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George Davies Centre (LCfM)

Location: Leicester, LE1
Completion Status: Complete & Certified 01/2016 Occupancy: Occupied 03/2016
Architect: Associated Architects Consultant: WARM, Couch Perry Wilkes, Ramboll, Bidwells, Gleeds, Gilliespies
Contractor: Willmott Dixon Client: University of Leicester
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UK Passivhaus Awards 2018 finalist decalFinalist in the non-domestic category of the 2018 UK Passivhaus Awards. A sizable and complex building breaking several Passivhaus stereotypes formally known as the University of Leicester Centre for Medicine. Accommodating 2400 occupants with a total floor area of approximately 13,000 m2, this is the largest certified Passivhaus building in the UK, and one of the largest in Europe.

 

 

The new George Davies brings together the University of Leicester's colleges of Medicine, Psychology and Biological Sciences under one roof for the first time. The £42m building, which opened to students in March 2016, includes a 1.6km-long ground-to-air heat exchanger (GAHE), exposed thermal mass with imbedded TABS inter-slab cooling and a highly insulated and airtight building envelope. The complex design and supersized construction posed tough new challenges for how to meet Passivhaus on such a scale.

The client originally wanted a zero-carbon building, but subsequently learned that Passivhaus would offer reliable occupant comfort, defined targets, and long-term reduced running costs that would soon outweigh initial capital costs. The Standard fit well with the University's ambition of creating sustainable low-energy campus buildings.

University of Leicester Centre for Medicine (LCfM) Credit: Martine Hamilton-Knight

George Davis Centre Mock UpThe scheme comprises of a two-storey podium structure, with three linked towers rising up from this. The building includes main teaching spaces, both a 300-seat and smaller 150-seat lecture theatre, and informal learning spaces. Along with a mixture of research laboratories, and cellular offices.

Refining the details of the specialised Schuco curtain walling system to minimise thermal bridging and to integrate the controls for external shading blinds was complex and had never been done to Passivhaus levels of performance in the UK before. Following extensive design development, a large mock-up panel was produced off site at a testing facility to enable the details to be tested before delivery to site.

 

Energy Performance

George Davis Centre energy performance

The building contract required that the design team and contractor worked towards achieving a DEC ‘A’ rating by the end of a three year ‘soft-landings period’. This was however achieved in under 18 months. The energy monitoring & feedback of the occupants are being acted upon to refine the buildings performance. The soft landings process has been instrumental in tweaking the buildings performance.

Overall the actual heating from sub-metered data is marginally higher than predicted but there is a discrepancy between heat delivered to the building verses heat supplied to the heat exchanger in the energy centre. Significant causes identified during the soft landings include:

  • Incorrect function of actuators in the valves (valves do not seem to be closing fully) This contributed to higher measured heat consumption compared to actual heat consumption. The Actuators have been replaced and the issue has been rectified.
  • The Centre uses considerably less energy than other campus buildings and hence the University has decided to use it more intensively with longer opening hours than originally envisaged. A corresponding reduction in the use of other buildings has lowered the University’s overall carbon emissions.
  • Occupants requested higher winter temperatures to what had been modelled in the PHPP by about 1-2 degrees Celsius degrees. This results in an increase of 5kWh/m2.yr in annual heat demand. It is challenging to maintain thermal comfort for all users in a building of this size, but solutions are being sought to reduce settings back to design levels without compromising occupant comfort.
  • Other factors include incorrect setbacks, faulty radiators, no separate time schedule for underfloor heating.

George Davis Centre 2018 UK Passivhaus Awards Finalist Non-domestic category

The actual Primary Energy consumption was also slightly higher than predicted. This was mainly due to electricity for lighting. Along with the longer hours of use, the overly sensitive PIR motion detectors were triggered unnecessarily – this has been rectified by reducing the switch-off time delay in corridors from 15 minutes to one minute. To avoid damaging the equipment and compromising user comfort a five-second fade up and fade down time has been added which has resulted in a smooth transition from dark to light and vice-versa. Daylight-linked dimming has been optimised in all spaces. These changes have resulted in 20-30% of energy saving in lighting.

Following interventions during the Soft Landings period, data discrepancy between heating submeters and District Heat Network meter have been continuously reducing and has been now been approximately eliminated.

The building has a 30kW PV array and building energy running costs for first 12 months occupation are less than £3/m2 per annum. An extensive BMS system allows extensive data collection and the University remains committed to analysing and interpreting the data for the benefit of future projects.

George Davis Centre 2018 UK Passivhaus Awards Finalist Non-domestic category

Staff have commented how warm the building is in the winter when other buildings on campus have been quite cold in comparison, and cool in summer even during heat waves. Another regular comment from staff & visitors is the amount of natural light flooding in through the large windows, atrium areas and teaching spaces.

 

feel honoured to work in the largest Passivhaus building in the UK. The George Davis Centre provides me and my colleagues with a comfortable, light and airy environment. However, I don’t just work in the George Davis Centre, I work with it. This provides me with sense of satisfaction, because I have learned so much from the building, I now feel that, albeit very small, I am positively contributing to the environment in which I live and work.

Debbie Oldham, Departmental Manager

Key Stats

  • TFA: 9863m2
  • Gross External Area: 14,700m2
  • Form Factor Ratio: 1.5
  • Construction: Masonry cavity, concrete frame & curtain walling
  • Heat Sources: District heating, Ground Air Heat Exchange (GAHE), electric water heaters.
  • Occupants: 2400 people
George Davis Centre site  

 

Lessons Learned

  • Involve all the supply chain with detailed design responsibility earlier in the process, ideally within pre-construction phase.
  • Allow sufficient design time to achieve a robust ‘tested’ design of key elements prior to construction – avoid traditional design & build routes where design & construction can overlap greatly.
  • Reduce the interfaces between change of materials. The complex interfaces between materials made it a challenge to achieve 0.3ACH. The non-compact building form required more stringet airtightness & thermal performance targets to make the PHPP figures work. Hence the 0.6ACH target to meet Passivhaus, was halved to 0.3ACH. 
  • The concrete frame provided a solid basis to make air tightness detailing easier to achieve.
  • Keep it simple. Both Passivhaus and non-Passivhaus elements should be as straight forward as possible to enhance buildability.
  • The scheme proves that up scaling Passivhaus is possible with creative design. Having a period of optimisation and fine-tuning i.e. Soft Landings has been very beneficial.

George Davis Centre monotage

The George Davies Centre

Further Information

Scaling up Passivhaus: UK Passivhaus Conference presentation - October 2015 

Previous PHT Story: University of Leicester Centre for Medicine receives certification - 23rd February 2016

The UK’s largest Passivhaus: University of Leicester’s Centre for Medicine: CIBSE Journal – April 2016

Monitoring studies at Leicester Medical Centre: UK Passivhaus Conference presentation - October 2016 

UK's largest passive building opens to 2,400 students and staff: Passive House Plus – December 2016

Previous PHT story: Students learn from the largest UK commercial Passivhaus - 28 April 2017

Previous PHT Story: Leicester Centre for Medicine: Multi-award winner – 15 May 2017


UK Passivhaus Awards 2018 finalist decalBack to 2018 UK Passivhaus Awards shortlist