The Problem

In hot, humid climates a large part of the cooling load is dehumidification. A sensible-only exchanger leaves that moisture in the incoming air.

Recommended Products

• Best - rotary enthalpy wheel (recovers temperature and moisture)
• Isolation needed - membrane plate (latent, no moving parts)
• Lower cost - sensible plate if humidity is manageable

Selection Checklist

• Size for latent (enthalpy) effectiveness, not just temperature
• Confirm the wheel or membrane handles the design humidity ratio
• Pair with the cooling coil strategy

The Challenge

Pools lose heat through evaporation and constant humid-air ventilation. Recovery plus a heat pump is the standard high-efficiency approach.

Recommended Products

• Pool hall ventilation - rotary or plate exchangers
• Water heating - heat-pump desuperheater recovering compressor heat

Selection Checklist

• Use corrosion-resistant, coated surfaces (chlorine air)
• Control humidity to protect the building fabric
• Size the desuperheater to the pool heat pump

The Challenge

Greenhouses vent warm, CO2-rich air. Recovery must move heat without moving the CO2 the plants need.

Recommended Products

• Primary choice - sensible plate cores (heat only, gas stays)
• Separated streams - run-around coils if a shared core is impractical

Selection Checklist

• Keep it sensible-only so CO2 is retained
• Control strategy must prioritise crop conditions
• Manage humidity to avoid condensation issues

The Challenge

Food plants vent warm, often greasy or moist air. Recovery cuts process heating and can pre-heat make-up air or water.

Recommended Products

• Make-up air - plate cores (hygienic, cleanable)
• Contaminated exhaust - run-around coils (streams stay separate)
• Water heating - air-to-water coils

Selection Checklist

• Use food-grade, cleanable surfaces
• Manage grease and condensate in exhaust
• Confirm freeze protection for cold make-up air

The Challenge

Hospitals need high air-change rates and strict infection control. Some zones forbid any stream mixing; others can use high-effectiveness recovery.

Recommended Products

• Isolation and OR zones - sensible plate cores (no carryover)
• General ventilation - rotary enthalpy wheels for humidity control
• Contaminated extracts - run-around coils

Selection Checklist

• Confirm which zones require zero cross-contamination
• Match effectiveness to the energy target
• Plan filter access and core cleaning

Why Combine

Recovery pre-treats the air, lowering the load on the heat pump. The heat pump then upgrades the temperature to what the building needs. Together they cut both capacity and running cost.

Common Configurations

• Plate or rotary recovery feeding an air-source heat pump
• Exhaust-air heat pump (the recovery unit is the evaporator source)
• Desuperheater recovering compressor heat to water
• CO2 (transcritical) heat pump for high-temperature water

Benefits

• Smaller heat-pump capacity needed
• Higher system efficiency (higher source temperature)
• Electrification-ready, lower carbon

Selection Note

Size the recovery first, then the heat pump on the reduced load. Verify the combined seasonal performance, not just the design point.

Two Recovery Paths

Air-to-air devices (plate, rotary, heat pipe) move energy directly between the two airstreams. Air-to-water devices use a coil to dump recovered heat into water for domestic hot water, process heating, or a buffer tank.

Comparison

Decision

If the recovered energy can be used to condition the incoming air, air-to-air is simplest. If you need hot water or process heat, or the streams are distant, air-to-water (or a run-around coil to water) is the better fit.

The Concept

A run-around coil system uses two coils - one in the exhaust stream, one in the supply stream - linked by a pumped fluid loop (water or water-glycol). Heat transfers from exhaust to supply through the fluid, with the airstreams completely separate.

Key Selection Parameters

• Coil size - larger coil surface raises transferred energy
• Loop fluid - water-glycol for freeze protection in cold climates
• Pump and loop length - shorter loops and correct pipe size cut pumping loss
• Fluid temperature - set the loop temperature to maximise the gradient

When to Choose Run-Around

• Airstreams are far apart or contaminated (kitchen, lab, industrial exhaust)
• Zero cross-contamination is required
• You want to recover heat without a shared core

Watch-outs

The pump uses energy, so net savings are lower than a direct exchanger. Size the loop to keep pumping power small, and insulate pipes to avoid losses.

What a Membrane Plate Does

A membrane plate exchanger uses a selective membrane instead of bare metal foil between the airstreams. Water vapour passes through the membrane while the air stays fully separated. You get latent (moisture) recovery with no moving parts and no stream mixing.

Key Selection Parameters

• Membrane type - standard vapour-permeable or engineered for higher flux
• Channel geometry - counterflow reaches higher effectiveness than crossflow
• Face velocity - keep within the band that balances effectiveness and pressure drop
• Condensate management - membranes condense on the exhaust side and need safe drainage

When to Choose Membrane

• You need humidity control but cannot accept a rotary wheel
• Isolation is mandatory (hospitals, labs, cleanrooms)
• You want no motor, seals, or bearings in the airstream

Size and Verify

Size like a plate core but confirm the latent effectiveness at your humidity ratio, not just the temperature. Check the EN 308 or AHRI 1060 rating at the actual operating point and confirm the drain path.

Why Documentation Matters

For funded or permitted buildings, the recovery performance you claim must be defensible. Self-declared numbers rarely survive an audit; certified ones do.

The Compliance Checklist

• Test standard - EN 308 (EU) or AHRI 1060 (North America) rating at stated conditions
• Certification - Eurovent certified performance where available
• CE mark - conformity with applicable EU directives
• ISO 9001 - factory quality management
• ErP / Ecodesign - minimum efficiency met for EU market (Lot 6)
• ASHRAE 90.1 - recovery threshold met for US jurisdictions

Reading the Paperwork

A credible submittal shows effectiveness versus operating point, pressure drop, leakage rate, and the test method. A bare percentage with no conditions is not_submittable.

Before You Sign

Look the model up in the Eurovent directory and compare certified values with the sales datasheet. Disagreement is a red flag. Keep the commissioning sheet as the baseline for future verification.