State of Progress
Constructed (completed May 2005) BMS and Monitoring system now being commissioned
Situated on the outskirts of Southampton, (latitude 51.5º N)Student Service (administrative) building of Southampton University. 2600 m2 of new construction adjoined to an existing 2000 m2 building
Expected Energy Demand (kWh/m2/yr)
Renewable Energy Systems contribution
The building aims to demonstrate a high level of innovation in planning and architecture. It is a three storey structure with basement and is physically attached to the existing administration office building on a triangular shaped site.
It provides a large, accessible, attractive space, able to accommodate large numbers of visitors at peak periods. It consists of a reception area, seating, customer service desks, computer work stations, events space and display space.
All aspects of the building have been designed to minimize the building’s environmental impact. This includes energy and water usage and construction materials. The most environmentally appropriate materials and components have been incorporated into the design. The definition of materials and components to be used for the building has been developed as part of the design process.
Materials have been selected to minimize the environmental impact of the building during its lifetime: in its construction, use and final disposal. The following aspects have been given priority:
The use of “rainwater harvesting” has been incorporated into the building. Rainwater is collected, filtered and used for toilet flushing. The expected reduction in water consumption is 1,830 m3/yr relative to a standard building. This has been unexpectedly popular as an awareness raising feature for building users.
|area||UK Regulation min U-values||Building values +|
See allso Deliverable D17, 07/2005 http://www.sara-project.net/IMG/pdf/SARA_D17_Final_Report.pdf
Materials giving high levels of thermal insulation. This includes glazed areas, walls, roofing and floor. U values exceed current UK building regulations.
Air conditioning is not provided, but free cooling by means of exposed structural mass and ground cooling from low-level air displacement units in the atrium combine with opening ventilation panels alongside each double-glazed fixed window, to provide occupiers with a comfortable environment, over which they can directly influence a degree of control.
The vertical atrium roofing elements include mechanically controlled natural ventilation systems.
The undercroft, concrete structures and foundations protecting existing pipes, is used to pre-cool the air that is injected into the atrium. A reduction of ambient temperatures of two degrees by this free cooling is achieved by this method. The contribution of the buried air pipes air passage to the whole cooling strategy is evaluated through the monitoring process.
14kWp photovoltaic and 67 photovoltaic modules.
The 14kWp Atrium integrated Photovoltaic system is expected to generate up to a third of the power consumed in the new office floor area, and provides solar shading. The design of the pitch and orientation of the larger glazed roof included PV considerations.
Building Integrated Photovoltaic System
See D12, 20/12/2005 for more details :
The vertical atrium roofing elements include mechanically controlled natural ventilation systems, which, like all services and environmental readings are continuously monitored by a Building Management System (BMS). Uniquely, much of this data will be made publicly available via the internet as part of the SARA project.
The building is connected to the University Building Management System which permits the monitoring and recording of performance of plant and systems. The data can be trend logged to ensure that optimum performance is maintained. User satisfaction levels together with internal and external temperature data and other parameters are used to feedback to optimise heating control. The monitoring system also allows performing and analysing post occupancy evaluation that are used as an input for the control system to set the main parameters of the building. This feedback process is very innovative and it is the main innovative contribution of this building. The data is collected daily using the Intranet network of the building and is integrated into the control system.
The BMS will monitor:
The building was “highly commended” with a 2nd prize in the UK Higher Education Energy performance Initiative, and continues to receive visits from policy makers and buildings professionals since its inauguration. The SARA display and on-line information of PV system performance in the building itself raises interest and awareness and is generating information requests from University students for use in project work; data will be available online on the SARA project web site in the future.
Costs / Savings
Energy efficiency design and an intelligent control system will reduce running costs of lighting, ventilation and heating by 40% compared to reference building. High energy efficiency and use of passive design will enable low primary energy usage. Energy performance will exceed current UK building regulations by at least 30%.
Building running costs for energy will be 20% lower than a reference building and primary energy usage will be lower than the Benchmark figures prepared by HEFCE in their report “Energy Management Study in the higher Education Sector” and with BRE benchmark figures for gas and electricity consumption.
Water efficiency will be high and water consumption figures will be 40% lower than for similar buildings.
COSTS: 1505 £/m2
(by John Brightwell, Project coordinator, Estates and Facilities Department, University of Southampton).
This interview of john was publish in the 4th SARA Bulletin, and can be downloaded here :“Southampton University from the inside” (SARA Bulletin 4)
Before the construction could begin, enabling works were carried out. Demolition was allowed over a slightly longer period than normal to enable the Contractor to hand sort the waste, and salvage facing bricks and some internal joinery for reuse.
Waste management during the building works was considered during interviews with potential Contractors. All agreed that it was desirable but that the site area and the size of the project were insufficient to enable site-based recycling or waste sorting. It is noteworthy that the much larger EEE project started off with the Contractor sorting waste on site, but half way through the job it was discovered that Cleanaway, a commercial skip company, offered better rates to cover both removal and sorting/recycling of waste, off-site.
Early consideration of structure led to internally exposed, in situ reinforced concrete being selected, to provide thermal mass and act as a thermal flywheel. In conjunction with the limited mechanical ventilation system and openable windows this enables night-time cooling of the structure under manual and part-BMS control. The structural walls and columns were designed to enable earliest possible weather exclusion, by designing prefabricated window units to exactly fill the gaps between perimeter columns. External cladding was reviewed for ease of maintenance, and brick rainscreen was chosen, as it combined good aesthetics (especially in relation to adjacent buildings), low maintenance, and could cope with the curve on plan.
Further detailed study of the brickwork led to innovative use of lime mortar, which enhanced the life cycle carbon emissions, as lime-based mortar is far more benign than Ordinary Portland Cement-based mortar. [World-wide, cement manufacture produces between 6 and 10% of all of mankind’s CO2 emissions; lime mortar is CO2 neutral, in that it absorbs CO2 from the air when curing]. A further benefit was the ability of lime mortar to accept limited differential movement without unsightly cracking. This allowed the 50m long curved elevation to be formed without movement joints, and ultimately (see 1 above) will allow all of the facing bricks to be reused when the walls are demolished. Modern, strong OPC mortar grips the bricks too strongly, resulting in breakage of the bricks when walls are taken down.
The choice of brick was conditioned heavily by budget, so the locally-made Michelmersh brick was beyond our purse. It would have been good to have used a local brick, but the choice was made on technical performance, appearance and price, the winner coming from the Midlands.
Local sand (Frith End) was preferred, as the lime mortar requires very particular grading characteristics, and this supplier offered a compliant specification. In the event, the supply was united as a premix, held on site in a large silo mixing plant, which offered reduced waste and very consistent quality control.
Window framing, external louvres and spandrel panels were selected to be made of timber, as was the main structural frame for the atrium roofing, and the vertical elements of the curtain walling. The joinery-standard framing was in “Multiplex” a high quality plywood, while the structural roof frame to atrium was in Kerto, a rather more industrial grade product. Louvres were in solid untreated larch, intended to weather naturally through a range of lighter colours. No maintenance of these materials is necessary in normal, relatively clean urban environments. The Kerto beams were sprayed at works with an ultra-violet protective lacquer, and were sized to provide the required fire resistance. No intumescent coatings were needed.
Atrium glazing was a major challenge, to incorporate 150 square metres of Building-Integrated Photovoltaics (part-funded by the Dti through the Energy Savings Trust) in such a way as to provide good natural light to the adjacent building (B37) and also to provide some solar screening against the excesses of summer sunshine.
A PV (photovoltaic) cell generates electricity from daylight falling on it, and each is a small dark square. Each cell has two wires linking it to the others in its glazed panel, and leading to the electrical panel where it is converted from Direct Current to Alternating Current and then connected to the mains supply for the building. The pattern of the cells was a balancing act between maximising electrical generation and allowing enough daylight into the offices and atrium.
The atrium is a heated workplace, and normally occupied by half a dozen staff, and some visitors. At busy times there could be 100 people there, so environmental control is not easy in this long, glazed, three storey-tall space. Underfloor heating was chosen (it operates well with the temperatures at which the district heating runs), and five large areas of mechanically opening windows are provided at the top of the atrium. The controls for these were initially, and deliberately, designed to be manual, so that the staff in the atrium could have some control of their environment. Subsequently, it has been decided to convert to BMS control, to maximise scope for automatic cooling at weekends or overnight when staff are not present.
The atrium main entrance faces almost North, and draughts would have been a major problem in winter were it not for the inclusion of a draught lobby with two automatic doors; while these added complexity, they save energy, and greatly increase comfort of occupiers.
Opening windows provide natural perimeter ventilation, and the design and fixing of the external timber louvres provide security, so that windows can be left open overnight to encourage cooling. The large fixed panes of glass each contain a sealed interstitial Venetian blind, to allow occupiers to control solar intrusion, whether purely as heat, or as glare affecting work at screens.
Rainwater falling on all of the flat roof and the atrium glazed roof is filtered then collected in an underground tank, and pumped to a header tank serving all of the WC flushing cisterns. For use in time of drought there is a mains standby connection to the header tank.
The design of the building took account of early use by all staff of TFT (thin flat transistor) screens, which produce much less heat and consume less power than the old CRT (cathode ray tube) screens. One aspect that was not carried through initially was a thorough review of printing, which is now seen as one of the remaining areas for efficiency improvements.
Acoustics were carefully considered at all stages, and an innovative system developed for the open plan offices. Normally, the lighting and fire alarm cabling would be concealed above an acoustic ceiling; the omission of the ceiling and use of exposed concrete soffit meant there was a need to manage cable routing and provide acoustic absorption. This was successfully combined in a main cable runway the length of the offices, on which cables were concealed, and from which they branched off into purpose-made light fittings. Both the soffit of the runway (perforated birch-faced ply) and the curved, perforated metal sides of light fittings contain acoustic damping material.
Lighting was designed to comply with and exceed the requirements of the latest Part L of Building Regulations, with automatic presence detection, and daylight sensing to minimise power consumption.
Radiators under each window are locally controlled by thermostatic radiator valves, allowing the user more direct control of their environment.
Partner Nº 7: University of Southampton, SOTON http://www.soton.ac.uk/
Nicholas Hare Architects http://www.nicholashare.co.uk/
Hoare Lea http://www.hoarelea.com/