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to the atmosphere, it is first routed to the AHUs to provide heating for the store. Any residual heat not utilised by the AHUs is then rejected via the gas coolers on top of the plant. While hot gas defrost is a common refrigeration practice replacing electric heating, extending this principle to provide heating for the AHUs and the retail space, rather than direct atmospheric discharge, represents a significant energy recovery strategy."
A notable challenge during the project ' s initial phase was the absence
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Front loading meat cold room. |
of permanent power on-site. " This necessitated a phased commissioning approach, operating only a limited number of units at a time to ensure plant functionality." This constraint was overcome with the commissioning of the store ' s rooftop solar power installation and the completion of the permanent mini sub-station. " The building is equipped with a solar power system to provide supplementary power. The subsequent commissioning of the Eskom mini substation provided sufficient power for full |
plant operation. The integrated system is now operating effectively at its full design capacity."
Massmart ' s response to this innovative system has been exceptionally favourable. " The client has expressed significant satisfaction, particularly as this represents a first-of-its-kind implementation for them. Consequently, they are actively exploring the adoption of this integrated approach for refurbishments at other existing store locations, and FGN is involved in those projects."
The integrated system is projected to yield substantial benefits in terms of energy efficiency and sustainability. " From a sustainability perspective, the impact is significant due to the utilisation of a natural refrigerant for both refrigeration and air conditioning." While acknowledging the potentially higher initial capital investment and operating pressures associated with CO2 systems, Arnold emphasised the anticipated energy savings. " This installation provides a tangible pilot for measuring the actual energy consumption and savings. Our estimations indicate a reduction in electrical usage of 20 – 30 % for the integrated plant, in addition to the energy offset provided by the solar power installation."
This energy saving figure is based on the plant ' s performance compared to traditional R404a refrigeration and chilled water air conditioning systems, and crucially, this calculation doesn ' t even factor
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in the significant contribution of the store ' s rooftop solar power generation.
The integrated CO2 system also achieves significant water conservation. " The plant generates hot water for the building by recovering waste heat, similar to the heating provided to the AHUs. This byproduct effectively pre-heats the water before any excess heat is rejected. Furthermore, condensate reclaimed from the AHUs and blower coils for the display cases is reused within the adiabatic gas coolers, reducing overall water consumption during their operation." By implementing waste heat recovery for hot water and condensate reuse in the gas coolers, the system minimises its water footprint.
Reflecting on the evolution of refrigeration plant design, Arnold highlighted substantial advancements over the last decade. " The design has evolved significantly. Previously, configurations often involved simplex or multiplex systems for each temperature requirement. Current
This necessitated a phased commissioning approach, operating only a limited number of units at a time to ensure plant functionality.
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