heat recovery ventilation

Heat recovery ventilation (HRV) is one of the usual techniques (next to demand controlled) to reduce the energy impact of ventilation in buildings. For a given air change rate, the energy savings of HRV are in the first place dependent of the heat-exchanger efficiency, usually measured in standardized laboratory conditions. However, many other factors can have an impact on the overall system performance in practice.

In a recently built zero-carbon neighborhood, demand controlled exhaust ventilation systems (DCMEV) and mechanical ventilation systems with heat recovery (MVHR) are compared under operational conditions, with focus on the energy performance of both systems. The analysis is based on automatically gathered monitoring data, complementary in situ measurements and occupants surveys. 

Demand controlled heat recovery ventilation systems, which combines heat recovery (HRV) and demand controlled (DCV) is growing fast among ventilation manufacturers.

Several categories can be identified, from global dwelling regulation, to fine room-by-room regulation of the airflow rate. Simulations show that room-by-room demand controlled heat recovery ventilation is the best compromise to optimize at the same time indoor air quality, comfort, and energy savings.

Both critical and optimistic claims have been made regarding the performance of heat recovery ventilation systems (HRVS) in dwellings. Such arguments are raised partly because two key aspects are not fully clarified, i.e. the performance criteria and the influence of uncertainties. In the current paper, an assessment method for HRVS considering the influence of uncertainties is described. This includes  adequate assessment criteria, the method of identifying the uncertainties, and the method of addressing the influence of such uncertainties.