Efficient Refrigerated Display Cases - Can They Flex Their Power? Preprint

Grant Wheeler, Omkar Ghatpande, Ramin Faramarzi, Alexander Bulk, Juan Montoya, Diane Patrizio, Frank Wallis, Don Wiesmann, Robert Nash, Suresh Shivashankar

Research output: Contribution to conferencePaper


Refrigerated display cases are widely-used, critical equipment in supermarkets for maintaining product safety and quality. Energy-efficient medium temperature liquid-cooled refrigerated display cases can save 25-70% of the total supermarket energy, according to manufacturers. Traditionally, cases operate by maintaining a temperature around a user-input setpoint that is dependent on the product in the case. Although cases are major electrical energy consumers, they are hardly ever considered for implementing load-flexibility strategies. With added load-flexibility capabilities, refrigerated display cases can shed (reduce), or shift (by adding and subsequently shedding) load. Supermarkets can reduce their energy costs and enhance electric grid integrity by implementing these smart load-flexibility control strategies. Advanced controls can also enable load-shifting to coincide with optimum periods of renewable energy generation. This will further improve operational costs and reduce greenhouse gas emissions without compromising food safety and quality. In this research, we have evaluated the energy savings of liquid-cooled medium temperature display cases and developed load flexibility strategies leveraging an advanced controls system, a variable speed compressor, and heat rejection via a water-cooled condenser. This study further assessed the impact of load flexibility strategies in a controlled environment chamber for a single refrigerated display case.
Original languageAmerican English
Number of pages17
StatePublished - 2022
Event2022 ACEEE Summer Study on Energy Efficiency in Buildings - Pacific Grove, California
Duration: 21 Aug 202226 Aug 2022


Conference2022 ACEEE Summer Study on Energy Efficiency in Buildings
CityPacific Grove, California

NREL Publication Number

  • NREL/CP-5500-82475


  • energy efficiency
  • load flexibility
  • refrigeration
  • smart commercial building technologies


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