Fan pack design: the next efficiency frontier in commercial refrigeration

As compressor technology in commercial refrigeration has reached high efficiency levels, the performance bottleneck has moved to the air movement system. Daniel Hofmann, Research & Development and Product Strategy Senior Director at Nidec Global Appliance (holder of the Embraco brand), argues that the fan pack—long treated as a secondary component—now represents the key frontier for further energy savings, with a well-designed system capable of delivering up to 7% energy reduction.

The scale of the opportunity

Total electricity consumption of commercial refrigerators across the EU 27 in 2020 (the most recent period with precise data available) was estimated at 52 TWh per year. A 7% efficiency gain through optimized air movement would translate into approximately 3.64 TWh saved annually—enough to power more than one million UK households for a full year, based on Ofgem's reported average residential electricity use of around 3,000 kWh per household.

How a fan pack works

Efficient air movement in a refrigeration system depends on the synergistic interaction of three elements: the motor, the blade, and the shroud. Together they form a fan pack, typically coupled to the heat exchanger through a housing. Acquiring the three components separately—even if each is individually optimized—introduces efficiency losses from mounting gaps and blade positioning. In an integrated fan pack, all parts are designed to work together to achieve the highest airflow rate for a given system impedance at minimum energy consumption.

Key design parameters include:

• Motor technology. EC (electronically commutated) motors allow fan speed adjustment according to demand and reach output efficiency levels of 70%, compared with roughly 30% for shaded-pole technology. This shift alone can more than double the efficiency of the air movement subsystem.
• Blade design. Critical variables include aerodynamic profile, angle of attack, pitch, hub-to-tip ratio, and number of blades. An optimum balance of these parameters can improve airflow by up to 40% without increasing motor power. The goal is to consume less energy at the same airflow rate, or deliver higher airflow at the same power level.
• Shroud. The shroud directs airflow through the heat exchanger while minimizing aerodynamic losses. Design relies on extensive CFD simulations, prototyping, and wind-tunnel evaluation. Material selection matters under high-temperature and humidity conditions; polymers with appropriate strength-to-weight ratios are preferred. Proper installation is also fundamental—a well-designed fan pack that is poorly installed will significantly compromise performance.

System-level impact

In the cold compartment, inadequate air distribution widens the temperature difference between the coldest and warmest zones, forcing the compressor to work harder to meet the temperature criteria defined by international regulatory standards. Because all evaporator fan energy is converted into thermal load during operation, high fan efficiency directly reduces the application's overall energy use. On the condenser side, insufficient airflow elevates condensing temperature and pressure, pushing the compressor into less efficient operating conditions. Hofmann notes that running a highly efficient compressor with inadequate fans is analogous to fitting a powerful engine in a vehicle with a deficient cooling system—the full potential cannot be realized.

Broader benefits

Beyond direct energy savings, proper air movement generates value in several areas:

• Product preservation. Uniform airflow eliminates hot spots, reducing waste from deterioration, extending shelf life for sensitive products, and ensuring regulatory compliance in medical and pharmaceutical applications.
• Useful volume. Optimized air movement allows more compact heat exchangers without capacity loss, opening the possibility of a 5–10% increase in useful internal volume—valuable for retailers seeking to maximize display space without enlarging the equipment footprint.
• Durability and reliability. Lower thermal stress on components, including compressors operating at lower condensing temperatures, can extend service life and reduce total cost of ownership.
• User experience. Reduced fan speed lowers noise, improving the shopping environment in retail and comfort in spaces where commercial refrigerators operate near people for extended periods (hotel mini-bars, office display cases).

Decarbonisation context

Hofmann frames air-movement optimization within the broader decarbonisation agenda. Because most global electricity still comes from fossil sources, each kilowatt-hour avoided reduces CO₂ emissions. Even with renewable generation, lower demand decreases infrastructure needs and increases system resilience. The path forward, he argues, does not depend on revolutionary technologies but on systematic optimization of each component—air-movement components among them.

Source: Embraco Blog.