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: Window Display Of The Year Frame Awards 2019...
21.06.2019   #displays #product presentation

'Window Display Of The Year' Frame Awards 2019

Window installation featuring the Ura raincoat

Fourteen waterproof raincoats are suspended from seven bicompartmental metallic structures strategically placed on the ceiling of the store simulating drops of water. The shoppers’ attention is therefore drawn directly upwards to the product ...

Thumbnail-Photo: What shop design can look like: Marktscheune in Berghaupten...
18.03.2019   #shop building #brick and mortar retail

What shop design can look like: Marktscheune in Berghaupten

Many wooden design elements, rustic flair, and the Farmer’s Café delight guests

Buy a piece of cake, have a cup of coffee and pick up some fresh vegetables and fruits to take home. Customers can run all of these errands at the Marktscheune (English: Market Barn). The so-called Naturpark-Bauernmarkt (English: Nature Park ...

Thumbnail-Photo: Power floor: power store
27.03.2019   #pos marketing #in-store marketing

Power floor: power store

Practical examples of amazing flooring designs

Sales promotion is also a matter of the floor. Take the time for some inspiration and discover different designs - from colorful and patterned to natural and neutral - in practical examples that we have put together for you. All projects can also be ...

Thumbnail-Photo: Year after year: Christmas decoration
11.06.2019   #decorative lighting #trend research

Year after year: Christmas decoration

From classic to modern - four styles for 2019

Every year, Annetta Palmisano and her colleagues of Stilbüro bora.herke.palmisano compile the decoration trends for the coming Christmas season. Below we outline four styles for the 2019 season. ...

Thumbnail-Photo: Expert tips: the best flooring options for your retail store...
15.04.2019   #shop building #visual merchandising

Expert tips: the best flooring options for your retail store

Ways to make a great first impression with customers

You need a new look for the flooring in your store – you have many options and they must be considered carefully. Industry experts told us what the different types of flooring from vinyl to carpet all the way to renovation lacquer systems have ...

Thumbnail-Photo: Retail holiday decorations: trends for the 2019/20 season...
09.05.2019   #decorative lighting #shop decoration

Retail holiday decorations: trends for the 2019/20 season

"The little affectionate details are always what’s most important." Interview with Annetta Palmisano

Many details or a simple design, artificial light displays or natural light – there are many ways to showcase window displays. Retailers who decorate with a light touch can use the emotional impact on customers and affect retail business ...

Thumbnail-Photo: Presentation of goods for convenience at gas stations...
28.02.2019   #product presentation #shelf systems

Presentation of goods for convenience at gas stations

POS TUNING and ARAL report on a successful multi-partner project

At this year's Annual Conference on Trade and Change in Gas Stations and Convenience Shops, Kristin Kolbe-Schade from POS TUNING and Carsten Biermann from Aral reported on a successful tobacco project which they implemented together with other ...

Thumbnail-Photo: One, two, go: get a new shop window!
27.02.2019   #shop decoration #brand management

One, two, go: get a new shop window!

Magnetic films make it possible

Redecorating an entire shop window in 30 seconds? Yes, that's possible! At the Panorama in Berlin we saw exactly that at the booth of the Pioneer Trading Company. The principle is simple: magnetic films with all kinds of motifs can be ...


POS TUNING Udo Voßhenrich GmbH & Co KG
POS TUNING Udo Voßhenrich GmbH & Co KG
Am Zubringer 8
32107 Bad Salzuflen
Pioneer Trading Company GmbH
Am Sohlweg 26
76297 Stutensee