1 Low Carbon Strategies at the University of East Anglia Low Energy Buildings Providing Low Carbon Energy on Campus Keith Tovey ( 杜伟贤 ) HSBC Director of Low Carbon Innovation Acknowledgement: Charlotte Turner CRed Carbon Reduction Buildings and our Changing Climate The Tate Britain, 16 November 2006

2 Original buildings Teaching wall Library Student residences

3 Nelson Court Constable Terrace

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

5 Constable Terrace Four Storey Student Residence Divided into “houses” of 10 units each with en-suite facilities Heat Recovery of body and cooking heat ~ 50%. Insulation standards exceed 2006 standards Small 250 W panel heaters in individual rooms.

6 The Elizabeth Fry Building 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.

7 Quadruple Glazing Thick Insulation Air circulates through whole fabric of building Principle of Operation of TermoDeck Construction Exhaust air passes through a two channel regenerative heat exchanger which recovers 85+% of ventilation heat requirements. Mean Surface Temperature close to Air Temperature

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

9 ZICER Building 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 kW of Solar Panels on top floor Low Energy Building of the Year Award 2005 awarded by the Carbon Trust.

10 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

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

12 Air enters the internal occupied space Return stale air is extracted from each floor Incoming air into the AHU Regenerative heat exchanger Filter Heater The air passes through hollow cores in the ceiling slabs The return air passes through the heat exchanger Out of the building Operation of the Main Building Mechanically ventilated that utilizes hollow core ceiling slabs as supply air ducts to the space

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

14 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 Draws out the heat accumulated during the day Cools the slabs to act as a cool store the following day Summer night Summer Night – night ventilation/free cooling

15 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 Summer Day Pre-cools the air before entering the occupied space The concrete absorbs and stores the heat – like a radiator in reverse Summer day

16 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 The concrete slabs absorbs and store heat Heat is transferred to the air before entering the room Winter day

17 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 When the internal air temperature drops, heat stored in the concrete is emitted back into the room Winter night

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

19 Load factors Façade (kWh) Roof (kWh) Total (kWh) Output per unit area Little difference between orientations in winter months Performance of PV cells on ZICER WinterSummer Façade2%~8% Roof2%15%

20 All arrays of cells on roof have similar performance respond to actual solar radiation The three arrays on the façade respond differently Performance of PV cells on ZICER - January Radiation is shown as percentage of mid-day maximum to highlight passage of clouds

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22 Performance of PV cells on ZICER

23 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.

24 Use of PV generated energy 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 Peak output is 34 kW

25 Actual Situation excluding Grant Actual Situation with Grant Discount rate 3%5%7%3%5%7% Unit energy cost per kWh (£) Avoided cost exc. the Grant Avoided Costs with Grant Discount rate 3%5%7%3%5%7% Unit energy cost per kWh (£) Grant was ~ £ out of a total of ~ £ Performance of PV cells on ZICER Cost of Generated Electricity

26 Engine Generator 36% Electricity 50% Heat GAS Engine heat Exchanger Exhaust Heat Exchanger 11% Flue Losses3% Radiation Losses 86% efficient Localised generation makes use of waste heat. Reduces conversion losses significantly Conversion efficiency improvements – Building Scale CHP 61% Flue Losses 36% efficient

27 Conversion efficiency improvements 1997/98 electricitygas oilTotal MWh Emission factorkg/kWh Carbon dioxideTonnes ElectricityHeat 1999/ 2000 Total site CHP generation exportimportboilersCHPoiltotal MWh Emission factor kg/kWh CO 2 Tonnes Before installation After installation This represents a 33% saving in carbon dioxide

28 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

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

30 A 1 MW Adsorption chiller 1 MW 吸附冷却器 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

31 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 cells to get the optimum use of electricity generated. 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. The Future: Biomass CHP? Wind Turbines? Lao Tzu ( BC) Chinese Artist and Taoist philosopher "If you do not change direction, you may end up where you are heading."