Oversizing and HVAC system operation

École de technologie supérieure, Montreal, Canada

^* Corresponding author: Stanislaw.Kajl@etsmtl.ca

Abstract

This paper presents the monitoring results for the HVAC systems installed in a university building, which prove that oversizing is a real problem with existing systems. In our study, how the zones served by systems are grouped is a major cause of oversizing. This is particularly obvious when monitoring the systems serving the zones on a single facade; monitoring those in zones situated on two facades shows that additional reasons must also be considered as well. The monitoring presented in the paper is carried out on four systems, two serving zones on a single facade and two others serving zones located on two facades. Following the processing of the ensuing data, the results obtained show that the systems mostly function at between 55 and 65% of their design capacity. An analysis of these results indicates that a better design approach could reduce the total airflow rate of HVAC systems, reduce building energy consumption, and promote better systems operation.