Improving the usability and performance of heat recovery ventilation systems in practice

The use of heat recovery ventilation systems is becoming more and more common. It is clear that these systems contribute to energy efficiency and good indoor air quality. Still there is room for improvement. Analyses by monitoring and modelling have uncovered drawbacks and flaws, especially for the use and application of HR ventilation in highly energy efficient dwellings. This paper will deal with these issues, turning them into suggestions to improve HR ventilation systems. 
An important finding is the poor ability of HR ventilation systems to anticipate on increasing differences in room heating/cooling needs within a dwelling. The HR ventilation systems are not able to redistribute recuperated heat with differentiated ventilation, distinguished in time and per location. This invokes additional window use, not only resulting in a poor control of the indoor environment, but also highly reducing the overall energy gain of the HR ventilation system. This energy gain itself is often overestimated, due to insufficient insulation of the unit’s outdoor ducting and blockage of the heat exchanger by condensation moisture. Furthermore, the high practical all year electricity use is not incorporated as well.  
Another finding is the rigidity of HR ventilation as the anticipation on seasonal fluctuations is concerned. In fact the system is designed for non-freezing winter use, despite its summer bypass. Hence it operates most of the year in a non-optimal mode. 
Several suggestions are done to improve the utilization of HR ventilation systems, such as zonal differentiation, incorporation of short term heat storage, moderations of the ventilation unit and improved control, as well as design recommendations for a low-noise moderate pressure ducting system.