appear to have significantly greater annual energy consumption. In addition to the comparison of energy consumption criteria, the paper also reviews recent Scandinavian indoor climate classifications.
Occupancy sensors have the potential to significantly reduce energy use by switching off electrical loads when a normally occupied area is vacated. While occupancy sensors can be used to control a variety of load types, their most popular use has been to control lighting in commercial buildings. Manufacturers claim savings of 15% to 85%, although there is little published research to support the magnitude or timing of reductions.
Office noise affects the productivity of every person in every office. Companies have woken up to the detrimental effects on productivity of stale air pumped out by air-conditioning systems, and they are replacing these with natural ventilation systems. However, air-conditioning provides a useful by-product: the steady masking of background noise. Tom. Dawn considers the options for creating a better acoustical environment.
The issue of sound quality in offices and other occupied spaces has been of continuing interest since the 1950s. Existing assessment methods do not adequately account for the Low-frequency background sound ( < 250 Hz) produced by operating heating, ventilating, and air-conditioning (HVAC) systems, in particular, Low-frequency rumble. This paper discusses the results of ASHRAE-sponsored research in which more than 75 HVAC noise samples were collected, normalized, and categorized in terms of sound quality.
The aim of this study is to assess the performance of the mechanical ventilation system and air quality in an office building. The perfluorocarbon tracer (PFT) technique was used to measure air flow in an air handling unit and to estimate flow rates supplied to the office. In order to validate the PFT technique as a viable means of measuring air flow in the mechanical ventilation system, the PFT measurements were compared with measurements made using a pitot-static tube. Air exchange range, ventilation effectiveness and age of air were examined.
A major increase of complaints has been observed by the occupants of buildings, concerning health symptoms and comfort. In this study, the occupants' experience of symptoms as well as the occupants' sensation of the environmental parameters were estimated in six office buildings, where the indoor air quality was investigated. It was found that the percentage of building related symptoms experienced by the occupants of the buildings was high and it was strongly related to human comfort and human sensation concerning the environmental conditions.
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