Rotary/Wheel Energy Recovery Heat Exchangers (R/WHEHX)
A rotary/wheel energy recovery heat exchanger (R/WHEHX) is a highly efficient device used to recover thermal energy from exhaust air streams and transfer it to incoming air streams. They are commonly used in ventilation systems for buildings, industrial processes, and even aircraft.
How it works:
- Wheel: The core of an R/WHEHX is a continuously rotating wheel made of a highly conductive material like metal, ceramic, or plastic. This wheel is divided into sectors that are alternately exposed to the exhaust and supply air streams.
- Heat transfer: As the wheel rotates, the warm exhaust air heats up the sectors passing through it. When these sectors rotate to the supply air side, they transfer the stored heat to the incoming cooler air.
- Types: There are two main types of R/WHEHX:
- Sensible heat transfer: This type recovers only the sensible heat (temperature) from the exhaust air. These wheels are typically made of hygroscopic materials that can also transfer some moisture.
- Desiccant wheels: These wheels are coated with a desiccant material that can absorb moisture from the exhaust air in addition to recovering heat. This enables them to transfer both sensible and latent heat (moisture content).
Benefits of R/WHEHX:
- Energy savings: Recovers substantial thermal energy from exhaust air, reducing the need for heating or cooling in buildings and industrial processes.
- Improved air quality: Reduces the need for outdoor air intake, which can be beneficial in polluted environments.
- Reduced CO2 emissions: By lowering energy consumption, R/WHEHX contributes to CO2 emission reduction.
- Versatility: Can be used in various applications with different air streams and temperature ranges.
Things to consider:
- Initial cost: R/WHEHX can be more expensive than other heat exchangers, but the energy savings over time can offset the initial cost.
- Maintenance: Requires regular cleaning and maintenance to ensure optimal performance.
- Cross-contamination: Potential for cross-contamination between supply and exhaust air in some applications.
Overall, R/WHEHX are a valuable technology for improving energy efficiency and air quality in various applications. Their effectiveness depends on factors like climate, building types, and specific system design.
I hope this provides a good overview of R/WHEHX. Feel free to ask if you have any further questions!