[E360 Webinar Recap] How Refrigerant and Control Selections Are Impacting System Design and Engineering
|Andrew Knight | Vice President/Refrigeration Team Leader
This blog is based on Emerson’s most recent 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. I recently had the pleasure of participating in an E360 Webinar where I discussed two emerging trends my company is currently encountering: small-store design and case-level control strategies. The webinar also featured Andre Patenaude, director of food retail marketing & growth strategy, cold chain; and John Wallace, director of innovation, both of Emerson.
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:
I) Compressor house: enclosure that contains refrigeration equipment, typically housed on the roof
- Consolidation of rack(s), condenser(s), electrical and centralized controls
- Service technician-friendly
- Large and heavy
- Is there space on the roof?
II) Machine room/equipment mezzanine: traditional way to house refrigeration equipment
- Consolidation of rack(s), electrical and centralized controls
- Good serviceability
- 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
- 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
- Service access isn’t ideal
- What happens when walk-in needs replacement?
IV) Exterior distributed system: roof-mounted packaged system for smaller applications
- Lighter-weight unit
- Integral condenser
- Limited capacities, depending on ambient temperatures
- No split-suction configuration available
V) Unitized exterior distributed system: roof-mounted unit that houses compressor cabinet with condenser next to it
- Lighter-weight unit with microchannel condensers
- All electronic valves
- Case controls separated from rack controls
- 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 Andre Patenaude’s and John Wallace’s 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.