The difference between recouperative and regenerative heat exchangers

Typically, heat exchangers are used to allow heat from liquids or gases to pass to other liquids or gases, without the two coming into direct contact. Essentially they transfer the heat without transferring the fluid that carries the heat.

Recouperative heat exchangers normally run at higher temperatures with two flows and shorter exchange periods, they are a more direct for of heat exchange and depending on type will normally be more efficient. The materials used are normally metal or plastic.

Regenerative heat exchangers have single intermittent flows that exchange heat via a third medium acting as a heat battery, so increase in efficiency with the time allowed for the temperature exchange to occur and so can run at lower temperatures. In general when compared with recouperative heat exchangers they are less efficient depending on the circumstances of the waste heat being recovered.

In buildings it is most common to have centralised whole house recouperative heat exchange systems that employ flate plate exchangers within mechanical heat recovery systems (MVHR) exchanging heat between waste warm air and colder fresh air. However there are more recently single room recouperative heat exchange units available, that act as a tube exchanger, traditionally though single room heat recovery ventilation units such as from bathrooms and showers were regenerative and therefore less efficient.

[edit] Related articles on Designing Buildings

• Air conditioning.
• Air infiltration testing.
• Condensation.
• Exhaust air heat pump.
• Heat recovery.
• HVAC.
• Mechanical ventilation.
• Mechanical ventilation with heat recovery MVHR.
• Decentralised mechanical ventilation with heat recovery dMVHR.
• Thermal comfort.