Drives for fans in commercial buildings

  • Overview
  • Products
  • Case studies

Optimize comfort and energy consumption in building ventilation

With user-friendly interfaces, distributed intelligence and reduced power consumption, Danfoss AC drives optimize the performance of fans.

The VLT® HVAC Drive and VLT® Refrigeration Drive convert velocity pressure sensor values into flow values, enabling setup based on fixed flow or fixed differential flow. This optimizes both comfort and energy consumption. To improve comfort levels even further, drives connected to fans can be set to avoid the frequency bands which create resonance and damage in the ventilation system.

Extended building management system capacity

When integrated into a building management system network, to extend the capacity of the controller, all HVAC drive I/O points are available as remote I/Os. For example, room temperature sensors (Pt1000/Ni1000) can be directly connected to the system. 

Improved air-handling performance

The VLT® HVAC Drive and VLT® Refrigeration Drive are fitted with a built-in Smart Logic Controller and four auto-tune PID controllers to control air-handling functions with fans, valves and dampers. The direct digital controllers of the building management system are released and valuable data points are saved lowering air-handling costs. The VLT® HVAC Drive handles logical rules and input from sensors, real-time functionality, and time-related actions. This enables the AC drive to better control a wide range of functions:

  • Weekend and working day schedules
  • Cascaded P-PI for temperature control
  • Flow balancing between fresh and outlet air
  • Belt monitoring – from the relation between current and speed, the AC drive is able to reliably recognize a broken belt. Lack of air flow is detected immediately so that action can be taken to reduce costs and downtime 

Protect applications and operators 

The VLT® HVAC Drive FC 102 provides the STO (Safe Torque Off) function in compliance with ISO 13849-1 PL d and SIL 2, according to IEC 61508 / IEC 62061. In high demand applications, this can be expanded with the VLT® Safe Option MCB 140, an external module that provides functions such as Safe Stop 1 (SS1), Safely Limited Speed (SLS) and Safe Maximum Speed (SMS), control of external contactors and safety door monitoring and unlocking.

Reliable harmonic mitigation

While AC drives increase precision, save energy and extend application lifetime, they also introduce harmonic currents to the hospital grid. If not kept under control, harmonic currents can affect the performance and reliability of generators and other equipment.

To ensure minimal disturbance, read more about our harmonics application know how, software tools and harmonic mitigation solutions.

Air quality and clean rooms

Air quality in the pharmaceutical industry

In the pharmaceutical industry air-quality is a concern to support employee health and safety and prevent cross-contamination. Using  Danfoss AC Drives to control dust collector fan speed is an efficient way to maintain airflow/static pressure while increasing energy savings. Reducing fan speeds by 20% can translate to 50% energy savings.

Pharmacy processing clean room applications have unique requirements, Danfoss AC Drives can help control the chilled and the hot water valves of machinery to ensure conditions are met accurately. 

Safety in hospital ventilation

Safety in hospital ventilation

Hospital ventilation has strict requirements regarding safety, compliance and efficiency. Danfoss provides AC-drive solutions for fire and smoke safety, heat dissipation, harmonic mitigation, and EMC and seismic compliance.

Fail safe with no trips

In hospitals, failure for any reason can jeopardize lives. Drives powering pumps and chillers must be extremely reliable and virtually immune to mains supply disruptions. To achieve this reliability, Danfoss AC drives are designed to ignore voltage sags and even short outages, maintaining full performance at all times.

Airport ventilation

Airport ventilation

With hundreds of thousands or even millions of passengers annually, ventilation is a top priority for international airports. To improve traveler comfort and safety, and to combat rising electricity prices, drives are increasingly being used to control and optimize the operation of air-handling units and reduce energy consumption.

VLT HVAC Drives extend from low- to high-power solutions. They come equipped with HVAC-dedicated functionalities and compatible soft starters and filters for EMC and harmonics mitigation. And the complete range of fieldbus communications options enables effective integration with the building automation system.

Tunnel ventilation

Tunnel ventilation

Metro and motorway tunnel operators demand strict ventilation performance for safe operation and optimized cost of ownership. The VLT HVAC Drive offerings, from low to high power, fulfill smoke and fire safety requirements and comply with seismic regulations. All our units offer the same HVAC-dedicated functionalities, standards compliance and compatible soft starters, filter and fieldbus communications options.

EC+ Concept

When building an HVAC system, to get the highest performance and system efficiency, the individual components – motor, drive and fan – need to be flexible and broadly compatible with each other. For instance, if you specify a high-efficiency motor that is only compatible with lower efficiency fans, the overall system efficiency would suffer and would not reflect the high performance – and investment – in the individual components.

Danfoss Drives’ EC+ concept allows ventilation system designers to combine a VLT® HVAC Drive with the most efficient fan and permanent magnet motor.

Advantages of the EC+ concept

  • Free choice of motor technology: PM, asynchronous or synchronous reluctance with the same AC drive 
  • Device installation and operation remain unchanged
  • Manufacturer independence in the choice of all components
  • Superior system efficiency thanks to a combination of individual components with optimum efficiency
  • Retrofitting of existing systems is possible
  • Wide range of rated powers for standard, PM and synchronous reluctance motors


Healthcare Data Center Takes Control of Uptime and Energy with Danfoss VLT® Drives

Physicians and clinicians often need access to medical data in real time — just a few minutes of downtime is unacceptable. The data center industry has created standards to define the level of uptime required for a given class of application and the infrastructure needed to maintain that level. The standard being applied to medical data centers — known as the Uptime Institute’s Tier III standard — calls for 99.982 percent uptime, which translates to no more than 1.6 hours of downtime per year. This standard requires an uninterruptible power supply (UPS) system that can handle a power outage of at least 72 hours. 


Case studies

  • if (isSmallPicture) { The factory seen from afar with a sunrise in the back ; } else if (isBigColumns) { The factory seen from afar with a sunrise in the back } else { The factory seen from afar with a sunrise in the back }
    How did this smart factory reach carbon-neutral?

    POLAND: The new Danfoss production hall in Grodzisk Mazowiecki has reached carbon-neutrality, thanks to full electrification, energy-saving solutions such as Danfoss drives, and energy from renewable sources.

  • if (isSmallPicture) { Gunn Hill Cheese; } else if (isBigColumns) { Gunn Hill Cheese } else { Gunn Hill Cheese }
    VFD's are Secret Ingredient for Artisan Cheese Maker

    Recipes for cheese are thousands of years old, passed down through generations and crossing continents —like the Swiss cheese recipes used by Shep Ysselstein, owner and “grand fromage” of Gunn’s Hill Cheese in Woodstock, Ontario, Canada.

  • if (isSmallPicture) { Boy using the Storm wind tunnel; } else if (isBigColumns) { Boy using the Storm wind tunnel } else { Boy using the Storm wind tunnel }
    How does Beat the Storm deliver more fun for 80% less CO2?

    DENMARK: Universe Science Park saves 80% on emissions and the power bill for its wind tunnel attraction “Beat the Storm”, with the intelligent VLT® HVAC drive.


  • if (isSmallPicture) { ; } else if (isBigColumns) { } else { }
    Drives secure fresh air inside South America’s tallest building

    A huge number of Danfoss drives secure comfortable temperatures and cut down energy use inside Chile’s famous Costanera Center.

  • if (isSmallPicture) { ; } else if (isBigColumns) { } else { }
    Danfoss ensures sustainable luxury in the heart of Sønderborg

    DENMARK: Hotel Alsik is proud to be 76% CO2-neutral, with sustainable solutions reflected throughout the entirety of this magnificent hotel – from the energy-efficient solutions in the hotel rooms, the design of the building and the power supply, to the 380 m2 solar cells on the roof.

  • if (isSmallPicture) { Las Vegas City Center; } else if (isBigColumns) { Las Vegas City Center } else { Las Vegas City Center }
    Reliability and Consistency Make Danfoss VFD's a Sure Bet in Las Vegas

    For the mechanical systems that manage the indoor environment in this desert city, consistency and simplicity are desirable traits. Owners of casino hotels and restaurants that operate around-the-clock require HVAC equipment that is reliable and easy to operate and maintain.