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Case History4_university-of-bristol-logo-opt200 - Peter Hawtin - peterh

District Heating Optimisation, Redesign and Commissioning

“At last we have someone who understands CHP and thermal stores, rather than having just read about them in a book and made up a design as they go along!”

Dave Baker, Mechanical Building Services Engineer

The University

Bristol is one of the most popular and successful universities in the UK and was ranked within the top 5% of universities in the world in the QS World University Rankings 2019.

The University has a long history of action on sustainability, winning numerous awards for its work. Sustainability is one of the central strands shaping the University's vision of the future. It has several teams working on sustainability activities, including the Estates Sustainability Team.

The challenge

The 4_langford-2-opt300 - Peter Hawtin - peterhUniversity’s District Heating System (DHS) at its Langford Campus serves a high percentage of the buildings including research and accommodation plus common areas with two independent Energy Centres for primary thermal energy for space and domestic hot water.

The Sustainability Team knew the system to be inefficient and wanted to know:

  • The least-cost path to using the thermal store better
  • How to best serve underutilised buildings
  • If increased efficiency could be achieved by linking two networks
  • If biomass could be cost-effectively integrated into the mix

The solution

The Green Consultancy (TGC) was commissioned to carry out a forensic study to reliably deliver the required objectives and provide a firm foundation for making all future decisions about the DHS.

The study entailed a thorough survey of the system and a comprehensive analysis of all relevant data including thermal/hydraulic modelling using software developed and tested on numerous DHSs over many years. Superior EU standards rather than UK ones (CIBSE etc) were used.

Stage 1 was a desk-top exercise to report on DHS sizing and efficiency with likely thermal losses from the transport of chemical/thermal energy from source to delivery and operational risks.

Stage 2 verified the likely losses and identified operational risks from Stage 1 and reported on cost-effective solutions to improve and/or rectify problems based on prioritised works with budget costs identified.

TGC then redesigned the DHS based on its recommendations and supervised the progressive commissioning.

The results

The redesign featured:4_langford-heat-store-opt-200 - Peter Hawtin - peterh

  • Making maximum use of existing gas CHP as the priority firing asset together with the existing thermal store to suit the existing site-wide hydraulic scheme
  • Existing four gas boilers to be secondary firing assets on a duty call basis based on main DHS header flow temperature
  • New hydraulic layout to make the maximum use of the existing CHP and 50m³ thermal store (illustrated) as priority suppliers of thermal energy.

The cost of progressive implementation of the new design was more than covered by the value of the immediate energy savings and it is expected that annual cost-savings of 60-70% will be achieved.

The savings will be verified in the 2019-20 heating season.

The reaction

“The Green Consultancy redesigned the District Heating System at our Langford site to dramatically improve its energy efficiency. Their consultant gave a clear and concise explanation of the new design and answered all questions from the team charged with progressively implementing and commissioning the new design in a way that fully inspired our confidence in the results. At last we have someone who understands CHP and thermal stores, rather than having just read about them in a book and made up a design as they go along!”
Dave Baker, Mechanical Building Services Engineer

Put us to the test NOW!

To discuss your requirements please call John Treble, Client Services Director on 01761 419081 or email John@GreenConsultancy.com

John Treble

Put us to the test NOW!

For over twenty five years we have been delivering superior outcomes for thousands of commercial, industrial and public-sector clients.

You need not take our word for it – hundreds of their comments are at the foot of these pages.

To discuss your requirements please call John Treble on 01761 419081 or email


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