Adtran Corporate Headquarters
Retro Commissioning and Continuous Commissioning
Location: Huntsville, AL
Owner: Adtran Inc.
ADTRAN is a global supplier of products for communications and networking. ADTRAN’s headquarters is located in Huntsville, Alabama. The Huntsville complex consists of three towers. The facility is used for research and development, administrative purposes, manufacturing, distribution, and food service.
SCOPE OF WORK
Since 2012, when SEA was hired to perform an ASHRAE Level I Energy Audit of the Huntsville headquarters complex, SEA and ADTRAN have had a successful working relationship. SEA has been brought back to identify and implement multiple energy savings strategies and projects and has had a chance to make use of SEA’s partnership with Texas A&M’s Energy Systems Laboratory and their proprietary Retro-Commissioning/Continuous Commissioning®principles.
Over the last several years, ADTRAN has reduced their energy consumption by 3,934,000 kWh which equates to $295,000, a 13% reduction of ADTRAN’s 2.4 million dollar utility cost when SEA started work. Below is a breakdown of each phase, starting with the most recent one.
Phase IV (December 2018)
ADTRAN & Sain Engineering Associates (SEA) evaluated ADTRAN’s East Tower chilled water and condenser water systems for ways to improve the plant operation to provide consistent occupant comfort at a reduced energy cost. We achieved this goal without ADTRAN incurring any additional costs through capital expenditures.
At the end of the project, we implemented changes that are saving ADTRAN over $71,326 annually in energy costs. The simple payback is 1.86 years. The savings are based on measurement and verification of data gathered over several years by Trane Software and actual power meter data for over 10 months.
In addition to these savings, ADTRAN and SEA has implemented changes that have achieved the following:
- Increased business continuity from changes that make it unnecessary for ADTRAN to run more than two chillers, which also creates another layer of redundancy in the system in the event that a chiller goes down.
- A cost avoidance equal to approximately $1,000,000 from not having to buy a fourth chiller, since only two chillers are now required.
Below are highlights of activities that took place under RCx Phase IV:
- Trended over 300 points pertaining to the plant in one-minute time intervals, capturing over 131 million readings using the building automation system (BAS) which aided in analysis of the plant’s current operation and aided in monitoring as changes were made.
- Installed four power loggers/analyzers capturing over two million power consumption readings in a time span of ten months which is used for measurement and verification of SEA’s savings calculations.
- Developed equations to calculate plant energy usage for individual equipment and total plant energy consumption which allowed us to model the plant’s energy usage to aid in decision-making and savings calculations. The equipment that was monitored is listed below:
- Three chillers, three chilled water pumps, three condenser water pumps, three cooling tower fans, multiple auxiliary pumps, a winterization water heater and pump, several water-cooled self-contained air conditioner units (SCUs), outside air supply fans, and exhaust fans
- Performed functional testing, evaluated all existing plant programming, monitored the chilled water system, and reviewed several years of historical building data.
- Modified chilled water flow and condenser water flow to maximize the amount of cooling capacity delivered to air handling units with the highest cooling demand which allowed those units to meet their cooling demand, a feat the units previously could not achieve.
- Simulated the building and chiller plant in multiple iterations of models with various configurations to help visualize the effects that various changes would have on the system.
- Developed new energy saving sequences of operation by reprogramming 30 existing inefficient programs while measuring the actual plant energy consumption reductions.
- Modified control setpoints to automatically calculate based on real-time building inputs received from the building automation system allowing the system to have better response times to changing building conditions.
- Tested all new programming through various scenarios, temperatures, flows, modes of operation and building loads to ensure that the programs would work across all situations.
In support of ADTRAN and SEA’s activities, below is a chart showing the EUI at ADTRAN over the past 13 years, with 2018 being the lowest EUI that ADTRAN has had on record.
Phase III (February 2017)
SEA performed retro-commissioning of the SCUs in order to optimize them as well as more programming modifications to the variable air volume (VAV) boxes. The annual savings for this phase was $106,000 which equates to 1,420,000 kWh.
Phase II (September 2016)
SEA performed retro-commissioning of the variable air volume (VAV) boxes as well as programming modifications. The pressure transducers were also relocated. The annual savings for this phase was $33,000 which equates to 448,000 kWh.
Phase I (4thQuarter 2014)
SEA performed retro-commissioning of the ventilation and exhaust system on the ADTRAN campus, as well as the North and South tower heat rejection loops. The annual savings for this phase was $84,000 which equates to 1,115,000 kWh.