Energy performance of buildings - Energy requirements forlighting - Part 1: Lighting energy estimation
Performance energetique des batiments - Exigencesenergetiques pour l'eclairage - Partie 1 : Estimation
energetique de l'eclairage
Energetische Bewertung von Gebäuden - EnergetischeAnforderungen an die Beleuchtung - Teil 1: Abschätzung
des Energiebedarfs für die Beleuchtung
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 169.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations whichstipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other languagemade by translation under the responsibility of a CEN member into its own language and notified to the Management Centre has the samestatus as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice andshall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATIONC OM ITÉ EUR OP ÉEN DE NOR M ALIS AT IONEUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
Foreword............................................................................................................................................................. 3 Introduction ........................................................................................................................................................ 4 1 Scope...................................................................................................................................................... 6 2 Normative References .......................................................................................................................... 6 3 Terms and definitions........................................................................................................................... 6 4 Calculating energy used for lighting................................................................................................... 8 5 Metering ................................................................................................................................................. 8 6 Calculation of lighting energy in buildings ........................................................................................ 9 7 Other considerations .......................................................................................................................... 27 8 Bibliography ........................................................................................................................................ 27 Annex A (informative) Metering of Lighting circuit ..................................................................................... 28 Annex B (informative) Measurement method of total input power of Luminaires and
associated Parasitic power................................................................................................................ 31 B.1 Requirement for tests ......................................................................................................................... 31 B.2 Standard test conditions.................................................................................................................... 31 B.3 Electrical measuring instruments ..................................................................................................... 31 B.4 Test luminaires.................................................................................................................................... 31 B.5 Test voltage ......................................................................................................................................... 31 B.6 Luminaire input power (Pi)................................................................................................................. 32 B.7 Parasitic input power (Ppi)................................................................................................................. 32 Annex C (informative) Daylight ..................................................................................................................... 33 C.1 Default values...................................................................................................................................... 33 C.1.1 Daylight supply, Factor FD,S,n ............................................................................................................. 33 C.1.2 Correction factor for shifted occupation times cD,t ......................................................................... 33 C.1.3 Daylight dependent artificial lighting control, FD,C .......................................................................... 33 C.1.4 Monthly Method, cD,S,n......................................................................................................................... 34 C.1.5 Determination of tD and tN operating hours ...................................................................................... 34 C.2 Methods for determination of FDS...................................................................................................... 35 C.2.1 Simple Approach................................................................................................................................. 35 C.2.2 Detailed approaches ........................................................................................................................... 37 Annex ZA (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive 2002/91/EC of THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 16 December 2002 on the energy performance of buildings ..................... 38
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Foreword
This document (prEN 15193-1:2005) has been prepared by Technical Committee CEN/TC 169 “Light and Lighting”, the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
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Introduction
This European standard was devised to establish conventions and procedures for the estimation of energy requirements of lighting in buildings, and to give methodology for the numeric indicator of energy performance of buildings. It also provides guidance on the establishment of notional limits for lighting energy derived from reference schemes.
Having the correct lighting standard in buildings is of paramount importance and the convention and procedures assume that the designed and installed lighting scheme conforms to good lighting practices. For new installations the design will be to EN 12464-1, Light and Lighting – Lighting of work places – Part 1: Indoor work places.
The standard also gives advice on techniques for separate metering of the energy used for lighting that will give regular feedback on the effectiveness of the lighting controls.
The methodology of energy estimation not only provides values for the numeric indicator but will also provide input for the heating and cooling load impacts on the combined total energy performance of building indicator.
Figure 1 gives an overview of the methodology and the flow of the processes involved.
The methodology and format of the presentation results would satisfy the requirements of the EC Directive on Energy Performance of Buildings 2002/91/EC.
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Lighting Energy Requirements
Calculated
Metered
methodComprehensive
methodQuick
method
Metered
Real data Standard data
Any period
Annual basedAnnual based
Monthly based
Hourly based
Common calculation methodology
Dependency factors t, FD F
O, A,
Figure 1 — Flow chart illustrating alternative routes to determine energy use
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1 Scope
This standard specifies the calculation methodology for the evaluation of the amount of energy used for lighting in the building and provides the numeric indicator for lighting energy requirements used for certification purposes. This standard can be used for existing buildings and for the design of new or renovated buildings. It also provides reference schemes to base the targets for energy allocated for lighting usage. This standard also provides a methodology for the calculation of dynamic lighting energy use for the estimation of the total energy performance of the building.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
EN 12193, Lighting and lighting — Sports Lighting
EN 12464-1, Light and lighting — Lighting of work places — Part 1: Indoor work places
EN 12665, Light and lighting — Basic terms and criteria for specifying lighting requirements
EN 13032-1, Lighting applications — Measurement and presentation of photometric data of lamps and luminaires — Part 1: Measurement and file format
EN 60598, Luminaires
EN 60570, Electrical supply track systems for luminaires
EN 61347, Lamp control gear
3 Terms and definitions
For the purposes of this European Standard, the following terms and definitions apply.
3.1 control gear components required to control the operation of the lamp(s)
3.2 power
3.2.1 luminaire input power (Pi) electrical power from the mains supply consumed by the lamp(s), control gear and control circuit in or associated with the luminaire, measured in watts
NOTE The luminaire rated input power (Pi) for a specific luminaire can be obtained from the luminaire manufacturer.
3.2.2 parasitic power (Pp) standby power for controls and battery charging power consumed by the emergency lighting system, measured in watts
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3.2.3 total installed lighting power in the room or zone (Pn) luminaire input power of all types of luminaires in the room or zone, measured in watts
3.3 time
3.3.1 operating time (to) default number of operating hours of the luminaire
NOTE This number is determined depending on the building use.
3.3.2 standard year time (ty) time taken for one standard year to pass, taken as 8 760 h
3.3.3 effective usage hours (tu) effective usage hours of the lighting systems
3.3.4 operating time of the parasitic power (tp) effective usage hours of the parasitic power
3.4 area
3.4.1 total useful floor area of the building (A) floor area inside the outer walls excluding non-habitable cellars and un-illuminated spaces, measured in m2
3.4.2 total floor area total illuminated floor area of the building, measured in m2
NOTE This area may be calculated using either external or internal building dimensions, resulting in gross and net reference floor area. Only one type of reference area is used throughout the calculations and certification process. The type is defined at the national level.
3.4.3 control zone (AS) largest area controlled by one switching device in a room, measured in m2
3.5 dependency factors
3.5.1 daylight dependency factor (FD) factor relating the usage of the total installed lighting power to daylight availability in the room or zone
3.5.2 occupancy dependency factor (FO) factor relating the usage of the total installed lighting power to occupancy period in the room or zone
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3.6 built-in luminaries all installed luminaires provided for the purpose of illumination in the building
3.7 n numeric indicator of lighting (LENI) the lighting energy numeric indicator (LENI) is a numeric indicator of the annual lighting energy required to fulfil the illumination function and purpose in the building requirements divided by the total area of the building in question
NOTE The LENI can be used to make direct comparisons of the lighting energy used in buildings that have similar functions but are of different size and configuration.
4 Calculating energy used for lighting
4.1 Annual total energy used for lighting
An estimate of the annual lighting energy required to fulfil the illumination function and purpose in the building (Wlight) shall be established using the following formula.
( ) ( ) ( ){ } × + × × + × =
∑ ∑pn p n D D O n Olight 1000
P t P t F F t FW kWh/year
NOTE It should be noted for existing buildings that Wlight can be established more accurately by directly and separately metering the energy supplied to the lighting (see clause 5).
4.2 Lighting energy numeric indicator (LENI)
The Lighting Energy Numeric Indicator (LENI) shall be established using the formula:
= lightLENIWA
kWh/m2/year
5 Metering
5.1 General
If possible, lighting consumption shall be separately measured using a meter to give a more accurate indication of the efficiency of the controls. Measurement shall be made using one of the following methods:
a) kWh meters on dedicated lighting circuits in the electrical distribution;
b) local power meters coupled to or integrated in the lighting controllers of a lighting management system;
c) a lighting management system that can calculate the local consumed energy and make this information available to a building management system (BMS);
d) a lighting management system that can calculate the consumed energy per building section and make this information available in an exportable format, e.g. a spread sheet format;
e) a lighting management system that logs the hours run, the proportionality (dimming level) and relates this to its internal data base on installed load.
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The lighting management system shall make the measurements available to a BMS for further reporting or available in an exportable format.
NOTE The output is a figure that can be calibrated within certain accuracy to the real kilowatt hours consumption during commissioning of the building.
5.2 Load segregation
The network of a BMS/lighting management system shall provide the same function as segregation in the power distribution.
5.3 Shared and remote metering
1) Shared or remote metering is recommended completely segregated power distribution systems.
2) Shared or remote metering can also be used for more intelligent (Lighting management) systems to provide data.
NOTE Annex A gives examples of metering methods.
6 Calculation of lighting energy in buildings
6.1 Building types
Using the quick method for estimation of energy use (6.3) shall be permitted for the types of building listed.
a) Offices.
b) Education buildings.
c) Hospitals.
d) Hotels.
e) Restaurants.
f) Sports facilities.
g) Wholesale and retail services.
h) Manufacturing factories.
i) Other types of energy consuming buildings.
NOTE The comprehensive calculation method (6.4) may be applied to any type of building in any location.
6.2 Installed lighting power
NOTE There are two forms of installed power in buildings: luminaire power, which provides power for functional illumination and parasitic power, which supports the control system and charges power for the standby condition.
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6.2.1 Luminaire
If a luminaire has a translucent covering for protecting the lamp or other component parts against solid objects and moisture it shall not interfere with light output to the surroundings.
Luminaires and electrical components of luminaires shall be designed and constructed in accordance with the relevant parts of EN 60598, EN 60570 and/or EN 61347.
6.2.2 Luminaire power (Pi)
The total rated input power (in watts) of a specific luminaire shall be measured in accordance with annex B.
NOTE The total rated input power “Pi” for a specific luminaire can be obtained from the luminaire manufacturer for specified conditions.
6.2.3 Parasitic power (Pp)
Parasitic power shall be measured in accordance with annex B.
6.3 Quick method
For a quick estimation of the annual energy consumption for typical building types (see 6.1) the following formula shall be used.
NOTE 1 The default values given in Tables 1 to 3, in general, will yield a higher LENI than the comprehensive method.
u nlight 6
1000t P
W A= + ∑ kWh/year
where
tu = (tD x FD x FO) + (tN x FO) and is the effective usage hour
Pn is the total luminaire power in a zone
tD is the daylight time usage from Table 1
tN is the non-daylight time usage from Table 1
FD is the daylight dependency factor from Table 2
Fo is the occupancy factor from Table 3
A is the total area of the building.
NOTE 2 The figure 6 is comprised of 1 kWh/m²/year for the emergency lighting charging energy and 5 kWh/m²/year for the controls stand-by energy and used when applicable.
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Table 1 — Default annual operating hours for relating to building type
Building types Default annual operating hours
tD tN ttotal
Offices 2 250 250 2 500
Education buildings 1 800 200 2 000
Hospitals 3 000 2 000 5 000
Hotels 3 000 2 000 5 000
Restaurants 1 250 1 250 2 500
Sports facilities 2 000 2 000 4 000
Wholesale and retail services
3 000 2 000 5 000
Manufacturing factories 2 500 1 500 4 000
Table 2 — Impact of daylight for buildings with controls
Daylight impact
Building type Control type FD
Manual 1.0
Photo cell dimming – constant illuminance 0.9
Office, sports, manufacture Photo cell dimming – constant illuminance with
daylight sensing 0,8
Manual 1.0 Hotel, restaurant, retail
Photo cell dimming – constant illuminance 0.9
Manual 1.0
Photo cell dimming – constant illuminance 0.9
Education, Hospitals
Photo cell dimming – constant illuminance with daylight sensing
0.7
NOTE Assumes at least 60 % of the lighting is under the given control
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Table 3 — Impact of occupancy for buildings with controls
NOTE Automatic controls with presence sensing should be allocated at least 1 per room and in large areas and at least one per 30 m2.
6.4 Comprehensive method
The comprehensive method allows for the accurate determination of the lighting energy estimations as given in 6.4.1 to 6.4.11.
6.4.1 Calculation
When using the comprehensive method of lighting energy estimations the following formula shall be used.
NOTE This method may be used for any periods and for any locations provided that the full estimation of occupancy and daylight availability is predicted.
( ) ( ) ( ){ } × + × × + × =∑ ∑pn p n D D O n O
light 1000
P t P t F F t FW kW/year
NOTE In zones without daylight, FD = 1 except where constant illuminance controls are used when FD = 0.9 including the impact at night.
6.4.2 Determination of FD
The daylight penetration into a building shall be determined in accordance with the procedures specified in 6.4.2 to 6.4.11.
NOTE 1 The values given in Annex C can be used to account for location and climate dependent aspects of daylight supply.
NOTE Other daylight supply systems that rely on enhancements to increase or make possible daylight penetration beyond the perimeter zones are available. These are not explicitly covered in this standard but may be considered by calculating daylight factor or other validated methods for the calculation of FD.
Occupancy impact
Building type Control type FO
Manual 1.0 Office Education Automatic ≤ 60 % of the connected load 0.9
Retail, Manufacture, Sports and Restaurant
Manual 1.0
Hotel Manual 0.7
Hospital Manual (some automatic control) 0.8
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Determine building zones
For each zone
Daylight penetration
Obstruction
No Yes
F D = 1
No Yes
Compute Obstruction Index
IO
IOOB IOO
V IOSF IOCA . ( equation 8)
IO = 1
Compute Transparency index IT ( equation 4)
Compute Depth Index IDe ( equation 5)
Classify Daylight penetration I = f
(I O,
I T, IDe ) (table 4)
Determine Daylight supply F DS = f (I,
E m , Location ) (table C1, C2)
No Yes Non - standard operating hours
Determine correction factor c Dt (Annex C 1.2)
No YesMonthly method
F D = 1 - F DS *F
DC
( equation 1)
Determine F DC (table C3)
Determine monthly daylight supply factor
F DS, month = F DS c DS , month ( equation 16)
For each month
Determine impact of control system F DC (table C3)
F D, month = 1 - F DS, month *F
DC ( equation 1)
Figure 2 — Flow chart illustrating the determination of the daylight dependency factor FD,n in a zone
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6.4.3 Energy Reduction through Daylight, Factor FD,n
The potential energy consumption reduction due to daylight supply in zone n, Factor FD,n, shall be determined using the following formula
D,n D,S,n D,C,n1F F F= − ⋅ (1)
where
FD,S,n is the Daylight Supply Factor, which takes into account the general daylight supply in zone n. It represents for the considered time interval the contribution of natural light to the total required luminous exposure in the considered zone.
NOTE 1 The higher the value the less energy is consumed.
FD,C,n is the Control Factor, which accounts for potential of daylight depending artificial lighting control system to exploit daylight supply in Zone n [-].
NOTE 2 The higher the value the less energy is consumed.
The Factor FD,n can be determined for any time period, e.g. on an annual, monthly, or hourly basis. FD,n has to be weighed with the operation time at daytime tD from Table 1 or be calculated. tD can be obtained according to the method defined in Annex C .
The product can also be regarded as an effective (i.e. equivalent full power) operation time:
tD,eff,n = tD,n * FD,n (1)
FD can be determined by other validated procedures providing they work on an integral basis for the considered time periods (annual, monthly, hourly) at the point of reference of the artificial lighting control system.
6.4.4 Daylight Supply Factor FDS,n
a) The Daylight Supply Factor FD,S,n shall be determined in three steps: segmentation of the building into zones/areas with and without daylight supply;
b) determination of the room parameters, facade geometry, and outside obstruction estimation of daylight penetration into the interior space;
c) prediction of the energy saving potential depending on the local - site dependent - daylight supply based on the estimation of daylight penetration.
NOTE 6.4.5 and 6.4.6 are linked methods to estimate daylight penetration and alternative validated methods for calculation of daylight penetration may be used.
6.4.5 Determination of operation hours profiting from daylight
For a given operating start time tstart and a given end time tend the following procedure, based on a monthly method, shall be used to obtain for a certain latitude ϕ the number of daytime hours tD and the number of night times hours tN. This method shall be used for detailed analysis replacing values in Table 1.
The Number N of days within each month is given by
The times tD,i and tN,i for each month are obtained by
tD,i = Ni * Cwe [(tend-tstart)-(tbs,i + tas,i)]
and tN,i = Ni * Cwe [ (tbs,i + tas,i)]
with Cwe = 5/7 representing a correction factor for weekends. If weekends are not accounted for Cwe = 1. Times before sunrise tbs,i and after sunset tas,i are obtained by
Annual daytime and night time hours are to be obtained by summing up over the monthly values:
12
D D,i1i
t t=
= ∑
and
12
N N,i1t
it
== ∑
6.4.6 Zoning, building segmentation
Rooms having windows and/or skylights, or parts of rooms adjacent to the facade, with identical daylight control systems shall be grouped to form a daylight zone with floor area AD. The factor FD,n shall be determined for each zone, following the procedure below.
Rooms without windows or skylights shall be assigned the value FD,n = 1
The considered zone shall be segmented into two parts:
one surface area AD, which can benefit from natural lighting
one surface area ΣAtot-AD, which cannot benefit from natural lighting. FDS coefficient of is 0, no further calculations have to be performed.
Vertical facades
The depth of a room shall be defined as the perpendicular distance from the interior surface of the window wall to a separating internal wall.
When buildings have floors or zones:
with depth to height ratio of less than 3.5 : 1 (i.e. approximately 10m deep);
where windows are on the facades perpendicular to the direction that the depth is specified;
they are considered as entirely exposed to daylight. In this case equation 3 applies.
AD,n = Σ Atot (2)
Where rooms with windows in walls at right angles to each other (corner rooms), the wall with the larger window area shall be used in the calculation.
For buildings not complying with these criteria, the part which can benefit from natural lighting comprises:
zones having wall openings and being less than 5 m deep,
Parts of premises located less than 5 m from a wall opening for premises more than 5 m deep, as long as the luminaires illuminating such parts are controlled independently,
Where the fenestration high point is located more than 4. 5m above the floor, the depth of the daylight zone will be extended up to 10 m.
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Horizontal Facades
The zoning for horizontal facades is under consideration.
Facades with different inclines
Facades with an inclined to less or equal to 45° to the Horizon are to be considered as horizontal facades. Facades with an incline of more than 450 are to be considered as vertical facades.
6.4.7 Daylight Penetration
The daylight supply to any part of a building or room depends on the geometric boundary conditions described by the transparency index IT, the depth index IDe, and the obstruction index IO. The type of transparent facade system employed influences the penetration of daylight.
A. Transparency index I T
The transparency index IT of the part of the building, which can benefit from natural lighting, shall be defined by:
IT = ΣAll windows AG/ AD [-] (3)
where
AG Glazed surface of the wall openings,
AD Total surface area of the premises of the building benefiting from natural lighting.
B. Depth index I De
Vertical facades
The depth index IDe of the part of the building, which can benefit from natural lighting IDe shall be defined by:
IDe = room depth/height of top of window above working plane (4)
Horizontal facades
A detailed measure for roof lights is under consideration.
C. Obstruction Index I O
The obstruction index IO accounts for obstruction of light which would otherwise be incident on the facade e.g. horizontal overhangs, other buildings and natural obstacles such as trees and mountains. The obstruction index is applicable for vertical facades only.
The standard does not consider obstructions of horizontal facades. The obstruction index IO shall be obtained using the following formula:
The simple model requires appropriate abstractions of real building geometries. It is in main parts analogue to models describing the impact of obstructions on solar energy penetration into buildings used in thermal methods (EN 832). Generally, a conservative estimate is given. To make better illumination levels eligible, separate calculation procedures have to be employed. IO,OB, IO,OV, IO,BL, IO,CA can be obtained as follows:
Linear Obstructions, IO,OB
γοob
Figure 3 — Definition of obstruction angleγγγγO,ob
IO,OB = cos(1,5 * γO,Ob) [-] (6)
where
γO,OB Obstruction angle from horizontal [°]
Overhangs, IO,OV
γοov
Figure 4 — Definition of horizontal overhang angle gO,OV.
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IO,OV = cos(1,33 * γO,OV) [-] (7)
where
γO,OB Horizontal overhang angle, measured at middle of window from zenith [°]
Overhangs IO,SF
γοVF
Figure 5 — Definition of vertical overhang angle gO,VF.
IO,VF = 1 - γO,VF/300° [-] (8)
where
γO,VF Vertical overhang angle, measured at middle of window from the facade [°]
Courtyards and Atria, IO,CA
kAT,1
kAT,2
τAt
Figure 6 — Quantities for defining the well-index
IO,CA = τAt kAT,1 kAT,2 kAT,3 (1 –0,85 wi) (9)
where
τAt transmission factor of atrium glazing kAT,1 factor accounting for frames of atrium roof kAT,2 factor accounting for dirt on atrium roof
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kAT,3 factor accounting for not normal light incidence on facade (0,85, in general sufficient for t d d l i )wi Well – Index of atrium, courtyard configuration [-]
where the well index is defined as
wi = hAt*(lAt+wAt)/(2*lAt*wAt)
hAt Height of atrium or courtyard [m]
lAt Length of atrium or courtyard [m]
wAt Width of atrium or courtyard [m]
D. Determination of Daylight penetration
Classification of Daylight
Penetration
According to 6.4.2.4
(Approx. Daylight factor)
Correlation with annual
(monthly) Lighting Energy
Demand
Classification of Daylight
Penetration
by Daylight factor
(external method)
Lighting Energy Demand
Figure 7 — Steps to determine daylight penetration
From the geometric indices IT, IDe and IO the access of the zone to daylight can be estimated for the initial facade opening
Ir = (4.13 + 20.0 x IT – 1.36 x IDe) IO [%] (10)
Ir Index accounting for daylight penetration for facade openings without fenestration and sun-protection system. [%]
The impact of the fenestration and shading system on the indoor lighting levels shall be determined by
using facade type dependent correlations of Ir with the expected energy demand, i.e. methods deriving the daylight supply factor FDs as function of the facade system. An example is provided in annex C.2.2; or
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where these dependencies are not available a simplified estimation, correlating static fenestration properties with the expected energy demand.
If only static transmission properties are known of the facade system, equation (10) can be extended such the daylight penetration is calculated by
I= Ir τ k1 k2 k3 (11)
τ direct. hemispherical Transmission of fenestration k1 factor accounting for frame of fenestration system k2 factor accounting for dirt on glazing k3 factor accounting for not normal light incidence on facade (the value of 0.85, in general
sufficient for standard glazing)
Depending on how to judge the impact of the fenestration and sun-protection system, using either Ir or I, the daylight penetration can be rated according to Table 4.
Table 4 — Daylight penetration as function of a simple index based and a daylight factor based estimation of daylight conditions (i.e. access of the zone to daylight).
Classification Ir I
Daylight Penetration (Access of the zone to daylight)
Ir > 6 % I > 3 % Strong
6 % > Ir > 4 % 3 % > I > 2 % Medium
4 % > Ir > 2 % 2 % > I > 1 % Weak
Ir < 2 % I < 1 % None
Under specified boundary conditions, Ir and I can be taken as an approximation of the daylight factor. Detailed calculation using more accurate modelling of geometric relations, can be used to determine the daylight penetration. The reference value for the daylight factor of the considered zone is the average over the centre axis of the considered area, parallel to the considered facade.
6.4.8 Daylight supply
According to annex C.1.1 FD,S can be determined as a function of the daylight penetration classification I according to equation (14) and Table C1, the maintenance value of illumination, the climatic properties and control strategy. Other occupation times may be regarded considering C.1.2. Where available suited and validated more detailed methods accounting for facade systems, facade orientation etc. may as well be employed. Appendix C.2 contains a simple and more refined method exemplarily for the location of Frankfurt, Germany. Daylight penetration has to be classified as according to Ir in equation (13) and Table C1.
6.4.9 Other operation times
FD,S values in Table C1 are supplied for daily operating hours from 8°°-17°° as for standard office hours. Different operating hour intervals may lead to different daylight supply. Annex C provides methods for calculating correction factors.
FD,S,n = FD,S,n * cD,T, n (12)
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cD,T ,n correction factor accounting for different operation time intervals.
6.4.10 Monthly Method
FD,S,n represents an average indicator for the annual saving potential. The annual saving potential FD,S,n can be redistributed on to monthly saving potentials:
FD,S,month,n= FD,S,n* cD,S,month (13)
cD,S,month redistribution factor for the specific month [-]
Default values of cD,S,month can be determined according to the method specified in appendix C.1.4. According to 6.4.2.6: for operating time intervals around noon the product FD,S,month,n * cD,T might exceed one. FD,S,month,n is then to be set to one, i.e. corresponding to 100 % daylight supply.
6.4.11 Daylight dependent artificial lighting control FDC
The daylight dependent artificial lighting control systems can significantly reduce the total energy demand of the lighting installation. Some of the different possible control strategies are:
1) Manual On / Manual Off: The lighting is switched on and off manually.
2) Manual On / Continuous dimming: The lighting is switched on manually and continuously dimmed in function of the instantaneous daylight availability. Manual On / continuous dimming with switch-off: The lighting is switched on manually, continuously dimmed in function of the instantaneous daylight availability and fully switched off when ample daylight is available, i.e. no residual lamp power.Annex C.1.3 provides default values for FDC.
6.5 Determination of occupancy time, FO
The determination of FO should me made by one of the methods in 6.5.1 to 6.5.3.
6.5.1 Default value
Whatever type of control system is used, FO may be taken as 1.0 in which case, no further analysis is needed. Otherwise, follow the rules below.
6.5.2 Detailed determination of FO
6.5.2.1 FO = 1
Take FO shall always be equal to 1 in the following cases: If the lighting is switched on 'centrally', i.e. in more than 1 room at once (e.g. a single automatic –
for instance with timer or manual switch for an entire building, or for an entire floor, or for all corridors, etc.). This applies whatever the type of 'off-switch' (automatic or manual, central or per room, etc.).
If the area illuminated by a group of luminaires that are (manually or automatically) switched together, is larger than 30 m2 Exceptions are meeting rooms where this area limitation does not apply (see below).
6.5.2.2 FO ≤ 1
In the following cases, a more favourable value than 1 may be obtained:
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in meeting rooms1) (whatever the area covered by 1 switch and/or by 1 detector), as long as they are not switched on 'centrally', i.e. together with luminaires in other rooms (see above)
in other rooms, if the area illuminated by a luminaire or by a group of luminaires that are (manually or automatically) switched together, is not larger than 30 m2, and if the luminaires are all in the same room. In addition, in the case of systems with automatic presence and/or absence detection the area covered by the detector should closely correspond to the area illuminated by the luminaires that are controlled by that detector.
In both cases, also the conditions with respect to timing and dimming level outlined below shall be fulfilled. If these conditions are not satisfied, F0 = 1 In these instances, FO shall be determined as follows2): for 0.0 ≤ FA < 0.2
FO = 1 – (1 – FOC) FA / 0.2 (equation 1) for 0.2 ≤ FA ≤ 1.0
FO = FOC + 0.2 – FA (equation 2) In these expressions:
FOC is a constant. Its value is fixed as a function of the lighting control system, as given in Table 5. FA is the absence factor. Its value is determined either on building or on room level3. Unless other values are known or specified, sample values are given in Table 6.
1) These include e.g. classical meeting rooms in office buildings and hotels, classrooms, cinemas, pubs,
2) For e.g. programming purposes, this can be rewritten as a single expression:
FO = min[(1 – (1 – FOC) FA / 0.2); (FOC + 0.2 – FA)] 3 Its value can range from 0 to 1. The absence factor corresponds to the fraction of the reference operating time (tD + tN) that a building or room is not in use. (Sleeping hours can usually be considered equivalent to absence.) When the building or the room would be permanently occupied during the reference time, FA would be 0.0. As a limit value, if a building or room would nearly never ever be entered into, FA would tend towards 1.0.
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Table 5 — FOC values4
Systems without automatic presence or absence detection FOC Manual On/Off Switch 1.00 Manual On/Off Switch + additional automatic sweeping extinction signal 0.95
... ... Systems with automatic presence and/or absence detection
Auto On / Dimmed 0.95 Auto On / Auto Off 0.90 Manual On / Dimmed 0.90 Manual On / Auto Off 0.82 ... ...
For systems without automatic presence or absence detection the luminaire shall be switched on and off with a manual switch in the room.
An automatic signal may also be included which automatically switches off the luminaire at least once a day, typically in the evening to avoid needless operation during the night.
For systems with automatic presence and/or absence detection the following situations shall be valid:
'Auto On / Dimmed': the control system switches the luminaire(s) automatically on whenever there is presence in the illuminated area, and automatically switches them to a state with reduced light output (of no more than 20 % of the normal 'on state') no later than 5 minutes after the last presence in the illuminated area. In addition, no later than 5 minutes after the last presence in the room as a whole is detected, the luminaire(s) are automatically and fully switched off.
'Auto On / Auto Off': the control system switches the luminaire(s) automatically on whenever there is presence in the illuminated area, and automatically switches them entirely off no later than 5 minutes after the last presence is detected in the illuminated area.
'Manual On / Dimmed': the luminaire(s) can only be switched on by means of a manual switch in (or very close to) the area illuminated by the luminaire(s), and, if not switched off manually, is/are automatically switched to a state with reduced light output (of no more than 20% of the normal 'on state') by the automatic control system no later than 5 minutes after the last presence in the illuminated area. In addition, no later than 5 minutes after the last presence in the room as a whole is detected, the luminaire(s) are automatically and fully switched off.
'Manual On / Auto Off': the luminaire(s) can only be switched on by means of a manual switch in (or very close to) the area illuminated by the luminaire(s), and, if not switched off manually, is automatically and entirely switched off by the automatic control system no later than 5 minutes after the last presence is detected in the illuminated area.
4 This table gives some values for FOC as a function of the lighting control system. For other types of control systems, other values may be determined; this table is open-ended. The "off-time" of the luminaires with respect to the reference operating time (tD + tN) can never be more than FA. (Remember "off-state" due to daylight is not considered here but included in FD.) Therefore FO can never be more than 1-FA. This implies that FOC must be at least 0.80.
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Table 6 — Sample FA values
Overall building calculation Room by room calculation
Manual On / Auto Off 1.000 0.910 0.820 0.720 0.620 0.520 0.420 0.320 0.220 0.120 0.020
… … … … … … … … … … …
6.5.3 Explanatory note: motivation for the choice of FO functions
The aim of the use of the FO factor is to give a (rudimentary) appreciation of the energy efficiency of the lighting control system. FO depends on 2 factors:
the type of control system
the degree of absence of the room or the building.
The simple model (i.e. the shape of the curves) is purely empirical.
FO decreases as the room/building is less and less occupied, i.e. as FA becomes larger. FO shall always be larger than 1-FA. Thus FOC shall be at least 0.80.
For values of FA below 0.2, the slope of the curves is different to make them all converge to FO = 1.0 for FA = 0.0. For values of FA above 0.2, the slope of the curves is identical, i.e. all curves are parallel. In this range the difference in FO among control systems is thus independent of the absence level.
Also the values of FOC are purely empirical.
Following qualitative (based on the real system monitoring) considerations have been integrated:
Complementing manual on/off switches with an additional 'automatic sweeping extinction signal', avoids that luminaires remain alight after all users have left the building (typically at night). So these systems get a better appreciation than purely manual on/off systems.
Automatic systems that remain alight in a dimmed state5 when there is no more presence in the illuminated area, consume more than those that switch off completely, hence a higher FOC and FO factor
Systems that automatically switch on, often do so when it is not needed. For instance, when a person briefly enters a room to pick up a forgotten item, to distribute mail, etc., he will usually not need the artificial lighting, but the system will switch on anyway. Many presence sensors also detect through open doors motion in corridors of passers-by, every time needlessly switching on
5 This control type with dimming was added on request of the lighting industry, because in large rooms (e.g. landscape offices) building users often object to the fact that the light completely switches off in other, unoccupied parts of the room. There is thus a real demand and application for this type of systems.
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the lights in the room, also after standard occupation hours (e.g. regular passage of a cleaning crew through a hall, a few late workers who go and see each other, go to the printer, copier, coffee machine or toilets, etc.). Therefore FOC is more favourable (smaller) for systems that only switch on when the user commands so through a manual switch6.
(Daylight influence on switching behaviour –during room occupation time– is taken into account in the factor FD.)
7 Other considerations
In some locations the outside lighting may be fed with power from the building. This lighting may be used for illumination of the facade, open-air car park lighting, security lighting, garden lighting, etc. These lighting systems may consume significant energy and it should be noted that they are fed from the building but will not be included in the Lighting Energy Numeric Indicator or into the values used for heating and cooling load estimate.
NOTE If lighting metering is employed, these loads maybe included in the measured lighting energy.
IEC 60050-845/CIE 17.4, International lighting vocabulary.
6 An additional advantage of systems that are switched on manually is that they do not need to detect entry into the room, but only exit. The detection system can therefore be switched off together with the luminaires. In many instances the 'off-hours' are a substantial fraction of the year. This configuration therefore constitutes a major means to reduce parasitic power consumption, apart from reducing the installed parasitic power itself.
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Annex A (informative)
Metering of Lighting circuit
1
2
3
4
57
6
8
Key
1. Lighting circuits 5. Floor 1 2. Power circuits 6. kWh lighting 3. Floor 3 7. Primary power 4. Floor 2 8. kWh other
Figure A.1 — kWh meters on dedicated lighting circuits in the Electrical distribution
In the example of Figure A.1, the kWh meter for lighting is in parallel to the kWh meter for the rest of the electrical installation. So the consumption for the total building is in this case the sum of both meters.
Wlight = Wlight metered in kWh/year
In the example of Figure A.2, the kWh meters for lighting distributed over the different floors are placed in series with the central kWh meter of the building. In this case the central kWh meter registers the total energy consumption including the lighting consumption.
Formula for monitoring:
Wlight = Wlight metered = ∑all floors (kWh @ date – kWh @ (date – 12 months)) in kWh/year
Local kWh meter values (as in Figure A.2) could be read and totalled by a Building Management System. No corrections for occupancy rate or control types are necessary.
Figure A.2 — Building with segregation of lighting circuits per floor and separately measured
1
2
3
4
A
1
2
3
4
Key
1. Bus line 2. 230 volt power 3. Light 4. Luminaires
Figure A.3 — Volt and ampere meters coupled to inputs of the light controllers
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Local power meters coupled to or integrated in the lighting controllers of a lighting management system. Information on the local consumed energy is made available to a building management system.
In Figure 3, volt and ampere meters or watt meters are put on the power input of every lighting controller. The individual lighting controllers calculate the local consumed energy by integrating these values over time.
These values are made available via the bus line to either the central computer of the lighting system or the central computer of the building management system. The central computer can process this information and present the consumed energy figures e.g. per area per month and / or for the total lighting of the building over a period of 12 months in an exportable format, e.g. Excel.
NOTE a) Lighting consumption of fixtures not controlled by the lighting control system is not measured.
b) Lighting consumption of fixtures indirectly controlled via external contactors is not measured.
A lighting management system that logs the hours run, the proportionality (dimming level) and relates this to its internal data base on installed load. The lighting management system makes this information available to a BMS for further reporting, or it can give the information in an exportable format.
The lighting controller sums the time per lighting load proportionality per output and makes these values available via the bus line.
NOTE 1 Lighting consumption of fixtures not controlled by the lighting control system is not measured.
NOTE 2 Lighting consumption of fixtures indirectly controlled via external contactors is measured.
NOTE 3 Calibration of this calculation method can be done by installing (temporary) a kWh meter in one of the supply groups for lighting and then calculate for a certain time period on one area equal to this supply group and compare the results. From this comparison a correction factor can be established by which the calculated results could be corrected when found necessary.
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Annex B (informative)
Measurement method of total input power of Luminaires and
associated Parasitic power
Introduction
The rated luminaire input power and the rated parasitic input power should be declared by the manufacturer so that the calculation of the energy performance of the building with respect to lighting requirements may be made with certainty accurately. The rated power values should be rounded to the nearest whole number for 10 W and above and should be to two significant figures when below 10 W. Both should be within an accuracy of 5 %. It is accepted that some variations will occur between luminaires of the same family but made at different times.
B.1 Requirement for tests
The object of the test is to measure the luminaire total input power during normal operation and the associated parasitic power (the standby input power for controls, sensing devices and charge power for emergency lighting circuits) at standard reproducible conditions that are close to the conditions of service for which the luminaire is designed. Ideally, these luminaire electrical measurements should be made during the photometric tests.
B.2 Standard test conditions
The test conditions used for photometric measurements as defined in EN 13032-1:2003 sections 5.1, 5.2 and 5.3 should apply.
B.3 Electrical measuring instruments
Voltmeters, ammeters and wattmeter’s should comply with the requirements for Class Index 0.5 or better (precision grade)
B.4 Test luminaires
The luminaire should be representative of the manufacturer’s regular product. The luminaire should be mounted in the position in which it is designed to operate in.
B.5 Test voltage
The test voltage at the supply terminals to the luminaire should be the declared rated voltage of the luminaire.
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B.6 Luminaire input power (Pi)
The luminaire input power should be the declared rated power of the luminaire Pi, including losses in all lamp(s), ballast (s) and other component (s), measured in normal full output operating mode or at maximum light output if the luminaire includes a dimming control gear.
B.7 Parasitic input power (Ppi)
The luminaire parasitic input power should be the declared rated power of the luminaire Ppi measured with the luminaire operating in standby mode. For controlled luminaires this is the input power to the detectors, for emergency luminaires this is the steady state input power for charging the batteries.
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Annex C (informative)
Daylight
C.1 Default values
C.1.1 Daylight supply, Factor FD,S,n
The provided values physically represent the relative utilizable luminous exposure and are derived with the method described in Appendix C.2.1. The values specified in Table C.1 are annual values, for daily operating hours from 8°°-17°°.
If daylight penetration is rated “None” in Table 4 the following applies FD,S,n = 0, i.e. FD,n = 1.
Table C.1 — Daylight supply factor FD,S for vertical facades as function of daylight penetration according to Table 4 into zone n and maintained illuminance Em.
Daylight supply factor FD,S
ranges from [0-1]
Em=300 lx Em=500 lx Em=>750 lx
Weather
Station / Location
weak medium strong weak medium strong weak medium strong
FD,C values for specific systems can be determined by measurements or by calculation. FD,C represents the ratio of the real system power consumption to the optimal power consumption, which is directly proportional to the relative utilizable luminous exposure. The relative utilizable luminous exposure corresponds to an ideal control system, which supplies over time at maximum the difference between task illuminance and illuminance by daylight at the reference point. The ratio FD,C does not consider power consumption of the control gear itself.
As function of the daylight supply Table C.2 provides the correction factor FD,C.
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Table C.2 — FD,C for vertical facades as a function of daylight penetration
FD,C,n as function of daylight penetration and Required Illuminance
Monthly distributions can either be computed using the method as described under C.2 on a monthly basis or any other validated approach or using monthly correction factors cD,S,i weighing the daylight supply factors FD,S,n. The correction factors are listed in Table C.3.
cD,S,i = ai + [bi sin((i- ci)/ di * 180°) (14)
cD,S,i redistribution factor for the specific month i, months denoted numerically [-]
C.1.5 Determination of tD and tN operating hours
Table C.3 — Monthly correction factor cD,S,i as function of daylight penetration
Factor FD,S,June,n for June for a medium daylight penetration at site Frankfurt can for instance be obtained from the annual Factor FD,S,n by
FD,S,June,n= FD,S,n* cD,S,6 = FD,S,n*1,35 (values bigger than one are set to one).
C.2 Methods for determination of FDS
C.2.1 Simple Approach
The described procedure has been used to derive daylight supply values FDS in Table C.1. The underlying climatic data are taken from TRY / TMY. If the method is applied for additional sites, i.e. other than in Table C.1, climatic data should be used synchronic to data sets used in thermal standards / models. Instead of the described method any other validated method can be used to derive FDS values.
At any given time the power consumed by a lighting system may represented as a function of the required illuminance, the daylight falling on to the working plane within the space and the illuminance generated by the lighting system when it operating at full power. It is normal to use
Power Fraction = P(DI, Daylight, SA) (15)
Where:
P() Power consumed by the lighting as a function of output fraction
DI Design illuminance
Daylight Illuminance at point due to daylight
SA The illuminance produced by the system at full power
Function P() depends on the type of lighting control gear and the method used to control it.
Design illuminance and the illuminance produced by the system at full power are determined by the lighting requirements of the space and the design of the lighting.
Daylight is determined by two factors the daylight penetration into the building and the daylight availability.
By studying the record of diffuse daylight illuminance for a given place it is possible to calculate the probability of a given level of daylight at a given time in a given month. Thus a function F can be developed that is the probability of a given illuminance occurring during a particular month at a particular hour.
probability = F(I,H,M) (16)
Where
F () the probability of a given diffuse external illuminance
I the diffuse external illuminance
H the hour of the day
M the month of the year.
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Thus the fraction of full power consumed by a lighting system at a given hour in a given month is
max
0( , , ) ( , , )
I I
IPowerFraction F I H M P DI DF I SA
=
== × ×∑ (3)
Where
DF the daylight factor of the space
Imax the maximum illuminance that occurs at that time and date
For a complete year the
( ) (4) ),,(,,13651 max
1∑ ∑∑=
=
=
=
=
=
×××−
××=EndTT
StartTT
II
I
DecemberM
JanuaryMMd MHIFSAIDFDIP
StarttEndtDF
Where
Fd Factor for daylight
Start t Time that the building opens at the start of the day
End t Time that the building closes at the end of the day
M The month of the year
DM The number of days in month M
The power fraction function P() is dependant on the type of control system used. For systems where the lighting is switched off when the illuminance in the space due to daylight exceeds a certain threshold TS usually twice the design illuminance. The function P() has the following values for such systems:
( )( )
S
S
, , 1 when Daylight
, , 0 when Daylight
P DI Daylight SA T
P DI Daylight SA T
= <
= =>
For systems that dim the luminaires the exact value of the function P() depends on the type of control gear used but typically the following formula may be used.
( ) ( )
( ) 0,,:
8.02.0,,
:
==>
−×+=
<
SADaylightDIPDIDaylightwhen
SADaylightDISADaylightDIP
DIDaylightwhen
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C.2.2 Detailed approaches
Where methods are available the determination of FD,S can be performed on a more detailed level. FD,S can be obtained in addition to the
The factor FD,S,n and the correction factor CD,S,n as a function of the general daylight supply, the control system, the facade types and room orientation (N,E,S,W) can be organised into a table for specific climate conditions and periods.
C.2.3 Hourly method
Climatic data provided, the methods described in annex C.2.1 can be adapted to an hourly bases method.
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Annex ZA (informative)
Relationship between this European Standard and the Essential
Requirements of EU Directive 2002/91/EC of THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 16 December 2002 on the
energy performance of buildings
This European Standard has been prepared under mandate M 343 given to CEN by the European Commission to provide a means of conforming to Essential Requirements of the New Approach Directive 2002/91/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL OF 16 December 2002 on the energy performance of buildings.
Once this standard is cited in the Official Journal of the European Communities under that Directive and has been implemented as a national standard in at least one Member State, compliance with the normative clauses of this standard confers, within the limits of the scope of this standard, a presumption of conformity with the relevant Essential Requirements of that Directive and associated EFTA regulations.
WARNING — Other requirements and other EU Directives may be applicable to the product(s) falling within the scope of this standard.
