Domestic-scale thermal storage using phase change materials and heat pumps.

  • Supervisors: Prof Andrew Knox, University of Glasgow & Dr Paz Vaqueiro-Rodriguez, Heriot Watt University
  • Sponsor Company: Sunamp Ltd.
  • PhD Student: Paul Mullen 

The three main categories of energy use in the UK are transport, heating and electricity. Electricity is the lowest consumption in absolute terms and considerable progress has been made in decarbinising its supply. Transport is being addressed  through various biofuel technologies which are now in their 2nd or 3rd generation. Low carbon heating is a critical component of the UK's 2020 targets and thus far little inroad has been made into what is becoming a rather intractable problem.

The primary purpose of this project is to demonstrate the use of phase-change materials (PCM) in conjunction with a solar thermal collector and heat pumps as a viable means of capturing and storing sufficient thermal energy at economic cost for domestic hot water and heating purposes. This demonstration requires an economic solution to a complex systems-level technical issue that is directly applicable to commercial product which will be brought to market towards the end of the research work.

The research work will build upon a “heat battery” recently developed by Sunamp Ltd and will examine a number of specific topics, including:

  • the optimum system configuration in terms of the capacity and temperature range of the battery’s cells and materials (solid to liquid transition temperatures in range 35°C to >88°C);
  • the maximum attainable heat pump Coefficient of Performance for air-source (ASHP) and fluid/fluid thermoelectric heat pumps, and the economic transition temperature range;
  • the opportunities to improve the heat pumps’ efficiency and temperature ranges;
  • and the extent to which the provision of “green heat” allows decoupling of domestic heat requirements from the energy networks (gas & electricity) and control strategies to implement.