Energy performance gap assessment and Post Occupancy Evaluation of UCL Cruciform Library / Main outcomes

By Vasiliki Kontopoulou, on 3 November 2015

This update includes the main results of my dissertation research regarding UCL Cruciform Library. The most important outcomes of the methodology used, including hygrothermal monitoring, occupant comfort surveys, dynamic thermal modelling and Carbon Buzz are presented.

After the monitoring period (6-20/7/2015), the results extracted from the Hobo data loggers were analysed. The most important findings are summarized below:


Hygrothermal monitoring plan

the average internal temperature in the majority of spaces (excluding computer clusters – average of 24 degrees Celcius) fluctuates between 21 and 22 degrees Celcius, really close to the external one (average of 18.9 degrees Celcius).

the average internal relative humidity in the majority of spaces fluctuates between 51 and 55%, falling inside the acceptable range of 40-70% according to CIBSE Guide A (2006).



Average temperature (degrees Celcius) recorded in each space of Cruciform hub



Average relative humidity (%) recorded in each space of Cruciform Hub

Regarding the BUS survey that was conducted during the week 20-27/7/2015 (sample of 56 students), the most important issues are summarized below:

  1. internal low temperatures
  2. natural ventilation not existent at present
  3. need for more working spaces, personal computers and facilities for practicing
  4. some spaces (mainly the entrance) are noisy
  5. lack of natural lighting

Average of students’ answers regarding 6 areas of interest (Scale 1-7)


comfort during summer

Average of students’ answers regarding comfort during summer (Scale 1-7)

Dynamic thermal modelling (IES VE software) / Design energy performance

The model was simulated on IES VE software, trying to make it as similar as possible to what the designers had proposed.

Meter readings _ Data obtained from Carbon Culture Platform / Actual energy performance

The actual energy consumption of the library was calculated using data from Carbon Culture Platform resulting in a value of 765.3 MWh.

Estimation of the performance gap

As demonstrated in the graph below, the actual energy performance is 59% higher than the estimated one.



Estimation of the performance gap


ies model

IES VE model


Performance gap factor (actual energy use / design energy use) : 2.49


CARBON BUZZ Platform – Comparison to CIBSE TM46 benchmarks

Carbon Buzz is a collaborative research platform that was launched by the Royal Institute of British Architects (RIBA) in collaboration with the Chartered Institution of Building Services Engineers (CIBSE) in 2008 (http://www.carbonbuzz.org/), enabling designers to compare calculated and real energy use for their buildings. This initiative emerged from the need to manage CO2 emissions from buildings.


Data obtained from Carbon buzz platform



Actual and design data compared to CIBSE TM46 benchmarks


case studies

Performance gap factor change for some case studies examined

Next update….

Conclusions of the research

Recommendations to UCL Estates

Further research

Vasiliki Kontopoulou

Supervisor: Anna Mavrogianni

In collaboration with

UCL Estates: Joanna Marshall – Cook

Green UCL: Alex Green



Degrees of Change briefing session (1.00-2.00pm, Thursday 5th Nov)

By Alex Green, on 29 October 2015

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Attend a session for Green Champions and any other interested staff on UCL’s proposed new plan for carbon reduction.

This is an informal briefing session for you to find out more about UCL’s proposed Carbon Management Plan, and what it means for you. Get resources to help spread the word and share your own thoughts on the approach we’re proposing.

This plan will shape how UCL tackles the pressing challenge of reducing its carbon emissions well into the future, so it’s essential that UCL gathers as much feedback on it as possible.

  • Thursday 5th Nov
  • 1.00pm – 2.00pm
  • 23 Gordon Square, Room 101
  • Lunch will be provided.

Please RSVP to Alex Green

Examination of the performance gap for one of UCL’s newly retrofitted buildings

By Vasiliki Kontopoulou, on 12 July 2015

I am an MSc Environmental Design and Engineering student at the Bartlett Faculty of the Built Environment, University College of London, currently conducting my dissertation thesis in collaboration with UCL Estates and Green UCL. I will be giving updates on the Green UCL blog to share my research into one of UCL’S newly retrofitted buildings over the coming months. More specifically, I will be looking in depth at the gap between the predicted and actual energy performance of Cruciform hub using hygrothermal monitoring, occupant comfort surveys and dynamic building thermal modelling. Possible causes causing this discrepancy will be examined in detail.

1A brief history of the building

Cruciform Building is a Grade II listed building (Date of listing: 12/3/1974) located on Gower Street in central London, in the London Borough of Camden. It is situated inside the Bloomsbury Conservation Area and it was firstly designed as a hospital block by Alfred and Paul Waterhouse.

The building’s diagonal plan, with a single service core and radiating wings, provided light and ventilation for the wards.

Materials were selected for their durability; hard red brick and terracotta were more economic and less susceptible to erosion than stone.

In 2000, a refurbishment was undertaken through a Private Finance Initiative (PFI), converting it into the Wolfson Center for Biomedical Research and the pre-clinical training facility for UCL’s medical school.

On the 12th July 2012, as part of the UCL Masterplan, a new hub and project learning space for the students of medical school was proposed on the basement of the building. Quiet study areas, a computer cluster and group workspaces were designed aiming not to overpopulate the spaces, as this would inevitably lead to uncomfortable conditions.


Computer cluster


Group workspace







Source: Stage D of Cruciform Student Hub report (12th October 2012)

Typical energy use of the  whole building 





Data obtained from:  https://platform.carbonculture.net/places/cruciform-building/1180/

Display Energy Certificate / CO2 emissions


Data obtained from:  https://platform.carbonculture.net/places/cruciform-building/1180/

Methodology of the research


Next steps…

Collection of monitoring data

Conduction of questionnaire surveys

Simulation of the modelled building on IES VE to extract information regarding the predicted energy performance

Comparison with benchmarks

Analysis of preliminary results


Student: Vasiliki Kontopoulou

Supervisor: Anna Mavrogianni

In collaboration with:

UCL Estates: Joanna Marshall Cook

Green UCL: Alex Green


Reasons to cycle…

By Alex Green, on 24 March 2015

Our friends at Cycle Confident and Transport for London have produced this great infographic on reasons to cycle around London. And if you’d like to boost your confidence, learn to cycle more safely, or just learn new routes and get a free lunch, make sure to book your place on one of our guided cycle rides around London.


Hydrogen-powered mulled apple juice…

By Alex Green, on 9 December 2014

As part of the Christmas Switch Off, we teamed up with UCell, a group of PhD students pioneering the use of hydrogen as a fuel source.

Using their fuel cell to produce electricity from hydrogen, we powered a slow cooker to make spiced apple juice. See below for pics of the cell in action.

Help save energy over the winter break. Find out more and take part in the Christmas Switch Off.

2014_12_09 hydrogen powered mulled apple juice V1

Are you ready for the Christmas Switch Off?

By Alex Green, on 27 November 2014

We’re getting ready to launch the Christmas Switch Off, a UCL-wide campaign to save energy by switching off unnecessary lights, appliances and equipment over the holidays.

In the meantime, here’s an animated Jeremy Bentham switching off UCL…


New permanent bike pump and repair stand installed in Foster Court

By Alex Green, on 25 November 2014

You can now keep your bike in tip-top condition with the new permanent pump and repair stand (with tools) that’s been installed in Foster Court, just off Malet Place…

2014_11_20 new bike repair stand montage V1

We’re recruiting!

By Alex Green, on 21 November 2014

Want to join UCL’s Sustainability Team and help improve the sustainability of our business and projects?

Want to receive high quality training and support?

Want to work in an exciting environment with a diverse range of students, staff and academics?

Find out more and apply now (closing date November 30th 2014).

You can find out more about the work of the Sustainability Team here. And don’t forget to Like and follow to get more regular updates too!


Will your department take part in UCL Green Impact?

By Alex Green, on 6 November 2014

Green Impact, UCL’s annual sustainability programme is now live for the 2014-15 period, and all departments and divisions are encouraged to get involved.

Green Impact runs from October 2014 – June 2015. You can find out about the programme here, or just contact the Sustainability Team.

2014_10_30 Green Impact infographic for the Week@UCL V2 SM

Why’s there a number on my building?

By Alex Green, on 29 October 2014

Seen the big numbers around UCL’s campus?

As part of Degrees of Change, we’ve rated most of UCL’s buildings in terms of their energy consumption per m2, ranked from lowest to highest energy use. The numbers on UCL buildings correspond to their position on the energy league table.

We know that some buildings will always use more energy due to factors like research activities; but we think it’s a great way to start identifying where UCL’s impacts are made, and what we can all do to tackle them. Find out how your building compares.

2014_10_28 building rating numbers degrees of change V1