The facilities team at the University of Wisconsin–Madison places a premium on improving the efficiency and productivity of their central cooling plants. 

After attending a technical presentation by the University of Virginia at the 2018 Big Ten and Friends Conference, Jeff Pollei, P.E., Director of Utilities & Energy Management and Travis Thoeny, Power Plant Manager saw an opportunity through Innovas Technologies’ Helios Tube Cleaning System® (Helios TCS) to eliminate heat exchanger tube fouling in the university’s Central Utility Plant chillers. 

At UW – Madison, when an innovative concept is discovered the team evaluates the innovation through the lens of all their facilities’ functional areas: engineering, operations, maintenance, and training to evaluate the potential to improve plant efficiency.  In this instance, the cross-functional team evaluated the fouling mitigation capability of the Helios TCS and its financial payback potential.  This evaluation process included review of chiller operations, cooling water quality, Helios TCS operating principles, and installation considerations.

Innovas Technologies worked with UW–Madison to analyze historical chiller operations data to evaluate and estimate chiller efficiency losses due to tube fouling.  This analysis found tube fouling-related efficiency loss in Central Utility plant chillers amounted to approximately 6-8% efficiency degradation. 

Satisfied with the potential payback of the Helios TCS, UW–Madison initiated a plan to test a chiller equipped with a Helios TCS side-by-side with an identical, non-Helios-equipped chiller for the 2018 cooling season.

MANAGING THE RISK OF INNOVATION

The UW–Madison team is fully invested in finding innovative ways to improve operations, but they also consider process stability and reliable delivery of cooling to the university critical.  Subsequently, UW–Madison’s priority is finding innovations offering expanded value while ensuring any change will not cause interruptions to their mission.  Any change, including integration of the Helios TCS, cannot cause unplanned cooling interruptions. 

Through collaborative meetings, Innovas and UW – Madison created a plan to install a Helios TCS for a cooling season, and measure and validate results compared to an identical chiller operating under the same conditions but without a Helios TCS.  Key to the plan was that Innovas would guarantee the risk, if the Helios TCS results weren’t as expected, Innovas would take it back.

Trial Details

The strategy for the trial was to run two identical chillers side-by-side under the same conditions and equal run-hours: one chiller (Chiller 2) retrofitted with Helios TCS systems and the other (Chiller 1) without.  The chillers share common chilled water and condenser water piping and were monitored throughout the trial period for the data listed below.  It was important for the trial to leverage multiple sources of comparative data in order to fully validate the Helios Tube Cleaning System® effectiveness.  To supplement the analysis and results from the side-by-side comparison, Chiller 2 operational data from 2017 (pre-Helios TCS) was compared to 2018 (post-Helios TCS) to demonstrate the change in efficiency after the Helios TCS installation.

Results

After careful analysis of the data it was clear that the Helios TCS had delivered a very significant efficiency improvement for Chiller 2 when compared head to head with Chiller 1.  Additionally, the measured efficiency improvement was further substantiated via comparison of Chiller 2 performance from 2017 (pre-Helios TCS) to 2018 (post-Helios TCS).  Interestingly, Chiller 2 also provided much greater capacity after Helios TCS installation—producing up to 400 additional tons of cooling due to its clean-tube performance.

The side-by-side analysis required juxtaposition of Chiller 1 and Chiller 2 operating data from the complete 2018 cooling season.  During the season, the operating hours on the chillers were balanced across the full operation range.  The result is a 14% efficiency improvement for the Helios chiller over the non-Helios chiller.  When the efficiency data for all four measured ECWT is averaged, the total improvement for Chiller 2 over Chiller 1 is 13%.  The data show an additional Helios TCS benefit for chiller productivity.   The Helios TCS kept the chiller tubes clean and optimized heat transfer efficiency.  The result is increased chiller capacity and cooling output.

Summary

The Helios Tube Cleaning System® provided exceptional efficiency gains for the University of Wisconsin-Madison as demonstrated by the 2017 – 2018 comparative chiller analyses results.  UW-Madison addressed the fouling-related chiller inefficiency problem and adopted an innovative but proven solution to substantially improve chiller plant productivity.