The UK heat pump field trial: findings from phase 2

Panel: 7. Monitoring and evaluation

This is a peer-reviewed paper.

Authors:
Jaryn Bradford, Energy Saving Trust
, United Kingdom
Tom Byrne, Energy Saving Trust, United

Abstract

The Energy Saving Trust’s heat pump field is the UK’s most comprehensive study to measure the performance of in-situ residential heat pump installations. Running from 2008 until 2012, the study has collected performance data from 83 heat pumps - including 29 air source and 54 ground source - installed in a varied range of housing conditions in the UK. The findings from Phase 1 (2008-2010) of the field trial, presented at the ECEEE 2011 Summer Study (Bradford, et al, 2011), discussed the results from in-situ monitoring and provided a comparison of measured UK performance compared with similar European field trials. Phase 1 identified a wide range of performance results, with many (53) installations exhibiting ‘poor performance’ with COP and annual SPF values below 2.5. Most of these sites were investigated further as part of Phase 2.

Phase 2 (2010-2012) undertook additional investigation to determine best practice design and installation of heat pumps in three steps: Firstly, UK installer standards were revised to encourage better design and installation. Secondly, interventions were undertaken at 33 field trial sites to determine if the performance of ‘poor performing’ installations could be improved by following new installation guidelines. Specific investigation was undertaken into areas such as heat pump sizing; heat emitters; and flow temperature. Finally, 40 heat pumps were monitored for a second year and results were compared to Phase 1 as a series of case studies. These heat pumps included 33 sites with interventions and 7 sites with no interventions as a ‘control group’.

Results from Phase 2 illustrate that 14 sites achieved improved performance; 20 sites performed about the same; and 6 sites performed worse. This paper will present the measured in-situ performance across the sample for both Phase 1 and Phase 2; identify the interventions undertaken; and discuss the impact of interventions on performance (e.g. COP and SPF).

ERRATA

Numbers have been corrected throughout the paper from the printed version.