What Happens When the Power Goes Out?

Extreme weather events have created unique and significant challenges when it comes to energy infrastructure. These challenges have resulted in an overburdened electric grid and, in turn, regional power outages across the country.

A power outage is difficult for any supermarket to manage even under normal circumstances. However, for stores operating equipment running on next-generation, low-GWP fluorinated refrigerants, the system comes back on as soon as the lights do. More importantly, these systems hold their charge long after the power fails. No spoiled food, no system repairs and no extended store downtime. Many retailers take for granted how resilient and reliable these refrigeration systems are, and how much time and money they save as a result.

Conversely, retailers using CO2 (R-744) systems are not afforded the same peace of mind. To them, a power outage is rightly viewed as a potential catastrophe. Unlike the systems described above, CO2 systems often lose their charge when the power fails. This is because they operate at a significantly higher working pressure than traditional technologies. When the power is on, the system can ensure the pressure remains stable and operable. When the power cuts out, the pressure mitigation stops, and the system pressure climbs to an inoperable level. This triggers the loud screech of the emergency transcritical relief valve, which signals an imminent loss of charge and potential system failure.

Under this latter scenario, the race against the clock has already been lost. It takes between four and six hours to charge a CO2 system in a typical supermarket. According to the USDA, refrigerated foods held at temperatures above 40°F for more than just two hours should not be consumed. The bottom line: For supermarkets, this means massive and costly losses of refrigerated perishable food, including meat, poultry, fish, eggs and more.

It is worth noting that mitigation tactics do exist to overcome CO2 system vulnerabilities. One such option is a backup refrigeration unit that uses tried and true refrigerant technologies and connects to a power source (typically a generator) and an uninterrupted power supply. A backup refrigeration unit can be effective, but it comes at a high cost and may not fully protect the entire system charge. Another tactic is to store a system charge onsite. This too can be an effective solution, but it requires a technician and engineer to visit the store and recharge the unit, which adds cost and operational complexity. While every CO2 system power failure mitigation strategy is not right for every retailer, they all have one thing in common: additional costs for the business owner.

To reiterate, these costly mitigation tactics are unique burdens on retailers with CO2 systems. And importantly, these costs must be considered on top of the already expensive proposition to install a new CO2 system or perform a CO2 system conversion. Operationally, store managers are already faced with so many day-to-day challenges; the last concern they should have is how to maintain their refrigeration charge in the event of a power outage.

In the near term, extreme weather events and associated power failures affecting stores may be unavoidable. However, costly product losses and extended store downtime can be prevented. Refrigeration system technologies and architectures that use low-GWP fluorinated solutions do not require expensive power outage mitigation technologies and preparation, and allow store managers to focus on what matters most: delivering safe products, providing exceptional service to customers and managing the sales floor.

About globalFACT

The Global Forum for Advanced Climate Technologies (globalFACT) promotes education, awareness, and policies that support the important role of new-generation, low- and reduced-global warming potential (GWP) advanced climate technologies in protecting the environment while meeting the rapidly increasing demand for safe alternatives. Learn more at www.globalFACT.org.