Energy Efficient Buildings | Recommissioning

Recommissioning (RCx) Guide for Building Owners and Managers

Appendix G - US-EPA Guide Related Case Studies⁴²

Case Study: Target Retrocommissioning Program RCx Guide, U.S. EPA Version, (Chapter 1)

Thanks to recommissioning at several SuperTarget^® stores, Target^® identified adjustments to its refrigeration systems which resulted in a $5,000 - $10,000 annual energy savings per store. Due to the potential risks associated with food quality if refrigeration systems do not perform, Target funded this effort not only as an energy savings measure, but also as a risk minimization strategy.

Source: Williams, Scott D., PE, "Owner's Strategies for In-house Commissioning", Proceeding of the National Conference on Building Commissioning. (New-York, NY, May 4-5, 2005.)

Case Study: Marriott Marquis RCx Guide, U.S. EPA Version (Chapter 2)

Marriott's flagship property, the Marriott Marquis, a 50-story structure located in Times Square in New York City includes 9 floors of retail and meeting rooms, 35 floors of occupant rooms, 5 restaurants, and a 1,500 person theatre. In order to achieve the goal of reducing operational energy consumption, Marriott used a retrocommissioning process to determine if improved operation could result in energy savings. In contrast to the efficiency measures the hotel had implemented in the past to maximize lighting and guest room controls, significant opportunities were found in areas separate from the guest facilities, allowing the hotel to improve its bottom line without altering its functionality to its guests. Among other improvements, by optimizing the facility's chilled water plant and installing variable speed drives on the air handling system, the facility was estimated to save $775,000 per year. Through this project, Marriott was able to improve on the building's mechanical systems, maximize efficiency, and shield against ever-rising energy costs all with simple payback of less than 2 years.

Source: NYSERDA case study drafted by Portland Energy Conservation, Inc.

Case Study: Symphony Towers RCx Guide, US. EPA Version (Chapter 2)

The Chief Portfolio Engineer of the Irvine Company, Inc., a 140-year old commercial real estate firm, decided to launch a retrocommissioning project, recognizing the importance of optimizing building performance as well as the value of the whole building engineering analysis offered by retrocommissioning. Of the more than 400 commercial office spaces in its portfolio, the company identified a building in downtown San Diego that qualified for a local utility incentive as its 1st candidate. Built in 1980, Symphony Towers is 714,000 square feet and has 34 stories. The retrocommissioning project identified potential annual cost savings of $65,000. The high savings opportunities identified, coupled with relatively low implementation costs and program incentives, resulted in a payback of only 4 months for the project. Even without the utility incentives the payback would be a reasonable 14 months.

Investigation and Implementation

Through an in-depth operational analysis and close collaboration with building staff, the retrocommissioning provider identified several significant savings opportunities, including:

• Correcting uneven flow through the cooling tower
• Improving chiller sequencing
• Adjusting chilled water temperatures and setpoints
• Reducing cooling system night operation during the summer
• Optimizing the control of air-handling units (AHUs) 

In all, 7 energy-saving measures were selected and implemented in less than 4 months.

Project Costs and Savings

• Estimated annual kWh savings: 497,000 kWh
• Estimated annual cost savings: $65,000
• Total project cost: $76,600, including investigation and implementation
• Total program incentive: $52,800
• Net Owner cost: $23,800
• Simple payback: 4 months
• Simple payback without incentive: 14 months

Non Energy Benefits

• Improved cooling tower operation and reduced maintenance costs
• Increased chiller efficiency and reduce chance of premature failure
• Quality documentation and training for building engineers
• Performance tracking of implemented measures and feedback to building engineers
• Improved tenant comfort

Source: The Irvine Company and the San Diego Gas & Electric (SDG&E^®)

Case Studies: Office Buildings RCx Guide, U.S. EPA Version, Chapter 2, page 15.

Crown Plaza is a 311,000 square foot office building built in 1979 and located in Portland, Oregon. In 2005, the building's owner applied to participate in the local recommissioning incentive program, which included a full recommissioning investigation of the property, as well as incentives to support implementation of measures. The recommissioning investigation identified many hidden problems and opportunities for improvement. The implemented measures included optimizing the supply fan duct static pressure set points, reducing reheat and increasing the number of hours the building is in economizer mode, trimming impellers on oversized chilled water pumps, and shutting terminal units in unoccupied floors during weekend occupancy. In addition, lighting in the parking garage, which was previously lit 24 hours a day, 7 days a week, is now scheduled. The building owner implemented a total of 19 identified measures, reducing annual energy expenses by an estimated $53,967.

Project Costs & Savings:

• Total project cost (including incentives): $47,100
• Estimated Annual Cost Savings: $53,967
• Estimate Annual kWh Savings: 775,339 kWh
• Simple payback: 0.87 years
• Non-Energy Benefits: Increased equipment life, including chillers and pumps; reduced replacement costs for lighting in the parking garage; improved control of equipment such as air handlers, air terminal units, and chillers

Source: Byron Courts, Director of Engineering Services, Melvin Mark Company, August 2007

The Ronald V. Dellums Federal Building is a 1.2 million sq. ft. office building built in 1994. In 2001, the building's owner (U.S. General Services Administration) hired a commissioning provider to install new software for the building's control system as a way to improve energy performance. In the initial assessment, the provider discovered that air handlers were operating inefficiently and poor programming required building operators to run the central chiller plant manually. The provider recommended that the owner retrocommission the building to effectively reduce the building's energy use. Retrocommissioning identified several low-cost and relatively simple operations improvement opportunities with dramatic savings potential. The implemented measures, which included relocating sensors, optimizing the static pressure setpoint, and repairing the economizer dampers, saved the owner $66,981 in annual utility expenses – providing a payback period of less than 1 year. 

• Project Cost: $35,000
• Size: 1.2 million sq. ft.
• Energy Benefits: $66,981 in annual utility expense savings
• Non-energy Benefits: Reduced staff time to manually operate systems, more efficient operations, increased controls stability, extended equipment life, better facility staff understanding of systems operation and diagnostics set-up

Source: California Commissioning Collaborative  

Case Study: Retrocommissioning at Marriott RCx Guide, U.S. EPA Version, Chapter Page 18

The competitiveness of the luxury hotel industry requires hotel business owners to continuously work to increase revenue – which means aggressively pursuing lower operating costs. A retrocommissioning project at the hotel determined that reactivating the parking garage's demand controlled ventilation system could save hotel $60,000 in electricity costs per year. The full retrocommissioning project identified improvements with energy reduction potential of 8.4% in Phase 1 of the project, and another 10.6% in potential savings for future implementation. Some additional benefits of the project included improvements to chilled water capacity, reduced chiller runtime (which will increase chiller life), documented operation and maintenance procedures, and training for the hotel's O&M staff. 

"At Marriott, we've found that retrocommissioning saves us time and money. At one property, we expect to save nearly $500,000 annually in energy costs from implementing retrocommissioning measures - and the project will pay for itself in less than 1 year. We're using the [local utility] RCx program to continue our efforts in this area." -E.J. Hilts, Regional Energy Manager for Marriott (Western Region).

Source: Portland Energy Conservation, Inc.

Case study: The Hatfield Court House RCx Guide, U.S. EPA Version, Chapter 2, Page 21

In 2003, the U.S. General Services Administration (GSA) initiated a full retrocommissioning (RCx) study of a federal Courthouse located in Portland, Oregon. The Hatfield Courthouse, built in 1997, has a total of 21 floors and a gross square footage of 591,689 sq. ft. The GSA's RCx goals included:

• Improve occupant comfort
• Identify O&M and energy efficiency improvements
• Train the building operators on how to help improvements persist
• Review and enhance building documentation 

Investigation involved reviewing the building's documentation and utility bills, inspecting building equipment, interviewing building operators, testing selected equipment and systems, and extensive trending of the heating, ventilating and air conditioning (HVAC) control system. The investigation process identified 29 findings which addressed GSA's RCx goals. The implementation process involved coordinating efforts among the commissioning provider, facility staff, and building services contractors. Twenty-three of the 29 recommendations to address these findings were implemented. This process resulted in a 10% reduction in energy use and significant improvements in building comfort and system operations.

Retrocommissioning increased the building's EPA energy performance rating from 65 to 75, allowing the building to receive an ENERGY STAR^® label. To ensure lasting benefits from retrocommissioning and achieve savings persistence, GSA is employing an "ongoing commissioning" approach.

The Numbers:

• Annual Utility Cost Savings: $56,000 (a 10% reduction of the facility's current utility expenditures) implemented, with $30,099 in energy saving improvements planned for future implementation.
• RCx Cost (investigation and implementation, including implementation project oversight costs): $172,459 - incentives and tax credits = $149,450
• Total RCx Cost: $0.25 per sq. ft.
• RCx simple payback: 2.7 years 

Source: GSA and Portland Energy Conservation, Inc.

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⁴² All monetary units are in USD.