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8:07 pm, March 1, 2024
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Warming Up to CO2 Cooling: E3 Controller Eases Transition to Transcritical Systems

When the central kitchen for California’s Coalinga State Hospital at Pleasant Valley State Prison (PVSP) installed a new cooling system, the Environmental Protection Agency’s (EPA) phase-out of hydrofluorocarbons (HFCs) in refrigerants prompted them to adopt a more sustainable system. The kitchen opted for a CO2 system designed by Freez-On Refrigeration Design. Manufactured by CryoBuilt, the system was both installed and started up by RSI, a CoolSys Company.

E3 supervisory control

The RSI/CoolSys team already had a long-term working relationship with Emerson, and as such, were very comfortable with the legacy E2 controller. They were impressed with the new E3 controller designed specifically for CO2 applications, especially after Emerson demonstrated a successful start-up test of a similar system at the Helix Innovation Center in Dayton, Ohio. The team also knew they could count on robust field support for the new system.
“We’ve worked with E2 controllers a lot in the past and we really enjoy the logic — for example, the effortless ability of programming virtual pointers between applications,” said Alex Kapelkin, energy management system specialist for CoolSys. “In addition, CryoBuilt manufactured many racks over the years, and we utilized the E2’s unique custom logic capabilities to improve operations and safety parameters. I’m glad the E3 controller retains most of the logic that we relied on in the past. As soon as we familiarized ourselves with the new and improved screen views, we were impressed how easy it was to understand the program and all the new helpful features.”
“It’s really easy to understand the Emerson architecture,” added Nick Ganaga, CTO of CryoBuilt. “We didn’t have to guess what was needed to be wired up where. Even though this is a transcritical CO2 system, all of our past experience working with Emerson wiring and installation was very applicable. There was also a lot of overlap with all the legacy E2 work we’ve done in the past.”

E3 supervisory control for CO2 applications
The E3 controller for CO2 applications is part of Emerson’s next-generation facility management and refrigeration control platform. Like all E3 controllers, this CO2-specific version streamlines management of essential facility systems. In addition, it provides advanced CO2 transcritical booster (TCB) refrigeration control in an easy-to-use platform. It’s designed to optimize E3 supervisory control system performance in multiple ways:
– Reduces set-up complexity by consolidating multiple applications into one CO2-specific workflow
– Provides a visual overview of the entire CO2 system operation in one screen, including visibility into the high-pressure controller and case controllers
– Supports customization of all required system values in one view
– Helps users to manage entire CO2 transcritical rack system, including alarming, safety operation and system control
– Enables faster system start-up via a simplified, one-time setup and tuning of system parameters

Getting with the program
A game-changing new feature for the installation team was the ability to conduct offline programming. Now, in addition to being able to work on-site, team members can work from home or other remote locations. Files can also be shared with others so that code could be checked and verified.
“In the past, you could only program if you were connected to the controller,” Kapelkin said. “Now, while our contact at Emerson was programming his portion of the controller, I was able to log in to the same project and add some of my features at the same time. Also, if you don’t have a controller handy, you can always connect to the offline programming manager from anywhere and edit your work. It’s a very useful feature.
“Another part of the design I really like is the ability to program a certain value and then share it with other applications. Say, for example, you want the defrost duration to be 30 minutes, and that applies to 10 circuits. Rather than programming all 10 circuits one by one, you can just send the values to all 10 of them and it gets updated automatically,” he concluded.

Streamlining the upgrade
While many things about the E3 controller are different and improved, Emerson ensured several key aspects remained the same, including the size. This made it even easier for the CryoBuilt team to make the switch.
“The rack originally came with an E2 controller, so it was very convenient to switch out the legacy E2 directly to an E3 controller,” Ganaga said. “It was seamless — the same dimensions — and it didn’t require any kind of com rewiring or special termination resistors.”
Overall, the entire team, including the local contractor, was surprised that the project wasn’t nearly as complex as they thought it would be. This was even the case when working with the iPro controller, which was new to most of the team.
“We have a lot of HFC systems out there, and we’ve used regular boards to control the compressors,” Ganaga said. “But when we go to a CO2 application, there’s a stand-alone iPro pack controller that’s responsible for critical pressure valves. Apart from this, there weren’t a whole lot of new things that we needed to consider.
“iPro controls your high-pressure valve and a flash gas bypass valve. One of the big decisions we had to make was whether to go with an Emerson-native iPro controller or utilize one from another manufacturer. Emerson assured us that their native solution would work, and it did. Both of our pressure valves respond quickly, and that’s a huge step forward. The E3 controller communicates with it via Modbus, so we’re able to look at all the values. Even if we need to fine-tune or change any settings remotely, we can do it now.”

Cooling a kitchen system
Prior to the upgrade, the central kitchen used an R-404A refrigerant system. CoolSys and CryoBuilt replaced it with an all-new CO2 rack, refrigeration control panel and eight evaporator control panels.
CO2 Rack
– Three low-temperature (LT) and four medium-temperature (MT) compressors
– Three heat exchangers/heat reclaim units, two to superheat suction (passive), one to heat up glycol
– Two variable frequency drives (VFDs)
– Adiabatic gas cooler
– Emerson oil management control on compressors
Refrigeration Control Panel (all manufactured by Emerson)
– iPro high-pressure valve/bypass gas valve (HPV/BGP) controller
– Eight MultiFlex input/output (I/O) boards
– E3 CO2 on outside of refrigeration control panel (previously using E2)
– Modular refrigerant leak detection sensor (MRLDS) 450 at bottom of panel
Evaporator Control Panels (one per walk-in)
– XM679 case controllers for evaporator coils
– MRLDS 450 leak detectors

Modern controls for a more sustainable future
The design and installation team was pleased with many other aspects of the E3 CO2 controller, including the capability to customize screen layouts, the professional look of its custom 3D floor plans, the ability to see the entire system and defrost schedule on a single screen, and remote access.
“Having remote capabilities is huge,” Ganaga said. “We can do a lot of remote diagnostics by pulling graphs and other data. Then if we see that we do need someone on-site, only then we’ll roll a truck. And even then, we’ll already have an idea of the right area to look at. The fact that this will connect via a web browser is also very helpful because you can have two different techs looking at the same screen remotely without interfering with you.”
“We’re looking forward to programming and installing more projects like this, because we know there’s more CO2 systems coming. And this is what a lot of technicians like us are passionate about,” Kapelkin added.

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