Principal Financial Group – Central Chilled Water Plant Upgrades

At the heart of Principal Financial Group’s 2,000,000 sqft downtown campus is a 5,000 ton central chilled water plant serving six buildings. The 5000 ton chiller plant consists of five, 1,000 ton chillers, four cooling towers, a 1000 ton plate and frame heat exchanger for waterside economizing and a network of primary, secondary, and tertiary distribution pumps. In 2016 Baker Group embarked on a massive active control and piping upgrade to the plant.

Through this renovation, Principal’s goals were to: reduce their energy footprint through system optimization and increase service ability with enhanced monitoring and data trending with zero impact to the building occupants.

How do you optimize a 5000 ton chiller plant?

• Chiller Staging – Continuous monitoring of system demand, pump energy consumption, and chiller performance allows the automation system to determine the optimum sequence to start and stop chillers to maximize performance and efficiency. Cycling large chillers “on” and “off” numerous times throughout a day can reduce the life expectancy of the machines. Not only does proper chiller staging insure optimal efficiency but it also prevents pre-mature failures due to over cycling.

• Chilled Water Temperature Reset – is vital in optimizing any plant. Proper resetting of the chilled water temperature extends your hours of operation for free cooling and increases chiller efficiency. A good rule of thumb is for every degree you can raise your chilled water temp you gain 2% in system efficiency. However, resetting the chilled water temperature without regard for air handling system operation can potentially have a negative impact on air handling system performance negating any energy gains. Through close monitoring of the air handling system cooling demand we can optimize the resetting of the chilled water supply temperature to maximize system performance.

Baker Group helped reduce the client’s energy footprint through deploying intelligent system control strategies, and overcame the challenges of upgrading a live system through careful planning and preparation.