Slurry ice • 05.10.2016

Cooling with liquid ice

Sustainable slurry ice refrigeration systems in food retail

The use of ice in food retail already enjoys a long tradition. Today, the cooled mass, and more accurately slurry ice, experiences somewhat of a renaissance in cooling technology. The reason for this is also the F-gas Regulation that went into effect in January 2015 and restricts or fully bans the use of hazardous refrigerants. This means food retailers need to change over to environmentally friendly cooling systems.

Slurry ice cooling systems could present the key alternative in this case since they forego climate-changing cooling agents that have a potentially damaging effect on climate. “The basic material for slurry ice is a mixture of water and a freezing point depressant material such as ethanol, glycol or salt, “explains Michael Kauffeld, Professor at the Institute of Refrigeration, Air Conditioning and Environmental Engineering at the Karlsruhe University of Applied Sciences.

Slurry ice is produced in a so-called scraper blade evaporator that works similar to a slush machine, Kauffeld adds. Ice particles are scraped off on the inside surface of a cylinder that is cooled from outside with cooling agents. A pump then moves the ice particles into a container. “The higher the percentage of ice, the more cooling energy can be transported with the liquid ice. It is relatively easy to store large amounts of cooling energy if the ice is kept in a container“.

Slurry ice storage at University of Karlsruhe.
Slurry ice storage at University of Karlsruhe.
Source: IKKU

Slurry ice is gentle on the environment

Traditionally, supermarkets use direct evaporative cooling systems. These contain R404A refrigerant, which significantly contributes to global warming at 3900 GWP (global warming potential). The already effective F-gas Regulation bans the use of refrigerants with high global warming potential of 150 or more starting in 2020. This affects thousands of supermarket cooling systems.

Kauffeld adds, “Natural refrigerants with near zero global warming potential are much better; those refrigerants being ammonia, propane or CO2. The latter is also the coolant that is by now favored by the food retail industry – at least by major equipment manufacturers. We use a combination of propane, slurry ice, and CO2 at our university cafeteria. The propane cooling system generates the slurry ice. It is pumped through the building and cools the intended food items. Small decentralized CO2 cooling systems are also used for low-temperature cooling. They release their heat to the slurry ice cycle“.

High level of financial commitment with quick amortization

The switch to a slurry ice-based cooling system is a good alternative for food retailers, but not just from a sustainability perspective. The expert knows, “The piping system would need to be completely updated during a remodel. The refrigeration units and heat exchangers can be reused in part. You only need to replace the expansion valve“. He adds that due to the high level of energy density of slurry ice (compared to a liquid refrigerant), merely one-eighth of the cooling mass needs to be pumped through the cooling system. As a result, pipes and pumps will decrease in size and subsequently so does energy consumption.

Even though the costs of newly acquiring slurry ice-based cooling systems are generally between 40 and 45 percent higher than the cost of conventional direct evaporation systems, the purchase can be quickly amortized with the right electricity plan. “The major advantage of slurry ice is that the cooling system of a supermarket is also able to run at night. This mostly makes ecological sense since the ice can be produced while ambient temperatures are lower. The slurry ice is then fed into the cooling system the next day, “says Kauffeld. What’s more, the likelihood of leaks is significantly lower than with direct evaporation systems. There is no need for additional safety installations and refrigerant leak detection sensors.

Flake ice also frequently injures the skin of fresh fish....
Flake ice also frequently injures the skin of fresh fish.

Slurry ice in the convenience food sector

The cooled mixture is not just being used in cooling systems. Canada in particular uses slurry ice in areas for convenience foods. To present products as fresh as possible, Canadian grocers generally prefer to place them on flake ice. A popular method that can frequently also be seen at fish counters in Germany.

However, the drawback of flake ice is that it requires strong associates to fill the counters and displays in the morning and empty them out again at night. That’s why one Canadian company has developed a slurry ice-based system where a large hose pumps the slurry ice into the displays. The water-salt mixture runs off through a drain, leaving behind pellets in which the products are placed. What’s more, in direct contact, slurry ice cools faster and more gently than flake ice, thereby eliminating the risk of damage to food from sharp edges.

A laboratory-scale ice generator

Liquid ice is a high efficiency, environmentally friendly coolant because no hazardous waste products or harmful substances are being produced. That’s why the number of slurry ice-based cooling systems will continue to rise over the next few years, not least due to the F-gas Regulation. For the use of this technology to expand, it would presently take a more efficient and cost-effective ice generator. Having said that, the researchers at the Institute of Refrigeration, Air Conditioning and Environmental Engineering already developed a laboratory-scale ice generator. The implementation of an industrial prototype is also already said to be in the planning stages.

Author: Melanie Günther; iXtenso

related articles:

popular articles:

Thumbnail: Photo: Commercial Audio Solutions

Company News • 19.02.2018

Commercial Audio Solutions

Expertise in PA technology

Thumbnail: Photo: What shop design can look like: The unique store of Mußler Beauty by...

Reinventing the perfume industry • 29.01.2018

What shop design can look like: The unique store of Mußler Beauty by Notino

Online/offline symbiosis: Inspired by Arabian bazaars and current trends

Thumbnail: Photo: Bizerba at Anuga FoodTec 2018

Company News • 17.01.2018

Bizerba at Anuga FoodTec 2018

New solutions for today’s and tomorrow’s process technology

Thumbnail: Photo: The perfect fit: APG Cash Drawer & Wordplays My Business Hub...

Company News • 23.01.2018

The perfect fit: APG Cash Drawer & Wordplay's My Business Hub

APG Cash Drawer selected as the preferred cash drawer supplier for Worldpay’s My Business Hub

Thumbnail: Photo: Refrigerants in supermarkets: Possible savings up to 51 thousand euros...

Interview • 22.11.2017

Refrigerants in supermarkets: Possible savings up to 51 thousand euros

Interview about the development of refrigerants in retail

Thumbnail: Photo: SES-imagotag wins the 2017 LSA Award

Company News • 16.01.2018

SES-imagotag wins the 2017 LSA Award

The company is recognized for ist automatic stockout detection solution

Thumbnail: Photo: Reliable foreign-body detection with Bizerba’s INTUITY metal-detection...

Company News • 10.11.2017

Reliable foreign-body detection with Bizerba’s INTUITY metal-detection coil

Detecting metallic contaminants in products or bulk goods

Thumbnail: Photo: Mister Baker: How the best Bakery Chain in the UAE remains at the Top!...

Company News • 12.01.2018

Mister Baker: How the best Bakery Chain in the UAE remains at the Top!

Modernizing the brand experience in-store

Thumbnail: Photo: Meijer unveils newly-remodeled Rockford Supercenter...

News • 12.12.2017

Meijer unveils newly-remodeled Rockford Supercenter

22nd Midwest location to be remodeled this year

Thumbnail: Photo: Bizerba doubles the digital printing capacity of its Bochum facility...

Company News • 31.01.2018

Bizerba doubles the digital printing capacity of its Bochum facility

Brand new HP Digital Press printing machine Indigo 8000


SES-imagotag Deutschland GmbH
SES-imagotag Deutschland GmbH
Bundesstraße 16
77955 Ettenheim
Zum Falsch 36
28307 Bremen
Steinerne Furt 67
86176 Augsburg
Ergonomic Solutions GmbH
Ergonomic Solutions GmbH
Kammerratsheide 43
33609 Bielefeld
APG Cash Drawer
APG Cash Drawer
5250 Industrial Blvd NE
55421 Minneapolis
Citizen Systems Europe GmbH
Citizen Systems Europe GmbH
Otto-Hirsch-Brücken 17
70329 Stuttgart
Elo Touch Solutions NV
Elo Touch Solutions NV
Kolonel Begaultlaan 1C11
3012 Leuven
Bizerba SE & Co. KG
Bizerba SE & Co. KG
Wilhelm-Kraut-Straße 65
72336 Balingen