Working with customers from many different industries I often get asked "What are the advantages of piezoelectric fans?" Long story short, piezoelectric cooling technology offers superior reliability, which is critical for applications such as aerospace actuators, telecommunications equipment and LED lighting.
Many applications are limited to passive cooling solutions because forced convection devices or standard cooling fans with some kind of bearing do not have adequate reliability. I don't know about you, but I don't want to be on an airplane where an actuator stops working! Check out my other post for my opinion on the best applications for piezo cooling technology. Packaged piezoelectric cooling fan technology offers thermal engineers a new tool in their arsenal to apply forced convection to applications where it was previously not possible or just not a good idea. The technology offers the following benefits:
- Extremely High Reliability - L10 Lifetime of > 15 years, better than any fan technology on the market
- Operation at High Temperatures, up to 125 degrees Celsius - without impacting lifetime
- Operation in dusty and corrosive environments with no impact on reliability
- No Electromagnetic Interference (EMI) output, ideal for medical applications
The Benefits of Solid State Piezoelectric Forced Convection
The benefits of piezoelectric fans are realized by two primary factors, the unique properties of piezoelectric materials and the robustness of piezo packaging technology. Piezoelectric materials offer a solid state solution that is critical for high reliability. There are no moving parts, no lubricants, greases or other materials that will break down over time and lead to failures witnessed in bearing based AC and DC fans. Additionally, piezo materials can operate at temperatures up to their curie temperature, typically over 200 degrees Celsius. However, without the benefits of protective packaging technology these unique properties of piezoelectric materials would not be applicable to real world applications.
The Benefits of Protective Packaging for Piezoelectrics
Packaging technology involves protecting the piezoelectric elements and their electrical connections by completely encapsulating the piezoelectric elements with copper etched thin film materials. Completely sealing the piezoelectric element, its electrodes and the electrical connection from the environment allows for operation in dusty, corrosive and humid environments with no impact on reliability. The packaging materials are typically a copper etched polyimide or FR4 material. High strength epoxies are used to make a composite structure that is extremely robust.
Is Piezoelectric Cooling Technology Proven?
The base technology of packaged piezoelectrics has been fielded for industrial applications for the last few decades. Additionally, due to the skeptical nature of reliability engineers substantial testing has been performed on the technology to prove its robustness. These tests include but are not limited to:
- Highly accelerated life testing (HALT)
- Humidity HALT
- Salt Fog
- Dust Ingress
- High temperature operating life (HTOL)