After Two Years, Longo’s Store Heads Towards Net-Zero Energy

The Canadian supermarket, which uses transcritical CO2 refrigeration and an absorption chiller, has cut its reliance on the grid by 70%.

Solar panels at the roof of the Longo's shop.

Longo Brothers Fruit Markets (aka Longo’s), a 36-store food retailer serving the greater Toronto area in Ontario, Canada, has gained a reputation for its environmentally friendly practices; these include installing transcritical CO2 refrigeration systems in 13 stores, being the first Canadian grocer to employ a solar energy and CCHP (combined cooling, heating and power) system tied to the hydropower grid, and offering electric vehicle charging stations

In November 2018, the chain went to the next level by opening what it called Canada’s first “near net-zero energy supermarket” in Stouffville, Ontario. The 40,000ft2 (3,716m2) store was designed to use 35% less energy than the average supermarket of that size, produce 65% of its own energy, and cut CO2e emissions by 1,500-2,000 metric tons per year (the equivalent of taking 274 to 366 cars off the road annually).

The Stouffville store is one of the few supermarkets in the world aspiring to be net-zero in energy production, which is especially challenging in Canada, given is climate and geography.

“This first-in-Canada project is a visible way for us to contribute to solving climate change,” said Anthony Longo, President and CEO of Longo’s, when the store opened in 2018. “It will also establish a new benchmark for the performance of future supermarkets in Canada and elsewhere.”

“We set our goals high because the stakes are high and we must reduce our environmental impact,” recently added Dave Mastroieni,Vice President, Procurement & Facilities for Longo’s. “Our team is focused on creating a culture that supports sustainable practices throughout our company and in our stores.”

To achieve near net-zero status, the Stouffville store has been equipped with leading-edge technologies. In addition to a transcritical CO2 system with heat reclaim (which by itself cuts an estimated 1,333 metric tons of CO2e), the store employs, a CCHP system (which includes an absorption chiller) and LED lighting. Longo’s enhanced the thermal efficiency by incorporating window glazing and best-in-class insulation while avoiding thermal bridging.

The store has also installed 235kW solar panels on the roof, and additional 39kW on a carport and 12kW on the building façade. It is also is in the process of hooking up a 100kW lithium-ion storage battery.

Air conditioning is supplied via an air handler and Lennox AC unit using R410A. The store supports four electric-vehicle charging stations.

To ensure that its opening months went smoothly, the Stouffville store gradually rolled out its energy-generation elements, starting with the solar panels in March 2019, followed by the CCHP system in May of that year. Battery storage was installed in March 2020, and its connection, delayed by the COVID-19 pandemic, is expected to be completed by the end of the year.

The total cost of the store is about 25% more than a typical location. However, given the store’s complexities and unknowns as the first project its kind, Longo’s expects future near-net-zero stores to cost less. Natural Resources Canada, Canada’s environmental agency, helped finance this project with a CA$1.995 million (US$1.5 million) grant.

Progress report

Almost two years after its opening, has the Stouffville store met expectations?

To find out, Accelerate recently spoke to Ady Vyas, Vice President of Energy and Digital Services for Neelands Group, the Burlington, Ontario-based contractor responsible for installing and maintaining the cooling, heating and control systems in the store. He joined Neelands in April, having previously worked for s2e Technologies, which, under his direction, partnered with Neelands Group on the net-zero development and supplied its solar photovoltaics.

“Longo’s could not have done this without a partner like Neelands Group, who have a shared vision of a sustainable future, and have guided us from the spark of this idea to the development of the store, and continue to analyze and optimize our operations,” said Mastroieni.

A “closet environmentalist who drives a Tesla,” Vyas pointed out that grocery stores have some of the highest EUI (energy use intensity) values among commercial buildings, and hence generate higher levels of GHG emissions.

A large portion of those emissions come from the refrigeration system, which led Longo’s to install the climate-friendly transcritical CO2 refrigeration system. Manufactured by Hillphoenix, it employs two racks and delivers a cooling capacity of 123 TR (432.9kW), with a low temperature of -25°F (-32°C) and a medium temperature of 19°F (-7.2°C). The waste heat from the system contributes to space heating and domestic hot water, along with heat from the CCHP system.

The CCHP system, via the absorption chiller, also delivers chilled glycol to the refrigeration system to assist in condensing CO2 gas and preventing the CO2 system from entering less-efficient transcritical mode during the warm summer months. Heat from the CCHP system drives the absorption chiller. “With this integration, you are able to not run the CO2 system in transcritical mode as long,” said Vyas. “You should be able to deploy it anywhere.”

Whereas a typical transcritical CO2 system might enter transcritical mode about 15% of the time in the Northern climate, resulting in higher energy consumption, the Stouffville store’s CO2 system enters transcritical mode far less. As a result it uses 65% less power in the summer months, said Tom Quaglia, Senior. Construction Manager at Neelands Group.

The transcritical system’s integrated, holistic design, utilizing free cooling from the absorption chiller, is what separates it from other transcritical CO2 systems, Vyas said. “There are stores that have individually used solar, CCHP and transcritical CO2. What makes this unique is that it’s the integration of all of those systems.”

The store’s use of solar, CCHP and waste heat has enabled it to reduce its energy consumption compared to a typical store. For example, natural gas is used in the CCHP system as well as to support prepared-food kitchens. However, with the application of waste heat from the refrigeration system and CCHP, the store has cut its gas usage by 50%, said Vyas.

In electricity usage, the store consumes about 1.9 million kWh per year, or 10% less than a typical store, while reducing reliance on the grid by 70%. Onsite power generation has helped cut demand charges at the Stouffville store by “at least 40%,” said Vyas. He expects them be reduced by another 10% when the battery is connected.

Combining electricity and gas, “we have seen a reduction in energy consumption by about 20%, resulting in a net cost savings of 40%, or more than $100,000, compared to an average grocery store, said Mastroieni. This could result in a return on investment on the store’s cost premium in a little over 6 years, noted Vyas.

Regulations in Ontario prevent the store from exporting excess solar energy to the grid when a natural gas-powered electricity source (in this case the CCHP) is also used, , but that energy will be stored in the lithium-ion battery. The percentage of energy derived from solar could be up to 100% were it not for the grid regulation, Vyas said.

The Longo’s store employs software called Kalder – developed by Neelands – to monitor energy consumption and equipment performance. “It looks at the compressor to make sure it’s not running too hard,” explained Vyas. The system can also modulate temperature set point to take advantage of times when more energy is available than can be stored in the battery – what is, effectively, “free energy,” he said.

Overcoming the status quo

Vyas contends that from a technology perspective, net-zero stores are possible, and future stores may include wind turbines on site, and geothermal energy if the location supports it.

The challenge comes from regulatory barriers as well as a change-averse retail mindset that prefers maintaining the status quo and eschews paying 20% more than usual for energy-saving systems. Most retailers insist that their business is “groceries, not energy,” he noted. “But everybody’s business is energy, so let me show you how to [save energy] and make more money.”

Some retailers may be open to energy-saving projects, but insist on an unrealistically short two-year payback period for the cost premium. “That kills more than half the projects,” Vyas said. “You need a longer-term horizon” – at least five years – “and then you’ll see that this pays off.

Longo’s “is one of the few retailers with the forward thinking” needed to embrace the net-zero opportunity, Vyas noted. “We are very fortunate to find a partner like Longo's that is willing to push the envelope with us in terms of sustainability.”

Neelands plans to pursue more net-zero projects, with Longo’s and other retail customers in Canada and the U.S., but only after collecting more data from the Stouffville project. Vyas put it this way: “In God we trust; everyone else brings data.”

Noel Neelands, President of Neelands Group stressed that he wants the Stouffville store to be an application model. “True success would be to replicate this more and more with different customers,” he said.  

System Specs

The 40,000ft2 (3,716m2) near-net-store Longo’s store comprise the following equipment

  • Two Hillphoenix transcritical CO2 racks
  • Cooling capacity: 123 TR (432.9kW),
  • Low temperature: -25°F (-32°C),
  • Medium temperature: 19°F (-7.2°C),
  • CCHP system (including absorption chiller),
  • LED lighting store-wide,
  • Window glazing,
  • Solar panels on roof (235kW), carport (39kW) and building façade (12kW),
  • 100kW lithium-ion storage battery,
  • Air conditioning is supplied via air handler and Lennox AC unit using R410A,
  • Neelands Group’s Kalder software to monitor energy consumption and equipment performance.

This article is included in a special issue of Accelerate focusing on Best Practices for Natural Refrigeration in Food Retail. Read the entire issue here.

By Michael Garry

Oct 19, 2020, 11:06




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