The Award-Winning AccuValve

Demand Based Static Pressure Reset Control for Laboratories

Laboratories are generally the largest users of energy in any facility. Whether in a pharmaceutical research facility or a university research facility, laboratories use much larger amounts of energy than other operations.

The industry has looked at ways to save on energy use by using VAV fume hood control systems as well as low flow fume hoods. These systems took a big bite out of energy use in labs.

In continuing efforts to reduce energy costs and make buildings "greener" and sustainable, Labs21 has recommended reducing the static pressure drop of the devices in the airstream for both supply and exhaust systems in labs.

Meets ASHRAE 90.1

The AccuValve® Meets
ASHRAE Standard 90.1-6.5.3.2.3

For systems with direct digital control of individual zone boxes reporting to the central control panel, static pressure setpoint shall be reset based on the zone requiring the most pressure; i.e., the setpoint is reset lower until one zone damper is nearly wide open.

This standard simply states that through network communications the BMS should:

  • Survey all of the valve positions for a given AHU
  • Determine which valve is most open
  • Adjust static pressure setpoint until the most open valve approaches wide open

These steps will insure that the fan is operating at the lowest possible static pressure while enabling the air flow control valves to maintain the laboratories in a safe manner for the people working in the labs. This simple control scheme provides the minimum brake horsepower for the fans, which uses the minimum electrical energy.

Demand Based Static Pressure Reset Control

Demand Based Static Pressure Reset Control enlarge »

AccuValve Response

The AccuValve design allows the Building Management System to monitor the position of each airflow control valve and determines which valves are most open (i.e.: the largest control output). If the control output of the valves that are most open is below 80%, the BMS reduces the duct static pressure setpoint then again looks at the position of each valve determining the valve(s) that are most open. This continues until the most open valve is approximately 80% open. This ensures that the system is operating at the minimum pressure while ensuring that there is enough pressure in the system to allow the controls to operate to maintain a safe lab environment.

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