BAS Optimization Tips
One way to add credibility to the case for upgrades is to verify that existing systems are at their most productive. Review all active or available energy optimization programs and applications. Consider the following standard strategies, both individually and in conjunction with each other.
- Economizer controls save energy by allowing the use of outdoor air ventilation for cooling. When the enthalpy, or total heat content, of outside air is less than the enthalpy of the recirculating air, using cooler outside air is more energy efficient than mechanically cooling recirculating air. Economizer controls should not be used when outdoor climates are hot and humid.
- Alarming and monitoring of critical equipment allows for early detection and troubleshooting of abnormal conditions. Consider EMS/BAS systems with remote alarming capabilities to PDAs or pagers.
- A start/stop optimization control strategy determines when to start up and setback HVAC equipment operation based on outdoor air temperature and internal building temperature. It’s not unusual for start/stop schedules to fall out of adjustment as building occupancy changes, equipment ages and staff turns over.
- At a minimum, take advantage of basic control functions that schedule the operation of equipment based on time of day.
- Measurement and resetting of supply-air temperature during air handler partial-load conditions can save energy in constant air-volume systems. Measurement and resetting of supply-air static pressure during air handler partial load conditions saves energy and is recommended for variable air volume systems.
- Indoor air quality can be monitored using carbon dioxide, temperature and humidity sensors, and the data trended and stored in the EMS/BAS. Seek opportunities to use demand-controlled ventilation control functions for carbon dioxide monitoring, which adjusts outside air quantities based on actual occupancy via the EMS/BAS. Demand-controlled ventilation saves energy by reducing over-ventilation.
- Electronic metering can collect data on water, gas, steam and electricity use. Once collected, the data interfaces with the facility’s EMS/BAS. The information can subsequently help facility operators control and adjust systems to maximize energy efficiency.
- Use EMS/BAS control functions to automatically shed HVAC or plant equipment to reduce energy consumption while maintaining overall facility environmental conditions.
- Explore use of an EMS/BAS communication interface to an existing lighting control system. A BAS software scheduler can index facility lighting control system “addressable circuit breakers” to occupied and unoccupied modes.
- Occupancy sensors can be connected to the EMS/BAS to reduce mechanical ventilation in conjunction with lighting use.
- Monitor outdoor and indoor airflow via airflow sensors to maintain building envelope pressure. Maintaining proper building differential pressure reduces total building energy consumption.