Thermal energy storage applied to the Passivhaus standard in the Irish climate

• Main Author: Colclough, Shane M.
• Published: University of Ulster 2011
• Subjects: 697.78
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.550825

Due to a unique combination of factors, low energy and passive houses in Ireland are particularly well suited to exploiting the advantages of solar thermal energy especially when combined with an Inter Seasonal Energy Store (ISES). However few documented examples exist of how this synergy can be exploited successfully in Ireland, thereby illustrating the manner in which sustainable fossil fuel-free space heating can be provided. This thesis presents the design rationale for such a system and provides an overview of the performance of a real installation over a full year cycle. It demonstrates that by oversizing a thermal solar array, solar energy surplus to Domestic Hot Water (DHW) requirements can successfully be stored in an ISES and that such stored energy can make a significant contribution to winter space heating needs. Key findings for this unique project are presented including DHW and Space Solar Fractions, ISES tank analysis including tank losses, it's impact on surrounding soil temperatures and ISES efficiency. In addition it is. demonstrated that solar energy, surplus to DHW requirements can make a significant contribution to direct space heating in temperate Maritime Climates and that Ireland has one of the most suitable climates in Europe for Direct Solar Space heating. Further, a detailed financial analysis is carried out demonstrating the economic feasibility of the Solar DHW and Space Heating and ISES installation. The financial analysis demonstrates a strong business case for the Direct Solar Space Heating and the ISES especially when the UK Governments Renewable Heat Incentive (RHI) is considered. Complementing the work done on storing heat, the research also looks at the use of thermal energy storage to store coolth by means of Phase Change Materials (PCM). Given the potential for overheating in well insulated, low energy homes, the potential for Thermal Mass to avoid overheating is analysed for the Irish Climate. This is highly relevant within Ireland currently due to the introduction of the 2010 building regulations, the thermal efficiency of which approaches that of the passivhaus standard. As an integral part of this analysis, a commercially available dynamic building simulation tool is validated and used to examine the case for the incorporation of latent thermal mass in the building envelope. The research finds that, while PCM does aid thermal comfort, the issue of overheating is not sufficiently prevalent in Ireland to warrant the introduction of PCM to reduce overheating.