AIVC - Air Infiltration and Ventilation Centre

Search form

EBC

You are here

Home  |  LBNL

Evaluation of flow hood measurements for residential register flows

Walker, I.S., Wray, C.P., Dickerhoff, D.J., Sherman, M.H., 2001
Bibliographic info: LBNL - Indoor Environment Department Publications, LBL
Languages: English

Flow measurement at residential registers using flow hoods is becoming more common. These measurements are used to determine if the HVAC system is providing adequate comfort, appropriate flow over heat exchangers and in estimates of system energy losses. These HVAC system performance metrics are determined by using register measurements to find out if individual rooms are getting the correct airflow, and in estimates of total air handler flow and duct air leakage. The work discussed in this paper shows that commercially available flow hoods are poor at measuring flows in residential systems. There is also evidence in this and other studies that flow hoods can have significant errors even when used on the non-residential systems they were originally developed for. The measurement uncertainties arise from poor calibrations and the sensitivity of exiting flow hoods to non-uniformity of flows entering the device. The errors are usually large -- on the order of 20% of measured flow, which is unacceptably high for most applications. Active flow hoods that have flow measurement devices that are insensitive to the entering air flow pattern were found to be clearly superior to commercially available flow hoods. In addition, it is clear that current calibration procedures for flow hoods may not take into account any field application problems and a new flow hood measurement standard should be developed to address this issue.


Related publications

This report summarizes the work of the initial working phase of IEA ECB Annex 62 Ventil
Maria Kolokotroni, Per Heiselberg, Lorenzo Pagliano, Jie Han, Regina Bokel, Peter Holzer, Annamaria Belleri, Denmark
This summary report presents insights on recommendations into how ventilative cooling i
Christoffer Plesner, Flourentzos Flourentzou, Guoqiang Zhang, Hilde Breesch, Per Heiselberg, Michal Pomianowski, Peter Holzer, Maria Kolokotroni, Annamaria Belleri, Denmark
Overheating in buildings is an emerging challenge at the design stage and during operat
Peter Holzer, Theofanis Psomas, Denmark