Operating around the clock and serving high volumes of daily commuters, one of Asia's leading transportation hubs holds itself to a high bar. Progressing toward Singapore's Green Plan 2030 and Net Zero goals is a clear priority, but so is maintaining world-class experiences and continuing to innovate. Remaining at the forefront necessitates a need to move first, even in spaces that are often overlooked.

Toilet facilities present one such space. High foot traffic and variable occupancy demand consistent air quality standards, yet conventional solutions struggle to determine the precise ventilation needed at any given time. An AC to EC fan retrofit paired with a Smart Energy Management System addressed what conventional solutions couldn't, and proved to be a meaningful step toward the organisation's broader goals.

The facility's toilet exhaust fans were originally fitted with AC axial fans, a conventional setup common across most buildings. AC motors, by nature of how they are constructed and operate, are inherently less efficient, and this limitation carries forward directly to the fans they power.

Retrofitting the toilet exhaust fans from AC to EC brings an immediate reduction in energy consumption. What makes EC fans valuable here is that their integrated electronics also make them naturally easier to connect to IoT systems.

In a facility running 24/7 with constantly shifting human traffic, there is more to the picture. The fans need to respond to how the toilets are actually being used throughout the day. Running them at full speed regardless of occupancy wastes energy; running them too slow risks air quality. This is where a Smart Energy Management System comes in, drawing on occupancy data to inform when the fans run and at what speed, so the system works in step with the facility rather than independently of it.

In the first step, the existing AC axial fan was replaced with a Box Fan that has been integrated with an EC centrifugal fan, resulting in significant operational and performance improvements.Key benefits include:

• Higher Efficiency: EC fans offer greater efficiency compared to conventional AC fans, and this advantage holds even under part-load conditions, which is how most systems spend the majority of their operating hours.
• Lower Noise Levels: The shift to EC fans brought a noticeable reduction in operating noise, creating a more comfortable acoustic environment for the facility.
• Reduced Maintenance Requirements: EC fans are fully integrated and built for durability, doing away with the upkeep that belt-driven systems demand, such as routine belt replacements and tension checks.
  
• Fewer External Components: Where AC fans rely on external variable speed drives for speed control, EC fans have this built in. The result is a simpler, cleaner system that is easier to install and manage.

In the second step, smart energy management equipment is installed. At the heart of this system is the intelligate Mesh, a dual-purpose device that functions as both an environmental sensor (monitoring carbon dioxide, temperature, and humidity) and a gateway, eliminating the need for a separate gateway unit.

Supporting devices, including people counting/occupancy sensors and Wi-Fi routers, work in tandem to enable seamless data transmission to the server. The people counting sensor tracks real-time occupancy, dynamically adjusting the air changes per hour (ACH) based on the number of occupants:

• < 5 people → 20 ACH at 30% fan speed
• 5–10 people → 25 ACH at 40% fan speed
• > 10 people → 30 ACH at 50% fan speed

This ensures humidity levels and odours are kept in check at all times. All relevant facility data is consolidated on a web-based dashboard, accessible from any workstation, giving the facility management team clear visibility into toilet conditions at a glance.

Through this two-step approach, significant energy savings of 73.9% was achieved. 

The first phase , retrofitting from AC to EC fans , delivered approximately 48.9% energy savings. The second phase , integrating the EC fan system with an IoT platform , contributed a further 24.9% reduction.

Together, these measures enhanced overall system efficiency and performance, bringing the transportation hub one step closer to achieving its net zero ambition.