University of Texas Austin Chilled Water Plant Optimization
Enduring partnership delivers innovation, efficiency and energy savings
Reducing Energy Usage While Growing the Campus
To meet campus growth needs, the University of Texas at Austin found it far more economical to be more efficient than to invest in new power production capacity. Working in partnership with Optimum Energy, UT achieved what seemed impossible: reducing the chilled water system’s overall energy usage even as the campus grew.
Improving plant efficiency began in 2007, when Juan Ontiveros, UT’s associate vice president for Utilities and Energy Management, began working with Optimum Energy to optimize the school’s only all-variable-speed, 15,000-ton, 3-chiller plant (Chilling Station 6; CS6), using OptimumLOOP® and the OptiCx® platform.
OptimumLOOP® uses patented power-based relational controls to dynamically adjust flows and condenser water temperatures in the cooling towers. By lowering the lift on the chiller and reducing the chiller speed, the solution brought the cooling cost as low as 0.3 kW/ton in the winter—delivering what Ontiveros called “a free cooling effect—with chillers.”
Annual Average kW/ton: 2006–2024
Campus efficiency improved steadily from 0.79 kW/ton in 2006 to 0.59 kW/ton by 2024—all while adding 3.5 million square feet of buildings.
Gaining Efficiency from an Already Efficient System
With CS6 already optimized, the team tackled three interconnected challenges to push efficiency even further.
Hydraulic Constraints
Physical hydraulic constraints were affecting flow in the campus chilled-water distribution loop. A real-time hydraulic flow model revealed the system was over-pressurized, creating false building loads.
Over-Pressurized System
Pumping too much water created false building loads, forcing excess steam production. Reducing to 8 psi at peak and 2 psi in winter cut 1,500 hp of pumping energy.
Static Chilled Water Temperature
Chilled water had been set at 39°F year-round. OptiCx® visibility enabled dynamic adjustment up to 44°F based on real-time conditions, significantly cutting chiller load.
Predictive Thermal Energy Dispatch
Thanks to their long partnership, Optimum and UT engineers could think differently about how to boost efficiency of a system already operating at peak performance. The question: could Optimum develop a solution using power generation data and weather forecasts to predict and dynamically handle cooling while optimizing thermal energy storage?
Optimum first captured historical plant and weather data going back 3 years. Using OptiCx®, the team built an automated control strategy that uses weather forecast information to determine power requirements for the entire campus 48 hours in the future.
The result was dramatic: differential loads dropped from 20 MW to just 4–5 MW. OptiCx® now raises the cooling load at night—running the most efficient chillers to charge the tanks—and during the day discharges the stored chilled water while keeping backup machines on standby.
Total annual power plant operating efficiency reached 88.59%. Since 2008, chilled water production’s overall energy use has remained flat despite adding 3.5 million square feet of buildings.
Savings That Defy Expectations
Compared to the baseline year of 2008, the results speak for themselves.
Annual Electrical Energy Savings
Compared to 2008 baseline levels, saved year over year
Annual CO₂ Emissions Reduction
Equivalent to taking tens of thousands of cars off the road every year
Peak Load Reduction
Electrical demand reduction vs. 2008 baseline
Post-Optimization Efficiency
Down from 0.79 kW/ton — a 25% plant efficiency improvement
Square Feet Added
Campus grew significantly (2009–2019) while energy use stayed flat
Power Plant Operating Efficiency
Total annual power plant efficiency achieved
Beyond Energy: Operational Gains
The secret to our success is having the right balance of plant equipment, marrying that with the optimization and dispatching opportunities Optimum provides, and doing it in a way they don’t compromise or fight each other. When they do good, we do good.
The Same Energy. A Much Bigger Campus.
“We’re now using the same amount of energy we did before we added CS7,” says Ontiveros. “And we reduced our fuel use. You’re not supposed to be able to do that.”
The UT Austin partnership demonstrates what’s possible when a university commits to a long-term, data-driven optimization strategy. By continuously pushing the boundaries of what’s achievable—from basic chiller optimization to predictive thermal dispatch—Optimum Energy and UT Austin have set a new benchmark for higher education energy efficiency.
“I think we both have learned a lot,” says Ontiveros. “Together, we take a very methodical approach. And Optimum also forced us to become almost religious about accurate data.”
