“New Zealanders tend to be very quick adopters of new and better technology,” said Philip Hitchins, Managing Director of Beijer Ref NZ.

As examples, he cited construction of transcritical CO2 racks by Beijer Ref subsidiaries Patton and SCM NZ  for two New Zealand retailers,  Fresh Choice Papamoa and Countdown Hāwera. A Melbourne-based refrigeration contractor, Engie Services New Zealand, designed and installed the systems.

Countdown Hāwera in Taranaki opened in April 2019 and is New Zealand’s first “Be Accessible”-accredited supermarket, designed to be inclusive and accessible to everyone regardless of ability. This project involved building a new store next to the existing supermarket, which was then demolished after the new store opened. 

The CO2 rack has the following capacities: 178kW (50.6TR) at -10°C (14°F) on the medium- temperature side and 36kW (10.2TR) at -35°C (-31°F) on the low-temperature side, with 150kW (42.7TR) heat reclaim. Other than the refrigeration system, Engie also provided a heat exchanger on the CO2 discharge from the medium-temperature side of the rack for HVAC. 

Fresh Choice Papamoa, part of the Woolworths New Zealand group, opened in June 2019. The refrigeration project was  designed and built by contractor  Engie, and ran alongside the HVAC contract, also handled by Engie. 

The CO2 rack has a cooling capacity of 98kW (27.9TR) at -10°C (14°F) on the medium- temperature side; and 11.5kW (3.3TR) at 35°C (-31°F) on the low-temperature side, with 78kW (22TR) heat reclaim. It is complete with Emerson controls and a variable-speed drive on the lead compressors to improve energy efficiency, same as for the Countdown store.

The design of the heat reclaim system for Fresh Choice is different from that of a typical installation, explained Kenneth Thysse, National Key Accounts and New Business Manager, Engie Services NZ. “Instead of having two heat exchangers on the rack, only one heat exchanger was used both for the hot water and the HVAC systems,” he said. 

With regards to energy efficiency and savings expected, Hitchins said that, although no real data are yet available, both stores are expected to typically save “5-8% over a new, well-engineered equivalent HFC system.” But this is an approximation at best, he said, as there are too many contributing elements, like ambient temperature, product loading/turnover and seasonal variation. 

Hitchins has noticed an increased use of CO2 in mid-to-large retail applications, and he believes this refrigerant is the best option of all the natural refrigerants as there are fewer safety concerns. “CO2 is a long-term option; it’s green; and it offers installation cost savings thanks to smaller diameter pipe requirements,” he said. “There is a lot of global investment by component manufacturers to support CO2 with technology, driving efficiency, the economies of scale, and competition.”

According to Hitchins, the biggest challenge is still industry knowledge and training for installation and servicing of CO2 systems. “There is a global lack of training in the sector, hence supply companies like Patton and SCM are opening their own training facilities around the world and developing digital-based training programs at local level.”

In New Zealand, Beijer Ref and SCM have 13 systems installed to date and are now engineering projects for 2020 that include smaller systems with capacity ranges from 13 to 30kW (3.7 to 8.5TR). It is also pricing larger projects in the industrial and horticulture sectors, with capacities of up to 1,000kW (284TR) per system. 

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