Implementation of the EPBD in Belgium : Performances of the simplified method for primary energy consumption calculations

Transcription

1 Implementation of the EPBD in Belgium : Performances of the simplified method for primary energy consumption calculations LCUBE Conference - Vienna - 17 April 2007 Ir. Stéphanie Nourricier Faculty of Engineering, Mons (Belgium) Faculty of Engineering, Mons

2 Introduction and background The Energy Performance of Building Directive (EPBD) in Belgium The principles of the Energy Performance of Buildings The calculation method The month-average calculation method adopted to evaluate the summer comfort in housings The hour-average method used for the comparison The analysis of the simplified method The buildings used The assumptions The parameters The results Conclusions Faculty of Engineering, Mons 2

3 European and international background (Europe: 16% of the world-wide primary energy consumption) : The Kyoto Protocol (reduction of greenhouse gas emissions) Sustainable development (careful and rational use of the natural resources) One of the required measures Increase the energy efficiency Residential and tertiary sector 40% of final energy consumption in the Community expanding Belgian background (3.8% of the european primary energy consumption) : The residential (and equivalent) sectors 36.7 % of final energy consumption Primary energy consumption profile of Belgium in 2005 interms of sectors I. Introduction and background : 10.8% 28.6% Industries Transportation 36.7% 23.9% Residential; agriculture ; services Non energetic uses (petrochemistry) Faculty of Engineering, Mons 3

4 The Energy Performance of Building Directive (EPBD) in Belgium : Published in January 2003 Member States had to comply at the latest on 4th January 2006 In Belgium : The implementation of the EPBD regulation in the 3 Regional administrations In Flanders the implementation is already achieved July 2004 : decree publication June 2005 : execution decree and calculation method January 2007 : application In Wallonia February 2007 : decree adopted by the government April 2007 : decree has to be adopted by the parliament The execution decree and the calculation method are being prepared Faculty of Engineering, Mons 4

5 The principles of the Energy Performance of Buildings : Definition : Energy Performance of a Building is the amount of energy actually consumed or estimated to meet the different needs associated with a standardised use of the building, which may include, inter alia, heating, hot water heating, cooling, ventilation and lighting. This amount shall be reflected in one or more numeric indicators which have been calculated, taking into account insulation, technical and installation characteristics, design and positioning in relation to climatic aspects, solar exposure and influence of neighbouring structures, own-energy generation and other factors, including indoor climate, that influence the energy demand. The Belgian numerical indicator : The primary energy consumption level : E-level PrimaryEnergyConsumption E level= x100 ReferencePrimaryEnergyConsumption Faculty of Engineering, Mons 5

6 The primary energy calculation method is the same for the whole country This method was developed by the BBRI (Belgian Building Research Institute) The calculation method for the determination of the reference primary energy consumption is different from one Region to another. In Flanders : The reference primary energy consumption : E prim,ref,rf = a.a t + b.v + c.q dedic A t = Transmission surface a,b,c = constant values determined by a statistical analysis V = Protected volume q dedic = ventilation flow-rate In Wallonia : Another expression : E prim,ref,rw = E prim,chauf,ref + E prim,ecs,ref + E prim,aux,ref E prim,chauf,ref = Reference Primary Energy for space heating E prim,ecs,aux = Reference Primary Energy for hot water production E prim,aux,ref = Reference Primary Energy for auxiliaries Faculty of Engineering, Mons 6

7 The calculation method : Month-average method based on a typical climatic year The main steps : 1. Determination of the net energy demand space heating (18 C) cooling (23 C) (transmission and ventilation losses ; internal and solar gains) hot water production 2. Determination of the overheating risk (summer comfort) Degree-hours of overheating (18 C) Energy consumption for cooling or for the fictitious cooling 3. Determination of the brute energy demand Efficiency of the systems Emission system Distribution system Storage system Faculty of Engineering, Mons 7

8 4. Determination of the final energy (heating; hot water; cooling; auxiliaries) Efficiency of the generators Solar contributions 5. Determination of the primary energy consumption Space heating Hot water production Cold production Auxiliaries Energy conversion factors (depending on the combustible) Energy savings due to electricity production by means of PV cells or CHP generation 12 E prim,cons,a = (E prim,heat,m + E prim,ecs,m + E prim,aux,m +Eprim,cool,m-Eprim,pv,m-E prim,cogen,m ) 1 6. Determination of the reference primary energy consumption 7. Determination of the primary energy consumption level : E-level Faculty of Engineering, Mons 8

9 The month-average method adopted to evaluate the summer comfort in housings : Calculation of the degree-hours of overheating over 18 C Evaluation of the overheating risk Taking all or part of the primary cooling energy consumption into account The degree-hours of overheating over 18 C : 12 overh,seci excessnorm,seci,a m=1 excessnorm,seci,m I =Q = Q (1-? util,overh,seci,m).q g,overh,seci,m.1000 Q excessnorm,seci,m = (H +H ).3,6 T,overh,seci V,overh,seci Q g,overh,sec i,m = Q i,sec i,m + Q s,sec i,m : internal and solar gains [MJ]? util,overh,sec i,m : utilisation factor of heat gains (according to the EN ISO 13790) H T,overh,sec i,m : heat losses coefficient caused by transmission [W/K] H V,overh,sec i,m : heat losses coefficient caused by ventilation (ß overh = 1 V/h) [W/K] Faculty of Engineering, Mons 9

10 The limits defined : I overh,sec i < 8000 Kh No risk I overh,sec i > Kh Banned 8000 < I overh,sec i < Kh Some risks exist ; a certain penalty is taking into account (contribution in E prim ) The conventional probability that an active cooling system gets installed : Ioverh,seci p cool,sec i =max 0;min ; The energy demand for cold production : Cooling system installed : p cool,sec i = 1 No cooling system : p cool,sec i = calculated Q cool,net,sec i,m = p cool,sec i. Q excessnorm,cool,sec i,m Q excess,cool,sec i,m : the excess gains (over 23 C) Faculty of Engineering, Mons 10

11 The excess gains : With 20% shading The solar gains are overestimated of 10% The outdoor temperature is overestimated of 2 C Q excess,cool,sec i,m = (1-? util,cool,sec i,m ).Q g,cool,seci,m Qexcess,cool Qcool,net pcool 72% 90% 82% 100% 75% 140% 120% 100% [MJ/m²] % 24% 17% 21% 22% 33% 50% 25% pcool [%] 80% 60% 40% 20% 0% "fictitious" cooling E-level without cooling % Faculty of Engineering, Mons 11

12 The hour-average method used for the comparison : Data : Global parameters K-level total internal heat capacity C Windows characteristics Ventilation flow rate Internal gains Building geometric characteristics Set inside temperature Weather Data Results : Calculation of F heat With t i = t instr, heat F heat = 0 F heat < 0 Calculation of t i With F heat/cool = 0 Temperatures and heat flows for each time step yearly or monthly energy consumptions Advantage : Few data required as for month-average method t i < t instr, heat t i > t instr, heat Calculation of F cool With t i = t instr, cool F cool < 0 F cool = 0 Faculty of Engineering, Mons 12

13 Dynamic analysis : ATG : Adaptative temperature limits (de Dear & Brager) Principle : People in naturally ventilated buildings can modify themselves the internal conditions they are more tolerant (psychological effect) The ATG theory is based on : - the Fanger theory of the PMV and PPD indicators - a statistical study from ASHRAE (RP-884 project) Allow to calculate which percentage of people are dissatisfied each hour Faculty of Engineering, Mons 13

14 The analyse of the simplified method : Fictitious buildings modelled for the comparison : Volume : 450 m³ - Heated area : 150 m² - Windows : 30m² Four facades housing Two facades housing, oriented North-South or East-West Apartment, 2 floors, oriented North-South or East-West Type of building At V/At Distribution of windows [m²] [m²] [m] North East South West 4 façades housing façades housing N-S façades housing E-W apartment N-S apartment E-W Assumptions : Internal gains : 4 W/m² Ventilation flow rate : 1 V/h No shading Same meteorological file (monthly and hourly) Faculty of Engineering, Mons 14

15 The parameters : The global insulation level : K45 and K25 The internal heat capacity C 30 buildings Structure C [kj/k] Lightweight Medium weight Massive Type of building K45 K25 ks [W/m²K] ks [W/m²K] 4 façades housing façades housing N-S façades housing E-W apartment N-S apartment E-W The results : Degree-hours of overheating (over 18 C) ATG for 10% of dissatisfied ATG for 25 % of dissatisfied Degree-hours of overheating (over 23 C) Net energy cooling demand (over 23 C) Faculty of Engineering, Mons 15

16 Monthly and hourly degree-hours of overheating (over 18 C) : % +10% Monthly degree-hours of overheating over 18 C [Kh] ? 13 cases rejected Houses? 11 cases rejected Apartments -10% -20% Hourly degree-hours of overheating over 18 C [Kh] 4F - K45 4F - K25 2F EW- K45 2F EW - K25 2F NS - K45 2F NS - K25 Apart EW - K45 Apart EW - K25 Apart NS - K45 Apart NS - K25 Equality 10% -10% 20% -20% Faculty of Engineering, Mons 16

17 Lightweight structure ATG Four facades housing K45 Indoor temperature [ C] Kh overheating / 18 C 2 h 10 % dissatisfied 0 h 20 % dissatisfied 0 h 25 % dissatisfied 0 h 35 % dissatisfied p,cool = 12% Running mean outdoor temperature [ C] Kh overheating / 18 C 458 h 10 % dissatisfied 317 h 20 % dissatisfied 276 h 25 % dissatisfied 215 h 35 % dissatisfied p,cool = 47% Indoor temperature [ C] Massive structure Running mean outdoor temperature [ C] Faculty of Engineering, Mons 17

18 Correlation between the degree-hours overheating over 18 C and the hours that exceed the limit of 10% dissatisfied users : Hourly degree-hours of overheating over 18 C [Kh] Kh overheating over 18 C 700 hours that exceed the limit of 10% dissatisfied users 700 h : 24/24h during 1 month 12h/24h during 2 months 8h/24h during 3 months 10% dissatisfied users : 1.2 persons/ 3 housings Hours that exceed the limit of 10% dissatisfied users [hours]- (ATG) global 4F - K45 4F - K25 2F EO - K45 2F EO - K25 2F NS - K45 2F NS - K25 Appart EO - K45 Appart EO - K25 Appart NS - K45 Appart NS - K25 Linéaire (global) Faculty of Engineering, Mons 18

19 Correlation between the degree-hours overheating over 18 C and the hours that exceed the limit of 25% dissatisfied users : Kh overheating over 18 C 380 hours that exceed the limit of 25% dissatisfied users Hourly degree-hours of overheating over 18 C [Kh] hours : 12h/24h during 1 month 25% dissatisfied users : 1 person / Hours that exceed the limit of 25% dissatisfied users - [hours] (ATG) Faculty of Engineering, Mons 19

20 Correlation between the degree-hours overheating over 18 C and over 23 C : Kh overheating over 18 C Kh overheating over 23 C Kh 570 hours at 30 C during 50 days (12h/24h) Hourly degree-hours of overheating over 23 C [Kh] Hourly degree-hours of overheating over 18 C [Kh] Faculty of Engineering, Mons 20

21 Monthly and hourly net cool demand : % +100% +50% Monthly Qcool,net [MJ] The evident reasons : Increasing of 10% of the solar gains Increasing of 2 C of the outdoor temperature 4 Façades 50% 2 Façades 100% Apartment Hourly Qcool,net [MJ] Faculty of Engineering, Mons 21

22 Monthly and hourly net cool demand without overestimations: % Monthly Qcool,net [MJ] % Façades 50% 2 Façades 100% Apartment Hourly Qcool,net [MJ] Faculty of Engineering, Mons 22

23 Monthly and hourly net heat demand : % % -20% Monthly net heat demand [MJ] Hourly net heat demand [MJ] Faculty of Engineering, Mons 23

24 Conclusions : About the month-average philosophy : Difficulty to give sense to the degree-hours of overheating over 18 C in terms of comfort We propose to translate it into an explicit indicator Difficulty to justify a fictitious cooling consumption by way of penalty and risk of wrong interpretation of this consumption Importance to avoid requirement of cooling energy in such countries (oceanic and moderate climate) About the calculation method : Importance of the weather file used for the summer the typical climatic year is to be updated Relatively good estimation of heat consumption and degree-hours of overheating but less accurate estimation of cooling consumption Importance of the modelling of lightweight structures like wood structures which become more common in high insulation levels buildings Faculty of Engineering, Mons 24