How do you generate energy savings to justify core plant replacement in a building with significant energy saving features already installed?
Feasibility, design and principal designer duties.
Background
The British Library is the national library of the United Kingdom and gives access to the world’s most comprehensive research collection.
Their collection includes over 170 million items including artefacts from every age of written civilisation. Their London and Yorkshire sites have everything from newspapers to sound recordings, patents, prints and drawings, maps and manuscripts.
The Brief
Identify the potential for further energy savings, by utilising the waste heat for dehumidification.
Challenges
We have worked on both sites with many successful commissions; however, St Pancras presented quite a challenge for us. The key to maintaining the artefacts in prime condition is temperature and humidity control, therefore, round the clock temperature and humidity control involves megawatts of central plant. The waste heat from their LTHW boilers is recuperated using flue gas economisers – up to 940kW of recovered energy, which is put back in to the LTHW system.
The primary challenges that we needed to overcome in this project included:
- Maintaining tight temperature and humidity control within the building
- Developing plant areas with tight areas for additional equipment
- Implementing energy efficiency measures already deployed
- Payback needed to be within a reasonable period
Process
We began by running permutations through energy calculations and simplified payback calculations to explore opportunities for savings (this included consideration of all available technologies). By using all of the means at our disposal we were able to identify a way of saving energy and generate a payback period of 4 years. Using the waste heat to generate chilled water through an absorption chiller gave us the solution we needed. In addition, this would be the lead chiller all year round and allow an older inefficient centrifugal chiller to be mothballed.
Outcome
We have undertaken full design and principal designer duties and tendered the works, which included further core plant replacement options.
