Research Challenge

FITS-LCD is addressing significant engineering and social challenges assocaited with the effective integration of thermal storage in low-carbon dwellings.

Integrating heterogeneous heat sources - The efficient integration of different heat sources with varying thermal and temporal characteristics within a viable thermal store - perhaps featuring a variety of storage media - will require more sophisticated storage topologies, balance of plant and controls than are seen at present with fossil-fuelled-based heating systems. The nature of the challenge is illustrated by the poor performance of many existing hybrid heating systems featuring solar thermal collectors in the UK ; a key reason for this is poor control of conventional heating plant when operating with a stochastic thermal source such as solar. Another reason is a lack of design tools capable of handling the complexity of dynamic, hybrid energy systems, which limits the ability of designers to test the performance of hybrid heating systems operating under realistic conditions. The design and construction of such systems in ways that are practically, economically and visually acceptable is fundamental.

Measurement of heat stored - the efficient operation of fabric-integrated thermal stores will require better measurement and estimation of stored heat than is seen at present, where often only a single sensor is used to characterise the state of a thermal store. Research is required into accurate state estimation of complex thermal stores - this is particularly important when attempting to maximise the utilisation of low carbon heat and maximise the benefits of phase change materials, which work best in a narrow range of operating temperatures (PCM stores operating outside their phase change range will perform more poorly than conventional sensible stores).

Incentives for storage - currently there is very little incentive for end users to accommodate thermal storage in their dwellings and communities, and energy and comfort benefits are not included in existing energy calculations for building standards. Indeed, the last 20 years have seen a huge reduction in domestic thermal storage with the advent of combination boilers and removal of hot water tanks and the reduction of effective thermal mass. There is a clear need for research to identify the fiscal mechanisms that would first incentivise developers, homeowners and communities to invest in thermal storage and secondly the mechanisms needed to participate in thermal demand control for the benefit of wider energy network operation.

End User Engagement - Engineering approaches to energy reduction and efficiency have tended to ignore the building occupant and their interaction with technology - this has led to ineffective use. Research related to end users and storage technology has focused on the acceptability of the concept of thermal demand management. However, a crucial issue for any innovative technology is the need for end users to engage with such systems and this is rarely considered. Domestic heating and storage systems have a poor reputation with regards to controllability and delivery of the heat. The added complexity of managing perhaps multiple energy sources, coupled with participation in energy networks could make the technology less attractive to end users. The need to deliver acceptable levels of comfort and ensuring effective control and maintenance (including by different tenure types) is critical.

Specifically, over a 3-year period the project will:
  • investigate the context for operation of domestic thermal stores, assessing heat supply and demand scenarios and how such systems could be integrated into housing design;
  • generate a variety of domestic FITS concepts (storage + balance of plant + control) using heat from different temperature sources and capable of operating over varying timescales
  • using modelling, conduct performance analysis of concept storage systems operating with heterogeneous thermal inputs and participating in energy networks;
  • undertake economic analysis of thermal storage developing the fiscal incentives required to promote uptake and facilitate participation in the operation of future energy systems at the individual and community scale;
  • identify energy services that could be offered through storage to future energy networks;
  • construct thermal storage demonstrations of the best performing storage concepts in order to measure in-situ performance and generate performance datasets;
  • develop and deploy user-interface and operational concepts for thermal stores offering energy services to future energy networks, collecting end-user reactions to interfaces, technology and energy services. Measurable outputs will include:
  • software models and performance appraisals for FITS concepts;
  • prototype control strategies and energy services for domestic storage systems;
  • physical models of fabric integrated storage system concepts;
  • concept designs for buildings and construction systems and outline design guidance;
  • technical, economic and environmental performance assessment metrics;
  • performance datasets for software model verification;
  • prototype end user interfaces for active fabric integrated energy stores;
  • studies of end user interaction with the technology.