30 October 2014
It is widely recognized that residential and commercial heat pump equipment experience significant “in-field” performance loss (i.e., capacity and efficiency) depending on how the components are sized, matched, installed, and subsequently field-maintained. IEA Annex 36 evaluated how deficiencies in these areas cause heat pumps to perform inefficiently and hence waste considerable energy. Some investigations (France and UK) included field tests and assessments. Other efforts included laboratory (France, UK, US) and/or modelling work (France, UK, US), and statistical analyses of large failure databases (Sweden).
The outcome from this Annex activity clearly identifies that poorly installed and/or maintained heat pumps operate inefficiently and waste considerable energy compared to their “as-designed” potential. Additionally, it is clear that small faults for a given field-observed practice are significant, that some attribute deviations (in various equipment applications and geographical locations) have a larger impact than others, and that multiple faults or deviations have a cumulative impact on heat pump performance.