Inhaltsverzeichnis
- Frost appears when exhaust outlet temperature drops near 0 C and the core surface is below freezing. The risk rises with higher exhaust humidity and lower outdoor temperature.
- Defrost bypass: Periodically send a share of untreated air around the core to melt ice. Simple, widely used on plates. Pre-heat the intake: A small heater raises supply-air temperature so the core stays above freezing. Reliable but uses energy. Frost wheel / glycol spray: Rotary units may use a frost sector or periodic warm-air purge. Heat-pipe self-balance: Heat pipes naturally moderate the cold-end temperature, reducing frost risk.
- Model the winter design day, not the average. Set the defrost cycle by exhaust outlet temperature, not a timer alone. Size pre-heaters for the coldest hour, with a safety margin. Add drainage so meltwater leaves the core.
- Does defrosting waste recovered heat? Briefly, yes, but a short, well-timed defrost prevents a full blockage that would waste all recovery. Which technology frosts least? Heat pipes and pre-heated plate cores handle cold climates best; unprotected rotary wheels need active frost control.
ICHn cold climates, exhaust air can be warm and humid while intake is far below freezing. When that exhaust cools below its dew point inside the core, frost forms. Left unchecked, ice blocks the airflow entirely.
Frost appears when exhaust outlet temperature drops near 0 C and the core surface is below freezing. The risk rises with higher exhaust humidity and lower outdoor temperature.
- Defrost bypass: Periodically send a share of untreated air around the core to melt ice. Simple, widely used on plates.
- Pre-heat the intake: A small heater raises supply-air temperature so the core stays above freezing. Reliable but uses energy.
- Frost wheel / glycol spray: Rotary units may use a frost sector or periodic warm-air purge.
- Heat-pipe self-balance: Heat pipes naturally moderate the cold-end temperature, reducing frost risk.
- Model the winter design day, not the average.
- Set the defrost cycle by exhaust outlet temperature, not a timer alone.
- Size pre-heaters for the coldest hour, with a safety margin.
- Add drainage so meltwater leaves the core.
Does defrosting waste recovered heat?
Briefly, yes, but a short, well-timed defrost prevents a full blockage that would waste all recovery.
Which technology frosts least?
Heat pipes and pre-heated plate cores handle cold climates best; unprotected rotary wheels need active frost control.