Supermarket redesign offers improved outcomes for all
Supermarkets can cut their power consumption by up to 50% tomorrow – resulting in opportunities for lower food costs, lower inflation and reduced carbon emissions. Supermarket owners just have to implement some simple design changes to start unlocking savings.
Independent testing has verified that some relatively simple design changes have reduced energy consumption in 13 Austrian supermarkets by 30-50%, in a collaboration between family-owned supermarket chain Mpreis and the Austrian arm of the Passive House Institute.
Supermarket fridge and freezer cabinets are essential elements in the modern food chain, but they also consume massive amounts of energy.
Those frozen peas, safely cooled sausages and chilled yoghurts may be a critical part of your daily diet, but they can be cooled more effectively and way more efficiently if their fridge cabinets are cocooned in glass doors.
In the Mpreis supermarket in the village of Patsch, just out of Innsbruck in Austria Passive House Institute scientist Laszlo Lepp enthuses about the opportunities to rapidly reduce climate change impact and supermarket costs with some simple changes.
“It’s like at home, we don’t leave the fridge door open all the time. If we place glass doors around the fridge cabinets in each supermarket that we upgrade, we can halve the energy that they use for food cooling straight away,” Mr Lepp said.
“Supermarkets are very energy consuming buildings and yet we can make a big difference to their energy consumption with some relatively small changes,” Mr Lepp said.
With a payback time of 5-7 years to incorporate passive house design into the building, the seven year-old Patsch supermarket is already past the payback window – and the company is now enjoying the reduction in energy costs each year, without having to lift a finger.
With double glazed doors across fridge areas, it was able to save about 50% of the energy used for refrigeration. Triple paned glass is used for freezer cabinets, because of the greater differential between the air temperature in the freezer and the air in the building.
The temperature difference between fridges and the air in the building is about 20 degrees Celsius – meaning open fridges have to work constantly to try to maintain that gap.
Heat created by the refrigeration equipment could be captured and used to heat the building – no additional heating is required. Insulation is built into each wall, double and triple glazing significantly reduces heat transfer to the outside world and draft gaps are sealed.
In addition, the building design seeks to eliminate thermal bridges – the use of materials that conduct heat between inside and outside, such as metal roof girders which poke out under the eaves, or metal window frames without a thermal block that can act as a summer internal radiator or a winter cooler.
Mr Lepp says the changes that can relatively easily be achieved through design can be applied to new commercial buildings or renovation of existing structures – as his team have helped achieve in the massive refit of ageing apartment buildings in Innsbruck through the SINFONIA project.
He started focusing on improving supermarket design after recognising that there were ways to reduce massive energy bills from the humble supermarket.
“The supermarket is a kind of passion for me, I have been happy to work on them for the last 10 years,” Mr Lepp said.
“Mpreis is a family-owned supermarket company here in Austria and the Passive House Institute started working with them 10 years ago. We now have 13 certified supermarkets meeting Passive House standards – 11 new build and two refurbished,” Mr Lepp said.
“Its really satisfying to work on a project demonstrating that you really can make a difference to running costs, energy consumption and the planet by developing commercial buildings with Passive House principles.”
Energy consumption of Austrian supermarkets:
- 40% refrigeration
- 20 % lighting
- 20% bakery,
- 20% other uses
Changes to the supermarket build
A thermal envelope – keeping the air outside separate from the air inside.
- Sealing gaps around doors and windows,
- Using double or triple glazed windows to reduce heat loss / transfer between inside and outside
- Installing strong and effective wall insulation
- Eliminating thermal bridges – for example a metal beam that extends from inside a building to the outside will conduct heat straight in or out. Creating designs that minimise or if possible eliminate thermal bridges significantly reduces heat transfer
Making better use of appliances
- Selecting high-quality energy efficient appliances
- Putting doors around open fridge and freezer cabinets to reduce heat loss
- Re-using heat from fridge and freezer motors for internal heating
- Turning off appliances when not required
- Installing solar and/or other renewable energy generation capacity on site
- Choose electrical appliances over other fuel sources so that they can be powered by renewable sources
Internal air movement
- Design and some simple mechanical ventilation assistance enable the whole building to be heated with heat from fridge and freezer motors without the need for strong fans pushing air around.