How Refrigerant and Control Selections Are Impacting System Design and Engineering

This blog is based on Emerson’s on E360 webinar, “Top Retailer Trends for Refrigeration, Controls and Facility Optimization.”

Today’s trends in refrigeration systems and electronic control schemas are having significant impacts on refrigeration design and engineering. We recently hosted an E360 webinar discussing two emerging trends we are currently encountering: small-store design and case-level control strategies.

Smaller stores present new challenges

As demographics are shifting to higher-density living, accommodating smaller-footprint grocery stores in high-rise or mixed-use buildings is becoming more common — and presenting new challenges. In many cases, these spaces were never intended to support refrigeration and HVAC operations. Because of this and other limitations, equipment integration discussions should begin in the early phases of a site’s evaluation process.

When it comes to refrigeration equipment options for small-footprint designs, there are many possible approaches:

1. I) Compressor house: enclosure that contains refrigeration equipment, typically housed on the roof

Pros

• Consolidation of rack(s), condenser(s), electrical and centralized controls
• Service technician-friendly

Cons

• Large and heavy
• Is there space on the roof?

1. II) Machine room/equipment mezzanine: traditional way to house refrigeration equipment

Pros

• Consolidation of rack(s), electrical and centralized controls
• Good serviceability

Cons

• Expensive to build
• Can take up sizable space
• Needs leak detection and exhaust

III) Distributed system: typically, interior systems mounted on top of walk-in coolers

Pros

• Saves space, quiet
• Available in a split-suction configuration (to serve low- and medium-temp loads)
• Served by roof-mounted condensers or fitted with a heat exchanger that utilizes a dedicated condenser loop, or is tied to main building condenser system

Cons

• Service access isn’t ideal
• What happens when walk-in needs replacement?

1. IV) Exterior distributed system: roof-mounted packaged system for smaller applications

Pros

• Lighter-weight unit
• Integral condenser

Cons

• Limited capacities, depending on ambient temperatures
• No split-suction configuration available

1. V) Unitized exterior distributed system: roof-mounted unit that houses compressor cabinet with condenser next to it

Pros

• Lighter-weight unit with microchannel condensers
• All electronic valves
• Case controls separated from rack controls

Con

• May not be available in split-suction configurations

Case-level control becomes more viable

Advancements in electronic expansion valves and controls technologies at the case level allow more flexibility for merchandising. For example, case temperatures can be more easily modified to accommodate a wider range of merchandise, within reason. Other benefits include:

• Case conditions (temperature and humidity) are monitored and controlled within the case instead of a centralized system.
• Technology is evolving to enable self-diagnostic capabilities to communicate issues before problems surface.
• Consolidation of 120 V circuits fans/lights/anti-sweat circuits means less wiring and fewer conductors are needed, saving time and money in installation.
• Owner operation is enhanced because products don’t have to be pulled from the case to adjust the electronic expansion valves.

Door or no door?

The battle rages on. Customer usability and reach are enhanced with no case doors; from an economic standpoint, adding doors reduces compressor horsepower up to 83 percent and energy usage by 75 percent. “To door or not to door” is largely a matter of merchandising, as doors work well with sealed products (like the deli or dairy) but not as well for meats and produce.

Installing new or retrofitting case doors depends on several engineering factors such as control valve, riser and piping sizes and rack considerations.

I encourage you to review our other blogs covering the E360 webinar on “Top Retailer Trends for Refrigeration, Controls and Facility Optimization for additional fresh insights on emerging trends in the refrigeration industry.