A Melbourne energy efficiency software company is attracting international recognition while slowly proving the possibilities of its service to larger and larger Australian clients.
Walking into a supermarket is like walking into an ice rink, where arctic blasts from refrigerated shelving and lidless chest freezers inspire shoppers to mourn the fact they didn’t don skiwear before setting out to grab an eight-pack of Paddlepops.
Don’t blame the shop-owners, though, because there are strict rules about how cold some food has to be. The cost of all that frigid air is included in your shopping bill, of course, but in its eternal effort to spend less Coles has enlisted a Melbourne energy efficiency company to help it run its fridges better.
Exergenics is collecting data at three Coles stores in the first stage of a pilot program to develop optimised control strategies for refrigeration equipment.
Racks of refrigeration in your typical supermarket include low-, medium- and high-temperature fridges. The low-temp units contain all the frozen stuff, medium will house milk and cheese and high-temp will display various other goods that prefer to be kept cold.
When your refrigerated inventory goes into people’s stomachs, it’s not simply a case of dialling the units to run on a warmer setting and save energy that way. Instead, Exergenics co-founder and CEO Iain Stewart expects to find energy savings by watching how compressors and rooftop fans operate.
“We’ll look at everything we can to maximise efficiency without impacting food safety,” Stewart tells EcoGeneration. To that end, the refrigeration levels won’t be toyed with. Instead, it becomes a game of looking at the back end. “We’re trying to look at how the compressors and the fans are working together to change the pressure of the fluid,” he says. “It’s all the equipment you never get to see, unless you’re in the back room. Without installing any new equipment, we want to understand how can we change the controls and get things to work more efficiently.”
Under the lid
In a set up at a large retailer, compressors and fans work together to reject heat from returning refrigerants. “We’re coming up with ways to look at how much load is on the fridges, what’s the outside temperature and how can we use that data to maximise the efficiency of the system,” Stewart says.
Coles has supplied data in 10-minute time steps which shows there may be room for improvement in the control of the fans. Rooftop fans will have different efficiencies at different outside air temperatures, and Exergenics’ software smarts will be set to work to find what those efficiencies are.
If it’s 25°C outside, for example, with 50% loading on the fridges, how fast should the fans run and how many compressors should be active to deliver adequate cooling using the least possible energy?
You might be running the fan too much and not the compressors, or the other way around.
The three refrigeration systems in a common supermarket may rely on four compressors each, all separate but in the same room. Separate fans on the roof will serve each of the three refrigeration systems. Fans are not as energy-hungry as the compressors, the machines that turn refrigerant gas back into a liquid, creating heat in the process. The fans are used to take the heart out of the compressed liquid, which then goes through an evaporator and sucks in heat as it travels through a circuit of narrow plumbing in refrigerators. Before it goes around again. Over and over. In an endless cycle of compression and expansion. That keeps all that ice-cream from melting.
The energy mind game
Any news about a huge business turning its attention to energy efficiency arouses feelings about how the “first fuel” is so overlooked. During his time as an analyst at ClimateWorks Australia Stewart recalls reports that showed the technical opportunity for energy efficiency is a possible 3% year-on-year improvement for industry, buildings and transport, “but we only access about 1% of that efficiency gain each year, and that’s typically due to equipment improvement over time.”
He blames the faulty internal human calculus, where future energy savings for efficient equipment are seen as less of an incentive than a saving today on cheaper, less efficient gear.
“Someone might say, I can spend $1,500 on a new air-conditioner today and make my money back in three or four years and profit for the next 10 years, but they’ll often spend $1,000 on a new air-conditioner and pay more over the lifetime of the piece of equipment.”
All of this is happening in an environment where businesses will grab attention by spending on clean energy generation before making all that much effort to understand and rein in their load. The energy efficiency crowd have felt left out for a long time now, when they are equally capable of contributing to the decarbonisation of the economy.
“The work we do is hidden away in these back rooms that not many people know exist,” he says. “It doesn’t have the same green-washing potential some of these other actions do.”
It’s easier not to use a kilowatt-hour of energy than it is to generate another kilowatt-hour, so why wouldn’t you spend on energy efficiency to avoid the enormous outlay of upgrading transmission and distribution lines?
As equipment becomes more efficient it is also becoming more complicated, Stewart says. About 20 years ago it was fairly easy to sit down and work out on a spreadsheet a reasonably optimal operation strategy for equipment in a facility. These days, it’s not as easy to work out the most efficient capacity levels for different pieces of gear, especially when they are running together.
It’s no fault of the equipment manufacturers, however. Rather, the job of working out the best control strategy is delegated down the chain. Take HVAC, for example.
“In a typical building the controls engineer is a subcontractor to the mechanical engineer, and the builder just wants to [complete construction] and get out of there, so there is not a lot of budget left for controls,” he says. “There’s a split incentive; who’s got the financial incentive to do this?” The developer only cares if stuff works.
The “green story” is being heard, though, and tenants are very slowly becoming aware of what energy efficiency means.
Can Exergenics’ smarts and others like them be incorporated into energy-hungry equipment at manufacture? “We are heading down that path,” Stewart says, hinting that the company is working on ways to ease the transference of data onto its platform so it can hand back recommendations.
Huge amounts of solar exports and the steep ramp to evening peak show “there is a massive opportunity there for large energy users” to cut costs by being flexible about their loads. “And the benefits for grid stability would be massive.”
Exergenics estimates annual cost savings across HVAC in offices, retail, hospitals, tertiary education, data centres and government buildings of about $500 million. In the supermarket sector, there is potential to save $40 million by better operation of refrigeration alone.
The work Exergenics takes on is not being ignored overseas. Iain and fellow co-founder and twin brother Tim, both 29, have been selected for the Forbes 30 Under 30 Asia List for 2021 in the category for industry, manufacturing and energy. It’s a fantastic result for a company that was only launched in 2019.