Auditing a 300,000 sq ft office tower in Atlanta on Georgia Power. The building has two 500-ton centrifugal chillers. Every morning at 6 AM both chillers start simultaneously, pulling about 900 kW for 15 minutes until they reach steady state. That 15-minute spike sets the billing demand for the entire month. The rest of the day peak demand is around 520 kW. The client is paying demand charges on 900 kW when their sustained demand is 520 kW. That gap is costing them roughly $8,200/month in excess demand charges.
Chiller startup causing $8K/month demand spike
Classic chiller startup problem. The fix is staggering the startup sequence — start chiller 1, let it reach steady state in about 10 minutes, then start chiller 2. The combined startup peak drops from 900 kW to maybe 600 kW. That alone cuts the excess demand charges by more than half. Most building automation systems can do this with a simple schedule change. No capital investment needed.
This is a great example of where interval data analysis reveals savings that bill analysis alone would miss. The monthly bill just shows 900 kW demand — it doesn't tell you it's a 15-minute morning spike. You need the interval data to see the pattern and recommend the fix. For the audit, this is both a billing finding (recommending staggered startup to reduce demand charges) and an operational recommendation. Some auditors avoid operational recommendations because they're outside traditional billing audit scope, but clients love them because the savings are immediate and permanent.
Building engineer staggered the startup sequence this week. First morning data shows peak demand dropped to 580 kW. If that holds, we're looking at $5,500/month in demand charge reduction. Client is ecstatic. My contingency fee on the annual savings will be about $20,000.
Love it when the fix is free and the savings are immediate. Nice work Derek.