RCx at Nationwide Telecom

National Communications Company Prioritizes Energy Efficiency and Saves Big With Retro-Commissioning Projects

Background

AT&T operates hundreds of phone switching facilities throughout the United States. These facilities enable telephone calls to work by making connections and relaying speech information. These energy intensive sites known as Central Offices range in size from small leased spaces to stand alone buildings with over 600,000 square feet of conditioned area. AT&T created a nationwide Energy Team with a corporate-wide campaign to identify and prioritize energy opportunities in Central Offices and other large facilities in the AT&T portfolio.

PG&E selected kW Engineering to provide energy consulting support to AT&T. Since then we continued to work closely with the AT&T West Region Energy Team to support their energy efficiency endeavors.

Energy Audits Results

kW Engineering completed 45 PG&E energy Audits at AT&T sites throughout northern California. Audit results include:

• Over 300 energy efficiency measures identified
• Combined savings potential of over 31 million kWh/yr
• Peak demand savings of more than 4.7 Megawatts
• Overall payback of 1.5 years after incentives
• Potential utility incentives of over $1.4 million
• Work completed in 8 months

We continue to assist AT&T with submission of incentive applications for projects completed.

Retro-commissioning Projects Results

Following completion of the audits, kW Engineering worked with AT&T to prioritize sites best suited to retro-commissioning (RCx) work. The team selected four large AT&T telephone switching facilities in San Francisco to participate under PG&E’s Core RCx program. These projects successfully achieved:

• Identification of 61 no/low cost energy saving measures
• Verified savings of 3.6 million kWh/yr
• 30% savings of base case energy use of the systems studied
• Utility incentives totaling $226,000

Retro-commissioning Project Process

At each site we followed the RCx process to help AT&T lower energy consumption and improve system reliability. The RCx process includes the following major phases:

• Planning

Defining RCx team, schedules, and team roles and responsibilities.

• Investigation

Conducting site visits, data monitoring and collection, measure development and presentation.

• Implementation

Working closely with AT&T’s Design and Construction and Property Management teams to select and implement improvements.

• Verification

Conducting post-implementation monitoring to verify project savings and train on site staff on how to maintain savings (persistence).

Measures Identified

Through energy auditing and retro-commissioning we identified many cost effective projects at AT&T facilities. Some examples of projects include:

• Installation/Optimization of variable frequency drive sequences and operation
• Lighting efficiency and control retrofits
• Chiller replacements
• Improved chiller sequencing controls
• Repaired/replaced malfunctioning economizers
• Optimized scheduling for fan and pump systems
• Trimmed pump impellers
• Installed CRAC central controls and airflow improvements in lab areas
• Installed Premium-Efficiency Motors