Retro-Commissioning Laboratories for Energy Efficiency

LABS21 - USEPA Technical Bulletin

The design laboratory ventilation rate is a key component impacting energy used by the lab. First, obtain the ventilation rate for the lab as originally designed.Second, examine of the derivation and reasoning that resulted in the specified rate(s). This examination is warranted due to the ever-changing research mission of most laboratories. Third, confirm the current usage of the lab and reestablish ventilation design parameters.

These usage data are critical since current lab safety needs will almost certainly be different than the original design. Reducing outdated, excessive ventilation rates, and related criteria such as fume hood airflow rates, will be the most advantageous starting point to maximize laboratory energy efficiency. Note that caution is advised during the evaluation of the original ventilation and airflow rates. Determining appropriate rates is an iterative process that must include all stakeholders. Lab safety must never be compromised to achieve a fixed energy-efficiency goal. Additional ventilation information resources are available through Labs21 to help evaluate and optimize the lab’s ventilation rate and airflow requirements.

Generally, one of two types of HVAC systems will be used for conditioning lab spaces: 1) constant volume (CV) or 2) variable air volume (VAV). When installed, VAV systems have features and components that figure prominently in evaluating a lab’s energy use, including:

•Variable speed drive (VSD) on supply and exhaust fans.
•Modulating valves and “VAV boxes.”
•Presence of reheat coils.
•Sash position monitors.
•Occupancy sensors.
•Sensor locations.
•Control sequences.

To read the rest of this article, go here.