HEATING & COOLING CONTROL SYSTEM
Application
Heating and cooling facility control system
Customer
Midwestern municipal district heating and cooling facility with existing process using integrated energy solutions, renewable cogeneration, hot-water district heating, and district energy operation and management
Challenge
The existing DeltaV™ control system was a retired software version, with controllers that had also transitioned to retired support status. When a product is in retired status, product support is limited and on a paid-for annual agreement basis, potentially slower and more costly, and subject to material and labor availability. The transition to retired status marks the completion of the standard product support.
The site has been struggling with improving the operator experience with the control system interface. Legacy graphics were not intuitive for operators to navigate, did not display actionable information, and were cumbersome to use when upsets at the plant needed to be addressed.
During initial plant construction, remote I/O scanners were installed on the upper levels of the plant to cost effectively bring in analog and discrete values without the cost of cabling these signals to the DeltaV control cabinets installed in the main level. As the plant expanded, chillers were installed at the upper levels that required communication interfaces unavailable at the remote I/O scanners, effectively stranding valuable data that could be used to improve the performance of the heating and cooling plant.
Through the DeltaV Version 14 upgrade, we sought to address their current system’s obsolescence, increase the plant’s reliability, and improve the operator performance, through enabling DeltaV graphics on future projects. We needed to do so without interruption to the customer’s district energy needs.
Solution
The initial solution was to perform a version upgrade and replace the retired controllers with the current generation controller. The facility set an initial budget with a “like-for-like” upgrade strategy. Through discussions with the customer and reviewing the current installation, additional latent pains were uncovered that the version upgrade could address.
The control room operator experience was a huge driver for the upgrade. A modern, built-for purpose and easy-to-configure operator interface was included in the upgrade to improve operator performance and capabilities.
The improved performance of the current DeltaV controllers enabled existing control cabinets to be consolidated under a single redundant controller pair. This reduced the total number of controllers that needed to be purchased to address the hardware obsolescence. To further advocate for the controller consolidation, the facility control engineer felt that the demonstrated reliability of DeltaV offset any concerns that consolidating process controls into fewer controllers would open the plant up to a greater single point of failure.
The reduced investment in replacement controllers opened up the budget to enhance the facility in new ways. The upper floor remote I/O scanners were replaced and a redundant controller pair put in their place, opening up a host of communication interface options to the chiller’s equipment. With the updated software version and controller platform at the upper floor of the plant, CHARMs are now a possibility to be deployed for any future expansion that may require an installation cost savings approach similar to what had remote I/O scanners initially installed.
The now-surplus remote I/O scanners are being redeployed to the basement to bring in lube oil skid information that currently is stranded and operated by local, single-loop controllers.
DeltaV Live, the next generation in operator interface solutions, is now available to the customer to begin addressing the legacy graphics and performance plaguing their operating staff. All of this upgrade effort was executed with a project methodology that reduced the risk of the upgrade and “brain transplant” disrupting the customer’s operations. Project management and defined processes were used to ensure that the execution of the upgrade went flawlessly.
The facility control engineer felt that the demonstrated reliability of DeltaV offset any concerns that consolidating process controls into fewer controllers would open the plant up to a greater single point of failure.
Benefits & Measurable Results
Operator performance improvements are now a reality for District Energy instead of being a future wish. DeltaV Live will bring a new level of interface to the operations team that will present benefits for years to come. By being able to optimize graphics using human-centered design concepts, operations, maintenance, and engineering can more quickly troubleshoot issues and solve problems when they arise. Behind the scenes, the reliability improvements by being on current software and hardware platforms will keep the reduced operating expenses standard the facility has benefited from since the initial DeltaV installation a reoccurring savings.
Future expansions, capturing of stranded data, and expanded control capabilities are all available at significantly lower costs with the expansion of controllers, availability of technologies like CHARMs, and the communication interfaces available in parts of the plant that were previously cost-prohibitive. With CHARMs, they can reduce the time and cost related to creating loop drawings, installation costs, cable, and cable tray, which allows them up to a 50% reduction in project costs. Furthermore, CHARMs capabilities allows them flexibility to cost-effectively control areas of the plant that had been manual processes.
