Devex Systems  and Danfoss jointly conducted a test case using the Danfoss AB-QM pressure independent balancing and control valve at the University of Technology, Sydney (UTS). 

This valve enables HVAC systems to stay automatically optimised delivering significant energy savings. The AB-QM valve also simplifies system commissioning and helps to reduce the overall capital cost of HVAC systems.

The testing compared two rooms positioned adjacent to each other that were identical in size and heat load. Each room was also serviced with its own fan coil unit located above the ceiling space in the adjoining corridor.

The AB-QM valve was applied to one of the rooms while the Classic control (control valve plus manual balancing valve) already operating in the adjacent room remained untouched.

The HVAC system consisted of:

A primary secondary system with conventional chillers using air-cooled condensers

  • Primary chilled water system 
  • Series of 12 air handling & 190 fan coil units
  • Chilled water supply temperature was 6 degrees
  • 2 high load demand chillers and 2 low load demand chillers
Fan coil units in the two rooms consisted of:
  • Air supply capacity of 520l/s
  • Blend return air from room (340l/s) with fresh air from hallway (180l/s)
  • Estimated design cooling load is around 6.86kW
The data comparing the two rooms was gathered over a two week period and the findings were as follows:
The AB-QM achieved a narrower range of room temperature of 2°C while the Classic control oscillated within a 4.5°C range over a typical day. At observed capacity, the AB-QM potentially saves 45% pumping power.

The AB-QM also achieved a chilled water temperature differential of 50% higher than the Classic control. Estimated savings per annum combining chiller, control and pumping costs are in excess of $95,000 with an estimated payback of less than three years on a conservative capital investment to retrofit.

The Danfoss AB-QM pressure independent balancing and control valves are available from Devex Systems.