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Home » Retail chain moves to over 90% CO2 on refrigeration systems

Retail chain moves to over 90% CO2 on refrigeration systems

  • marimac 
Image credit: Future Green Now

Image credit: Future Green Now

By Shaun Hadfield, director at Future Green Now

This project’s achievement was reached with the latest store re-build in Pietermartiburg, KwaZulu-Natal, after it was essentially destroyed in the 2021 unrest period and subsequent looting.

Having started the re-build process in May 2022, the Makro Pietermaritzburg store was again opened to customers at the end of November 2022.

One of the particular elements that impacted the progress of the project staying on schedule was the growing concern over the supply of equipment – both locally and internationally as lead times of the equipment required ranged from 20 to 60 weeks. Over this period, significant raw materials and component shortages were evident that needed to be navigated.

From start to finish we had a very tight deadline and thus there was little to no room for mistakes. As stated this project, from start to finish, was merely a 7-month timeframe.

Design specs and system solution

Image credit: Future Green Now

Image credit: Future Green Now

Makro requested a CO2 refrigeration system from the start. This retailer, as one of the largest in the country, has continued to lead the way in commercial refrigeration by opting for the implementation of natural, future-proof systems across their network.

The system installed at the Pietermaritzburg site, collaboratively supplies to the store approximately 504kW cooling capacity. The refrigeration system is made up of two parallel compression refrigeration packs – namely pack A and B.

Pack A produces 175kW and 77kW for medium-temperature and low-temperature, respectively. Pack A consists then of four medium-temperature compressors evaporating at -5 C, two parallel compressors evaporating at +3.3 C, as well as three low-temperature compressors evaporating at -30 C.

Pack B produces 175kw and 77kw for medium-temperature and low-temperature respectively. Pack B consists of four medium-temperature compressors evaporating at -5 C, two parallel compressors evaporating at +3.3 0C, and three low-temperature compressors evaporating at -30 C.

Packs A & B are arranged in such a manner that each pack’s cooling capacity is distributed evenly according to design and demand between display cases, cold rooms, freezer rooms, chiller rooms, or preparation areas, and so on, which are located within the shop floor.

Pack B additionally provides cooling for the liquor store’s cold room.

There are two blower coils that are mounted in the plant room with the main objective of cooling all the equipment that is located in this space. This ensures that the equipment operation occurs at acceptable and safe ambient temperatures.

Packs A & B have also been designed with the ability of reclaiming heat for domestic water applications – this is achieved by the inclusion of a heat exchanger on the discharge line.

All distribution piping as well as tube fittings are stainless steel, and are used to connect to all appropriate components – as was specified to the installation team. Where necessary and/or unavoidable, high pressure copper piping is used to connect components that are manufactured with copper connections.

All electrical components are linked with an array of cables, controlled by switchgear and programmable controllers to ensure that the refrigeration system is able to operate at optimum performance. All controls are connected to a computer-based logging system which can be found in the office of the maintenance manager.

Image credit: Future Green Now

Image credit: Future Green Now

Energy efficient/sustainability

With this installation, we are expecting to see a 25% to 35% energy saving. There will be significant savings in domestic hot water – where low temperature heat reclaim will be used for domestic hot water requirements.

Hot gas defrost has also been utilised on the freezer rooms as well as the walk-around freezers.

Additionally, all reusable condensate water has been reclaimed and re-utilised for the adiabatic gas coolers and for watering of the gardens at the site.

This installation is mirrored at other Makro sites around the country, where Makro has a total of 22 stores out of 24 that are now operating on CO2 refrigerant.

List of professionals and suppliers

Project name:  Makro PMB Rebuild
Owner Capensis Investments 241 (Pty) Ltd
Developer Makro
Architect / Designer R&L Architects (Pty) Ltd
Project manager   Orion Projects CC
Quantity surveyors Sky Line
Consulting engineer Electrical KKA Consulting Electrical Engineers (Pty) Ltd
Mechanical Future Green Now (Pty) Ltd
Wet services Air Conditioning Solutions CC
Civil Bazi Dukhan Consulting Engineers CC
Contractors Main building Ruwacon
HVAC & R HVAC – First Cool

Refrigeration – Matador

Wet services N/S
Electrical N/S
Product suppliers Compressors – Bock
Controls – Carel
Evaporators and Adiabatic Gas cooler – HC