Optimisation of Air Source Heat Pump Applications in NZEB Residential Retrofits

The Challenge

The Irish Government has committed itself to an 80% reduction in emissions from the energy system by 2050. Heat makes up 15% of Ireland’s overall CO2 emissions, with oil & solid fuel heating (55%) dominating in our existing housing stock, making decarbonisation of our built environment a critical component in addressing Ireland’s carbon emissions. ESB’s Brighter Future Strategy recognises the significant potential for the electrification of heat to enable this transition, with the 2019 Irish Government Climate Action Plan reinforcing that ambition.

While progress was being made enabled by changes to the Building Regulations in stimulating increased deployment of heat pumps in new build homes, progress on building capability to address the 1.6 million existing homes that required "deep" renovation to achieve appropriate energy/carbon efficiency standards has been limited. Specifically there is a lack of knowledge about the performance of heat pumps in residential dwellings and a lack of confidence that this technology could deliver hugely ambitious electrification of heat targets on a large scale outlined in the Climate Action Plan.

The Solution

Superhomes 2.0, is an IERC-funded project to undertake an in-depth analysis on the performance of Air Source Heat Pumps (ASHPs) in residential retrofitted buildings in Ireland. The key aims of the research were to complete the first longitudinal study of the performance of ASHPs within residential retrofits in Ireland; test a range of optimisation measures to increase the Seasonal Performance Factor (SPF) of the systems; test a specific Time of Use (ToU) tariff appropriate for ASHPs and to investigate approaches to integrate Solar PV, ASHP and battery storage solutions as well as consideration of electricity network impacts of extensive ASHP applications. Over a 2-year period, ESB, Electric Ireland and ESB Networks worked in partnership with Limerick Institute of Technology (LIT) and Tipperary Energy Agency (TEA), to complete a detailed study to assess the performance of heatpumps across 20 homes.

The Benefits

Superhomes 2.0 has filled a knowledge gap related to ASHP performance in retrofitted Near Zero Energy Buildings (NZEB) in Ireland while also developing innovative optimisation control solutions. The project has demonstrated to the industry, policy makers and society that ASHPs in residential retrofits are very effective with high performance levels in deep retrofits and that ASHPs can and will contribute significantly to Irelands energy transition. The findings from the project have been utilised as part of training programmes within LIT to part-time and full-time undergraduate students thereby disseminating knowledge of this emerging activity. The outcomes have also been presented by LIT and TEA at European meetings involving EASME and EU Commission and to the International Energy Agency Heat Pump Task Force.

The Future

The Climate Action Plan has targeted the renovation of 500,000 homes by 2030, with 400,000 of those to have heat pumps deployed. Appropriate standards and best practice guidelines must be established in order to provide assurance for our citizens that this low carbon technology can be depended upon to deliver energy/carbon efficiency benefits. This research will be invaluable in developing these standard and best practice guidelines leading to much progress in the electrification of heat as part of the Irish Government Climate Action Plan.