Role of daylight in the existent and future French building regulations

Transcription

1 Role of daylight in the existent and future French building regulations Christophe Martinsons Lighting Electromagnetism and Electricty Division 13 May rd VELUX Daylight Symposium Page 1

2 Centre Scientifique et Technique du Bâtiment Centre for Building Science and Technology CSTB is an industrial and commercial public institute (known in France as an EPIC) About 800 employees, turnover 2008 ~ 80 M Activities : Tests & certifications (40%) Research (23%) Consultancy (25%) Knowledge dissemination (8%) 13 May rd VELUX Daylight Symposium Page 2

3 CSTB : fields of expertise 13 May rd VELUX Daylight Symposium Page 3

4 Lighting, Electromagnetism & Electricy Division Daylighting Algorithm for 3D lighting simulation Combined daylighting and artificial lighting design Optical laboratory for materials and luminaires z (m) E y (m) db Electromagnetic propagation indoor/outdoor Sensors for home automation Wireless sensor networks Electromagnetic laboratory 13 May rd VELUX Daylight Symposium Page 4

5 The building sector in France What do buildings represent in France? 30 millions homes Over 800 millions m² of tertiary buildings An average lifetime of about 100 years The largest energy user: 43 % of energy use (31 % for transportation, 20% for industry) 25 % of the CO 2 emissions (28% for transportation, 21% for industry) Today, the average building energy consumption in France is about 400 kwh pe / m² / year About 330 kwh pe / m² / year in the residential sector About 550 kwh pe / m² / year in the tertiary sector 13 May rd VELUX Daylight Symposium Page 5

6 Daylighting in French regulations Labor code Accessibility regulation Building energy regulation No European daylighting standard at the present time.. Such work should soon start at CEN / TC May rd VELUX Daylight Symposium Page 6

7 Daylighting in the French labor code Labor regulation code du travail Availability of daylight on work places (1984) It is mandatory to have windows at eye level with an exterior view (1993) Task areas must be protected from solar glare by fixed or mobile sun protections ¼ of the facade area of buildings should be glazed Minimum of 120 lux in all working areas (artificial and/or daylighting) Labor code does not give any minimal amount of daylight 13 May rd VELUX Daylight Symposium Page 7

8 The French building energy code(s) in France, the building energy code is called «RT» : réglementation thermique Until 1988, regulations were only applied to heating systems, thermal insulation and hot water production. Lighting energy consumption was first introduced in RT RT 2005 is the current building regulation in use RT 2012 is the next step with the first milestone in Jan May rd VELUX Daylight Symposium Page 8

9 The current regulation : RT 2005 Context of RT 2005 : France signs the Kyoto protocol in February 2005 Transposition in France of the European directive on the energy performances of buildings (EDPB /91/EC ) from Dec to July 2005 Objectives of the RT 2005 : Reduce greenhouse gases emissions Limit the total cost of housing (e.g. utility bills) Promote efficient systems and building techniques 13 May rd VELUX Daylight Symposium Page 9

10 Principles of RT 2005 Building compliance is defined by three different criteria : Energy consumption Cep in kwh EP /m²/an heating, cooling, hot water production, auxiliary, lighting (in non-residential buildings) In non-residential buildings : Cep (Cep) reference RELATIVE approach In residential buildings : Cep (Cep) max ABSOLUTE approach Maximum allowed consumption varies : from 80 kwh ep /m²/yr (mediterranean climate, fossil fuel heating) to 250 kwh ep /m²/yr (northern France, electric heating) Summer indoor temperature (Ti) Ti (Ti) reference RELATIVE approach balancing is possible! Minimal requirements for components insulation, HVAC, heating systems, hot water, etc. 13 May rd VELUX Daylight Symposium Page 10

11 RT 2005 energy calculations Lighting in residential sector (2005) : 7-8 kwh ep /m²/yr (appartments) 9-10 kwh ep /m²/yr (houses) auxiliaries ventilation lighting cooling hot water heating house elect. heating North France house elect. heating South France Appart ments. gas heating North France Appart ments. gas heating South France Offices Heat pumps North France Offices Heat pumps South France 13 May rd VELUX Daylight Symposium Page 11

12 RT 2005 Offices L L L 13 May rd VELUX Daylight Symposium Page 12

13 RT 2005 : Calculation method RT 2005 includes a very detailed calculation method : Climate-based method 8 climate zones in metropolitan France Hourly method carried out for a whole year Physics is treated using simple mathematical approximations Building is segmented in zones, groups and rooms The authorized calculation method is implemented by CSTB in a raw numerical code which is distributed to software editors. 13 May rd VELUX Daylight Symposium Page 13

14 RT 2005 building segmentation Building is split in zones having the same usage Use of predefined usage and occupancy scenarios in each zone Zones are split in groups having similar needs For lighting calculations, groups are split in rooms or parts of room according to the daylight availability. 13 May rd VELUX Daylight Symposium Page 14

15 RT 2005 occupancy scenarios Residential lighting scenarios : Monday to Friday : 7h to 9h & 19h to 22h Saturday and Sunday : 7h to 22h Office lighting scenarios : Monday to Friday : 8h to 18 h 13 May rd VELUX Daylight Symposium Page 15

16 Lighting calculations in RT 2005 RT 2005 provides a daylight calculation method. Daylight calculation is intended to know whether electric lighting has to be used, hour by hour, in each room. Overview of the method Building segmentation Calculation of transmittances of fenestrations systems Calculation of average indoor daylight illuminance Calculation of daylight dependency factor Calculation of hourly lighting energy consumption Summation of rooms, summation of hour-by-hour values 13 May rd VELUX Daylight Symposium Page 16

17 Daylighting in RT 2005 The French building energy code includes daylighting as a mean to assess the artificial lighting energy use. There is no requirements on daylighting! RT does not prevent bad practices in daylighting 13 May rd VELUX Daylight Symposium Page 17

18 Lighting calculations in RT 2005 Within each group of each zone : Identify rooms having an access to daylight Define the effective depth of daylight penetration depth = 2.5 * height of lintel above floor Deduce partial area with access to daylight Compute luminous transmittances of fenestration system Glazing + frame + sun protection Mandatory calculation of solar transmission factors g Luminous transmittance = 0.9 * g normal hemispherical 13 May rd VELUX Daylight Symposium Page 18

19 Lighting calculations in RT 2005 Proceed to hourly calculation : Outdoor vertical solar illuminance Includes direct, diffuse and ground-reflected components E eq = E dif + (0,2 E dir + 0,6 E refl ) Expressed as an equivalent illuminance produced by a diffuse source Varies with local latitude and climate-zone Includes orientation and tilt of facades Includes near-horizontal masks (overhangs, etc. )and far vertical masks Constant efficiency of solar radiation of 100 lm/w - Luminous illuminance = solar illuminance * May rd VELUX Daylight Symposium Page 19

20 Lighting calculations in RT 2005 Estimation of the fraction of mobile sun protections in use No mobile sun protection are considered in use in residential buildings In non-residential buildings : Values based on observations of users behaviors 0 if outdoor vertical illuminance is zero Maximum ratio of 0.5 when outdoor vertical illuminance is lux 13 May rd VELUX Daylight Symposium Page 20

21 Lighting calculations in RT 2005 Compute daylight factors : Daylight factor without mobile sun protection D fvi1 = 1,8 T 4,5 A l1 ecln at Abaie 0,75 Daylight factor with mobile sun protection D fvi2 = 1,8 T 4,5 A l 2 ec ln at Abaie 0,75 Compute indoor daylight illuminance E inat w = (D 1 fvi1 ( 1 Plin ) + Dfvi2Plin ) Eb eq average value in partial area with access to daylight 13 May rd VELUX Daylight Symposium Page 21

22 Lighting calculations in RT 2005 Daylight dependency factor (mean time of luminaire use during an hour) daylight dependency factor in RT ,8 0,6 Automatic gradation Manual sw itch 0,4 0, daylight indoor illuminance (lux) 13 May rd VELUX Daylight Symposium Page 22

23 Lighting calculations in RT 2005 Occupation dependency coefficient : Manual switch 0.9 Switch + clock 0.8 Presence sensor May rd VELUX Daylight Symposium Page 23

24 Lighting calculations in RT 2005 Energy consumption in a room per hour (Wh) : lighting daylight occupancy room power * dependency * dependency area density factor factor Primary energy = electrical energy x 2,58 In residential buildings, all these parameters are fixed : occupancy dependency factor : 0.9 (manual switches) indoor illuminance = 200 lx daylight dependency factor = 0.05 Lighting power density = 2 W/m² installed power 20 W/m² with 10% of luminaires switched on at any given time 13 May rd VELUX Daylight Symposium Page 24

25 RT 2005 : the reference building in non-residential buildings, the energy consumption must be compared with the energy consumption of a reference building : Hypothetical building with same architecture Mandatory reference characteristics Mandatory reference equipment Two calculations are necessary, it is a relative approach! Project building Reference building 13 May rd VELUX Daylight Symposium Page 25

26 Drawbacks of RT 2005 Drawbacks of the relative approach : Lack of confidence in the absolute energy consumption values A good architectural design cannot be emphasized by comparison with a reference building Bioclimatic aspects : Only described by a global thermal parameter U bat (W/m²/K) RT 2005 does not give guidelines during the design phase 13 May rd VELUX Daylight Symposium Page 26

27 Towards the new regulation RT 2012 Today s context : French summit on energy and environment in 2008 Grenelle de l environnement Decision to accelerate energy savings and reduction of greenhouse gases Promote low energy buildings ( BBC ) in France : 2011 : 50 kwh EP /m²/yr for non-residential buildings 2013 : 50 kwh EP /m²/yr for residential buildings 2020 : positive energy buildings! Drastic reduction of energy consumptions! 13 May rd VELUX Daylight Symposium Page 27

28 Objectives of RT 2012 Absolute maximum of energy consumption : Energy criterion : C < 50 kwh ep /m²/yr Maximum value can be slightly adjusted to climate, building use and characteristics. No more reference building! More accurate estimation of energy uses Compliance will be defined by 4 criteria Energy consumption, indoor summer temperature, minimal requirements NEW : BIOCLIMATIC REQUIREMENT replacing requirement on U bat Introduce practical indicators for building designers 13 May rd VELUX Daylight Symposium Page 28

29 RT 2012 Bioclimatic requirement Bbio Definition of bioclimatic requirement Bbio : Characterizes the building envelope (architectural design) Bbio should emphasize low cooling, heating and lighting needs provided by a good architectural design, taking advantage of solar inputs. Bbio is the energy needed to ensure : Correct temperature in winter : Correct temperature in summer : Correct lighting throughout the year : Work in progress : how to add lighting and thermal needs?? heating needs = thermal kwh/m²/yr cooling needs = thermal kwh/m²/yr lighting needs = klumen.h/m²/yr or primary energy in kwh/m²/yr or luminous kwh/m²/yr 13 May rd VELUX Daylight Symposium Page 29

30 RT 2012 Bioclimatic requirement Bbio is the architectural contribution to the energy consumption C Bioclimatic indicator for lighting needs Daylight factors Simple Necessary but far from being sufficient Daylight autonomy of building More accurate, climate-based. Easily computed with an hourly method (software needed) - Number of hours with insufficient indoor daylight illuminance 13 May rd VELUX Daylight Symposium Page 30

31 RT 2012 : challenge for lighting Lighting is becoming the main energy consumer in office buildings One typical office in France with 500 lux on the task area : Fluo. tubes T8, ferromagnetic ballast, manual switch : 47 kwh EP /m²/yr Fluo..tubes T5, elec ballast, presence sensor, automatic dimming : 12 kwh EP /m²/yr 13 May rd VELUX Daylight Symposium Page 31

32 RT 2012 : challenge for lighting Promote a better use of daylight! Better characterization of sun protections and glazing More accurate description of indoor daylight illuminance Promote intelligent controls of electrical lighting : Dimming Automatic switching off with presence sensors Commissioning of lighting systems Maintenance, monitoring, etc. 13 May rd VELUX Daylight Symposium Page 32

33 RT 2012 : new lighting calculations Many technical improvements in the hourly calculation method Use of EN standard lighting energy requirements Better characterization of fenestration systems : New calculation rules of luminous transmittances Better characterization of daylight luminous efficiency Accurate luminous efficiencies (lm/w) for direct and diffuse solar components Better estimation of daylight indoor illuminance Use of direct and diffuse transmittances of fenestrations 13 May rd VELUX Daylight Symposium Page 33

34 RT 2012 : new lighting calculations Detailed values of occupancy dependency factors Based on EN Several lighting control strategies will be included in RT 2012 Definition of default values when characteristics are unknown This work is currently in progress Detailed results cannot be presented yet! 13 May rd VELUX Daylight Symposium Page 34

35 RT 2012 Schedule 2009 Work on calculation methods in each technical field Finding optimal balance between individual energy uses 2010 Programming & software engineering Running application examples 2011 Application to new non-residential buildings 2012 Application to new residential buildings 13 May rd VELUX Daylight Symposium Page 35