Analysis of global energy savings in the frozen food industry made possible by transitioning from conventional isobaric freezing to isochoric freezing

Authors: ZHAO, YUANHENG - University Of California; POWELL-PALM, MATTHEW - University Of California; WANG, JUNJIE - Chinese Academy Of Sciences; Bilbao-Sainz, Cristina; McHugh, Tara; RUBINSKY, BORIS - University Of California

Submitted to: Renewable & Sustainable Energy Reviews
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/27/2021
Publication Date: 9/2/2021
Citation: Zhao, Y., Powell-Palm, M., Wang, J., Bilbao-Sainz, C., McHugh, T.H., Rubinsky, B. 2021. Analysis of global energy savings in the frozen food industry made possible by transitioning from conventional isobaric freezing to isochoric freezing. Renewable & Sustainable Energy Reviews. 151. Article 111621. https://doi.org/10.1016/j.rser.2021.111621.
DOI: https://doi.org/10.1016/j.rser.2021.111621

Interpretive Summary: The current global cold-chain operates at significant energetic costs; domestic food cold-storage alone was estimated to account for nearly 4% of all global electricity consumption annually. Thus, in envisioning an energy efficient future food chain, capable of meeting the needs of a soaring global population, fundamental innovations in the cold-storage space are needed to reduce the economic burden, the energetic burden and the carbon footprint of the cold-storage infrastructure. We have developed a new concept for food storage at subfreezing temperatures, “isochoric cold storage”. This storage modality aims to replace industry-standard cold storage, which occurs under constant atmospheric pressure (isobaric) conditions, with cold storage that instead occurs under constant volume (isochoric) conditions. The total global frozen food capacity in 2019 was approximately 31.3 billion kg. If all of this food was processed under isochoric conditions at the industry-standard of -18°C rather than under isobaric conditions at -18°C, a total savings of about 3 billion kWh could be realized. This energy saving translates to an annual economic savings of approximately 350 million USD and an annual environmental savings of 2 billion kg of CO2 (equivalent to removing of roughly 400,000 cars from the road).

Technical Abstract: An efficient global cold food chain is critical to the sustainability of the growing world population, and it is anticipated that the global frozen food market will reach $366 billion by 2026. Storage of food at sub-freezing temperatures is integral to global food capacitance and safety but comes at extreme energetic and carbon costs. While efforts to reduce this energetic toll have traditionally targeted the devices used to generate refrigeration, we identified that significant energy savings may be attainable by altering the fundamental thermodynamics of the freezing process itself. Here we show that preserving frozen food under isochoric (constant-volume) thermodynamic conditions, as opposed to the industry-standard isobaric (constant-pressure) conditions, may reduce annual global energy consumption by as much as 6.49 billion kWh with carbon emission savings of 4.59 billion kg. As important, these savings can be achieved rapidly and inexpensively, without any costly changes to the current global refrigeration infrastructure.