Can you use refrigerators to heat stores?

Supermarket Fridge

As we all know, heating can account for a chunk of your business’s energy bills. But a new venture by Sainsbury’s is using the technology behind ground source heat pumps to reduce their consumption by 30% – and it might be an energy solution for businesses all across the country, too. But first, it’s worth knowing a little about how the technology works.

Ground source pumps provide low cost heating

Thanks to the insulating effect of earth and rock, there’s a fairly constant temperature all year round just a few metres underground. And with a ground source heat pump, homes and businesses are able to take advantage of the free heat that’s generated below the surface.

A loop of pipe that carries a mixture of water and anti-freeze is buried underground. As the mixture is circulated through the loop, it picks up heat from the earth and then passes through a heat exchanger into a heat pump, which uses the heat gained from the ground to warm up the building’s radiators or underfloor heaters.

But they can also be used to store excess heat under the earth

Have you ever felt the back of a big fridge? It kicks out a lot of heat. That’s because it’s essentially one big heat pump. It draws heat energy from the inside of the fridge, cooling the contents, and pushes that heat out and into the air behind it.

And if you’ve got a lot of fridges, that could be a lot of wasted heat.

That’s why Sainsbury’s have recently rolled out a new way of recycling heat from their in-store fridges. The new technology soaks up the excess heat pushed out from the back of their refrigeration units and pumps it into an underground heat chamber. The insulating effect of the underground rock helps to retain this heat until it’s needed, when it gets pumped back out of the ground and into the store’s heating system.

As you know, the average supermarket has plenty of fridges: dairy aisles, cold beer and wine, deli counters, frozen foods and meat. So it should be no surprise that this new energy-saving investment has reduced overall energy consumption in the shops using ground source tech by 30%.

Sainsbury’s has already seen success in 30 of their stores across the country, and they’re currently working with us to fit another 70 shops with the new technology.

‘We’re delighted to be leading the way on this groundbreaking technology – helping to reduce energy use and carbon,’ announced Paul Crewe, Head of Sustainability, Engineering and Energy at Sainsbury’s. ‘I hope that with British Gas and Geoscart’s help, we’ll now see more retailers following suit.’

And if you aren’t ready to invest…

Perhaps your business only has a fridge or two – or even just a chilled vending machine. Or perhaps you could benefit from the new innovation, but you can’t afford to start digging around your premises just yet. In the meantime, here are a few quick tips to help minimise the energy your fridges waste.

• Don’t overstock. A fridge with too many goods inside, or goods blocking the air vents, pushes cool air into the aisles rather than using it to cool the stock
• Keep it clean – especially the back. The back of almost any fridge holds a condenser and a loop of piping that lets the heat disperse into the air. Dirt, grime and dust can block this transfer of heat, meaning your fridge has to work even harder to keep things cool inside.
• Set it only as low as you need it. If you can safely – and lawfully – set your fridge a few degrees higher, you can reduce how much energy it uses. Raising the temperature of a freezer by just 5°C could reduce energy consumption by as much as 11%, according to one academic study.

You can get even more tips from the Carbon Trust here (pdf).

Would you like your business’s heating come straight out of the ground? Join the discussion on LinkedIn or Google+.

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