6 Lighting control

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6 LIGHTING CONTROL SYSTEMS,Actuators 161,Networks 163. Component analysis 169,6 5 Recommendations 169,6 6 Illustrations 172. 6 6 1 Illustration 1 NOSS National Office for Social Security Belgium 172. Control and management of the daylight 172, Control and management of the artificial light 172. 6 6 2 Illustration 2 The Berlaymont Building a louvres fa ade Belgium 173. Fa ade description 174,Control and management of the daylight 174. Control and management of the artificial light 176. 6 6 3 Illustration 3 Intecom project France 176,6 6 4 Illustration 3 DAMEX project Finland 178.
6 7 Conclusions 180,References 181,6 LIGHTING CONTROL SYSTEMS. 6 Lighting control systems,6 1 Introduction, A building can be compared to a system with a variety of physical processes interacting with each. other and with the environment From the control point of view it is considered as having multi. variant dynamic subsystems showing linear or non linear behaviours Environmental and occupancy. changes in a building increase the complexity of control operations Occupants not only impose. control goals related to thermal comfort visual comfort or indoor air quality but also influence the. building processes impacting indirectly on the control functions of the different processes HVAC. lighting etc, Due to the increase of environmental concerns lighting control systems will play an important role. in the reduction of energy consumption of the lighting without impeding comfort goals As. mentioned in the IEA Annex 31 IEA 2001 energy is the single most important parameter to. consider when assessing the impacts of technical systems on the environment Energy related. emissions are responsible for approximately 80 of air emissions IEA 2001 and central to the. most serious global environmental impacts and hazards including climate change acid deposition. smog and particulates Lighting is often the largest electrical load in offices but the cost of lighting. energy consumption remains low when compared to the personnel costs Thus its energy saving. potential is often neglected According to an IEA study IEA 2006 global grid based electricity. consumption for lighting was about 2650 TWh in 2005 which was an equivalent of 19 of total. global electricity consumption European office buildings dedicate about 50 of their electricity for. lighting whereas the share of electricity for lighting is around 20 30 in hospitals 15 in. factories 10 15 in schools and 10 in residential buildings EC 2007. Figure 6 1 Low energy building concept, The human requirements and the quality of the working environment are often expressed in terms of. thermal and visual comfort The optimal conditions of thermal comfort can be easily described as. the neutral perception of the interior environment where occupants do not feel the need for change. towards warmer or colder conditions Visual comfort however is not described easily Rather than. referring to a state of neutral perception of the interior environment it is perceived as receiving a. message Aspects such as daylighting glare luminance ratios light intensity and contact to the. outside have their influences on our perception of visual comfort. 6 LIGHTING CONTROL SYSTEMS, To fulfill the the requirements about comfort and energy efficiency building managers have.
implemented programs to reduce lighting energy requirements by installing more efficient light. sources and luminaires However this is not sufficient Lighting energy management has to provide. the optimal lighting level for the tasks being performed using the most efficient light source suitable. for the application and providing light only when and where it is needed This can be achieved by. using lighting control strategies and lighting control system The main purpose of these systems is to. reduce energy consumption while providing a productive visual environment This includes. Providing the right amount of light,Providing that light where it s needed. Providing that light when it s needed, In fact lighting control will depend on the considered zone Thus it is necessary to define the. following factors beforehand, The lighting needs level of illumination ambience etc. The task zone area position size disposition etc,The occupation time. The control needs of the user,6 2 Identification of the lighting control needs.
Development of a questionnaire for users, Lighting control is continuously evolving due to the constant evolution of requirements for visual. comfort and the increasing demand for lighting energy savings But there is often a lack of a clear. identification of the needs Annex 45 proposes hereby a questionnaire in order to help the designer. to identify the needs so that optimized solutions can be adopted Note that the identification of the. person answering the questionnaire is useful to understand the needs a building energy manager. pays more attention to the energy consumption and the energy savings than the occupant The. questionnaire available in appendix B should provide information on. The different practices within the building,The perception of the control barrier s. The needed control type,The controlled area, The flexibility and modularity of the lighting control system. For example the identification of the usages helps the designer to understand the way he has to. design the installation In a school an On Off system coupled with daylight dimming may be. adequate but in some offices it could be necessary to go one step further by integrating more. advanced techniques Similarly asking the perception of the people on the barriers of lighting. control may give information about the type and quality of lighting control system that can be. applied basic On Off switching system advanced daylight dimming system etc It is also. important to collect information about, Flexibility and modularity of the lighting system which gives information. about the future affectations of the building For some buildings e g. rented offices light structure walls are displaced and spaces are. reorganized regularly A change of the lighting control system then has to. be possible and easy,Maintenance scheme and needs,6 LIGHTING CONTROL SYSTEMS.
6 2 1 Specification book, The building owner needs an efficient lighting system. An objective evaluation of a system requires the definition of performance parameters In addition. it depends on baseline conditions to which the performance should be compared Performance. parameters include,Visual performance and comfort,Building energy use. Cost effectiveness,Ease of use,Maintenance,Flexibility versatility. Existing building constraints,System stability,Systems integration. An optimal system performance needs not only to reach a good performance with respect to saving. electrical energy but also to be accepted by the end user The end user may be disturbed by the. operation of the system and disable it A high user acceptance guarantees undisturbed operations. and consequently energy savings Existing buildings have specific constraints and requirements. There is a need to analyze the existing lighting system and to determine the upgrade possibilities. considering the technical and economical constraints Therefore an audit of the existing lighting. installation is necessary Advanced control requires elements such as electronic dimmable ballasts. and distributed electric indoor grids Similarly the use of wireless technologies switches sensors. etc is a suitable solution for retrofit so that the placement and exploitation costs can be limited. The occupant needs to control the system, Within the limits of comfort it is difficult to define exactly what the needs and priorities of the.
occupant are They vary from one occupant to another and also with time for the same occupant. For instance some occupants may be concerned by energy savings and some prefer better. algorithmic lighting scenes even if it requires more energy and generates higher costs Therefore it. is recommended that the occupant should have the possibility to change the system s behaviour. according to his will,The occupant needs to understand the system. The user acceptance of a lighting control system is better if the system and its working principle. have been explained On site visits by practitioners and informal discussions with end users showed. that about 90 of them accept the system operation if they know understand what its aims and. working principles are It has also been demonstrated that occupants react to a need a specific. condition but not necessary to the disappearance of this need For example if an occupant switches. on the lights due to a sudden obstruction of the sun the probability that he will switch off when the. high daylight levels have turned low,The lighting control system must be easy to use. The usability of the system must be defined to address all the types of users building operators. occupants facility managers maintenance teams installers etc Usability expresses the quality of. the experience of an user when interacting with a system. 6 LIGHTING CONTROL SYSTEMS, It is the combination of factors affecting the experience of the user with the product or system. a Ease of learning, How quickly can an untrained user learn to operate the system sufficiently. b Efficiency of use, How well and fast can an experienced user carry out tasks using the.
What about the required time for servicing and maintenance. c Error frequency and severity, How often do users make errors when operating the system. How severe are these errors and how easily can they be detected and. d Subjective satisfaction,Does the user feel comfortable with the system. Does the user feel that using the system brings any advantages. In what way does he interacts with,e Maintenance, What about determination and implementation of the maintenance. 6 3 Suitable Lighting Control Strategies,6 3 1 Introduction. Lighting and lighting control represents a significant contribution to the energy consumption of. building In order to estimate the lighting energy consumption and related impact of controls the. simplified equation from the European standard EN 15193 could be used. W W L t W P t, W Total energy used for lighting the amount of energy consumed in period t by the.
luminaires when operating and parasitic loads when the luminaires are not operating. in a room or zone measured in kWh, WL t Energy consumption used for illumination the amount of energy consumed in. period t by the luminaires to fulfill the illumination function and purpose in the. building measured in kWh, WP t Luminaire parasitic energy consumption the parasitic energy consumed in period. t by the charging circuit of emergency lighting and by the standby control system. controlling the luminaires measured in kWh,Pn Fc t D F O FD t N FO. W L t kWh 6 2,tD Daylight operating hours,tN Non daylight operating hours. Pn Total installed lighting power measured in watts. FD Daylight dependency factor factor relating the usage of the total installed. lighting power to daylight availability in the room or zone. FO Occupancy dependency factor factor relating the usage of the total installed. 6 LIGHTING CONTROL SYSTEMS, lighting power to occupancy period in the room or zone.
FC Constant illuminance factor the factor relating to the usage of the total installed. power when constant illuminance control is in operation in the room or zone. The estimation of the parasitic energy WP t required to provide charging energy for emergency. lighting and for standby energy for lighting controls in the building is established using the. following equation,Ppc t y t D t N Pem t e, ty Standard year time time taken for one standard year to pass taken as 8760h. tD Daylight hours the operating hours during the daylight time. tN Non daylight hours the operating hours during the non daylight time. te Emergency lighting charge time the operating hours during which the emergency lighting. batteries are being charged in hours, Ppc Total installed parasitic power of the controls in the room or zone the input power of all. control systems in luminaires in the room or zone measured in watts. A detailed description of these equations is given in Annex 4 EN 15193. The reduction of the energy consumption is possible by playing on the different elements of the. equations for example, The installed power can be reduced by using low consumption light. sources and efficient control gear electronic ballasts electronic DC. transformer etc, Daylight dimming can lead to an important reduction of the energy. consumption by adjusting the light flux smartly according to the daylight. level This is what is done by the FD parameter, Operating hours can be reduced by adjusting lighting according to.
predicted or real occupation strategies through the FO parameter and the. amount of working hours tN and tD In fact only a fraction of a. building s lighting system is required at any given time Lights frequently. are left on in unoccupied places where there is no need for lighting. Through the reduction of the tN tD and FO values energy savings can be. calculated, The first lighting controls level also the most widely used is the manual switch to put on or off an. individual luminaires or a group of luminaires This type of control is not robust enough with. 6 Lighting control systems 6 1 Introduction A building can be compared to a system with a variety of physical processes interacting with each other and with the environment From the control point of view it is considered as having multi variant dynamic subsystems showing linear or non linear behaviours Environmental and occupancy

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