CASE STUDY

Despite all the innovations in the field of HVAC efficiencies, it is still challenging to optimise HVAC systems so that they are consistently able to operate at their optimum efficiency. The Danfoss AB-QM pressure independent balancing and control valve (PIBCV) enables HVAC systems to stay automatically optimised delivering significant energy savings. The AB-QM valve also makes system commis- sioning quick and easy for the installer and helps reduce the overall capital cost of HVAC systems.

• 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

A central air handling unit provided pre-cooled fresh air and the space above the suspended ceiling was used for air distribution from the central air handling unit to the fan coil units.

Fan coil units in rooms C1.11 and C1.13:

• 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 10kW

• The test results were logged using a Hydronic Analyser (Danfoss CCR2/CCR3)The data was recorded in 5 minute intervals and stored on an SD card which was later analysed with a tool developed specifically for the Hydronic Analyser.The AB-QM DN32 valve was used in Room C1.11:
  • Capacity (Qmax) = 0.89L/S
  • Setting was 40% =0.36L/S

  The data comparing the two rooms was gathered over a period of 2 weeks in March 2012 . From the data collected, the following observations were made:

  • 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 achieved a chilled water temperature differential (∆) of 50% higher than the Classic control.

Estimated savings per annum combining chiller, control and pumping costs is in excess of $95,000 with an estimated payback of less than 3 years on a conservative capital investment to retrofit.

READ FULL TEST CASE: Local Case Study using the Danfoss AB-QM PIBCV