The “first fuel”, as we’ve heard before, is the energy you don’t use. The replacement of polluting generation with clean energy solutions is required, for certain, but business and industry can do a lot to solve the problem by simply using less electricity.
Business owners who shudder to consider the consequences to their operations shouldn’t fear, however, because chances are there is plenty of opportunity to cut load and save costs.
Melbourne company Exergenics is marketing a new service to businesses that targets savings in energy-hungry air-conditioning. If chillers can be optimized to garner financial savings by reducing peak demand, a fall in demand charges should follow.
Exergenics uses BMS data to make a model of all the equipment required for cooling and then runs an algorithm to find optimal settings. “We find out what’s the existing performance of the plant and then work out how do we optimise that to deliver the required cooling with peak efficiency,” says founder Iain Stewart.
The model of an existing plant becomes a testbed where different strategies can be trialled. For example, it might be possible to achieve the same cooling outcomes using a cheaper, more energy-efficient strategy. “Chiller sequencing is quite a common one, in terms of when you stage on and off certain chillers,” Stewart says. “There can be significant savings there.”
The Exergenics dashboard includes a baseline energy measurement and real-time plant performance, so the two can be compared and fine-tuned. “There is a lot of transparency in how it’s functioning and the actual energy savings being delivered in real time.”
The system can also be used to optimize load balancing among chillers, for example to work out which chillers are best suited to take load to deliver cold water around a building. “A lot of peak demand savings come from that aspect of the technology rather than just the chiller staging itself.”
The “glaring deficiency” in chiller-specific optimization packages is that they only work for a manufacturer’s own chillers, he says. “Our major difference is that we measure and verify all of our energy savings, which isn’t commonly done.”
Stewart is exploring the possibility of the Exergenics model directly controlling the settings of chillers in host locations, rather than then being manually adjusted. The system requires installation of an Optergy Proton data collection hardware on site, to feed data to Exergenics for modelling.
Built on data
As is often the case with helping business owners understand the value in energy efficiency improvements, things can be complicated by the clunky nature of data collection. Data points delivered at 15-minute intervals may have been state-of-the-art once upon a time but systems can be much more finely tuned if there is access to data at a far more granular level. “If we can reduce that time to one or two minutes then we can start to discover more about transient states of equipment; if we’re ramping a chiller up or down, how much more or less efficient is that if it’s at a steady state?”
The system refines its thinking as it tests different strategies.
Data availability is a major challenge, Stewart admits. Generally it is stored for six months, after which time it’s deleted. It makes it hard to work out a plan for businesses that operate in all seasons. The beginning of winter is a sweet spot for data access, he says, because the previous six months will include consecutive hot days. “We’ve got everything ramped up to it’s full capacity, or near enough, to be able to train our models,” he says. It will be far harder if access to data is granted late in the year, when only the cooler months will be documented. “We lose that ability to build a full model – that’s one of the big challenges.”
As energy costs are elevated to boardrooms as operational concerns, energy efficiency will be discussed more as a concern to the bottom line than a sustainability benchmark.
The solution is being trialled at two sites at Monash University: a building in the Clayton Campus with three air-cooled chillers and a building in the Caulfield Campus with three water-cooled chillers. A simulation of Exergenics’ control strategy is being compared with the existing cooling-management strategy to calculate energy and peak demand savings at the sites. At the Clayton Campus building savings of 17.7% and peak demand reduction of 13.2% are expected. “That’s just the chilled plant room,” he says.
Stewart expects the system should prove a powerful tool to help managers reduce demand charges. “That’s where the system delivers most of the value,” he says. “Even though the energy savings are higher [as a percentage], it’s that peak demand reduction that saves customers a lot of money.”
Refrigeration is next
Stewart and his team are out there drumming up business for the air-conditioning service while also tinkering on a refrigeration product they are preparing to trial in the months ahead. It’s an optimal time to talk to business about the air-conditioning service while their systems still hold data from the summer just past.
Universities were eager early listeners to the Exergenics pitch, Stewart says, but the dreaded covid-19 has dealt their budgets a cruel blow. “It’s been a tough time in the commercial space as well,” he says, where property groups are focused on keeping tenants that have in turn suffered downturns as consumers endured lockdowns.
The service is offered with no upfront costs and Exergenics, a clean tech startup selected for the EnergyLab 2020 accelerator program, charges a service fee. “We operate on a shared savings model where everything in measured and verified.”