Phoenix Convention Center Phoenix, Arizona HVAC Re-tuning at GSA and Army Reserve Facilities: A Low-Cost Path to Energy Efficiency and Cost Savings Integrated.

Phoenix Convention Center • Phoenix, Arizona

HVAC Re-tuning at GSA and Army Reserve Facilities: A Low-Cost Path to Energy Efficiency and Cost Savings

Integrated Energy

Low/No Cost Solutions through Building Automation System Control Technologies

James Goddard and Danny TaasevigenPacific Northwest National Laboratory

August 13, 2015

Energy Exchange: Federal Sustainability for the Next Decade2

• A systematic process to identify and correct building operational problems that lead to energy waste

• Implemented primarily through the building control system at no cost other than the labor required to implement

• May include small, low-cost repairs, such as replacing faulty sensors

• Includes identifying other opportunities for improving energy efficiency that require capital investment

• Might be thought of as a scaled-down retro-commissioning focused on identifying and correcting operational problems

What is Re-tuning


• Improve the building’s energy efficiency through low-cost and no-cost operational improvements (mostly through building controls)

• Identify opportunities to increase the building’s energy efficiency• Adjust set points, schedules, economizer operations, etc.

• Identify system and equipment problems requiring physical repair

• Identify and pursue the big energy saving opportunities

Purpose of Re-tuning


• Major Focus Areas in Re-tuning– Occupancy scheduling– Discharge-air temperature control– Discharge-air static pressure control– Air-handling unit (AHU) heating & cooling– AHU outside/fresh air makeup– AHU economizer operation– Zone conditioning– Central plant Operations– Meter profiles

Re-tuning Process


• Army Reserve Command– Regional Energy Manager and local

site staff– 2-3 buildings per site – Building types include office, drill

hall, storage and maintenance– HVAC varies from packaged to built-

up systems– Building occupancy hours vary from

day-to-day, week to week with sporadic weekend use

– O&M staff limited– May or may not have a BAS

connected to HVAC equipment• Programmable Thermostats possible

– Whole building energy data sporadically available

– BAS trend data and remote access difficult

Examples of Different Re-tuning Applications

• General Services Administration– Regional Energy Manager and local

site staff– 1 building per site– Large commercial office buildings– HVAC almost always consists of built-

up systems– Building occupancy hours fit typical

commercial building office space (Monday through Friday 6:00 a.m. – 6:00 p.m.)

– O&M staff consists of several positions (electrical, mechanical, plumbing, etc.).

– Always have a central BAS connected to majority of HVAC systems

– Whole building energy data almost always available

– BAS trend data and remote access possible


Re-tuning Model for the Army Reserve

• Army Reserve Re-tuning Steps– Pre-site visit

• Call with the Region Energy Manger and the local site staff• Questions asked to the site staff and the energy manager

– Ask for historical building control data– Building Control Vendor– HVAC equipment in the building– Problem areas – Level of access to the building controls – Does the staff use the building control system– Schedule a site visit



• Army Reserve Re-tuning Steps-cont.– Site visit

• Walk down the building• Look at the HVAC equipment• Look at the building control system• Identify re-tuning measures• Implement measures• Train staff and energy manager on measures that are implemented• Identify additional energy measures that can be turned into capital

projects for the



• Army Reserve Re-tuning Steps-cont.– Post site visit

• Trip report• Estimation of savings• List of recommendations• Project development


Re-tuning Case Study for the Army Reserve

Building Overview– Built within the last 5-7 years, 2-stories, 200,000 square feet– Used for the reserve command and as a training center on weekends– 24/7 operation of the HVAC equipment– Built-up air-handling units (AHUs) with variable-air-volume (VAV) boxes – Air-cooled chillers and hot water boilers with variable speed secondary loops– Full BAS integration of AHUs, chillers, boilers and VAV boxes

Building Controls Review– Occupancy schedules did not work in the controls– Economizer dampers were not functioning correctly– Chillers were active during cool outdoor temperatures – AHU discharge-air temperature set points constant at 55°F– Constant AHU discharge static pressure sets points– Constant chilled water supply temperature set point

Re-tuning Opportunities– Scheduling, static pressure reset, discharge-air temperature reset– Other?


Re-tuning Case Study Results for the Army Reserve

Average daily electrical consumption before and after re-tuning show significant savings from re-tuning implementation

Before re-tuningAfter re-tuning


Re-tuning Future for the Army Reserve

• The Army Reserve Command understands the value in re-tuning

• Infrastructure limitations create difficulty with re-tuning process and sustaining re-tuning savings

• Adoption of Enterprise BAS System can enable continuous monitoring, analysis and reporting of Army Reserve buildings, as well as provide access for continuous re-tuning of control sequences.– Benchmarking– Trend analysis– Diagnostic Tools – Performance Dashboards– Monitoring of renewables


Re-tuning Future for the Army Reserve


Re-tuning Model for the GSA

• GSA Re-tuning Steps– Pre-site visit

• Screening evaluation to determine likelihood of re-tuning success• Is the building likely to succeed (yes/no)?

Criteria Status Weight ScoreBuilding Size (sf) 481,621 25% 25.0%Part of a campus of buildings? No 0.0%Climate Region 3B-CAEUI (kBtu/sf) 55 18% 7.4%Server Room Area 3 N/A 0.0%BAS Type Siemens 7% 7.0%BAS Age of last update <5 years old 7% 7.0%IS PNNL authorized to make changes directly on BAS? Yes 0.0%AHU primary type Single-Duct 5% 5.0%DOAS/ERV wheels? No 3% 0.0%Digital Controls (% of building) 100% 12% 12.0%Variable Speed Drives (% of pumps and fans) 100% 10% 10.0%Condensing Boilers? No 4% 0.0%Heating Plant Integrated with BAS? No 3% 0.0%Cooling Plant Integrated with BAS? No 3% 0.0%Lighting Integrated with BAS No 3% 0.0%

100% 73.4%Score



GSA Re-tuning Steps• Pre-site visit cont.

– Call with the Region Energy Manger and the local site staff• Review building history• Review current energy use (based on utility bills)• Discuss current and on-going energy projects• Discuss problem areas in the building• Plan trip logistics• Provide BAS trending requirements list• Remote BAS access (if possible)



GSA Re-tuning Steps• Pre-site visit cont.



GSA Re-tuning Steps• Site Visit

– 2-3 days onsite– Review trend data/proposed measures—In-Briefing– Walk down the building– Review the BAS– Finalize proposed measures and discuss with site staff– Implement agreed upon control system measures with site staff (training)

• Monitor building response to implementation• Start conservative with recommendations

– Document all changes, before and after– Formal Exit Briefing



GSA Re-tuning Steps• Post Site Visit

– Deliver Interim Report to building and regional staff within 8 weeks of site visit which includes:• Details on recommended measures and implemented measures• Energy savings estimates for implemented measures and total for all recommended

measures• Monitoring plan for site staff’s troubleshooting and long-term monitoring of

implemented measures

– Post-site visit implementation call• Discuss implemented measures, any issues or complaints, changes etc.• Discuss plan for further implementation of measures that were not implemented

onsite

– Monitor BAS trends, interval meter data, and utility data for 6 months to validate re-tuning implementation and monitor other performance-related issues

– Offer email/phone support to site staff as-needed



GSA Re-tuning Steps• Post Site Visit-cont.

– Deliver Final Report to building and regional staff after 6 month monitoring period which includes:• Actual energy and cost savings from Targeted E4 efforts• Pre and post Targeted E4 energy use intensity (EUI), and project EUI after 12

months


Re-tuning Case Study for the GSA

Building Overview– Built within the last 20 years, 16-stories, 600,000 square feet– Typical office building with courthouse space– Scheduled operation of the HVAC equipment (Monday through Friday 6:00 a.m. to 6:00

p.m.)– Built-up air-handling units (AHUs) with variable-air-volume (VAV) boxes – Water-cooled chillers and combination of condensing and non-condensing hot water

boilers with variable speed secondary loop control– Full BAS integration of AHUs, chillers, boilers and VAV boxes

Building Controls Review– Static pressure reset strategy had been overridden by operator (modified maximum and

minimum limits to be equal)– Night setback strategy routinely started AHUs as early as 12:00 a.m. during the heating

season– Optimal start strategy was configured for up to 4 hours of runtime prior to building

occupancy

Re-tuning Opportunities– Re-implement static pressure reset, modify night setback and optimal start strategies


Re-tuning Case Study Results for the GSA

• 6 months after site visit, 12.6% whole building energy savings measured (8.6% electricity and 15.7% natural gas)

• 1.1 year simple payback for Targeted E4 at this building


Re-tuning Future for the GSA

• The GSA has been an advocate for re-tuning for over 7 years, helping to improve the model

• Although Targeted Re-tuning for the GSA improves building efficiency and saves energy at a 1-2 year payback, long-term improvement of their energy portfolio will require more saturation – Current program covers 15-20 buildings per year

• Data-driven monitoring and diagnostics, although not required, helps to achieve optimal re-tuning results– Future direction may include data driven detection and automated re-

tuning for basic principles– Site visits, training, and hands-on implementation currently offers the

best results for re-tuning


http://retuningtraining.labworks.org/training/lms/

Re-tuning Training Materials

Phoenix Convention Center • Phoenix, Arizona

THANK YOU!! -- QUESTIONS?

James [email protected]

Danny [email protected]

Phoenix Convention Center Phoenix, Arizona HVAC Re-tuning at GSA and Army Reserve Facilities: A Low-Cost Path to Energy Efficiency and Cost Savings Integrated.

Documents

building energy data

energy exchange

big energy

energy waste

buildings energy efficiency

region energy manger

building control system

site building types