The expanding natural refrigerant commercial refrigeration market is likely to see steady growth in the US, due to a number of factors. To begin with, members of The Consumer Goods Forum (TCGF) have pledged to phase-out HFCs, a pledge which was reaffirmed in July 2014. On top of this, the EPA is proposing to ban some high-GWP HFC refrigerants in new and retrofit applications, and to allow some new natural refrigerant-based applications. As a result, retailers are facing pressure to reduce their impact on the environment, and to adopt climate friendly refrigeration systems.
As retailers, we own the responsibility to meet this challenge,” said Harrison Horning.
Lesson learned to date: CO2 project economics depend on many variables
When it comes to environmentally benign R744 solutions, CO2-HFC hybrids solutions have thus far been the preferance of many US retailers, which is also the case in Eastern Europe, South America and China. In Northern Europe, Japan and Canada, on the other hand, CO2 transcritical solutions are preferred.
However, US experiences with both types of systems have been that the energy performance can be good, that the maintenance can be manageable, and that engaging all contractors early in the process can ensure a CO2 project’s success.
The end for HFCs in Delhaize stores?
In July 2013 Delhaize Amercia opened a new Hannaford store in Turner, Maine, that features a transcritical CO2 rack with series heat reclaim. The 36,000 ft2 (3,345m2) store has shown good energy performance, reliability and maintenance, with very little downtime. In particular, the measured electric energy consumption of the CO2 booster rack in the Maine store was lower than that of the refrigeration systems in two similar sized stores, with the following installed equipment:
- Three DX R407A racks, full-condensing (parallel) heat reclaim (glycol) installed in Bradford, Vermont in 2013
- Three DX R507 racks, combination of series and full-condensing (parallel) heat reclaim (direct), installed in Portland, Maine in 2005
Horning emphasised that Delhaize plans to complete more pilot stores, and learn what they can from the 3000+ CO2 transcritcal stores installed globally.
I am fully confident that next pilot we do will be much better then 187 kbtu,” said Horning.
The company is also considering remodels and retrofits for locations where existing equipment is reaching its end-of-life and where there is sufficient space for new equipment. Although the latter will depend on the proposals received.
First CO2 supermarket system in the US had comparable installation costs to DX
In his presentation, Benny Smith from Price Chopper talked about his company’s investment in the first US CO2 supermarket, a cascade R404a/CO2 system, in a store in Saratoga New York. The 2008 installation, a combined SNLTX2/SNMT system, with a CO2 charge of 700lbs has helped to reduce the store’s carbon footprint by 5,132 tones of CO2 equivalent.
Thanks to their early involvement in the project, the feedback from the technicians working on the system has been positive. What is more, the installation cost for the CO2 cascade system $9,63 ft2 (€75 m2) was comparable to a DX system at $9.61 ft2 (€74.9 m2).
Walgreens pioneers coupling of CO2 with geothermal energy
In 2013 Walgreens opened its first ‘net zero’ store in Illinois, which features a CO2 transcritical system and geothermal energy, a pioneering coupling of technologies that enables the efficient use of CO2 transcritical refrigeration in more southerly climates thanks to the steady condensing temperature provided by the georthermal loop.
According to the FMI presentation by Jamie J. Meyers, LEED AP, Manager of Sustainability, Walgreens, and Rob Olden, CEM, Director of Engineering, North America, GI Energy, these are the key lessons learned since the opening of the store:
- There are UL Certification hurdles related to 5x pressure rating at 90 Bar
- Incorporating HVAC into refrigeration rack breaks down historic barrier to innovation
- Geothermal loop adds redundancy and increases operational flexibility
- Aluminum piping is a no-brainer
- US suppliers lack sufficient stock of 80 Bar rated components
- Real time monitoring and transparency are vital