1 Low Energy Cooling BRE, 17th April 2007 Low Energy Buildings - heating/cooling of Termodeck Buildings at UEA. Life Cycle Issues Providing Low Carbon Energy and cooling on the UEA Campus Case Study: Termodeck Buildings at the University of East Anglia and Low Carbon Strategies at UEA Low Energy Buildings - heating/cooling of Termodeck Buildings at UEA. Life Cycle Issues Providing Low Carbon Energy and cooling on the UEA Campus Keith Tovey ( ) Energy Science Director HSBC Director of Low Carbon Innovation Acknowledgement: Charlotte Turner CRed Carbon Reduction CRed

2 Original buildings Teaching wall Library Student residences

3 Nelson Court Constable Terrace

4 Low Energy Educational Buildings Elizabeth Fry Building ZICER Nursing and Midwifery School Medical School Medical School Phase 2

5 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. Careful Monitoring, Analysis and Adaptive control can reduce energy consumption.

6 ZICER Building Heating Energy consumption as new in 2003 was reduced by further 57% 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.

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 ~ U – value ~ 1.0 W m 2 K -1

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

9 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

10 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 Space for future chilling

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

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

13 Effect of New Control Strategies on Thermal Comfort NumberMean VoteNumberMean Vote Winter Summer Only data for relevant Metabolic Rates included in above table

14 As Built GJ Air Conditioned GJ Naturally Ventilated GJ Life Cycle Energy Requirements of ZICER as built compared to other heating/cooling strategies Materials Production Materials Transport On site construction energy Workforce Transport Intrinsic Heating / Cooling energy Functional Energy Refurbishment Energy Demolition Energy 28% 54% 34% 51% 61% 29%

15 Life Cycle Energy Requirements of ZICER compared to other buildings Compared to the Air-conditioned office, ZICER as built recovers extra energy required in construction in under 1 year.

16 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

17 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

18 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

19 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

20 A 1 MW Adsorption chiller 1 MW 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

21 The Future New Medical School –5 th Termodeck Building on Campus –Will have full backup central computing server in basement. –Cooling for this area will reject heat into heater banks for heating building during winter. –May not need any other heating for building. –Initially chilling provided locally – ultimately connected to UEA chilling network Top Floor of ZICER – Seminar Room –Investigate provision of Heating / Cooling of room linked to room booking – i.e. only provide heating cooling to a high thermal acceptance level if room is booked in advance.

22 Conclusions The Termodeck construction is an effective method to provide heating and cooling. Pre-cooling building overnight is an effective method to avoid /reduce the need for air-conditioning Close integration between client and designers regarding functional use of building is required to ensure effective provision of cooling. 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. Lao Tzu ( BC) Chinese Artist and Taoist philosopher "If you do not change direction, you may end up where you are heading."