www. refrigerationandaircon. co. za RACA Journal I November 2025 33
Project
supports stable humidity control, ensuring consistent indoor comfort across varying load conditions. Additionally, the unit incorporates precise air pressure regulation to maintain optimal indoor-outdoor pressure balance. This enables reliable fresh air delivery and improved indoor air quality( IAQ), even in high-traffic retail environments where door cycling and occupancy fluctuations are common.
• Adaptive multi-functional platform design: The Sinclair Model SRF range is built on a modular, scalable platform that allows contractors and consultants to adjust capacity in line with project growth or evolving layout requirements. This flexible architecture simplifies installation and facilitates seamless integration into a variety of commercial applications. To support the design and commissioning process, the system includes a digital pre-configuration tool that streamlines unit selection. During operation, the integrated DDC( Direct Digital Control) platform offers intuitive control, advanced fault diagnostics and compatibility with building automation systems – delivering efficiency across the system’ s entire lifecycle.
PROJECT EXECUTION BY METRO AIR CONDITIONING SERVICES Metro Air Conditioning Services executed the installation of the Sinclair Model SRF280 units with minimal disruption to ongoing retail operations. With a strong portfolio servicing large clients such as Broll, ERIS, RMB, PCC and Shoprite, Metro Air Conditioning’ s team conducted extensive site evaluations to ensure structural readiness and co-ordinated the placement of units to maintain architectural harmony. Revit-based duct modeling was employed to optimise airflow distribution and static pressure balancing as per Figure 4. Model generation was pivotal in manufacturing custom ductwork which connected the RTU’ s topological supply and return connections to the main supply network. operation and achieve volumetric equilibrium across the supply and return branches, final airside balancing remains critical to achieve optimal indoor environmental control.
Project: SHOPRITE WEST PACK SYSTEM 1: Fan Pressure [ Pa ]
SYSTEM 2: Fan Pressure [ Pa ]
Fan Pressure
[ Pa ] Supply 1 472 536 365 Supply 2 459 448 387 Return 445 444 306 Table 1: Initial Commissioning ESP Readings.
AOS CONSULTING ENGINEERS’ CONTRIBUTION AOS Consulting Engineers, headquartered in Johannesburg and led by Chris Groenewald for this project, validated the system load calculations and ducting strategy. The design followed bestpractice engineering guidelines, including SMACNA duct design standards for pressure loss estimation, and leveraged Revit-based simulations to model airflow under real operating conditions. AOS confirmed a consistent cooling load estimate of 185W / m ² across both retail stores, which guided appropriate equipment selection and duct sizing. Their involvement ensured the system met performance and energy efficiency targets without oversizing, while maintaining airflow delivery aligned with zonelevel demands. AOS’ s technical oversight and close co-ordination with the contractor played a critical role in achieving a balanced, reliable HVAC installation.
BROADER BENEFITS OF HIGH-EFFICIENCY RTUS The Sinclair Model SRF280 project illustrates the benefits of adopting energy efficient, multistage-controlled compressor RTUs in large-scale retail. These include significant energy cost
Figure 4: Ducting model in Revit exploded view.
Table 1 reflects the initial onsite commissioning ESP recorded, illustrating the potential variability introduced by real-world duct design and site-specific layout constraints. This iterates the importance of ensuring that the fan selection is based on the highest-pressure segment of the system. To ensure stable
Figure 5: Gold Find Coated condenser segment.
www. refrigerationandaircon. co. za RACA Journal I November 2025 33