SCHOOLS & EDUCATION FACILITIES SUPPLEMENT COLLEGE REFURBISHMENT
Annual total demand for existing building and new building
80 000 60 000 40 000 20 000 0
Existing building New building
70 301
Total energy (kWh) 20 357 Heating
Figure 2: The expected reduction in energy demand at GE Fogg, based on design-stage estimates and post- sectional completion tests (full post occupancy survey due in 2012)
400 000 350 000 300 000 250 000 200 000 150 000 100 000 50 000 0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Figure 3: Anticipated energy generation arising from PV installation at GE Fogg
The outer pane is the PV cell and the inner pane is coated with a solar-controlled film to reduce solar gain.
Airtightness The new windows and insulation significantly improved airtightness from an estimated 0.5 air changes per hour before refurbishment to a design value of 0.35 air changes per hour post-refurbishment. The combination of factors results in a 70%
LESSONS LEARNED
Sustainable recladding of an occupied, mixed-use academic building dating from the 1970s is affordable and desirable in terms of the resultant benefits.
Even buildings with extremely complex geometries can be overclad to reduce running costs and improve user comfort.
Close partnership working between academics and staff, architect, consultant, contractor and subcontractors can achieve a high level of user satisfaction throughout the whole project – a significant achievement with such a complex, room-by-room decant, decommissioning and reoccupation schedule.
The life of a building can be extended for a fraction of the cost of a rebuild.
A striking new image can be achieved using high-quality design on a limited budget.
8 CIBSE Journal March 2012
reduction in energy demand, corresponding to a CO2 reduction of 5 kg/sq m. Coupled with the benefits of using renewable energy, the total CO2 reduction arising from the project is 6 kg/sq m. By laminating the
the façade has been fully operational since May 2011 and is estimated to produce 2,700 kWh of electricity per annum. Figure 3 shows anticipated energy generation, based on design-stage modelling. However, actual readings for August 2011 show only 217.5 kWh compared with an estimated reading of 327 kWh for the month – indicative of the low levels of sunshine last summer. The team believes the design-stage
cells between the rooflight glazing, the team significantly reduced the cost of the photovoltaics. This was further reduced with a grant from the then- available Low Carbon Building Programme to bring the total extra expenditure to £100/ sq m. The total cost of the PV panels was £1,150/
The project has extended the life of the building for a fraction of the cost of rebuild, with a significant reduction in energy consumption and carbon emissions
assumptions are still valid in terms of the trend in performance. These correspond to a saving of approx 1 kg/CO2/ sq m of occupied floor area per annum. Overall, the
improvements were expected to reduce the building’s CO2 emissions by 6 kg/CO2/sq m/per annum, comprised of 5 kg/CO2/sq m/y
through reduction in energy demand plus 1 kg/CO2/sq m/y from the PV cells, based on dynamic thermal modelling. There can be no doubt that adding a new
sq m. With the LCBP grant contributing £550/sq m, this reduced the cost to £600/ sq m, which compared favorably to the cost of a standard spandrel panel of £500/sq m. The 120 sq m PV array incorporated into
striking identity to the previously dull and drab building will raise the profile of the department. The project has extended the life of the building for a fraction of the cost of rebuild, with a significant reduction in energy consumption and carbon emissions. A lesson for all. CJ
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Demand (kWh)
Energy (kWh)
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