U.S.-based multinational food processing company Cargill has said that it is moving from HFC chillers to CO2 (R744)-based systems for its smaller industrial refrigeration applications ranging from 100 to 500kW (28.4 to 142.2TR) in capacity.
The company installed its first CO2 chiller at one of its factories in Norway in 2022 and is currently considering the technology for other projects in Europe, according to Aurélie Grélot-Liénard, Cargill’s Global Cooling and Refrigeration systems Lead.
Grélot-Liénard shared details of Cargill’s adoption of natural refrigerants during the End User Panel session at the ATMOsphere (ATMO) Europe Summit 2023. The conference took place September 19–20 in Brussels and was organized by ATMOsphere, publisher of R744.com.
The company has a wide range of cooling and heating needs across its operations, including deep freezing for its meat and poultry processing, medium-temperature cooling for its chocolate and animal feed production, and cold storage facilities, as well as heating for various production processes and spacing heating in its offices.
Cargill has a long history with ammonia (R717), with more than 75 of its factories using ammonia-based refrigeration systems. However, regulations prohibiting the use of large quantities of R717 are driving the food processor to rethink its approach to industrial refrigeration.
“We have worked a lot with ammonia, [and it] remains the most sustainable and efficient refrigerant for large cooling capacities, but what we’re now seeing, especially in Europe, is more and more constraints from cities and local authorities that are pushing us away from ammonia,” said Grélot-Liénard. “That’s why we’re looking more to CO2.”
Where ammonia is still being used, the company is choosing packaged units and cascade systems to ensure that the R717 is fully confined to the machinery room, she added. For example, two years ago, Cargill installed a CO2-ammonia cascade system that decreased the quantity of R717 in the system from 8 metric tons to less than 1.5 metric tons.
For its lower-capacity application, Cargill has historically opted for HFCs, but f-gas regulations and other factors – such as the cost of HFCs and HFOs – are driving the food processor to transition to natural refrigerants.
“For smaller systems, between 100 and 500kW, ammonia isn’t always the best fit, so we’re also looking at CO2 there,” said Grélot-Liénard. “We’re moving to CO2 to have an environmentally-friendly, sustainable and long-term solution.”
She noted that CO2 is also a good solution for combined heating and cooling systems and that the cost of CO2 systems has started to decrease in recent years, making them most competitive with systems using synthetic refrigerants.
“There has [also] been a lot of improvement in the performance of natural refrigerant-based cooling units, which has helped us choose these units,” she said.
For capacities up to 1MW (284.3TR), Cargill is also exploring propane (R290) as an option.
“There has been a lot of improvement in the performance of natural refrigerant-based cooling units, which has helped us choose these units.”Aurélie Grélot-Liénard, Cargill
Barriers to natural refrigerants
During her presentation, Grélot-Liénard highlighted a number of challenges that Cargill is encountering in its efforts to transition to natural refrigerants.
So far, the main barriers have been installation constraints in retrofitting existing systems and the complex requirements of industrial refrigeration applications – such as requiring various evaporation temperatures – making it difficult to find the right equipment.
“It would be great to be quicker on the installation with standardized system and product designs,” she explained.
She also discussed the problems Cargill is facing around technician availability in some countries and that, while there might be companies who can supply the technologies, there is no one available locally to service them.
There also needs to be greater awareness of natural refrigerants and guidance on transitioning to new technologies, she said. To overcome this challenge, Cargill is developing best practices to support the selection of cooling and heating systems that focus on the total cost of ownership, she added.
Cargill is currently working to reduce its greenhouse gas emissions by 10% by 2025 and is on target to reach this goal while still growing, according to Grélot-Liénard. The company has also committed to reducing its supply-chain emissions by 30% per ton of product sold by 2030, which is a bigger challenge, she added.
To achieve these targets, Cargill has invested US$70 million (€66.8 million) to implement a range of energy efficiency and emissions reductions initiatives. The company is also currently working on developing targets to reduce refrigerant leaks and phase down f-gases.
Initiatives include improving building efficiency, adjusting temperature set points and recovering waste heat for space heating, hot water production and processing heat with the help of heat pumps. The company is also exploring how it can combine its cooling and heating demand into integrated HVAC&R systems for improved efficiencies.