Seeking Solutions to Reduce the Energy Consumption of Ice Cream Freezer Cabinets

Unilever is the largest ice cream manufacturer in the world, with over a billion smiles delivered every year in over 40 countries. Every day, millions of consumers choose our products from the frozen cabinets in the local baker, at a beach kiosk, or in a convenience store. These point-of-sale freezer cabinets keep our ice cream perfect for consumption, but also represent a significant proportion of our greenhouse gas (GHG) footprint, due to the energy required to maintain ice cream frozen at -18°C. 

Retail emissions—specifically ice cream freezers—account for 10% of Unilever’s value chain GHG footprint, and Unilever owns a fleet of over 3 million point-of-sale freezer cabinets. These freezers are typically set to a temperature below -18°C. 

We are looking for solutions to lower the energy use per cabinet while maintaining the required ice cream quality.  These solutions could relate to the refrigeration system as well other construction aspects of the cabinet.

Our ice cream cabinets currently work using the widely used vapour compression refrigeration system. While most of the fleet uses static refrigeration, some of the special models as in scooping or verticals work with ventilated systems. Over the last few years, we have been working to reduce energy consumption of our freezers by moving to hydrocarbon refrigerants (propane and isobutane), use of energy efficient components (compressors, fan motors, and low E glass).

Other solutions that we have assessed 
The use of solid insulated lids have been considered, however ice cream being an impulse product category, the visibility of the products is key for improved sales hence use of solid/opaque lids that prevent consumers from seeing the ice cream is not accepted by the trade. Solar films and other electrically activated films that change from opaque to transparent have been tested but have either been ineffective or too expensive to implement.

We would like to seek solutions that are able to reduce energy consumption of ice cream cabinets through the main technical components of, but not limited to, compressors, natural refrigerants, fan motors, insulation, temperature controllers and glass panels.

Proposed solutions for the ice cream cabinets needs to meet the following requirements:

• Improved energy consumption to be less than 2 kWh/24 hours
• Achieve -18°C temperature 24/7 in ambient conditions of up to 40°C and a relative humidity of 75%
• For insulating material solutions, thermal conductivity to be improved from 0.02 – 0.03 W/m·K
• Innovative compressor solutions should be compact and fit into a 500mm*400mm*300mm compact space
• Meet all safety considerations in terms of food contact
• Meet all electric and fire safety standards for use at points-of-sale

Other relevant information:

• Cabinets operate on single phase 220V 50 Hz AC electricity source in most countries, except in some countries like the US where it is 115V 60 Hz AC
• Internal volume of cabinets range from 200 – 500L (static) and 100 – 150L (mobile)
• In existing cabinets, the insulation material consists of polyurethane foam, with an environmentally friendly blowing agent like cyclopentane
• The glass lids on cabinets are mainly single pane with a low emissivity (low-E) coating
• Relevant standards - Any cabinet purchased by Unilever must comply with the regulation of the country in which it will be installed (e.g., CE, UL, CCC, NOM 022 etc.). Where no local legislation is applicable, the cabinets must anyway comply with CE or UL (Underwriting Laboratories) rules. 

Solutions like more efficient insulation or a refrigeration technology that is more cost effective than vapour compression systems may be adopted on Unilever’s new ice cream cabinets or retrofitted on the current fleet of cabinets in the field. 

Solutions proposed to reduce energy consumption on existing cabinets in the field should be easily retrofittable at the point-of-sale or in the warehouse as a single man operation taking no more than an hour. For new cabinets being produced in a factory for which solutions may be proposed this can be flexible.

If approvals are difficult or time consuming to achieve during the prototype phase, we could consider prototypes for in-house lab testing. However, units that are to go into point-of-sale outlets later would need necessary approvals.
 

Ice cream cabinets are mass produced and relatively low cost (ranging from around €120 to €400 depending on the size/volume of the models). Hence any add on cost required for the new features suggested would need to be extremely low or provide substantial benefits that outweigh the increase investment.

Unilever currently has a cabinet fleet of around three million ice cream cabinets globally with a large addition to the fleet annually.

Solutions should be available for testing in 2022, with a view towards industrial application in 2023.

• While no budgets have been set apart for this development, Unilever would consider supporting cost of prototypes for testing. However, we would expect to know indicative costs of these prior to any development prototypes being produced. Support for field testing including test locations can be provided.
• This is strategic as part of the ongoing initiatives to bring Unilever another step closer to achieving net zero by 2039.
• Target innovator community (students, SMEs, start-ups) can be considered.
• Early test of prototypes in one country or region but the application if successful will be global – in all countries where Unilever has an ice cream business.
• Unilever would ideally like to own the IP or have exclusive use of the IP if development funding is provided. However this can be discussed in more detail going forward.