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Carrier Refrigeration has blazed a trail in the delivery of CO2 systems to retailers on the continent. Now, with the unveiling of its new Co2oltec booster system at an Aldi store in Oxford, the company believes the tide is turning for the UK market. Andrew Gaved reports

Anyone who needs convincing that discount supermarkets are increasing their influence on the Great British Public should go to Aldi’s new Oxford store and take a good look around. If you can get an unimpeded view, between the constant stream of shoppers browsing the aisles, you will observe that, these days, there is a wide range of goods on display, rather than the eclectic mix of ultra-low priced basics and exotic imports from continental suppliers.

An Aldi spokesman confirms that these recessionary times have ushered in a new era for the discounters, propelling their market share upwards against the giants of the retail trade. “We are now focused on the ‘full shop’ for customers, rather than just the ‘second shop’ that we used to provide,” he says. But this growing influence among shoppers offers the prospect of an equally significant impact in the UK rac sector. As the discounters drive a different way of doing things to traditional supermarkets, they will require a different approach from their rac suppliers.

That is certainly what Phillipe Delpech believes. President of Carrier Commercial Refrigeration, the company responsible for the installation at Oxford Aldi (see box), his view is informed by a decade’s success in continental Europe and a claimed 70 per cent share of European discounters’ refrigeration installations.

“Discounters have characteristics that are good for a refrigeration supplier like us,” he says. “First, their stores have more standardisation than you would find with the traditional supermarkets and local management have less influence on specification. This means that they are able to replicate the same concept across lots of stores.”

Aldi’s Oxford installation

Certainly the Aldi Oxford store is high spec, the first UK discount store to have a transcritical CO2 installation. The 10,000 sq m is cooled by Carrier’s Co2oltec two-stage concept, which is designed to utilise high pressure in the plant room at around 100 bar but lower pressures of 40 bar in the store areas.

The Oxford store’s dual temperature CO2 pack cools seven Carrier Monaxis multidecks (lowered for additional merchandise volume), a roll-in milk cabinet and two coldrooms.

Aldi also runs AHT integral freezers, running on R290, to claim an HFCfree store.

The 57 kW pack itself comprises two MT and one LT Bitzer compressor in Carrier’s ‘booster configuration’, with the LT compressor connected to the suction side of the MT unit, avoiding heat exchangers and thereby improving efficiency. The pack rejects heat to a three-fan Guentner gas cooler, with one of the fans EC-controlled.

Carrier points out that there are a range of pressure relief valves, both permanent and service valves, to reduce risk from the high pressure of the refrigerant. Project
engineer Stuart Webb says: “All aspects of the plant have relief valves. There is no way the system cannot vent to atmosphere under a catastrophic situation.”

The advantage of the CO2 system is that, in the UK’s climate, it only operates transcritically in high ambient summer conditions, whereas for the rest of the year the
condensing temperature can be cut significantly, boosting energy efficiency.

Aldi UK is not yet committing, publicly at any rate, to a wholesale changeover to CO2 at this stage, and the next batch of planned stores are based on HFCs. But there is plenty of optimism around.

Aldi’s spokesman says: “This is a trial and we are very happy with the way it is performing, so we will see how it goes. Having said, we know that Aldi in Europe hasa substantial number of stores working on CO2, and that the gas is both efficient and environmentally friendly, so we would like to embrace it.”

Economy of scale

The advantage of this for the supplier, of course, is that they can leverage economies of scale. But it also means that turnkey suppliers that provide the skilled labour as well as equipment can introduce benchmarking across regions, for customer service levels and so on, benefiting supplier and customer alike. Both of these elements can extend across national boundaries, if necessary,

“One of the other discounters, for instance, has one system across Europe, moving to one service protocol,” Mr Delpech says. “So, as a turnkey supplier across Europe, we are the right partner for a company like that.”

Secondly, he says, the discounters appear to be much more willing to invest in the right equipment: “They are not so focused on first cost only. You might not at first expect that, since their whole aim is to promote low-priced goods, but they are actually very sophisticated in their purchasing, with their decisions based on whole-life costing. Rather than being followers, they are leading the way.”

And it is end-users such as Aldi and Lidl that may end up ushering in a new era of refrigeration, he believes, not just based on natural refrigerants, but based on a wholesale change in engineering culture.

“I think the next decade will see refrigeration change fundamentally because there is so much pressure on the environment, and shoppers are becoming more cost-conscious and environmentally conscious. By 2013 I expect a third of new installations will be transcritical CO2 - it will be the driver for the northern climate because it provides the ideal conditions for cooling food.”

The fact that CO2 systems are most efficient in mild to cold climate conditions obviously plays well to the north of Europe, offering significant energy savings. A sample of 25 Swiss stores delivered 10 per cent reduction in electrical consumption over R404A, and the UK climate is expected to produce gains on that.

In addition, Carrier’s Co2oltec ‘booster’ transcritical system offers a further 2 per cent reduction against the CO2 cascade version used in Switzerland, along with the potential for better heat recovery, thanks to its high discharge temperature.

“We quote a 10 to 12 per cent saving, but some stores have achieved much more,” says Mr Delpech,

The future is CO2

But add in the claim of a 60 per cent reduction in carbon footprint over R404A direct evaporation, and it is clear why Mr Delpech envisages a predominantly CO2 future: “One store presented a 55 per cent reduction. Working on a 5 per cent leak rate, that store would offer a 3,500-tonne saving in CO2. But imagine the CO2 saving it the leak rate was 25 per cent.”

However, he is also concerned that the British refrigeration industry should change its habits first: “The current model has got to change because it is wrong - youcannot continue to have a 25 per cent leak rate in stores. We know better results are possible, as in Germany, for instance, where it is only 5 per cent. Imagine that the leakage would fill up a store like this one in Oxford four times over in 10 years. I think the people that allow this should be held responsible.”

And the way that companies deliver the installations is set to change, he believes, since he sees the turnkey approach offering a fundamental advantage over conventional contracting for CO2: guaranteeing the skilled engineers.

“Turnkey projects are key as soon as you have a technical barrier, since you can guarantee the expertise, and with a service package you can guarantee the
reliability too,” he says. “I think up to 80 per cent of the work in supermarkets in the future will be turnkey.”

Naturally, given the fact that Carrier claims 100 turnkey transcritical sites in Europe, with a million hours of operation between them, Mr Delpech believes his firm is well placed to capitalise on the potential.

One of the challenges for Carrier will, of course, be finding sufficient CO2-skilled workers to accommodate the anticipated rise in UK projects.

But the current model only accounts for the northern parts of Europe, not the warmer southern zone. Naturally, Mr Delpech is working on that.