Investigation on a ventilation heat recovery exchanger: Modeling and experimental validation in dry and partially wet conditions

The present paper focuses on the development and experimental validation of a model of air-to-air heat
exchanger dedicated to domestic mechanical heat recovery ventilation. The proposed model describes
dry and partially wet regimes.
The first part of the paper presents a semi-empirical model based on the physical characteristics of the
heat recovery device and relying on empirical correlations available in the literature for the convective
heat transfer coefficients. In the case of partially wet regime, a moving boundary model is applied in order
to predict sensible and latent heat transfer rates. A model developed with friction factor coefficients estimated
by correlations from the literature is also presented in order to predict the hydraulic performance
in dry conditions.
The second part of the paper describes the experimental investigation conducted on an off-the-shelf
heat exchanger.
Experimental data are used to tune correlations for the determination of the convective heat transfer
coefficient and validate the proposed simulation model of the ventilation heat recovery exchanger in
partially wet conditions. The model developed to determine the hydraulic performance with existing
correlations for the friction factor coefficient does not require a calibration.
Finally, examples of use of the developed model are presented, which includes coupling the model
with a building simulation model, a study of the influence of the humidity on the evolution of the latent
and sensible heat transfer rates and strategies to avoid freezing in the heat exchanger.