CO2 Refrigeration system for supermarkets
Frigrite Refrigeration is a fully owned and operated Australian refrigeration company with branches around the country and in Cheltenham, Victoria.
Frigrite are working with a major Australian supermarket chain to incorporate the benefits of environmentally sustainable energy initiatives into the design of their refrigeration for a ‘green’ supermarket. This involves supplying CO2 cascade technology into supermarket refrigeration cabinets to greatly reduces emission of greenhouse gases.
Frigrite Refrigeration has formed a consortium with Danfoss (Australia) Ltd, Bitzer Australia Ltd and CSIRO to commercialise the technology. Both Danfoss and Bitzer are component suppliers. Frigrite and Bitzer have manufacturing plants in Melbourne. The fourth partner is CSIRO Energy Technology.
Supermarket refrigeration accounts for approximately 1% of the Australia’s electrical demand. There is currently a major technology step change in supermarket refrigeration under way around the world due to requirement for reduced refrigeration cost and to lower greenhouse gas pollution. Several approaches are being taken, in Europe the trend is towards using CO2 in cascade systems.
Sustainability Victoria has supported Frigrite Pty Ltd in a two-step process. First there was the design, building and testing of a pilot refrigeration equipment cabinet suitable for supermarkets, replacing the conventional hydroflourocarbon refrigeration plant with a cascade of a hydroflourocarbon stage in conjunction with a liquid CO2 stage that reduces fugitive emissions.
The proposed system uses a secondary refrigerant CO2 (R744A), as well as the commonly used refrigerant R404A in a cascade design. The system uses about half the refrigerant of comparable R404A and reduces equipment costs by allowing smaller size piping to be used, reduction of evaporators from four fans to two and other benefits including less energy consumption and cheaper overall costs of the refrigerant needed.
The cascading CO2 refrigeration cabinet maximises the efficiency of the shelving and energy usage. By reducing the height of the cabinet it allows a better flow of refrigerated air and improved lighting placed at angles for optimal wattage, thereby also producing less heat.
After successful testing of the prototype, the second step will involve installing the technology in a sample Victorian supermarket. A successful demonstration will provide an energy efficient alternative for supermarkets at about the same capital cost.
The capital cost for the project is estimated at $1.65 million for full in-store installation, with a total of $400,000 allocated towards the development of the CO2 cascade refrigeration cabinet itself.
Sustainability Victoria has been closely involved in the project management with Frigrite, beginning with systems design, procuring components, examining best practices with overseas experts, assembling the prototype and initial testing. Development of the business case involved initiating an independent project review and coordinating transfer of the results to the public. Sustainability Victoria then helped with the implementation of the commissioned plant and collation of project outcomes to demonstrate the project outcomes. One major deliverable is to measure the actual energy saving of the prototype and CSIRO will verify the analysis.
The project commenced in March 2004 and is expected to be commissioned and fully operational by November 2005.
The total energy saving being targeted by Frigrite Refrigeration is 15% (200MWh) and is gained from 7% energy savings from use CO2 as the refrigerant through the compressor plus another 8% due to improved heat transfer from using liquid CO2 in the condensing tubes.
With a full roll out of the technology based on a planned expansion of 12 new supermarket stores per year, and a possible 22 refurbished stores each year, there is a year on year energy saving potential of 6.9GWh.
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