LowExergy Systems for High Performance Buildings and Communities

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1 LowExergy Systems for High Performance Buildings and Communities December 6 th, Houston Texas 4 th German American Energy Efficiency Conference Christina Sager Fraunhofer-Institute for Building Physics Building on Knowledge

2 Brief introduction Joseph von Fraunhofer ( ) Researcher discovery of Fraunhofer Lines in the sun spectrum Inventor new methods of lens processing Entrepreneur head of royal glass factory

3 Brief introduction Fraunhofer-Gesellschaft e.v. founded in 1949 head office in Munich 60 institutes all over Germany, >80 worldwide > 14,000 employees > 1.4 bil. Euro yearly turnover IBP (Fraunhofer Institute for Building Physics) is one of the oldest institutes (1929 since 1959 in FhG) 252 employees in 3 locations 17,4 mil. Euro turnover

4 Brief introduction Fraunhofer Institute for Building Physics Branch Kassel Branch Holzkirchen Institute in Stuttgart Kassel Stuttgart Holzkirchen

5 Brief introduction Fields of Competence Acoustics Heat Technology Life Cycle Engineering Hygrothermics Building Chemistry, Building Biology, Hygiene Indoor Climate and Climatic Impacts Energy Systems

6 Structure Introduction Challenges for Energy Efficiency from Building to Community Scale From Energy to Exergy Exergy Thinking on Community Level

7 Global challenges for cities Relevant Megatrends until 2050 World energy demand Drinking water demand Demographic development Economic structural changes Shanghai High population densities Worldwide trade Digital networks Living standards in developing countries Global migration processes Living standards in Europe Electromobility until 2020 Cities as transition drivers

8 The global drivers in the 21 st century Influence factors for cities of the future Development until 2050: increase in world population growth by 2,3 Bil. people Growing urbanization doubling of city population to 6,8 Bil. Limitation of ressources predicted demand of 2,3 planets for our living standard 9 Bil. 8 Bil. 7 Bil. 6 Bil. 5 Bil. 4 Bil. 3 Bil. 200% 100% world population ressources urbanization New urban spaces for a growing world population 2 Bil. 1 Bil Quellen: UN population division, global footprint network

9 From single measures to holistic approaches Problem oriented approach and system integration food education security politics and administration service and trade communication/it Central fields of action buildings and living urban space and structure convergence in city systems mobility and transportation energy and ressource infrastructure urban production transport and logistics accompanying fields of action environment and climate health people and life style

10 Legal requirements for energy efficiency in buildings.

11 Beyond low energy 800 primary energy demand per year [kwh/m²a] vor WSchV WSchV WSchV EnEV 2002 economic standard for retrofitted existing buildings 60 Low Energy Houses 40 Passive Houses economic standard for new buildings future? Zero-energy-houses Energy-plus-houses

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13 The exergy approach going one step further First Law of Thermodynamics Energy cannot be created or destroyed, but can only be converted into different forms. Energy going in.... and all Energy going out

14 Limits of the energy approach Energy is not equal to energy Regarding only the MJ or kwhs neglects the different energy types with their potentials and qualities. Q Energy balances: = Q h + Q w + Q aux Q =? r Heat at 130 F (55 C) Heat at 140 F (60 C) Electricity Solar radiation

15 Exergy - The valuable part of energy Second Law of Thermodynamics Exergy = Energy x Energy-Quality-factor 100kJ 12 V 2.3 Ah 1 kg water at 110 F (43 C) Known method for, e.g. power stations => here application for buildings

16 Exergy in Buildings High valued energy going in.. Primary Energy Boiler Storage Distribution Transmission Room Air.. and useless energy going out

17 Target Matching demand and supply side source q 1 energy supply fossil fuels electricity energy demand q 1 appliances, lighting Source: VTT use 0 district low temp heating C low supply temp C supply ultra low 55 temp 0 C supply 40 0 C energy quality 0 Business Use low efficient energy as usual appliances building sauna domestic hot water space heating

18 Example : LowEx Kassel Oberzwehren CO 2 -neutral heating (and cooling) optimised thermal insulation under ecological and economical aspects optimised urban structure from energy perspective development of a tailored supply system Total area of construction site 21 acres (85,000 m²) 100 living-units total

19 Urban development plan - north

20 Energy demands Northern area (Low Energy Houses) Heat demand : 128 MWh Heat power: 83 kw Kasseler Werkstatt Heat demand: 500 MWh Heat power: 400 kw Willy-Brandt-School Heat demand: 530 MWh Heat power: 350 kw Southern area (Low Energy Houses) Heat demand: 125 MWh Heat power: 80 kw

21 Existing energy supply infrastructure District Heating Natural Gas Highly energy-efficient buildings with LowEx distribution systems Solar energy for DHW and fotovotaics for CO 2 -balance Use of District Heating return to supply buildings Grid improvemnet for overall efficiency benefit

22 Supply side: mine water Warm reservoirs (800m): C Cold reservoirs (200m): C

23 Heerlerheide Centre New CBS office

24 Boundary conditions: What is extra needed to make a building minewater proof/lowex? Building Reg s NL Practice 2007 NL Mine water Lowex Thermal insulation Envelope U = 0.37 Glazing U = 3.0 Ventilation No system requirements Air tightness n 50 = 3 Emission system No requirements HVAC system/efficiency No requirements (but in EPR) Energy Performance (EPC) dwellings 0.8 Thermal insulation Envelope U = 0.30 Glazing U = 1.5 Ventilation 50% ME/50% MVHR Air tightness n 50 < 2 Emission system Radiators HVAC system/efficiency Condensing boilers η = 95% No cooling EPC dwellings 0.8 Thermal insulation Envelope U < 0.25 Glazing U < 1.2 Ventilation MVHR η = 95% Demand controlled Air tightness n 50 <1 Emission system Floor heating and cooling HVAC system/efficiency Mine water with heat pumps (boiler back up) Sustainable cooling EPC dwellings 0.5

25 Direct heating and cooling

26 Indirect heating and cooling

27 Source pumps with primary grid Gemeente Heerlen Weller Energie BV Tertiary net Primary distribution grid Secondary grid Mine water circa 18 C Return well Energy Station with secondary grid (only heat delivery is shown) To tertiary net in complexes Mine water circa 28 C Heat Generation (winter season)

28 Source pumps with primary grid Gemeente Heerlen Weller Energie BV Heat pump shut off EWP Tertiary net Primary grid E Secondary grid E Mijnwater circa 18 C Retourbron Energy Station with secondary grid (only cold delivery is shown) To tertiary net in buildings Mijnwater circa 28 C Cold supply (summer)

29 Thank you very much! Building on Knowledge