Nearly Zero Energy Buildings Framework and Definitions

Transcription

1 Nearly Zero Energy Buildings Framework and Definitions Carsten Wemhoener, University of Applied Sciences Rapperswil NZEB Workshop, Chillventa, October 8, 2012

2 Preface Net zero energy self-sufficient building at 2883 m Paradigms 90% self-sufficiency strived Very good envelope (passive house level) Optimised renewable production Water/waste water system CHP plant as back-up Predictive control to optimise generation and storage Systems 84 m 2 BIPV / 55 m 2 ST Biomass (rape oil) CHP Cooking by electricity / back-up liquid (bio)gas for cooking Rain water collection and waste water treatment Mechanical ventilation with heat recovery source: Tonatiuh Ambrosetti 2

3 Preface Net zero energy self-sufficient building at 2883 m Characteristics 90% self-sufficiency strived Very good envelope (passive house level) Optimised renewable production Water/waste water system CHP plant as back-up Predictive control to optimise generation and storage Systems 84 m 2 BIPV / 55 m 2 ST Biomass (rape oil) CHP Cooking by electricity / back-up liquid (bio)gas for cooking Rain water collection and waste water treatment Mechanical ventilation with heat recovery source: Tonatiuh Ambrosetti 3

4 Preface Net zero energy self-sufficient building at 2883 m Self-sufficiency? Mobility? Carbon emissions? Only one definition? Operational Energy? Embodied energy? Grid interaction? Exergy? source: Tonatiuh Ambrosetti Delivered energy? Appliances? Primary energy? One building or clusters? Load mismatch? 4

5 Outline of the presentation Framework and political targets IEA Framework for the definition of NZEB Swiss MINERGIE A label as implementation of an NZEB standard Definition MINERGIE-A Evaluations of first buildings 5

6 Framework Political targets and strategies EU strategy: until % renewable energy shares 20% energy efficiency New buildings shall reach Nearly Zero by % reduced CO 2 -emissions Heat pumps in Nearly Zero Buildings are an economical way to cut CO 2 emissions USA (DOE) /Canada Marketable new residential (commercial) NZEB by 2020 (2025) All buildings shall be Net Zero by 2050 Japan source: Dieryckx Heat pumps and high performance buildings are considered as key technologies to mitigate climate change 6

7 Market state of low energy buildings High performance buildings Low energy and passive houses have strongly growing market shares in particular in AT, CH, DE, but also e.g. NO Low energy houses are becoming the current building standard legal requirement 50 kwh/(m 2 a) NZEB are rather in the P&D Phase Limited number of NZEB worldwide, mostly to demonstrate net zero or plus energy balance 7

8 NZEB Definition Political targets indicate: Next step will be Nearly or Net Zero Energy Buildings (NZEB) DEFINITION Nearly Zero Energy Building Means a building that has a very high energy performance Nearly or very low energy amount should be covered to a very significant extent by energy from renewable sources, including renewable energy produced on-site or nearby =>Presently no common definition of NZEB, neither in policy nor in the market Timeline of EPBD recast of 2010 for NZEBs source: Jakobs 8

9 Outline of NZEB Definition Framework IEA ECBCS Annex 52/SHC Task 40 Towards net zero energy solar buildings Task 1: Consistent and complete definition of NZEB Definition shall be suitable for setting political targets Common understanding of the concept NZEB Building connected to the energy grid Energy generation from renewable sources on the building estate Compensation of its energy requirement on an annual basis Is a one and only definition useful? Different countries may have different requirements (climate, building tradition) Different countries may want to set different political focus => Formal, consistent and comprehensive framework for a definition is needed 9

10 NZEB Definition Framework Terminology source: Sartori et al. 10

11 renewable energy generation energy supply NZEB Concept Principle of Nearly Zero Energy Buildings (NZEBs) energy efficiency passive approaches energy consumption based on Voss / Lollini Missing items for thorough definition Building system boundary Physical boundary Balance boundary Weighting system Metrics Symmetry Time dependent weighting Net ZEB Balance Balancing period Type of balance Energy efficiency Energy supply Temporal energy match characteristic Load mismatch Grid interaction Measurement and verification 11

12 Physical Boundary Physical Boundary: What is the Building (on-site)? Single building or clusters of buildings On-site: inside the physical boundary Building footprint?, Building property? Are off-site supply options allowed? Different priorities? Investment in RES installations Off-site RES investment can be accounted on-site On-site RES installation could be off-site, if energy is sold Connection to two-way energy grids Electricity grid normally bi-directional, but frequency and voltage tolerances Thermal energy grids: Temperature level 12

13 NZEB Definition On-site and «nearby» System boundary around the building 76 m 2 of solar thermal collector 200 m 3 seasonal storage in the house Solar system cost less than 10% of total cost Results of year-round measurement In February 80 C in the storage Second building is currently constructed with reduced collector area and storage tank source: Marszal, Bourrelle et al. 13

14 Balance Boundary Balance Boundary: What energy services are accounted? At least operational energy Additionally appliances Additionally embodied energy Additionally mobility (electric hybrid vehicle) Connection to two-way energy grids Electricity grid normally bi-directional, but requirements for frequency and power Thermal energy grids: Temperature level 14

15 NZEB Definition Balance Boundary embodied energy Zeroheatingenergy-house energy heating electricity appliances auxiliary electricity electricity ventilation energy DHW energy heating Zeroheatenergy-house Zerooperationalenergy-house energy DHW energy heating auxiliary electricity electricity ventilation energy DHW energy heating Zeroenergy-house electricity appliances auxiliary electricity electricity ventilation energy DHW energy heating embodied energy Zero-LCA-house electricity appliances auxiliary electricity electricity ventilation energy DHW energy heating source: MINERGIE 15

16 Boundary conditions for the balance Boundary conditions: What impacts on energy demand? Functionality (residential, office etc.) Comfort level to be considered? Climate impact Space effectiveness 16

17 Weighting system - Metrics Weighting system: What shall be compared? Conversion of physical metrics to uniform metrics Comparison of different energy carriers and process chains Fuel switch between generation and consumptions (e.g. PV electricity in summer for biomass in winter) Metrics Site energy (delivered energy) Source energy (primary energy) Energy cost Carbon emissions Conversion factors Difficult task: regional difference => politically corrected conversion factors political (strategic) factor to support the adoption of certain technologies? 17

18 Weighting system - Symmetry Weighting system: Shall be equally or asymmetrically compared? Symmetrical weighting: Substitution effect of feed-in energy Asymmetrical weighting: Negative effect of feed-in energy Delivered energy is weighted higher: Grid loss are taken into account Promotes self-consumption of on-site generated energy Exported energy is weighted higher Promotion of on-site generation technologies, e.g. PV-systems (strategic factors) Also dynamic time dependent accounting possible Hourly energy prices (already today) and CO 2 -emissions and PEF (future) 18

19 Net ZEB Balance Balancing period: What time steps shall be used? Yearly balance period Often implicitly set to one year in order to exclude seasonal effects Shorter balance period Takes into account seasonal effects, but could be hard to meet, especially in winter Longer balance period Takes into account life cycle effects Type of balance Load/generation balance No interaction between building generation system and grid Load entirely satisfied and all generated energy is fed into the grid Import/export balance Considers self-consumption, but values may not be available 19

20 Titelmasterformat Net ZEB Balance durch Klicken - Balancing bearbeiten period source: Sartori et al. 20

21 Net ZEB Balance Energy efficiency: What requirements should be set? Requirements could consider cost-optimality Tendency in the EPBD, but still under development Requirements on load reduction as prescribed in the national building codes No requirements leaves it to the designer to find cost-optimum Energy supply: Explicit requirements on energy systems e.g. explicit requirement for certain renewable installations hierachy of supply options (on-site options better than off-site options) supply side renewable generation can be exported and sold, like PV electricity and hot water district heating demand side renewable generation only available to reduce load, like geothermal heat pumps and passive solar gains 21

22 Net ZEB Balance Energy efficiency: What requirements should be set? Requirements could consider cost-optimality Tendency in the EPBD, but still under development Requirements on load reduction as prescribed in the national building codes No requirements leaves it to the designer to find cost-optimum Energy supply: Explicit requirements on energy systems e.g. explicit requirement for certain renewable installations hierachy of supply options (on-site options better than off-site options) supply side renewable generation can be exported and sold, like PV electricity and hot water district heating demand side renewable generation only available to reduce load, like geothermal heat pumps and passive solar gains 22

23 Temporal energy match characteristic Temporal energy match: Is generation consistent to the needs? NZEB can be characterised by the ability to match the load Target group are building owners and designers, local and urban planners, local grid operators in the context of smart grids Load match: Poor load match implies high reliance on the grid Better load match offers more options to fine-tune self-consumption and react to grid needs Applies to the load / generation balance of the building Grid interaction: What is the impact on the grid? Temporal match between on-site generation and needs of the grid Applies to the import/export balance in correlation to the base/peak load of the grid 23

24 Swiss MINERGIE-A Label Zero operation energy building Certification requirements Building envelope losses must not exceed 90% of legal requirement ( 50 kwh/(m 2 a)) Weighted delivered energy metric = 0 kwh/(m 2 a) Weighted delivered energy must be compensated with on-site renewable generation 15 kwh/(m 2 a) storable biomass can be substracted => also concepts with solar thermal systems and wood heating possible Q H,nd Q 3.6 V,rvd / Q 3.6 Embodied Energy < 50 kwh/(m 2 a) f MIN gen W,nd / On the way to Life Cycle Assessment (LCA) In highly efficient buildings embodied energy may be in the same size as operational energy Currently relatively high limit, all certified buildings are below the limit f MIN gen E CV,in E 3.6 PV,out f MIN 0 24

25 Swiss NZEB Standard MINERGIE-A Evaluation of MINERGIE-A buildings Most of the buildings use PV but with building below the weighted energy of 15 kwh/(m 2 a) biomass possible Biomass can also reduce the required PV area in houses with higher consumption than 15kWh/(m 2 a) 25

26 Swiss NZEB Standard MINERGIE-A Evaluation of MINERGIE-A buildings Heat pumps are the dominant heating system partly combined with solar thermal systems Embodied energy in most buildings significantly below the limit 26

27 Reference More details on the definition framework I. Sartori, A. Napolitano, K. Voss Net Zero Energy Buidings: A consistent definition framework, Energy and Buildings 2012 Website IEA SHC Programme => Task 40 MINERGIE-A Standard 27

28 IEA HPP Annex 40 Summary IEA HPP Annex 40: Heat pump concepts for NZEB Scope Concepts and technologies for NZEB with heat pumps Residential and small commercial buildings All buildings services as needed Steps Task1: Ranking of concepts (new buildings and retrofit options) Task 2: Optimisation of configuration (performance and cost) Design and control of integrated systems for NZEB Task 3: Technology development (prototypes) and field evaluation Task 4: Specific information on (seasonal) storage, DSM, grid interaction source: SPD, Pogharian Expected Deliverables Technical recommendations on design and layout of optimised NZEB technologies Best practice systems and concepts, prototype technologies, field results 28

29 IEA HPP Annex 40 Heat pump concepts for NZEB Thank you for your attention! Kick-off meeting in July 2012 at HSR, Rapperswil, Switzerland 29