44 RACA Journal I March 2026
RETROFITS technical
Background image by HVACInformed. com
Under these conditions, total energy savings could reach as high as 50 %. At full operation, the 21 Ziehl-Abegg ZAplus fans achieved an airflow of 300 000 CFM at 1.9cm of static pressure, proving the system’ s ability to meet demanding cooling requirements.
Reliability and redundancy were also greatly enhanced. Unlike a single large fan that creates a single point of failure, a multi-fan array ensures continuous operation even if one unit goes offline. Remaining fans can automatically compensate by increasing speed, maintaining stable airflow without disrupting HVAC performance. This built-in resilience makes EC fan arrays particularly valuable in mission-critical environments such as hospitals, government facilities and data centres.
Safety in installation and maintenance was another clear benefit. The smaller, lightweight fans – each weighing only a fraction of a traditional fan – significantly reduced the risks associated with lifting and handling heavy equipment. Installation required fewer workers, minimised downtime and created safer working conditions. Over the long term, these improvements help protect skilled labour resources and reduce the likelihood of workplace injuries.
Cost-effectiveness and ROI further strengthened the case for retrofitting. The retrofit cost represented only about 10 % of
what a full cooling tower replacement would require. Based on energy savings and reduced downtime, the return on investment is projected at three to four years, closely mirroring the two- to three-year ROI already proven in mature AHU retrofits.
MARKET POTENTIAL AND FUTURE OUTLOOK The Raleigh project is just one example of a much larger opportunity. In New York City alone, the cooling tower retrofit market is estimated at USD140-million, with nationwide potential extending across nearly every large facility that relies on cooling towers. Growing electricity costs, tightening energy efficiency regulations and an ever-increasing demand for reliable system performance are all driving adoption of this new approach.
Retrofitting cooling towers with EC fan arrays provides a viable alternative to replacing single large AC fans. The Raleigh case study demonstrates measurable energy efficiency gains, safer installations, enhanced redundancy and rapid ROI.
As building operators face mounting pressure to reduce energy consumption and improve reliability, EC fan arrays are poised to become a new standard in cooling tower modernisation. RACA
Source: HVACInformed. com
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44 RACA Journal I March 2026
AIR CONDITIONING