University of Nebraska- Lincoln
The Facilities Management team at the University of Nebraska-Lincoln (UNL) found a unique solution to improve operational efficiency through technology adoption, workflow adjustment and benchmarking.
Innovas Technologies Case Study
The Helios TCS™ has helped change operations on the maintenance floor for the UNL Utilities Services team by eliminating the need for manual chiller tube cleaning and freeing up skilled maintenance staff for higher return work.
Background
The Facilities Management team at the University of Nebraska-Lincoln (UNL) is continually exploring means to improve operational efficiency through technology adoption, workflow adjustment, and benchmarking.
Facilities management believes all these methods merge to form directional momentum towards comprehensive excellence. Central to their thinking is the careful consideration of the role new technology plays in advancing the work effectiveness of its team.
It was important to UNL Utility Services that any adoption of new technology at Central Utility Plants provide multiple levels of value including energy savings, sustainability impacts and improve workforce effectiveness.
The results reported by UVA were compelling to UNL and they began investigating of how Helios TCS™ could benefit their central plant operations.
UNL possessed strong data acquisition systems and they quickly completed the value analysis and proceeded to acquire a Helios Tube Cleaning System to serve as a platform for system evaluation. UNL’s first Helios installation was unique in that it was installed to serve two separate condensers operating in parallel as a single 2000-ton chiller.
Analytical Methodology
Controlling the evaluation environment was important. The following Evaluation Set-Up & Test Plan was implemented:
- Install Helios on Chiller Condenser Units 6A & 6B.
- Record Chiller Data for 2019 & 2020.
- Evaluate Chiller Performance Data Pre- and Post-Helios TCS Installation.
- Conduct Quantitative Analysis of Performance Data From Chillers 6 and 7.
Method 1:
Measuring Trend Approach Temperature
Method 2:
Simultaneously Consider Multiple Factors affecting chillers.
Use Case
UNL structured the M&V evaluation to include a high degree of qualitative and quantitative measures. While data-based measurement of the energy savings was the highest priority, closely considered also was how the new systems affected the workflow culture in the organization.
Specifically, UNL planned to measure:
- Effects on chiller energy efficiency – Quantitative.
- Workflow requirements associated with Helios Tube Cleaning System operation – Qualitative.
- Manual Chiller Tube cleaning requirements after Helios installation – Qualitative and Quantitative.
Specifically, Innovas Technologies personnel made bi-monthly visits to assist in ball change efforts and system inspection. This provided ample opportunity to train the operations and maintenance personnel to self-reliance in operating the Helios system.
The method of analysis involved two approaches. In the first method, Trend Condenser Approach Temperature would be measured. This is the simplest way to measure heat transfer efficiency of a heat exchanger.
The second method would simultaneously consider multiple factors affecting chiller efficiency including load, chilled water supply and entering condenser water temperature, and tube fouling. Data would then be plotted along performance curves at identical operating conditions to see how curves to shifted over time.
Results
Demonstrated in Figure 1, the approach temperature of Chiller 6B’s condenser improved dramatically after Helios Tube Cleaning System® installation, and the chiller operated with condenser approach temperatures at or below the design values for the both the 2019 and 2020 cooling seasons. Additionally, the chiller was never opened for manual tube cleaning after Helios installation.
The control chiller (7B) without a Helios system installed, continued to experience elevated condenser approached temperatures in the 2019 and 2020 cooling seasons. Additionally, the condenser required opening, and the tubes had to be manually brushed between each cooling season.
The installation of the Helios Tube Cleaning System® at the University of Nebraska – Lincoln resulted in both qualitative and quantitative validation of significant contribution to:
- Improved Chiller Energy Efficiency – (9% improvement valued at $45,000 per season)
- Enhanced Chiller Capacity W/No Added Energy Cost – (Up to 10% improvement)
- Elimination of Manual Tube Cleaning Requirements for Helios-equipped Chillers Reduction in Overall Maintenance-Related Chiller Workflow
From an energy savings perspective, the energy savings attributed to the Helios TCS ranges between 8 and 10% equating to $45,000 dollars in energy savings for Chiller 6. Furthermore Chiller 6 did not require manual tube brushing—resulting in another $5,000 in savings.
The energy savings and cleaning-related labor savings are compelling and stand on their own merits. Added to this, though, is the change in maintenance flows in the plant. University of Nebraska – Lincoln is now able to focus their highly-trained maintenance personnel on higher priority tasks rather than the manual cleaning of chillers throughout the cold weather season.
University of Nebraska – Lincoln is now able to focus their highly-trained maintenance personnel on higher priority tasks rather than the manual cleaning of chillers throughout the cold weather season.
Most importantly, the detailed evaluation of the Helios Tube Cleaning System impact on plant efficiency has led UNL to proceed with continued technology adoption. A Helios® system has already been procured for Chiller 7 and an additional implementation is being planned for other chillers in the district cooling system.
The end of tube fouling is now within UNL’s grasp.
Fig 1.
Figure 1. Comparison of Condenser Approach Temperatures in Chiller 6B and 7B Demonstrates Improvement in Condenser Heat Transfer Efficiency with Helios Tube Cleaning System® Installation. From April 2018, the condenser served by the Helios TCS™ ceases to experience increases in condenser approach temperatures. The untreated chiller (7) continues on the cycle of fouling-related inefficiency.
