UK: Mitsubishi Electric’s Ecodan air source heat pump is said to have shown better efficiency than a gas condensing boiler in year-long trials.

 The data collected by Mitsubishi Electric from the trials was audited and analysed by the Energy Saving Trust (EST) using the same methodology as in the EST’s recently published Phase 2 heat pump trials report. Mitsubishi’s data was gathered from Ecodan systems at 23 sites around the UK, in places as far apart as North Wales, Cornwall, Cumbria, Yorkshire, Bedfordshire, Northumberland and the Isle of Wight.
 
As calculated by the Energy Saving Trust (EST), Ecodan demonstrated average estimated annual operating cost savings of 8% over a gas condensing boiler, 36% over an oil condensing boiler and 67% over a direct electric heating system. 

Estimated carbon emission savings of 21%, 41% and 67%, respectively, were also demonstrated and the EST report also shows that after future grid decarbonisation, these carbon savings rise to 85% over gas and 88% over oil. 

According to the results, Ecodan achieved an average seasonal performance of 2.9 when measured against the Government’s preferred boundary condition for calculating heat pump performance – known as the Seasonal Performance Factor (SPFH4)

The EU defines the renewable threshold as an average seasonal performance of 2.5, when measured against reduced boundary conditions covering the performance of the heat pump in isolation (known as SPFH2).

SPFH4 conditions widen the monitoring by including all auxiliary power consumption and this gives a much clearer indication of overall system performance. 15 of the Ecodan sites also achieved an SPFH4 average of 2.98 across the winter of 2011-2012 – one of the coldest on record for decades, and seven of the sites achieved an average of 3.04.

“These tests measured all auxiliary power consumption as well as that of the heat pump itself so it gives a much more accurate indication of the overall performance,” explains John Kellett, general manager of Mitsubishi Electric’s Ecodan heating range.