Incorporating the latest technology, today’s food display cases can compensate for less than ideal environmental conditions, reducing energy usage and cutting costs.
Like a chameleon that changes colors to blend with its surroundings to survive, today’s food display cases with self-contained refrigeration systems must also be able to adapt to the environments they are operating in.
Smart thermostats and energy management systems have been incorporated into buildings and locations using food display equipment in order to reduce energy consumption and save money.
These systems can be a challenge. An environment that is well controlled to maintain 75 degrees Fahrenheit. and 55% relative humidity during the day can easily reach much higher temperatures during non-operational hours. As a result, refrigeration systems that are preset to operate in a specific set of temperature parameters are required to work harder as the operating conditions become more extreme.
The overtaxing of the refrigeration components that occurs while working in these environments ultimately results in temperature performance issues, an increase in food safety risks, and the potential loss of fresh food product and sales.
“The environment will impact display cases in a manner that the refrigeration systems have to account for increases in temperature and humidity,” says Mike Kohler, associate technical director at NSF International. “This equipment would typically run more in warmer environments. In more humid environments, the refrigeration system would not only run longer, but also potentially have to go through a defrost period more often.”
Display cases that are certified NSF 7 are broken into different categories based on ambient conditions perceived by manufacturers.
“As they design this equipment for different applications, display case manufacturers can choose to have their units rated in different ways,” Kohler explains.
Where environmental conditions are concerned, display cases are tested with ambient conditions at 86 degrees Fahrenheit. This is a four-hour no-load test, where the air temperature in an empty compartment is measured, along with the compressor run time.
“To be certified, the compressor can’t exceed 70% run time and the air temperature cannot go above 40 degrees Fahrenheit,” Kohler says. “This test works well for closed cases.”
There are environments and conditions that are not conducive to this standard test, including operations where display doors are frequently opened and closed. The test also isn’t favorable for open cases.
NSF International’s Type I and II operating condition standards are geared for refrigerated displays in retail environments, like grocery stores, convenience stores and grab-and-go applications.
“When we added this load test to our standards in the late 90s, we referenced ASHRAE Standard 72 from the American Society of Heating, Refrigeration and Air Conditioning Engineers,” Kohler says. “This has performance testing methodology for testing refrigeration units in a loaded condition.”
This test, which monitors temperatures over 24 hours, encompasses defrost cycles and has no compressor run time requirement.
“NSF International initially proposed to reference this test, since it’s the industry standard. Although regulatory committee members deemed the ambient temperature requirement of 75 degrees Fahrenheit suitable for grocery store applications, some considered it too low for convenience store applications,” Kohler says. “As a result, an optional ambient temperature requirement of 80 degrees Fahrenheit was added using the same methodology in terms of test mechanics to establish a Type II category.”
Now NSF International categorizes display cases as general display, Type I or Type II. Once equipment is NSF-certified, the listing heading distinguishes the difference.
In a Type I environment, the operating conditions within which the equipment is performing are held constant at 75 degrees Fahrenheit and 55% relative humidity. In a Type II environment, operating conditions can be as high as 80 degrees Fahrenheit and 60% relative humidity.
Most food display equipment with self-contained refrigeration is certified to safely operate in Type I conditions, although some manufacturers offer equipment designed for Type II conditions. Regardless of level, the key to success is consistency and that’s often tough to guarantee given the “smart technology” that is being used to manage energy in the building.
Refrigeration systems are getting smarter. Influenced by robotic advancements and other technologies, components are becoming increasingly more available for savvy manufacturers to capture in their equipment designs.
Equipment that uses time to manage the refrigeration cycles is quickly being replaced by refrigeration systems that sense the conditions of the environment and adjust the refrigeration cycle accordingly. These adjustments can range from minor to major based solely on what’s going on in the environment, and the benefits are tremendous. This intelligent equipment operates efficiently and consistently no matter how the environment is changing around it, to ensure safe product temperatures are always consistent.
For example, when tested, Structural Concepts’ refrigerated self-service merchandiser model CO47R with EnergyWise refrigeration utilized 19.3 kilowatts per hour in 24 hours, with average power of 803 watts and an average test simulator temperature of 36.4 degrees Fahrenheit. Its yearly energy use is 7,040 kilowatts per hour. This is significantly less than other refrigerated grab-and-go food displays being offered to the foodservice industry.
“By integrating efficient technologies into the case, Structural Concepts was able to cut the energy usage in half,” says Denis Livchak, research engineer at PG&E Food Service Technology Center, located in San Ramon, Calif. “Overall, these improvements were due to more efficient compressors, fans, evaporator coils and improved air curtain design, as well as controllers that integrate those components.”
With more fresh food being offered in a variety of locations, it’s critical that food display equipment is reliable in order to safely maintain proper food temperatures. Equipment that includes the latest advancements in adaptive technology provides operators with the peace of mind that equipment will operate properly at all times.