Low Temperature Heat Recovery and Distribution Network Technologies
LoT-NET was a six year project funded by EPSRC. The aim was to study all the prerequisites for connecting renewable energy and waste heat streams to low temperature heat networks. This was combined with thermal storage and optimal heat pump technologies to meet the heating and cooling needs of buildings and industrial processes.
Aims
LoT-NET has supported the development of low cost, low loss, flexible heat distribution networks that integrate intermittent renewable energy supplies, waste heat outputs, low-carbon heat emitters, multi-scale thermal storage and smart thermal energy transformers to provide affordable, secure and sustainable energy to consumers and businesses, whilst ensuring compatibility with future electricity networks. The members of the research team were advised by industrial partners to ensure the relevance of the work and best practice.
Mobirise
Background
Heating and cooling produces more than one third of the UK's Greenhouse Gas (GHG) emissions, and represent approximately 50% of overall energy demand. The UK Government's Department of Business, Energy and Industrial Strategy (BEIS) has concluded that heat networks could supply up to 20% of building heat demand by 2050. Traditionally, heat networks have supplied high temperature hot water to serve buildings and processes, however, more recently 4th and 5th generation networks are seeking to use much lower temperatures to increasing the range of waste heat sources that can be utilised and reducing heat losses. These potential waste heat sources, for example data centres and wastewater i.e. sewage systems, are typically low temperature (e.g. 30-40 °C for data centres, and 18-22 °C for wastewater) and making full use of them often requires the application of appropriate technologies. For example, low temperature heat sources generally require upgrading e.g. using heat pumps, to generate temperatures which are suitable for domestic use.

Also, since electricity input is needed for the heat pump, optimal utilisation of these heat resources can be achieved by the integration of heat and electricity networks. This can be facilitated by the use of thermal storage, as it can reduce peak loads on the electricity grid as well as enhance the efficiency of the distribution network. In addition, waste heat source availability often varies with time,so smart controls may be needed for efficient use of these energy systems. LoT-NET investigated the integration of these technologies into smart thermal networks to demonstrate the steps required for the decarbonisation of space heating in the UK.

Project Outline
The original plan was for an interdisciplinary collaboration between the four Universities (University of Warwick, Loughborough University, London South Bank University and Ulster University), but this became impractical due to COVID-19 and the associated lockdowns and travel restrictions.
It is notable that to date, smart thermal networks are less well understood than smart power networks, although significantly more energy is used in our homes and businesses as heat rather than electricity. The programme addressed these issues through a focus on how waste heat (and cold) can be recovered and used, for example by incorporating low carbon energy resources in smart, thermal and electrical energy systems.
The four universities carried out a series of case studies into technologies required for the adoption of Low-Temperature Networks.  The aim was to identify best practice in each area, leading to recommendations for policy development and strategic planning as part of the UK’s commitment to Net Zero by 2050.
  • University of Warwick:
    • Studies into the operation and optimal control of buildings connected to a heat network.
    • Development of an adsorption heat pump and thermal transformer to use heat more efficiently.
  • London South Bank University: Identification of sources of recoverable heat that would reduce the electrical power required by heat pumps.
  • Loughborough University:
    • Simulations and experimental work into thermal stores at both small scale (domestic) and very large scale. This allows heat pumps to run whilst electricity is cheapest and even for seasonal storage to obviate the need for electrical power during periods with no wind.
    • Consumer surveys into the acceptability of low-carbon heating measures.
  • Ulster University: Development of advanced heat pumps with variable output, high COP and high delivery temperature for ease of retrofit or industrial use.
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Page contact: Angeles Rivero Pacho

LoT-NET is funded by EPSRC/UKRI under grant agreement EP/R045496/1
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