In a notable project, a new chiller with a Variable Frequency Drive (VFD) and advanced controls was installed in a plant housing six chillers. The project also included installing VFDs on the primary pumps, with all chillers powered by electricity. The plan was to operate the VFD-driven chiller under part-load conditions. During peak design conditions, both the VFD-driven chiller and a standard efficient chiller were activated, with the VFDs on the pumps adjusting in response to the chiller’s performance.
During the Measurement and Verification (M&V) process, we monitored the chilled water plant for a month. Our analysis revealed that the actual energy savings were lower than initially projected. To investigate, our analysts developed an analytics algorithm and subjected the data to a series of tests. We discovered that the energy-efficient chiller with the VFD and controls had been taken offline halfway through the M&V period.
When our project manager questioned the engineers about the chiller’s operation, they initially denied that it had been shut down. However, after presenting the M&V data, the operating engineers recalled that the chiller had indeed been offline for “a few days” to allow an insulation contractor to complete a punch list item.
Despite this setback, the story ended on a positive note. We re-ran the M&V process, ensuring accurate data, and ultimately secured the customer’s cash incentive payment.