22 May 2008


The energy need for space heating is decreasing significantly in modern highlyinsulated
dwellings. Thus, in the recent years ventilation compact units with heat pump have
been developed for low energy houses, which combine the functions space heating (SH),
domestic hot water (DHW) and ventilation in one unit. To assess the overall performance, the
seasonal performance factor (SPF) has to be calculated by a standardised method.
In the draft standard (prEN 15316-4.2) a temperature class based calculation method (bin
method) for heat pump systems with SH and DHW operation has been introduced to
calculate the SPF and respectively the electricity input. This standard is to support the
implementation of the Energy Performance of Buildings Directive (EPBD 2003). The method
has now been extended to multi-function units with ventilation, heat recovery and optional
solar collector and ground-to-air heat exchanger.
The results of the calculation method have been validated with measurements of two pilot
plants. Furthermore, an exergy analysis for heat pump compact units provided a method to
compare system layouts by showing the influence of the different loss mechanisms on a
uniform basis.