Reality-checking sustainability in schools

Transcription

1 Reality-checking sustainability in schools Roderic Bunn, BSRIA & Usable Buildings Trust

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3 Where are we today with sustainable schools?

4 12 case studies of new and existing primary and secondary schools, and one academy Measured energy consumption against DCSF benchmarks and design targets (where available) Occupant satisfaction surveys of five schools, using the Building Use Studies methodology

5 What we found Energy targets theoretical at best (cut n paste BB87), at worst nonexistent. Operational energy data variable and often not available Gas energy consumption for heating often near to benchmarks (top 25% of DCSF database), but Electricity often 2-3 times the original design targets Carbon emissions therefore much higher

6 Academy in Liverpool 900 pupil capacity (530 March 2006) 7000 m 2 3 full-time FM staff Predicted carbon dioxide emissions: 94 tonnes/y Actual carbon dioxide emissions: 437 tonnes/y

7 Data courtesy Ian Pegg/Buro Happold

8 Data courtesy Ian Pegg/Buro Happold

9 Tools for sustainability Roderic Bunn, BSRIA Data courtesy Ian Pegg/Buro Happold

10 Things that don t always work Photovoltaics Very expensive technology Payback is very long Associated technology (inverters) often difficult to maintain May not deliver the amount of electricity anticipated Diverts capital budget and design attention away from more important issues

11 Our mission, should we wish to accept it Design zero-carbon new schools by 2016, with clear targets and milestones Find the best way of delivering this through BSF and non- BSF projects Identify the limits for energy efficiency for school types and locations where zero carbon cannot be achieved Identify exemplary developments, either existing (such as where low carbon energy infrastructures are in place) or planned (such as eco towns) and explore their potential Reduce carbon-dioxide emissions in refurbishment projects

12 How will you be asked to do this? Identify cost, benefits and affordability Adhere to a working definition of a zero-carbon school, covering heating, cooling and lighting, and the energy for equipment and plug-in power Calculate the performance of a zero-carbon school Identify and use technologies to meet the 2016 target Use the opportunities provided by a zero-carbon schools for the benefit of the curriculum

13 The Carbon Calculator A DCSF-sponsored spreadsheet tool to assist in early consideration of the renewables options for reducing carbon emissions Additional investment of 50/m 2 (around 500k for a typical secondary school) will be made available for investment in energy efficiency and renewable energy measures to help reduce carbon emissions from new school buildings by 60% Local authority-funded projects will be expected to meet the same targets within devolved funding limits The 60% saving is necessary to win the extra funding

14 The Carbon Calculator Forces designers to generate a kwh of power by LTZ technologies before saving a kwh by better design Rewards on-site systems rather than off-site community systems, but the latter are far more likely to be cost-effective and easier to manage Biased towards biomass boilers: often a politician s dream but a premises nightmare Some LAs are arguing that reductions in CO 2 (beyond Building Regulations) achieved by fabric and other means will not count towards the renewables target

15 Kingsmead Primary School 2.37 million project Occupied: September m 2 GIA Occupancy: 210 pupils Single-storey, naturally ventilated, north facing classrooms with south facing rooflights 60 kw th biomass boiler, solar panels, PVs and rainwater recovery

16 Kingsmead s biomass system Proved difficult to commission - problems persisted Controls configured to favour the gas back-up boiler Not able to supply instantaneous heat (base load not high or continuous enough) Snuffs out in tick-over mode Struggles to work at low loads 111 kwh/m 2 /y for gas 110 kwh/m 2 /y good practice)

17 Initially, the wood pellets were burning so hot there was some damage to the ashbox. The local authority changed the fuel to wood chip Sources of biomass can fluctuate, so choose kit that can run on different fuels without overheating or tripping out

18 The design dream The school s nightmare

19 Things that don t always work Automatic lighting controls At Venerable Bede School, PIR detection in corridors means lighting comes on during the day No daylight-linking technology as it was value-engineered out Simple wall-mounted interval timers would be more reliable and much cheaper

20 Things that can work User-controlled lighting At Howe Dell Primary School, PIR detection kept its daylight linked controls, plus

21 Things that can work User-controlled lighting At Howe Dell Primary School, PIR detection kept its daylight linked control, plus Hand-held remotes that school-appointed eco-warriors can use, which means... pupil power can be as powerful as a bems when it comes to truly intelligent lighting control

22 It s not just about carbon-dioxide

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25 Zero-carbon schools: the reality check Zero carbon will not be about procuring complex technologies, with often dubious sustainability credentials, that put facilities managers on a maintenance and management treadmill and annoy occupants Zero carbon is about reductions in loads, more efficient and better controlled fabric and services, and improved user controls Zero carbon will be about delivering the design intention, not just believing that design features will automatically deliver functionality and reduced carbon-dioxide emissions

26 Zero-carbon schools: the reality check Halve demand review standards, improve insulation, reduce air leakage, use daylight more, buy efficient equipment, and make sure things are switched off when not needed Double the energy efficiency of the installations that meet this reduced demand (more efficient heating, ventilation, lighting and electronic equipment and control systems); and Halve the carbon in the fuel supply (by measures both on and off-site, and by energy and utility suppliers)

27 Zero-carbon schools: the reality check With demand reduced and efficiency increased, investment in renewables will also go much further and be more cost effective In addition, a given capacity of renewables will represent a higher proportion of national energy supply, making it much easier to achieve - and to exceed - national percentage targets for renewable energy generation Reduced demand comes first

28 Zero-carbon schools: what you need to know How much electricity is the building using? How does it compare with benchmarks? Just because electricity is from a low-carbon source doesn't mean that it s OK to waste it How much fuel and energy from other sources is the building using? Is there anything special? These need to be considered on their own merits, otherwise reporting and benchmarking can be confused What is the contribution of on-site renewables? Don t conceal an inefficient building under lots of renewable generation What are you doing with off-site supplies? What supplies of energy are you purchasing, and what s the carbon content?

29 Green buildings are not better because they have green features, they re better because people have put more care and thought into them. Gratuitous green can bring the worst of all worlds Bill Bordass

30 Hope this was food for thought