This paper illustrates the principles of demand controlled ventilation systems (DCV) as applied to office buildings. Appropriate ventilation approaches and control strategies are demonstrated in this paper for small area control (ieboardrooms) and for office buildings as a whole. Findings are illustrated by the results of field experiments. Impacts on energy consumption, indoor air quality and occupant response are examined. General conclusions and recommendations applicable to similar building types are also presented.
The performance of a system for demand-controlled ventilation was investigated for a period of 1.5 years. Presence sensors of the passive infrared type are used to control the ventilation rate in each classroom. The signal from the presence sensors was recorded, as well as the CO2 concentration in the classrooms. One of the classrooms was equipped with displacement ventilation. A comparison was made between displacement and mixing ventilation to investigate the CO2 concentration in the stay zone.
A test programme has been designed to evaluate the performance characteristics of sensors for the automatic control of ventilation rates. The test programme consists of two main parts, one being the evaluation of sensor performance in laboratory tests and the other referring to long term characteristics of sensors in actual buildings. Included in thepresent evaluation are eight different types of humidity sensors, two carbon dioxide sensors and five mixed gas sensors.
Field investigations were undertaken on five houses to determine the potential for improved performance and lower costs through the use of a demand controlled ventilation (DCV) systems. All 5 houses were energy efficient, low toxicity construction, and were chosen to reflect a range of mechanical systems consistent with Canada's new ventilation standard (CSA F326). Three of the test houses were extensively monitored and, after 90 days of conventional operation, were converted to DCV using a wide variety of sensors and controls.
"Air Movement and Ventilation Control within Buildings", held 24-27 September 1991, Ottawa, Canada, proceedings published September 1991, Volume 1, pp 141-142. #DATE 00:09:1991 in English",An overall presentation will be given of the final report from Annex 18 experts are proposing DCV-systems in various building types. The presentation will be focused on strategies and pre-requisites and on DCV-systems in the building types not presented separately.
This paper is based on field measurements in auditoria which were carried out in Norway and in Switzerland. In both cases carbon dioxide (CO2) was chosen as the relevant indicator to establish ventilation demand.
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