Energy Moves in Two Forms

When warm exhaust air passes near cold incoming air, energy crosses from the warm side to the cold side. That energy has two parts: sensible heat (dry-bulb temperature) and latent heat (water vapour).

Sensible Heat

Sensible heat is the energy that changes temperature. It is carried by the air mass itself. The amount moved is Q = m_dot x cp x DeltaT, where m_dot is mass flow, cp is specific heat (about 1.006 kJ/kg.K for air), and DeltaT is the temperature difference.

Latent Heat

Latent heat is the energy bound up in water vapour. When vapour condenses, it releases this energy. Recovering moisture (enthalpy recovery) moves both the temperature and this hidden load.

Why It Matters

A sensible-only device ignores latent heat. In humid climates that is most of the cooling load, which is why enthalpy recovery can outperform a simple plate core.