- A variable frequency drive (VFD) is a proven energy management tool for commercial HVAC system.
- Businesses can install VFDs in nearly any commercial HVAC systems and use the drives to lower their energy
- Along with energy savings, a VFD can help a company reduce wear and tear on its commercial HVAC system’s motor.
- An expert commercial electrical services contractor can provide a business with insights into VFDs, along with tips and recommendations to help the company optimize the performance of its commercial HVAC system.
Here’s how a variable frequency drive can help your business lower its energy costs and extend your commercial HVAC system’s lifespan.
You want your commercial HVAC system to perform at peak levels 24/7. At the same time, you want to keep your system costs as low as possible. One option to consider that delivers the best of both worlds is a variable frequency drive (VFD).
A VFD can be installed in virtually any commercial HVAC system to manage the speed of the drive motor in response to the building’s current load. Once you install one, you can enjoy the benefits — including reduced energy cost and longer motor life — long into the future.
VFDs are quickly becoming must-have technology in commercial HVAC applications. To understand why, let’s answer some of the biggest questions surrounding how they work and their benefits.
What is a VFD?
In a traditional commercial HVAC system, fans and pumps work at a constant speed despite the fact that building loads can vary. The system uses a form of mechanical throttling to reduce water or airflow as needed, but the system’s drive motor continues to work at full speed. Thus, the amount of energy the drive motor requires remains the same, even when the water or airflow is reduced.
A VFD provides an efficient alternative to mechanical throttling commonly used in commercial HVAC systems that accounts for three factors that frequently hamper these systems’ efficiency:
1. Commercial HVAC systems are generally sized for peak load conditions
Most of the time, a commercial HVAC system does not need to operate at peak load conditions, but they are typically designed and implemented with peak load conditions top-of-mind. This means the system’s pump and fan motors often use more energy than required.
2. Commercial HVAC systems are often oversized
In addition to being designed for peak load conditions, a commercial HVAC system may be implemented to account for underestimated or unexpected loads, depending on how the building is used. The result: The system’s pump and fan motors will use high amounts of energy regardless of how much energy they actually need.
3. Commercial HVAC systems often come equipped with induction motors
Induction motors are rugged and cost-effective, which makes them good options for many commercial HVAC systems. However, HVAC induction motors do not draw power in relation to speed. Instead, the motor runs consistently no matter how much power is required.
When used as part of a commercial HVAC system, a VFD converts 60-cycle line current to direct current. It then moves the direct current to an output that varies in terms of voltage and frequency based on the load placed on the system. Therefore, the VFD accounts for system load decreases and increases. As a result, the VFD’s controller can reduce the system motor’s operating speed and still ensure that its flow rate does not exceed its load requirements.
Do you need a VFD for your commercial HVAC system?
Reasons to incorporate a VFD into a commercial HVAC system include:
1. You can lower your energy bills
A VFD ensures your HVAC system motor can run at less than full speed, which has major benefits when it comes to energy consumption. Reducing the motor speed by 25% lowers energy consumption by nearly 60%, according to the Affinity Laws for centrifugal pumps and fans. Decreasing the motor speed by 50% cuts energy consumption by almost 90%.
The bottom line: Using a VFD to reduce your HVAC system’s motor speed by even a small percentage can deliver significant energy savings.
2. You can reduce wear and tear on your system’s motor
As a commercial HVAC system ages, its components start to wear down — and its motor is no exception. Without ongoing maintenance, these components can deteriorate to the point where the system malfunctions or stops working.
A VFD won’t stop your motor’s condition from declining over time, but it can help slow the aging process. This is due to the fact that a VFD allows the motor to complete a “soft start” and gradually ramp up to full speed. In doing so, the drive uses less energy than a standard motor’s start, which helps prolong a commercial HVAC system motor’s lifespan.
3. You can minimize your demand charges
Commercial facilities can be subject to demand charges if a business requires large peaks of electricity at different times during the year. A VFD can limit motor inrush currents that can otherwise be substantially higher than a full-load current. This allows the building to minimize demand charges associated with its commercial HVAC system.
Take advantage of a VFD on your commercial HVAC system
There are many benefits to using a VFD as part of your commercial HVAC system. In order to get the most value out of a VFD, you need to partner with an expert commercial electrical services contractor.
Universal Electrical Services knows the ins and outs of commercial HVAC systems and VFDs. We can teach you everything you need to know about VFDs and help you identify ways to optimize your commercial HVAC system’s performance. To learn more or to request a free consultation, contact us today.