How To Make A Building Energy Efficient

Transcription

1 Nood aan geïntegreerde simulaties voor nul-energie gebouwen Ruben Baetens Building Physics Section Department of Civil Engineering, Faculty of Engineering KU Leuven Kasteelpark Arenberg 40 bus 2447, BE-3001 Heverlee

2 top-down.. bottom-up power transmission system kv, managed by TSO (Elia) eg. 2 connections per city eg buildings per HV/MV transformer gas transmission system 67 bar, managed by TSO (Fluxys) 2

3 top-down.. bottom-up medium-voltage power system 10 kv, managed by DSO (Eandis) eg. 190 distribution- and 170 client- MV/LV transformaters eg. 10 tot 150 dwellings per distribution-transformer medium-pressure gas system 15 bar, managed by DSO (Eandis) 3

4 top-down.. bottom-up low-voltage power system 230 V, managed by DSO (Eandis) eg. 2-6 feeders per transformer eg dwellings per feeder low-pressure gas system 5 bar, managed by DSO (Eandis) 4

5 wh-words integrated simulation Simulation is the imitation of the operation of a real-world system over time. * The act of simulating requires that a model be developed, which represents the key behaviors of the selected process. * whát might happen? ie. qualification model dev. whén will this happen? ie. quantification hów to solve or use this? ie. optimisation feedback / iteration * J.Banks, J.S.Carson, B.L.Nelson & D.M.Nicol (2010), Discrete-event system simulation, 5th ed. Prentice Hall, 622p. 5

6 Whát might happen? Qualifying the need for integrated simulations with nearly-zero energy buildings

7 whát might happen? directive 2010/31/EU Member States shall draw up national plans for increasing the number of nearly zero-energy buildings. aiming at or resulting in /> a strongly reduced building energy demand, combined with towards nzebs HP & PV systems time lag supply & demand /> an increased ratio of renewable energy in the building stock. though not yet fully defined (..) all new buildings are nearly-zero energy buildings cu lo Directive 2010/31/EU Article 9, point (1) OJ L 153, 18 juni 2010, p

8 whát might happen? directive 2010/31/EU integrated building design towards nzebs? low-energy standards for the building envelope high efficient heating and/or ie. question cooling system HP & PV systems time lag supply & demand curtailing losses re gr u /> eg. combination of heat pump (HP) with floor heating renewable energy /> eg. photovoltaic (PV) system 8

9 whát might happen? directive 2010/31/EU integrated building design virtual grid storage HP & PV systems daily and seasonally time lag between the energy (ie. electricity) ie. quantification demand and PV electricity supply time lag supply & demand curtailing losses required grid upgrades p p distribution grid seen as virtual storage P net, kw 9

10 whát might happen? directive 2010/31/EU integrated building design virtual grid storage system safety regulations time lag supply & demand maximum allowable voltage ie. optimisation deviation compared to nominal values LV/MV transformer overload curtailing losses required grid upgrades panic politics Groene stroom valt uit bij bewoners van wijk met te veel zonnepanelen Belga donderdag 10 mei 2011 co sa re 10

11 whát might happen? directive 2010/31/EU integrated building design virtual grid storage system safety regulations unforeseen consequences curtailing losses building investment cost is not the overall social cost reduced return-on-investments required grid upgrades panic politics compensatory response Kiezen tussen netvergoeding of slimme meters Eandis De Standaard, maandag 08 oktober 2012 re D p 11

12 whát might happen? directive 2010/31/EU integrated curtailing building design virtual losses grid storage system safety regulations unforeseen consequences required grid upgrades building investment cost is not the overall social cost reduced return-on-investments panic politics compensatory response reduced DSM potential Keuze voor zonne-energie was fout Minister F. Van den Bossche De Standaard, maandag 18 april

13 whát might happen? ling directive 2010/31/EU integrated required building design virtual grid grid storage upgrades system safety regulations unforeseen consequences panic politics building investment cost is not the overall social cost reduced return-on-investments compensatory response (etc.) euro premie voor warmtepomp Minister F. Van den Bossche De Standaard, donderdag 08 november

14 When will this happen? Quantifying the need for integrated simulations with nearly-zero energy buildings

15 traditional building energy simulation (BES) integrated district energy assessment simulation (IDEAS) thermal building response thermal mass and insulation level solar gains and shading (summer comfort) external boundary conditions climate at a sufficient resolution internal boundary conditions occupancy at a sufficient resolution control and dynamics of HVAC system (for energy consumption instead of energy demand) 15

16 traditional building energy simulation (BES) thermal building response thermal mass and insulation level solar gains and shading (summer comfort) external boundary conditions climate at a sufficient resolution internal boundary conditions occupancy at a sufficient resolution control and dynamics of HVAC system (for energy consumption instead of energy demand) integrated district energy assessment simulation (IDEAS) thermal building response + intra-building differentiation external boundary conditions + district system dynamics internal boundary conditions + intra-building differentiation + control and dynamics of HVAC systems 16

17 IDEAS * thermal building response transient multi-zone building models transient multi-building models solar gains and shading control * R. Baetens, et al. (2012). Assessing electrical bottlenecks at feeder level for residential net ZEBs by integrated system simulation. Applied Energy 96,

18 IDEAS * thermal building response external boundary conditions sub-hourly climate data power flow analysis * R. Baetens, et al. (2012). Assessing electrical bottlenecks at feeder level for residential net ZEBs by integrated system simulation. Applied Energy 96,

19 IDEAS * thermal building response external boundary conditions internal boundary conditions stochastic sub-hourly occupancy behavior control and dynamics of HVAC system power flow analysis * R. Baetens, et al. (2012). Assessing electrical bottlenecks at feeder level for residential net ZEBs by integrated system simulation. Applied Energy 96,

20 neighborhood case study set of 33 dwellings 4 architectural types 2 thermal zone models balanced ventilation with recovery exterior solar screens /> controlled by building management system /> hysteresis function on irradiation level of 150 and 250 W/m² 20

21 neighborhood case study set of 33 dwellings interior boundary conditions modulating air-to-water heat pump /> multi-variable performance map /> COP of 3.17 (at 2/35 C) and 2.44 (at 2/45 C) 250 l storage tank for DHW and SH /> HP control based on sensor temperatures low-temperature radiators /> ie. 55/45 C at -8 C 21

22 neighborhood case study set of 33 dwellings interior boundary conditions high-resolution stochastic user behavior /> embedded Markov chain, with mixed 1-min and 10-min resolution /> including presence, activity, appliance use and lichting /> excluding SH setpoint /> cfr. Richardson et al. (2010), Domestic-electricity use: A highresolution energy demand model. Energy and Buildings 42(10),

23 neighborhood case study set of 33 dwellings interior boundary conditions exterior boundary conditions BIPV system /> different sizing to see the impact of design AC 230 Volt IEEE radial 34-node test feeder /> different sizing to see the impact of design /> Single-phase representation of a three-phase symmetrical load 23

24 neighborhood case study set of 33 dwellings interior boundary conditions exterior boundary conditions general results transient system behavior T op, C P net, kw T tank, C V AC, V 24

25 neighborhood case study set of 33 dwellings interior boundary conditions exterior boundary conditions general results transient system behavior annual results at building level 25

26 curtailing losses level of net ZEB, ƒ zeb the ratio of the total (renewable) energy supply, P S, to the total energy demand, P D. eg. 0.8 depicts an under-sizing by 20% at annual basis of the provided local supply of renewable energies design level of net ZEB, ƒ zeb,des proposed level of net ZEB in the design phase (ie. at building level) for sizing of the system of renewable energy supply (ie. photovoltaic system). effective level of net ZEB, ƒ zeb,eff effective level of net ZEB determined after integrated simulation. 26

27 curtailing losses PV inv Feeder inv. 0 Savings /yr Total payback.. 18 yr nzebs of 33 Total energy loss.- 14 % Max energy loss % Total payback. 21 yr nzebs of 33 Total energy loss % Max energy loss - 52 % Total payback. 23 yr nzebs... 3 of 33 Total energy loss Max energy loss Total payback. 34 % % yr 27

28 curtailing losses cover factor, γ [t 1,t 2 ] a cover factor indicates to which extent a set of threads is covered by another set of threads supply cover factor, γ S [t 1,t 2 ] the ratio to which the local supply is covered by the energy demand indicating the self-consumption γ S = min{p Dem,P Sup } dt / P Sup dt demand cover factor, γ D [t 1,t 2 ] the ratio to which the energy demand is covered by the local supply indicating the self-generation γ S = min{p Dem,P Sup } dt / P Dem dt 28

29 curtailing losses 29

30 How to solve (or use) this? Optimizing nearly-zero energy buildings through integrated simulations

31 Ctrl / Alt / Del (?) control demand side management requires an intergrid (unless for rule-based control) reverses the problem /> implies the impact of the building on the neighborhood, instead of vice versa evaluating the total cost of ownership differently 31

32 Ctrl / Alt / Del (?) control alternative design complementary mix of technology choices /> including thermal renewable energy /> including (thermal and/or electric) storage technology allowing for demand side management including feeder design 32

33 Ctrl / Alt / Del control alternative design delete the occurring problem by not aiming for a ZEB level at building scale /> requires a low-emission energy grid system 33

34 Fin. Questions? mendeley.com/profiles/ruben-baetens/