Upcoming seminar

Hand-over documentation and automated load test for DCV!
February 18, 2015

Hand-over documentation and automated load test for DCV!

VAV control form

Problems during operation occur most often for maximum or minimum airflow rates. Tests should therefore be carried out for these two operating situations. For each of these situations, it is necessary to consider each DCV unit and to override the control signal from the room sensor (e.g. temperature) in order to force the DCV unit to respectively max and min airflow rate, and to document both the airflow rate and the opening rate. The opening rate tells whether the DCV units work within a favorable range (40 to 80%) and whether the pressure set point is balanced.

This requires four control measurements per DCV unit. Such a control procedure is particularly relevant for DCV systems with pressure-control and limited control possibilities from the BMS. A special VAV control form is designed for this purpose (http://www.sintef.no/Projectweb/reDuCeVentilation).

Procedures for load tests at maximum and minimum loads/airflow rates have been developed (Mysen and Schild, 2013).

Automated load test

Manual load test are time consuming, and it has proven to be very difficult to override DCV units during a load test. One should therefore strive to automate the load test completely by programming it in the control panel, or in the BMS. This has several advantages: it can be a complete test (not spot-checking) with all combinations of overriding, it reduces costs significantly, and can be repeated as often as needed (one time per year during normal operation, or after changes in the system).

Source from article on “Commissioning for energy-optimal Demand-Controlled Ventilation” by Mads Mysen, Peter G Schild, Axel Cablé and John Woollett