SOLVING THE PUZZLE
RACA Journal I April 2026 www. refrigerationandaircon. co. za 29
REFURBISHMENT
The design specifications and client brief for the project were focused on upgrading the existing HVAC infrastructure to improve efficiency, control and overall performance within the supermarket and associated office areas. Central to the brief was the refurbishment of the existing masonry air handling units, integrating a new VRF system coupled with a fresh air supply. This fresh air system incorporates motorised fresh air dampers which open and close based on CO₂ levels within the store to ensure appropriate ventilation in response to occupancy.
In addition to the main supermarket system, the design included the installation of new inverter-driven, split-type aircooled units to serve the management office areas, providing independent and energy-efficient temperature control. To integrate these new systems effectively, modifications to the existing internal ducting within the supermarket were required and formed part of the overall scope. This included abandoning the air-conditioning plant at the front of the supermarket and supplying everything from the back of the store. This also resolved operating billing issues that had long been problematic.
Additionally, TROX advised VMG on the use of their highly effective drum louvres. These were subsequently added to the ends of the existing supply air ducts, which are now used to aircondition the checkout area of the supermarket.
The installation presented several challenges due to the constraints of working within an existing and operating building. Fixed structural grids, a defined plant room footprint, and established service routes limited flexibility and required a high level of co-ordination. Particular care was needed when routing refrigerant pipework, electrical services and drainage to avoid clashes with existing structural and architectural elements. These challenges were addressed through detailed site investigations, the development of well co-ordinated design drawings and minor adjustments to service routes. Throughout this process, full compliance with the Retailer Specification and, by extension, the latest SANS Building Regulations was maintained.
From an energy efficiency and sustainability perspective, the impact of the installation is significant. Both the refurbished and new plant have been designed in accordance with the latest Retailer Specification and are expected to achieve at least a 50 % improvement in energy efficiency compared to the previous plant. This improvement is driven by resolving previous design issues, the use of modern VRF technology, high-efficiency components such as EC plug fans, and improved system control strategies such as the CO2 control of the fresh air component.
What makes this project particularly distinctive is the re-use of a masonry plant room to house the HVAC systems. Masonry walls and concrete slabs provide a robust and durable enclosure with a service life aligned to that of the building itself. Unlike lightweight
The original water-cooled chiller plant room before removing any equipment.
steel or panelled enclosures, a masonry plant room offers longterm protection against impact, weather exposure and accidental damage. This level of resilience is especially important for critical VRF systems serving a retail or supermarket environment, where system downtime is highly disruptive and unacceptable.
In addition, the plant refurbishment was carefully sized based on detailed heat load calculations and VRF equipment selections and included the installation of fan walls incorporating high-efficiency EC plug fans, further contributing to improved performance, reliability, and energy efficiency.
SOLVING THE PUZZLE
By Eamonn Ryan
When Elmecair and VMG first walked into the existing plant rooms at the Ottery supermarket, their reaction wasn’ t alarm – it was intrigue. What lay before them was not a conventional refurbishment challenge, but a puzzle. And it was one they relished solving
From the outset, the sheer scale of the plant stood out. Compared to many retail HVAC installations they had completed in recent years, this was something else entirely. project
RACA Journal I April 2026 www. refrigerationandaircon. co. za 29