Comparison of calculation methods in designing a nearly zero energy building refurbishment

Transcription

1 Comparison of calculation methods in designing a nearly zero energy building refurbishment Clima th May Géza BARÁTH, Zoltán MAGYAR B u d a p e st U n i vers i t y o f Te c h n o l o g y a n d Economics 1

2 Outline Background: regulations Nearly zero energy building (nzeb) Definitions of nzeb RePublic_ZEB project Reference building Comparison of calculation methods 3

3 EPBD recast 2010/31/EU directive The requirements of energy performance should be on cost optimal level. All the public buildings built after 31. December 2018 and all the buildings built after 31th December 2020 should be on nearly zero energy level. 4

4 EPBD definitions The number of definitions in the directive is low, and they are not exact definitions. The exact definitions should be formulated by a Member States according to the local conditions. There are (or can be) big differences between the Member States! 5

5 EPBD definition: nzeb Nearly zero-energy building means a building that has a very high energy performance, as determined in accordance with Annex I. The nearly zero or very low amount of energy required should be covered to a very significant extent by energy from renewable sources, including energy from renewable sources produced on-site or nearby. 6

6 EPBD definition: nzeb Nearly zero-energy building means a building that has a very high energy performance, as determined in accordance with Annex I. The nearly zero or very low amount of energy required should be covered to a very significant extent by energy from renewable sources, including energy from renewable sources produced on-site or nearby. 7

7 Establishing the nzeb requirements By establishing the local numeric requirements local conditions have to be taken into consideration: Local climate Heating and cooling degree day Intensity of solar radiation Economy Energy prices GDP Tender possibilities Engineering Technical and energetic condition of the current building stock Available knowledge 8

8 An example: zneb in Hungary Modification of 7/2006. TNM statue in force from 1st January 2016: U values on cost optimal level Specific heat loss depends on A/V Total energy performance: Residential 100 kwh/m 2,a Office 90 kwh/m 2,a Educational 85 kwh/m 2,a Cooling + 10 kwh/m 2,a Renewable energy ratio: 25 % 9

9 RePublic_ZEB REFURBISHMENT OF THE PUBLIC BUILDING STOCK TOWARDS NZEB Aims: Analysis of the public building stock, defining reference buildings Evaluation of the current state, analysis of possibilities to renovate public buildings towards nzeb Cost-benefit analysis of packages of measures for renovations towards nzeb Strategies and guidelines for nzeb public buildings Communication 10

10 RePublic_ZEB Participating countries: Italy (CTI - coordinator, POLITO) Portugal (LNEG) Spain (IREC) Slovenia (ZRMK) Hungary (BME) Romania (URBAN-INCERC) Bulgaria (BRES) Croatia (EIHP) Macedonia (MACEF) Greece (CRES) UK (BRE) 11

11 Total energy performance requirements on nzeb level RESIDENTIAL BUILDINGS - primary energy consumption according to nzeb requirement Italy, A and B climatic zone Italy, C climatic zone Italy, D climatic zone Italy, F climatic zone Italy, E climatic zone Bulgaria, class A, lower limit Croatia, coastal, multiap. buildings Croatia, continental, multiap. buildings Slovenia, multifamily building Romania I climatic zone, collective residential Romania II climatic zone, collective residential Hungary Romania III climatic zone, collective residential Romania IV climatic zone, collective residential Romania V climatic zone, collective residential Primary energy, [kwh/m 2 a] 12

12 Total energy performance requirements on nzeb level OFFICE BUILDINGS - primary energy consumption according to nzeb requirement Croatia, coastal Croatia, continental Romania I climatic zone Italy, C climatic zone Italy, D climatic zone Romania II climatic zone Italy, F climatic zone Italy, E climatic zone Italy, A and B climatic zone Romania III climatic zone Bulgaria, class A, lower limit Slovenia Romania IV climatic zone Romania V climatic zone Hungary Bulgaria, class A, upper limit Primary energy, [kwh/m2a] 13

13 Total energy performance requirements on nzeb level EDUCATIONAL BUILDINGS - primary energy consumption according to nzeb requirement Bulgaria, school, classa, lower limit Bulgaria, kindergarten, classa, lower limit Croatia, coastal Bulgaria, school, classa, upper, limit Croatia, continental Bulgaria, kindergarten, classa, upper limit Hungary Romania I climatic zone Romania II climatic zone Romania III climatic zone Romania IV climatic zone Romania V climatic zone Primary energy [kwh/m 2 a] 14

14 RePublic definition for nzeb Refurbishment on nzeb level is: Refurbishment of structures and HVAC systems with materials and technologies, whereby: Lower energy consumption, than on cost optimal level Minimum renewable energy ratio The refurbishment must be cost effective Life cycle costs have to be analysed: Investment costs (including change of parts in the future!) Energy costs Operational and maintenance costs 16

15 RePublic definition for nzeb 17

16 Comparison of calculation methods Dynamic energy simulation EN standards National calculation method 18

17 Comparison of calculation methods Dynamic energy simulation Software: TRNSYS Annual heating energy demand Calculation step: 1 hour Meteorology: TMY from the last 30 years 19

18 Comparison of calculation methods Excel tool is developed by Corrado and Paduos at Politecnico di Torino, Italy EN 15603:2008. Energy performance of buildings - Overall energy use and definition of energy ratings EN ISO 13790:2008. Energy performance of buildings - Calculation of energy use for space heating and cooling EN 15316:2007 (series). Heating systems in buildings - Method for calculation of system energy requirements and system efficiencies EN 15243:2007. Ventilation for buildings - Calculation of room temperatures and of load and energy for buildings with room conditioning systems EN 15193:2007. Energy performance of buildings - Energy requirements for lighting EN 15459:2007. Energy performance of buildings - Economic evaluation procedure for energy systems in buildings 20

19 Comparison of calculation methods Calculation method in Hungary based on harmonised EN standards contains simplifications on several points Meteorology: average of the heating or cooling season of the last 100 years internal heat gain is attached to the function of the building simplifications are to the benefit of the safety 21

20 Reference building: student hostel Gross volume V g m 3 No. floors n 6 - Net floor area A f,n 8311 m 2 Area of building envelope A env 6494 m 2 A env /V g 0,289 22

21 Packages of measures Structure Nr. Value 1 0,23 U Wall wl 2 0,21 [W/m 2 K] 3 0,19 1 1,1 Windows Roof U w [W/m 2 K] g [-] U r [W/m 2 K] 2 1,0 1 0,61 2 0,33 1 0,17 2 0,16 3 0,15 No. of Wall Roof Window package 1 existing existing existing 2 1 existing existing 3 2 existing existing 4 3 existing existing 5 existing 1 existing 6 existing 2 existing 7 existing 3 existing 8 existing existing 1 9 existing existing

22 [kwh/m 2 a] Heating energy demand 90,0 Heating energy demand 80,0 70,0 60,0 50,0 40,0 30,0 20,0 10,0 0, Nr. of package of measures National method - simplified National method - detailed Dynamic simulation EU standards 24

23 Differences 80,0% Differences between the results 60,0% 40,0% 20,0% 0,0% -20,0% -40,0% Nr. of package of measures Simulation - Nat. simplified Simulation - Nat. detailed Simulation - Eu standards 25

24 Predicted savings 50% 45% 40% 35% 30% 25% 20% 15% 10% 5% Predicted savings 0% Nr. of package of measures National method - simplified National method - detailed Dynamic simulation EU standards 26

25 Differences 200,00% 175,00% 150,00% 125,00% 100,00% 75,00% 50,00% 25,00% 0,00% -25,00% Differences between the results -50,00% Nr. of package of measures Simulation - Eu standards Simulation - Nat. simplified Simulation - Nat. detailed 27

26 Conclusions Designing a building renovation with low energy demand the importance of reasonable choice of methodology when calculating the effects of the refurbishment of a building is much higher: Exact meteorological data Exact calculation of internal heat gains Detailed calculation of solar radiance Designing the g-value of glazing 28

27 Thank you for your attention! dr. Zoltán Magyar Géza Baráth 29