Supermarket Refrigeration: HFCs reduced as Waitrose shelves CO2 for ‘greener’ future

Supermarket Refrigeration: HFCs reduced as Waitrose shelves CO2 for ‘greener’ future


IN what has been seen as a ground-breaking move, Waitrose has announced its intentions to use hydrocarbon refrigerants in all its new stores and refurbs. Neil Everitt looks at the reasons for the decision and how the system will work.

In 2007, and probably in response to this environmental pressure, six of the top supermarkets announced their intention to move away from HFCs – but where could they go?

A lot of work has been done with CO2 but there are continuing concerns over its suitability – particularly with regard to it being a high pressure refrigerant and the apparent lack of a sufficient number of technicians conversant with this type of equipment.

Waitrose has poured a reported £55m into improving its refrigeration systems in the last five years but has previously admitted that trials of CO2 have been complex, and a lack of technical know-how has been seen as a major barrier to adoption. Even so, it came as some surprise when Waitrose recently broke ranks with its competitors by announcing its intention to use hydrocarbons on all future new stores and refurbishments.

Unbeknown to most people, Waitrose had been carrying out trials with the technology over the last 18 months, both live in the field and within test labortories.

The system it has developed in association with Synergy Building Services Consultants, Carter Retail Equipment and chiller manufacturer Geoclima is based on the hydrocarbon refrigerants propane and propene, a choice which it says will enable it to cut its carbon footprint by 20%. It is being installed in Waitrose’s Altrincham store which is due to be opened this month and then rolled out in new and refurbished stores across the country.

Waitrose’s new solution employs hydrocarbon refrigerants as the primary cooling medium with water as the secondary heat transfer medium. The primary plant uses air-cooled liquid chillers utilising propane (R290). The cabinets and cold room evaporators will be charged with propene (R1270). In addition the refrigerated cabinets, chillers, cold rooms and freezers incorporate integrated DX units with refrigerant and water plate heat exchangers.

A typical system will include two 140kW Italian-made Geoclima air-cooled liquid chillers supplied by Klima-Therm and running on R290. The chillers use a combination of LPA Pumps, with floating head pressure and traditional free-cooling to significantly increase operating efficiency. They also use high efficiency aluminium coils.

Commenting on the system, Tim Mitchell, who is heading up the project for Klima-Therm, said: “The relatively high temperature of water returning from the chill cabinets to the chillers means that the chillers can operate in full free-cooling mode from 12ºC ambient downwards. This means that for more than half the time (around 55%), the chiller operates in free-cooling mode, without having to power up the compressor – delivering huge efficiency benefits and reducing carbon emissions.”

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Supermarket Refrigeration: HFCs reduced as Waitrose shelves CO2 for ‘greener’ future

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