The Frost Problem
When cold outside air meets warm, moist exhaust, the exhaust surface can drop below 0 C and ice forms. Left unchecked, frost blocks channels and collapses effectiveness.
Selection Choices That Help
- Wider channels - slow frost buildup and ease defrost
- Preheat coil - warm intake air above the frost point
- Defrost bypass or recirculation - periodic warm-air purge
- Frost-resistant media - hydrophobic surfaces
Technology Note
Rotary wheels handle frost well via purge sectors and modulation, but need controls. Plate cores need an explicit defrost strategy set from the coldest expected temperature, not the annual average.
Climate Thresholds
Below about -2 C exhaust dewpoint, plan active frost protection. The colder the design temperature, the more robust the strategy must be.
Verify
Model the worst week of the year, not the average, and confirm the controls actually trigger defrost at the set point.
What This Product Does
This unit is built as a compact air-to-air heat exchanger that transfers thermal energy between two separate air streams without allowing them to mix. Warm exhaust air passes over one side of the core while cooler supply air passes over the other, and the temperature difference drives heat from the warm stream to the cool one. The result is pre-conditioned make-up air that needs far less external heating or cooling, which lowers the load on the building or process system.
Construction and Materials
The core is formed from corrugated aluminium or stainless-steel plates bonded into a counter-flow pack, with sealed channels that keep the two air paths isolated. Frames are typically galvanised or powder-coated steel, and service doors give access for inspection and cleaning. Gasket materials are selected for the operating temperature and any mild chemical exposure, so the unit stays reliable in demanding ventilation duties.
Where It Fits
In the Selecting a Heat Exchanger for Cold Climates configuration the exchanger is suited to HVAC make-up air units, paint and coating ovens, food and pharmaceutical drying, and general process ventilation where energy cost is a concern. It can be mounted horizontally or vertically to match the available plant layout, and it connects with standard flanged ductwork for straightforward integration with existing fans.
Frequently Asked Questions
Does it need power to operate? The passive core needs no electricity; only the associated fans and controls consume power. How often should it be cleaned? Inspect at least once per season and clean the exhaust side when temperature recovery begins to drop.