After modeling the performance of its new boosted, direct CO2 (R744) heat reclaim technology, Canada-based HVAC OEM Flō Energy Solutions has found that it can recover three times more waste heat from a supermarket’s refrigeration system than a standard heat reclaim approach.
Peter Reist, Director of Product and Sales Strategy at Flō Energy Solutions, told NaturalRefrigerants.com that the tests also show the new technology is twice as efficient at providing grocery store comfort heating than the air-source heat pumps offered by the company.
“An optimized coil ‒ factory installed in our standard DOAS+ with Adaptive Multi-Path Technology platform ‒ integrates with the CO2 rack to provide an energy-efficient way to decarbonize grocery store heating,” Reist said.
The HVAC manufacturer, founded in 1998, caters to grocery stores and provides standard package solutions along with customizable ones for specific applications. Its offerings include air- and water-source heat pumps, chilled water units, split systems, traditional rooftop units and more, with heating and cooling capacities ranging from 6‒140TR (21‒492kW).
In a pilot demonstration with U.S.-based OEM Hillphoenix on a retrofitted small-format supermarket in Pennsylvania, the optimized technology was found to cut the natural gas used for winter comfort heating by 84%. Reist and Scott Martin, Senior Director of Industry Relations and Compliance at Hillphoenix, presented the findings at the ATMOsphere (ATMO) America Summit 2024. ATMOsphere is the publisher of NaturalRefrigerants.com.
“This is an exciting time for retailers,” said Martin during the presentation. “We can heat a store with its CO2 refrigeration system to enhance the payback of that system.”
Increased energy savings
Company models indicate discharge temperatures from CO2 refrigeration compressors run roughly 30°F (16.7°C) hotter than those of R449A. According to Flō’s modeling, this higher discharge temperature means CO2 systems equipped with heat reclaim can provide greater energy savings than similar systems using R449A.
Over the past 15 years, Flō Energy Solutions has installed more than 1,000 standard direct CO2 heat reclaim coils, Laura Semidey, Director of Engineering and Innovation at Flō, told NaturalRefrigerants.com.
“This winter, we have over a dozen new projects with multiple grocery chains installing the optimized technology,” she said. “CO2 projects are quickly becoming a majority of what we do.”
NaturalRefrigerants.com recently spoke with Semidey, Reist and Bryan Elliott, Founder and CEO of Flō, about the development of the optimized direct CO2 heat reclaim technology and what it means for the industry.
The interview has been edited for length and clarity.
What sets Flō Energy Solutions apart from its competitors?
Bryan Elliott: Our focus is supermarket expertise. Rather than designing a standalone HVAC system for a grocer, we seek to integrate it with the refrigeration system for full ecosystem impact. We have two customers: the people in the store and the refrigeration equipment.
How does the optimized heat reclaim coil operate?
Peter Reist: The new coil acts like a standard coil to passively recover heat until the store needs additional comfort heat. At that time, the system slightly lifts the pressure head of the rack, allowing us to capture all the waste heat and put it to work in the airstream.
Laura Semidey: Our years of CO2 experience and our capability to model the refrigeration and the HVAC systems on a granular level with refined algorithms allow us to optimize the design point. The new coil, integrated with the CO2 refrigeration system, captures the heat to treat the space effectively.
What does the new coil mean for the industry?
PR: It’s transformational. We see the grocery sector moving toward CO2, especially in new construction. Decarbonizing heating without increasing the electrical demand or service coming to the building is the holy grail of projects today. This coil allows us to put to work heat that would otherwise go to waste. In some cases, we can provide all the comfort heat needed without using any auxiliary electrical heat.
Clients already comfortable with CO2 refrigeration feel this is the next step in leveraging CO2 technology. In addition to our upcoming new construction projects, we have a couple of retrofits scheduled for this coming winter.
BE: It’s accelerated what’s possible with CO2, with our models showing unexpected, surprising results throughout an entire year of data.
What changes in the grocery store refrigeration sector do you see coming in the next five years?
BE: We see a deeper integration of HVAC and refrigeration, with the food retail sector partnering with other technologies to advance efficiencies. The collaborative approach has led us to patents and joint patents with other companies.
PR: We are also working on a patented technology called Multi-Flo Reclaim to function as a free mechanical subcooler for the rack, especially for hot, humid climates. Grocers in the deep Southeast hesitate to use CO2 technology because adiabatic coolers don’t work as effectively with such a high wet bulb temperature. This technology will have perfect application in that area.
In the future, we’ll look to provide comfort cooling with the rack, too.
