Italian OEM Euroklimat has supplied a high-efficiency air-cooled propane (R290) chiller for air-conditioning to a new Coles supermarket in what is believed to be Australia’s first such retail installation.
The Coles supermarket in Glebe Hill Village, Howrah (Tasmania) opened on August 3, 2022 and is testing a new HVAC solution, using CO2 (R744) heat pumps for the store’s heating instead of a natural gas-powered heating system, as well as well as the propane-based AC system instead of a conventional, high-GWP synthetic refrigerant-based cooling system. The refrigeration system is transcritical CO2.
“This trial lowers our global GWP from [more than] 2,000 to [less than] 3 and aligns with our Together To Zero ambitions to reduce our impact on the environment across key sustainability areas including climate change, waste and hunger,” said Michael Englebright, National Engineering Store Development Manager at Coles.
The installation of CO2 heat pumps for store heating and an R290 chiller for AC is regarded as one of the first such store deployments in Australia. However, other Australian retailers – Woolworths and a Michael’s SUPA IGA store – have installed integrated transcritical CO2 refrigeration systems that also support heating and AC.
Two-circuit R290 chiller
Euroklimat supplied a 210kW (59.7TR) chiller with two separate circuits – each charged with 4.5kg (9.9lbs) of R290. With inlet temperatures of 12°C (54°F), the chiller provides 6°C (43°F). The chiller includes two Frascold reciprocating semi-hermetic single-stage compressors, specifically designed and optimized for operation with R290 refrigerant.
The regulation of the compressor capacity is done through RSH partitioning technology that adapts the thermal power supplied by the system to the actual requests of the users, explained Giovanni Lo Nero, Sales Area Manager at Euroklimat. “The main advantages of this technology are shown in the easy achievement of high levels of efficiency and reliability of the system, in the reduction of the on-off cycles of the compressor, in the greater stability of the suction pressure, in the absence of operating time limits, and in the high mechanical stability of the compressor compared to full load conditions.”
Furthermore, four low-speed axial fans are directly coupled to an electronically communicated (EC) motor with an external rotor. The regulation of the fan rotation speed (0–100%) occurs through the variation of a 0–10 V signal to considerably improve the efficiency in partial load conditions, explained Lo Nero.
Additional to the fans and compressors, the chiller also includes:
– Hydronic kit on-board machine (electric pump and buffer tank)
– Heat exchanger with microchannel technology
– Brazed plate heat exchanger
– Electronic switchboard
– Electronic regulation/control
“We are expecting to achieve a higher energy saving compared to the traditional chillers with HFC refrigerants,” said Lo Nero.
Safety measures
To ensure a high level of safety throughout the useful life of this propane unit, special measures have been introduced that make this product unique, said Lo Nero. The refrigeration circuit is watertight and sufficiently robust, the pipes have been designed to have few joints and welds and all the materials used are compatible with R290 refrigerant.
The electrical panel is installed in a separate compartment. The unit is also equipped with an ATEX and IECex-certified refrigerant gas leak detector located in the compressor compartment and a centrifugal blower expulsion fan below the electrical panel. The sensor, equipped with a separate power supply and a remote signal via Modbus, provides an alarm level set at 10% of the propane’s lower flammability limit.
Safety devices are managed by the microprocessor. If a gas leak is detected, a red LED status indicator on the control panel lights up instantly, and a series of emergency provisions are activated that guarantee the highest possible level of safety. The alarm immediately shuts down the machine and turns on the centrifugal extraction fan, which ventilates the compressor compartment by diluting the concentration of R290 up to values below the flammability threshold.
The structure is provided with a dedicated air intake and exhaust air for the ventilation fan, both equipped with special weather protection made of galvanized steel sheet. The safety valves installed on the refrigerant circuit are located outside the machine to ensure greater safety during unit operation.
Using R290 for AC
“The R290 is a very good refrigerant for all applications (high, medium and low temperature), and particularly in comfort cooling (A/C), it suits very well… better than ammonia [NH3/R717] and CO2” Lo Nero said in explaining the choice of propane for this application. It also aligns better with climate targets than high-GWP HFC refrigerants – a key consideration for Coles.
This is the first chiller of this kind Euroklimat has installed in Australia. “It’s not popular at this stage, but there is a lot of interest in it, especially from the big retail companies,” said Lo Nero. “It’s believed to be an Australian first for such capacity.”
The biggest barrier to wider uptake, according to Lo Nero, is the “mental barrier” around the flammability aspect of R290. “People are worried about it (or not confident), not so much for the equipment itself, but mostly in terms of the installation, service and maintenance. There is still a lot to do in our industry in regards to the training and education around the use of hydrocarbon refrigerants.”
Furthermore, in Australia, the regulations around using hydrocarbon-based equipment vary from state to state. “As you can understand, this makes the choice of hydrocarbon refrigerants more difficult, especially for big chillers/heat pumps, even though they are outdoor installations, and with a low charge of refrigerant,” explained Lo Nero. This particular chiller contains the same amount of propane refrigerant as the propane cylinder that many Australians have in their backyard for their grills.
“Nevertheless, this technology is ready and has been well used in Europe for many years now, and we believe that the retail companies – and not only in Australia – are ready and willing to use it,” said Lo Nero.
“We are expecting to achieve a higher energy saving compared to the traditional chillers with HFC refrigerants.”
Giovanni Lo Nero, Euroklimat
Inclusion of CO2 heat pumps
In addition to the R290 chiller, the Glebe Hill store also features four 75kW (21.3TR) heat pumps from Automatic Heating, an Australian provider of heating and cooling systems. (Read more about this CO2 installation on R744.com)
Achieving sustainability with NatRefs
“At Coles Group, we have an ambition to become Australia’s most sustainable supermarket – and we’re always looking for opportunities to make a positive difference,” the company said in a recent LinkedIn post.
“Incorporating sustainable low-GWP heating and/or cooling solutions within Coles Supermarkets Blueprint will help position us to meet our 2050 HVAC targets on greenhouse gas emissions in alignment with our HVAC & Refrigeration strategies,” said Rahil Gandhi, National Engineering Manager.
In new Coles supermarkets, the majority (more than 90%) now use natural refrigerants (predominantly transcritical CO2), according to the Coles 2022 Sustainability Report. At the end of Coles’ 2022 financial year, natural refrigerants were in use in 28 supermarkets (double that of the 14 in financial year 2021) and 15 Coles Liquor stores (eight in financial year 2021).
“It is evident that Australia is going in the right direction on the use of natural refrigerant in our industry, following the same path we have been seeing in Europe in the last few years,” said Lo Nero.
Read more news on hydrocarbons in Australia.
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