Among the host of technologies that are helping Walgreen’s to open America’s first ever “net zero energy” retail store is a ground-breaking heating and cooling solution by GI Energy that is claimed to be 60 percent more efficient than a standard Walgreen’s store.

The US store integrates green technologies including two wind turbines, 850 solar panels, LED lighting, daylight harvesting and advanced shading controls, along with GI Energy’s exceptionally efficient ground source HVAC/R system.

Walgreen’s stated aim is to run a retail store that will generate more energy than it consumes – a first for the country – by using the best technologies available. The company already has stores that use wind turbines, solar installations and ground source systems.

Mark Wagner, Walgreen’s President of Operations and Community Management, said: “This is the first time we are bringing all three of these technologies and many more together in one place. Our purpose as a company is to help people get, stay and live well, and that includes making our planet more livable by conserving resources and reducing pollution.”

When Walgreen’s called on GI Energy to produce the MEP/FP design packages and then install the combined ground source, mechanical and refrigeration system, GI Energy came up with an innovative solution that can achieve a coefficient of performance (COP) of up to 6 – which means that for every kilowatt of power required to run the system, six kilowatts of heating or cooling is produced.

These high levels of efficiency are achieved because the system is designed so that heat can be transferred from the store’s refrigerators, freezers and air conditioning to its heating and domestic hot water as required. Excess heat can be expelled to the ground, where it will be stored naturally and can be used again, via the ground source heat exchanger, or to the air, via a “gas cooler” on the roof. The choice will depend on the weather and ground conditions at the time.

Dan Couillard, Vice President of GI Energy, said: “At GI Energy we strive to provide the highest possible value to our clients in the design-build, site-specific energy industry. Our two core competencies are Ground Source Heat Pump (“geothermal”) systems and Combined Heat and Power systems. In this case we were able to bring to the table our geothermal expertise to help Walgreen’s bring to life a truly unique project. My hat’s off to them for what they’ve accomplished.”

Rob Olden, Engineering Director for North America at GI Energy, said: “We have made some real breakthroughs in the application of ground source technology on this project.  Thanks to Walgreen’s innovative spirit and commitment to advancing practical applications of clean technology, we were able to lead the design of a truly ground-breaking system.”

What makes the system unique is that all of the building loads are served by a single compressor plant that supplies all of the heating and cooling for the building, as well as all the cooler and freezer refrigeration needs. The key to this is a “transcritical CO2 ” compressor pack that manages heat recovery automatically to optimize overall system efficiency. GI Energy worked closely with the plant manufacturer, Green and Cool, to model and design the ground source system to meet the net zero energy requirements.

As the first project of its kind, it proves the value of combining CO2 , also known as R744 refrigerant, with a ground source heat exchanger as a sub-cooler. The integrated and flexible ground source heating and cooling system is more efficient than a R744 pack would be on its own.

For this project GI Energy created strategic partnerships with other local designers and installers to make sure that Walgreen’s numerous requirements for the store were met. Drilling for the ground source field was conducted while the building foundations were being installed and the new store was constructed on time within Walgreen’s nine-month timeframe. The store opened on time just ahead of the Thanksgiving holiday.

Taken together, all of the building’s features and systems are expected to produce more energy than they consume. The store is expected to require 200,000 kilowatt hours a year of electricity to run, while the renewable energy features will generate approximately 220,000 kilowatt hours per year.

To encourage the public to take an interest in the technologies that make this Walgreen’s the first zero-carbon store in the United States, the mechanical system is on display on a mezzanine level which shoppers can see while they tour the aisles.

The achievement has been hailed by Illinois Governor Pat Quinn who said: “I am proud that an Illinois-based corporation like Walgreen’s is taking the lead in the use of green technology, which will be a model for all retail operations across the country.

“The best energy sources are free, renewable and have little environmental impact – and that’s exactly what Walgreen’s is doing in Evanston.”

GI Energy

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