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Multiplex Refrigeration System Lays Foundation for Café’s Green Mission

If you’re a restaurant owner who decides to put the word “green” in your name, sustainability better be a significant part of your culinary story. The Green Sage Café in Asheville, N.C., embraces this challenge with a green vision that permeates every facet of their operation.

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Owned and operated by Randy Talley and Roger Derrough, the Green Sage Café has three locations across Asheville. While their first café incorporated many green elements, its refrigerated fixtures each operated on independent compressors — a refrigeration architecture that Talley identified as an area for improvement in their second restaurant.

Talley leaned on his background in the natural foods grocery industry to find a better solution. There he had utilized rack refrigeration systems with minimal compressors to provide cooling for multiple fixtures. He wanted to implement a similar architecture — now commonly referred to as multiplexing — but wasn’t sure if this technology would translate into his foodservice applications. That’s when Talley tapped Refrigeration Design Technologies (RDT), experts in eco-friendly refrigerated system design, to implement a system that would take his second location to the next level of energy efficiency.

“Our goal was to create the greenest restaurant possible. We wanted to cut energy consumption in half without compromising the quality of the food we’re serving,” Talley said.

Keeping (Eco)-Cool Under Pressure

Brent Dyess, RDT’s president, knew that Talley’s lofty goals were within reach. Dyess selected RDT’s proven Eco-Cool refrigeration system based on the Copeland Scroll Digital™ compressor for the second Green Sage Café location. Eco-Cool was specifically designed to meet the demands of environmentally responsible foodservice outlets, relying on lean multiplex refrigeration architecture to deliver the highest degree of energy efficiency.

The Green Sage Café’s unique energy and environmental requirements made it an ideal candidate for the Eco-Cool system. The system minimizes the compressors needed to provide refrigeration, servicing eight fixtures in the café’s medium-temperature suction group with one 4 HP Copeland Scroll Digital compressor. With their ability to digitally modulate capacity from 10 to 100 percent, the Copeland Scroll Digital enables precise matching of refrigeration requirements to the variable operating loads typical of a foodservice application.

Surprising Energy Savings

Dyess originally estimated that the system would provide the restaurant up to 30 percent in annual energy savings. But when the Green Restaurant Association (GRA) evaluated the Green Sage Café’s environmental profile for certification purposes, they commissioned RDT to perform an independent, third-party study on the Eco-Cool system. The results were surprising.

The UL energy study simulated a foodservice application, comparing a multiplex system (with one Copeland Scroll Digital compressor servicing six fixtures) to a conventional system. The study replicated actual foodservice conditions, such as varying demands and frequent refrigerator door openings and closings. The data revealed that in 90 °F ambient conditions, the Copeland Scroll Digital-based Eco-Cool delivered 48 percent energy savings.

The multiplex refrigeration system also helped Green Sage Café owners check other significant items off their sustainability list. By placing the Eco-Cool unit outside the restaurant and removing condenser surface areas that are present on each fixture in conventional systems, they eliminated 53,856 BTUH of heat, or the equivalent of 4.5 tons of air conditioning. Not only does this contribute to the café’s eco-friendly footprint, it helps create a better dining experience for patrons and improved working conditions for the staff.

“If our customers see the value in reusing a natural by-product of the refrigeration system, then we recommend it,” Dyess said. “Green Sage Café had the vision and commitment to utilize every available natural resource.”

This blog is a summary of the article State of the Art Sustainability from our recent edition of E360 Outlook. Click here to learn more about our involvement with the Green Sage Café.

CO2 as a Refrigerant – Introduction to Retail Cascade Systems

This is post number 11 of a series.

Retail Cascade Systems

The cascade system comprises:

  • The low stage, which provides cooling for the load. It uses R744 and is always subcritical
  • The high stage, which absorbs heat from the condensing R744 at the cascade heat exchanger

Within the cascade heat exchanger the evaporating high-stage refrigerant absorbs heat rejected by the condensing R744. The condensing temperature is maintained below the critical point. The high stage is usually a simple, close-coupled system controlled by the pressure in the low-stage receiver.

Figure 5

Figure 5: Simple cascade system

In this case the high stage provides cooling for the MT load as well as removing heat from the condensing R744 in the low stage at the cascade heat exchanger. The high-stage refrigerant is usually an HFC,HC or Ammonia, in which case the cascade is a hybrid system. In some systems R744 is used in the high stage. It will be transcritical at ambient temperatures above 68 °F to 77 °F (20 °C to 25 °C ).

In the next article of this series we’ll take a closer look at secondary systems.

Andre Patenaude
Director – CO2 Business Development, Emerson Climate Technologies

Visit our website for additional information on CO2 Solutions from Emerson. 
Excerpt from original document; Commercial CO2 Refrigeration Systems, Guide for Subcritical and Transcritical CO2 Applications.


To read all posts in our series on CO2 as a Refrigerant, click on the links below:

  1. Series Introduction
  2. Criteria for Choosing Refrigerants
  3. Properties of R744
  4. Introduction to Trancritical Operation
  5. Five Potential Hazards of R744
  6. Comparison of R744 with Other Refrigerants
  7. R744 Advantages / Disadvantages
  8. Introduction to R744 Systems
  9. Introduction to Retail Transcritical Systems
  10. Retail Booster Systems
  11. Introduction to Retail Cascade Systems
  12. Introduction to Secondary Systems
  13. Selecting the Best System

 

Industry Sets Sights on Reducing Refrigerant Leaks

For decades, refrigerant leaks have been considered an inevitable yet unfortunate consequence of operating typical supermarket refrigeration systems. Often thought of as a cost of doing business, refrigerant leaks and their far-reaching impacts are largely underestimated.

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With increased consumer, business and regulatory focus on minimizing the environmental impacts of hydrofluorocarbon (HFC) refrigerants, food retailers are recognizing the importance of reducing refrigerant leaks through effective leak detection practices.

Before implementing strategies to reduce refrigerant leaks, it’s important we fully understand the regulatory landscape to better align our efforts with existing and proposed regulations.

Increased Regulatory Focus on Leak Detection

The EPA introduced Section 608 as part of the Clean Air Act (CAA) in the 1990s to address emissions of ozone-depleting substances such as chlorofluorocarbon and hydrochlorofluorocarbon refrigerants used in stationary refrigeration and air conditioning. The main tenets of the ruling are designed to ensure proper use, handling and disposal of these refrigerants.

In October 2015, the EPA announced a significant new alternatives policy (SNAP) proposal to amend Section 608 of its CAA.1 It incorporates some of the key elements of the CARB initiative and lowers the leak rate threshold for penalties.

As with all SNAP proposals, the EPA encouraged the industry to submit public comments to the federal register. We don’t yet know when the final rule will be announced, but given its alignment with the CARB regulations, the proposal will likely lower the leak threshold and recommend automated monitoring or more frequent leak inspections.

Key Elements of Effective Leak Detection Programs

Accurate detection methods, reliable notifications and continuous monitoring are the key elements in an effective leak detection program. When developing your program, your aim should be to not only establish proper leak detection response protocols, but also institute proactive measures to minimize or eliminate leaks altogether.

Detection — an effective program starts with detection. There are differing technologies available depending on your requirements, and I will address these in the last section of this blog. But installing devices in the locations most likely to produce refrigerant leaks — particularly racks and cases — is as equally as important.

Notifications — ensure that the correct individuals in the organization are alerted when a leak has occurred. Alarms are typically remote, local or a combination of the two. Most remote notifications are tied into the store’s energy management system that will alert a technician or monitoring center to ensure that the leak is handled correctly.

Continuous monitoring — is one aspect that is often overlooked. By recording and analyzing the data around leak events, retailers can correlate the leaks with different types of equipment or maintenance events. In doing so, they can identify problem areas, develop more effective leak detection programs and improve their overall operations.

Conclusion: Leak Detection Makes Good Business Sense

With the renewed regulatory focus on reducing refrigerant leaks, retailers are taking a closer look at developing effective leak detection strategies. Through the help of ALD devices, retailers can achieve continuous monitoring, satisfy reporting requirements and reduce the need to perform manual inspections.

But achieving compliance with current or future regulations is only one benefit. When you examine the cost of lost refrigerant, the degradation of refrigerated system performance and the potential for eventual food loss, the business case for implementing effective leak detection programs is as clear as refrigerant-free air.

This blog is a summary of the article Industry Sets Sights on Reducing Refrigerant Leaks from our recent edition of E360 Outlook. Click here to learn more about effective leak detection.


References

  1. http://www2.epa.gov/snap/608-proposal

CO2 as a Refrigerant – Retail Booster Systems

This is post number ten of a series.

Retail Booster Systems

Two-stage compression is used for transcritical low temperature applications because the discharge temperature of R744 is high and will potentially result in lubricant breakdown. Figure below shows a simple two-stage booster or externally-compounded system:

Figure 4

Simple booster system without oil management

The refrigerant from the low-temperature loads is drawn into the low-stage compressors. The discharge from these compressors goes into the suction of the high-stage compressors.

The refrigerant from the medium-temperature (MT) loads is drawn into the suction of the high-stage compressors. The refrigerant from the receiver pressure-regulating valve is also drawn into the suction of the high-stage compressors. The flash gas from the receiver pressure-regulating valve and the suction gas from the medium temperature loads provide some interstage cooling. This is usually enough to maintain the discharge temperature of the high-stage compressors below the level at which the lubricant will deteriorate. Additional interstage cooling can also be provided if required.

In the next article of this series we’ll take a closer look at retail cascade systems.

Andre Patenaude
Director – CO2 Business Development, Emerson Climate Technologies

Visit our website for additional information on CO2 Solutions from Emerson. 
Excerpt from original document; Commercial CO2 Refrigeration Systems, Guide for Subcritical and Transcritical CO2 Applications.


To read all posts in our series on CO2 as a Refrigerant, click on the links below:

  1. Series Introduction
  2. Criteria for Choosing Refrigerants
  3. Properties of R744
  4. Introduction to Trancritical Operation
  5. Five Potential Hazards of R744
  6. Comparison of R744 with Other Refrigerants
  7. R744 Advantages / Disadvantages
  8. Introduction to R744 Systems
  9. Introduction to Retail Transcritical Systems
  10. Retail Booster Systems
  11. Introduction to Retail Cascade Systems
  12. Introduction to Secondary Systems
  13. Selecting the Best System

 

The Evolution of Predictive Protection – By Ben Picker

For years, the outdoor refrigeration condensing unit has been the workhorse of small- and large-format food retailers. It’s called upon to endure extreme climates and continuously support walk-in refrigerator and freezer operations.

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With energy costs rising, corporate sustainability goals increasing, and embedded electronics and equipment technologies emerging, many food retailers are looking to add efficiency and eco-friendliness to their refrigeration checklist. The Copeland Scroll Outdoor Refrigeration Unit (X-Line) is Emerson Climate Technologies’ answer to those questioning the long-term practicality and viability of their refrigeration technology.

Addressing this need in the market is not new to Emerson — X-Line units were introduced to North America back in 2008. The new, second generation X-Line (X-Line 2.0), builds upon the technology of the original models to offer best-in-class energy efficiency, uptime and flexibility, all while providing advanced diagnostics and protection from an integrated suite of electronic controls.

Unique Proactive Diagnostics

What is most unique about X-Line 2.0 compared to others in the industry is the comprehensive range of system protection it offers. Based on a fully integrated electronic control system that combines pressure, defrost, electronic valve, fan speed, diagnostics and communications controls into one modular control, X-Line 2.0 offers comprehensive control, protection and smart store technology that meets the demands of modern food retail requirements. Using our proven CoreSense technology for Copeland compressors, the unit’s controls and sensors are designed to provide both proactive and reactive protection.

Increase Efficiencies

X-Line 2.0 units utilize Copeland Scroll compressors that are compatible with the emerging class of newly approved, low-GWP refrigerants. The condenser’s sizing has been optimized as well, with large coils and integrated electronic controls. This design not only meets the DOE’s annual walk-in efficiency factor (AWEF) standards, it also provides 15–20 percent energy efficiency ratio improvements for every 10 °F drop in head pressure. At test sites, users are saving 20 percent on average in energy costs with X-Line 2.0 units compared to other units. See our energy savings calculator here: http://xjenergycalc.emersonclimate.com/xjenergycalc/.

Maximize Uptime

X-Line’s electronic controls provide the advanced diagnostics and complete system protection to prevent catastrophic compressor failures and accelerate the repair process. X-Line’s diagnostics and communication capabilities further enable advanced warnings and improved uptime. By connecting the unit to a site supervisory control — such as an E2 or ecoSYS Site Supervisor available from Emerson, or other controls available from third parties — system issues can be identified and scheduled for repairs before leading to a system failure or product loss. Some issues can even be diagnosed and repaired remotely.

This blog is a summary of the article The Evolution of Predictive Protection from our recent edition of E360 Outlook. Click here to learn more about our Copeland Scroll Outdoor Refrigeration Unit.

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