Partnering with New York State Energy Research and Development Authority (NYSERDA), Citigroup began the process of improving component and system-level efficiency in their space-tapped, 40,000 ft2, 1986 legacy data centre. They received funding from NYSERDA’s FlexTech program to improve energy efficiency using the VF, an engineering simulation tool offered in the 6SigmaDCX software suite from Future Facilities.
After a comprehensive site audit and VF analysis, Citigroup used The Green Grid’s Performance Indicator (PI) to quantify and evaluate their data center’s performance. The facility’s IT thermal compliance, space utilisation, and year-averaged PUE were used to calculate a baseline PI for the facility.
Citigroup’s objective for this project was to achieve cost savings by reducing the energy consumption of their HVAC system. However, as a mission critical facility, they had to first ensure 100% IT Thermal Conformance and 100% IT Thermal Resilience for their assets.
The VF allowed Citigroup to pursue remediation with full visibility into the immediate impact on IT thermal compliance. Moving forward, this visibility will allow them to safely continue with their IT growth plan.
“Engineering simulation was especially attractive to us because often what you’re expecting to see as a result [in a data centre], you don’t always get. Simulation was a really good interim step for us to understand the impact of any changes we wanted to make,” comments Christian Pastrana, VP Data Center Planning at Citigroup.
Optimisations in detail
Citigroup used the engineering simulation results to find and fix a range of issues in the facility, which were primarily within the cabinets. For example, in several of the facility’s network cabinets, simulation results showed IT exhaust flow directly feeding into the inflows of neighboring IT, raising equipment inlet temperatures and contributing to the facility’s thermal compliance issues.
Citigroup designed and simulated custom blanking solutions to prevent recirculation in their network cabinets. The VF pinpointed the worst performing cases, where remediation efforts would have the biggest impact. This prevented over-engineering and blanket solutions, which kept remediation costs down.
The designed solutions reduced inlet temperatures by 27%. Without the visibility provided by simulation, it would have been impossible to arrive at such an optimal and low-cost solution within such a short timeframe. Remediations like these allowed all cabinets in the facility to fall within the ASHRAE allowable and recommended temperature ranges.
Post-remediation, the data center secured 100% Thermal Conformance and Resilience, thus meeting Citigroup’s objectives. The PUEr score was improved to be within 1% of The Green Grid’s suggested range of compliance, and additional HVAC system savings were unlocked for facility cooling loads beyond the data center. Substantial energy savings were made achievable without risk to the facility’s Thermal Conformance or Resilience.
Citigroup’s economic analysis estimated that the facility’s remediation efforts resulted in a over $290,000 in potential annual energy savings. With an estimated total cost of $28,500 for the remediation plan, the project is expected to see an ROI in 6 months (not including FlexTech funding) after implementation.
In the future, Citigroup plans to implement 6SigmaDCX and utilize VF models across their data centre portfolio. The software’s integrations with a wide range of asset management and DCIM tools will expedite this process, allowing Citigroup to utilise its existing data for faster VF model building and calibration. It can then rely on engineering simulation to optimise cooling performance and realise further cost and energy savings throughout its global facilities.