An air-to-air plate heat exchanger (PHE) is a device that transfers heat between two air streams without mixing them, using a series of thin, closely spaced metal plates. It’s commonly used for energy recovery in HVAC systems, improving efficiency by preheating or precooling incoming air with exhaust air.
Key Features:
- Construction: Alternating plates create separate channels for the two air streams, with heat transferring through the plates due to temperature differences.
- Types:
- Cross-flow: Air streams flow perpendicularly, simpler design.
- Counter-flow: Air streams flow in opposite directions, higher efficiency.
- Efficiency: Typically 50-80% heat recovery efficiency, depending on design and airflow.
- Materials: Plates are often aluminum, stainless steel, or polymers, balancing cost, durability, and thermal conductivity.
- Applications: Ventilation systems, industrial processes, data centers, and residential HVAC for energy savings.
Benefits:
- Reduces energy costs by recovering heat.
- Maintains indoor air quality by preventing air mixing.
- Compact and scalable design.
Limitations:
- Potential for frost buildup in cold climates.
- Pressure drop across the exchanger may require additional fan power.
- Maintenance needed to prevent fouling or clogging from dust/particulates.