C-Store supermarket cuts 11% off energy bill

Friday, 3 December 2010
The Centra supermarket in Rathdangan in Ireland is a typical small store serving the local community.

A review of the refrigeration system of one of the Centra supermarkets in Ireland led to the installation of the Danfoss ADAP-KOOL® combined with the Small Store System Manager. The energy savings amounted to 11% every year.

The good results of the refrigeration retrofit have encouraged Cross Refrigeration, who serves a lot of similar customers in Ireland, to recommend the turnkey refrigeration solution to other supermarkets.

“We can see many advantages for our many other supermarket customers of similar size and design, which can achieve significant and improved energy savings by targeting and applying this equipment to specific energy consumables within the store,” says Colin Singleton, Project Engineer from Cross Refrigeration.

The opportunities are far from exhausted and even better results can be achieved by extending the use of the Danfoss AK-PC pack controllers.

“Due to the fact that this was a retrofit into an existing system, the setup did not allow for full control of compressor operation, where most energy is consumed. Extended use of Danfoss AK-PC pack controllers would certainly have allowed even further savings through floating condensing temperature/pressure and suction pressure optimization, which can also be controlled and coordinated via the system manager,” says Shane Fleming, Danfoss Ireland.

The Centra supermarket in Rathdangan, County Kildare, Ireland is a typical small store (approx 500 m2) that supplies a variety of grocery products to the local community. While independently owned, the store operates under the franchise banner of the Musgraves Group.

In 2009, during an installation review by Cross Refrigeration, a leading supplier of commercial and industrial refrigeration systems in Ireland, the company’s engineers identified potential energy efficiency enhancements and performance boosts. Colin Singleton, Project Engineer from Cross Refrigeration, explains ”The equipment in the store was installed in late 2008 with the latest equipment on the market, including digital scroll compressors and new modern case designs from Costan. This provided an ideal platform to start, as we could see that it was possible to increase performance and reduce running costs.”

Cross Refrigeration therefore contacted long-time partner, Danfoss, who has a long history of providing systems and solutions that reduce the energy consumption of refrigeration applications. With the storeowner’s permission, the two companies joined forces to evaluate the potential savings in more detail. Together the companies drew up a plan to optimize the store’s refrigeration system and ancillary facilities.

From the review, Danfoss and Cross Refrigeration engineers fitted a variety of Danfoss ADAP-KOOL® controllers in the store’s display cases and cold rooms, and linked them with other Danfoss AK controllers already applied. At the same time, they installed the new dedicated AK-CS small store system manager and power meters to supervise and monitor the power consumption.

This setup successfully connected the many different display cases, cold rooms, units and compressors, which until then all operated independently from each other. With the AK-CS functioning as the front end system manager, it was then possible to control and monitor night setback, lighting schedules on cases, fan cycling, thermostat modulation and defrost scheduling.

The system conversion was relatively easy to install, and after a total of 12 weeks of before and after test running, Cross and Danfoss reviewed and evaluated the comparative results.

“First, we measured the energy consumption over a six week period without optimizing the performance of the store system. Then, we used the basic features of the ADAP-KOOL® platform through the AK-CS controller to optimize the system’s settings,” says ADAP-KOOL® Projects Engineer, Shane Fleming from Danfoss Ireland.

The logging system used to monitor performance was accessible remotely through the built-in WEB server in the AK-CS system and a wireless 3G router, which added installation flexibility compared to a fixed broadband line. This allowed for full temperature overview, alarm monitoring and response, remote repair/fix as or if needed, and data download of the system’s performance.

After a further six weeks running, the results spoke for themselves, as the store’s energy consumption had dropped by 11%, translating to approximately 8,000KWH a year, or reducing energy costs by approximately €1,200 annually.

Furthermore, the logging capabilities of the AK-CS system also satisfy the store’s HACCP requirements, giving live status overview and saving valuable time by automatically compiling compliance documentation.

According to Shane Fleming this is merely the tip of the iceberg.

“Due to the fact that this was a retrofit into an existing system, the setup did not allow for full control of compressor operation, where most energy is consumed.

Extended use of Danfoss AK-PC pack controllers would certainly have allowed even further savings through floating condensing temperature/pressure and suction pressure optimisation, which can also be controlled and coordinated via the system manage.”

Mr. Fleming adds that the AK-CS system can be easily extended to control and manage, outdoor canopy/signage lighting, water heaters, air curtains, in-store A/C, etc., with additional potential savings.

For Colin Singleton, the project also provided an opportunity to review and evaluate new developments within energy savings and efficiency for C-Store applications at first hand: “We have a lot of Danfoss systems in the market in Ireland, but it is always good to learn about new advances. We can see many advantages for our many other supermarket customers of similar size and design, which can achieve significant and improved energy savings by targeting and applying this equipment to specific energy consumables within the store.

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