Institution of Civil Engineers 30 th January 2006

Institution of Civil Engineers 30 th January 2006 Carbon Reduction Strategies at the University of East Anglia • Low Energy Buildings • Providing Low Carbon Energy on Campus Keith Tovey (杜�� ) MA, Ph. D, CEng, MICE, CEnv CRed Carbon Reduction Energy Science Director CRed HSBC Director of Low Carbon Innovation Charlotte Turner 1

Original buildings Teaching wall Library Student residences 2

Nelson Court Constable Terrace 3

Low Energy Educational Buildings Medical School ZICER Nursing and Midwifery School Elizabeth Fry Building 4

The Elizabeth Fry Building 1994 Cost ~6% more but has heating requirement ~25% of average building at time. Building Regulations have been updated: 1994, 2002, 2006, but building outperforms all of these. Runs on a single domestic sized central heating boiler. Would have scored 13 out of 10 on the Carbon Index Scale. 5 8

Conservation: management improvements – User Satisfaction thermal comfort +28% air quality +36% lighting +25% noise +26% A Low Energy Building is also a better place to work in Careful Monitoring and Analysis can reduce energy consumption. 6

ZICER Building Low Energy Building of the Year Award 2005 awarded by the Carbon Trust. Heating Energy consumption as new in 2003 was reduced by further 50% by careful record keeping, management techniques and an adaptive approach to control. Incorporates 34 k. W of Solar Panels on top floor 7

The ZICER Building Description • Four storeys high and a basement • Total floor area of 2860 sq. m • Two construction types Main part of the building • High in thermal mass • Air tight • High insulation standards • Triple glazing with low emissivity Structural Engineers: Whitby Bird 8

The ground floor open plan office The first floor cellular offices 9

Operation of the Main Building • Mechanically ventilated using hollow core ceiling slabs as supply air heat ducts to the space Regenerative Recovers 87% of exchanger Ventilation Heat Incoming Filter. Heater Requirement. air into the AHU Air passes through hollow cores in the ceiling slabs Out of. The the return air passes through the building Return stale air is Air enters the internal heat exchanger extracted from each floor occupied space 10

Importance of the Hollow Core Ceiling Slabs The concrete hollow core ceiling slabs are used to store heat and coolness at different times of the year to provide comfortable and stable temperatures Cold air Summer Night night Draws out the –heat ventilation/free cooling accumulated during Cools the slabs to the day act as a cool store the following day Summer night Cold air 11

Importance of the Hollow Core Ceiling Slabs The concrete hollow core ceiling slabs are used to store heat and coolness at different times of the year to provide comfortable and stable temperatures Warm air Summerthe Day Pre-cools air before entering the The concrete occupied space absorbs and stores the heat – like a radiator in reverse Warm air Summer day 12

Importance of the Hollow Core Ceiling Slabs The concrete hollow core ceiling slabs are used to store heat and coolness at different times of the year to provide comfortable and stable temperatures Winter Day Heat is slabs The concrete transferred the absorbs andtostore air before entering heat the room Winter day 13

Importance of the Hollow Core Ceiling Slabs The concrete hollow core ceiling slabs are used to store heat and coolness at different times of the year to provide comfortable and stable temperatures Winter Night air When the internal temperature drops, heat stored in the concrete is emitted back into the room Winter night 14

Good Management has reduced Energy Requirements The space heating consumption has reduced by 57% 350 15

ZICER Building Photo shows only part of top Floor • • Top floor is an exhibition area – also to promote PV Windows are semi transparent Mono-crystalline PV on roof ~ 27 k. W in 10 arrays 16 Poly- crystalline on façade ~ 6/7 k. W in 3 arrays

Performance of PV cells on ZICER 17

Arrangement of Cells on Facade Individual cells are connected horizontally As shadow covers one column all cells are inactive If individual cells are connected vertically, only those cells actually in shadow are affected. 18

Use of PV generated energy Peak output is 34 k. W Sometimes electricity is exported Inverters are only 91% efficient Most use is for computers DC power packs are inefficient typically less than 60% efficient Need an integrated approach 19

Performance of PV cells on ZICER Cost of Generated Electricity Actual Situation excluding Grant Actual Situation with Grant Discount rate 3% 5% 7% Unit energy cost per k. Wh (£) 1. 29 1. 58 1. 88 0. 84 1. 02 1. 22 Avoided cost exc. the Grant Avoided Costs with Grant Discount rate 3% 5% 7% Unit energy cost per k. Wh (£) 0. 57 0. 70 0. 83 0. 12 0. 14 0. 16 Grant was ~ £ 172 000 out of a total of ~ £ 480 000 20

Conversion efficiency improvements – Building Scale CHP 3% Radiation Losses 11% 61% Flue Losses Exhaust Heat Exchanger Engine heat Exchanger 36% 86% GAS efficient Localised generation makes use of waste heat. Reduces conversion losses significantly Generator 36% Electricity 50% Heat 21

Conversion efficiency improvements Before installation 1997/98 MWh electricity gas oil 19895 35148 33 Total Emission factor kg/k. Wh 0. 46 0. 186 0. 277 Carbon dioxide Tonnes 9152 6538 9 Electricity After installation 1999/ Total CHP export 2000 site generation MWh 20437 15630 977 Emission kg/k. Wh -0. 46 factor CO 2 Tonnes -449 15699 Heat import boilers CHP oil total 5783 14510 28263 923 0. 46 0. 186 0. 277 2660 2699 5257 256 10422 This represents a 33% saving in carbon dioxide 22

Conversion efficiency improvements Load Factor of CHP Plant at UEA Demand for Heat is low in summer: plant cannot be used effectively More electricity could be generated in summer 23

Conversion efficiency improvements Normal Chilling Adsorption Chilling Heat from external source Heat rejected High Temperature High Pressure Desorber Heat Compressor Exchanger Condenser Throttle Valve W~0 Evaporator Absorber Heat extracted for cooling Low Temperature Low Pressure 24 19

A 1 MW Adsorption chiller • Adsorption Heat pump uses Waste Heat from CHP • • Will provide most of chilling requirements in summer Will reduce electricity demand in summer Will increase electricity generated locally Save 500 – 700 tonnes Carbon Dioxide annually 25

Results of the “Big Switch-Off” Target Day With a concerted effort savings of 25% or more are possible How can these be translated into long term savings? 26

Conclusions • Buildings built to low energy standards have cost ~ 5% more, but savings have recouped extra costs in around 5 years. • Ventilation heat requirements can be large and efficient heat recovery is important. • Effective adaptive energy management can reduce heating energy requirements in a low energy building by 50% or more. • Photovoltaic cells need to take account of intended use of electricity use in building to get the optimum value. • Building scale CHP can reduce carbon emissions significantly • Adsorption chilling should be included to ensure optimum utilisation of CHP plant, to reduce electricity demand, and allow increased generation of electricity locally. • Promoting Awareness can result in up to 25% savings • The Future for UEA: Biomass CHP? Wind Turbines? "If you do not change direction, you may end up where you are heading. " Lao Tzu (604 -531 BC) Chinese Artist and Taoist philosopher 27

Carbon Reduction Strategies at the University of East Anglia WEBSITE cred-uk. org/ This presentation will be available from tomorrow at above WEB Site: follow Academic Links Keith Tovey (杜�� ) Energy Science Director HSBC Director of Low Carbon Innovation Charlotte Turner 28