Intelligent Household LED Lighting System Considering Energy Efficiency and User Satisfaction

Transcription

1 70 IEEE Transactions on Consumer Electronics, Vol. 59, No. 1, February 2013 Intelligent Household LED Lighting System Considering Energy Efficiency and User Satisfaction Jinsung Byun, Insung Hong, Byoungjoo Lee, and Sehyun Park, Member, IEEE Abstract Saving energy has become one of the most important issues these days. The most waste of energy is caused by the inefficient use of the consumer electronics. Particularly, a light accounts for a great part of the total energy consumption. Various light control systems are introduced in current markets, because the installed lighting systems are outdated and energy-inefficient. However, due to architectural limitations, the existing light control systems cannot be successfully applied to home and office buildings. Therefore, this paper proposes an intelligent household LED lighting system considering energy efficiency and user satisfaction. The proposed system utilizes multi sensors and wireless communication technology in order to control an LED light according to the user s state and the surroundings. The proposed LED lighting system can autonomously adjust the minimum light intensity value to enhance both energy efficiency and user satisfaction. We designed and implemented the proposed system in the test bed and measured total power consumption to verify the performance. The proposed LED lighting system reduces total power consumption of the test bed up to 21.9% 1. Index Terms household LED lighting system, situation awareness, minimum light intensity control, adaptive middleware. I. INTRODUCTION Energy-saving solutions have been becoming increasingly essential in recent years because of environmental issues such as climate change and global warming [1]-[4]. Environmental problems are very important issues and these problems are largely caused by the excessive use of energy. A light accounts for approximately 20 percent of the world s total energy consumption [5]; thus the related studies of an energy efficient lighting system have been done by 1 This research was supported by the MKE(The Ministry of Knowledge Economy), Korea, under the ITRC(Information Technology Research Center) support program (NIPA-2012-H ) supervised by the NIPA (National IT Industry Promotion Agency) and by the Human Resources Development of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy ( ). Jinsung Byun is with the School of Electrical and Electronics Engineering, Chung-Ang University, Seoul, Korea ( jinsung@wm.cau.ac.kr). Insung Hong is with the School of Electrical and Electronics Engineering, Chung-Ang University, Seoul, Korea ( axlrose11421@wm.cau.ac.kr). Byoungjoo Lee is with the Aurora Design Lab, Seoul, Korea ( bjlee@auroradesignlab.com). Sehyun Park is with the School of Electrical and Electronics Engineering, Chung-Ang University, Seoul, Korea ( shpark@cau.ac.kr). various researchers around the world [7]-[14]. The invention of a light emitting diode (LED) is expected to significantly alleviate the energy consumption of a light, because the LED lighting device consumes 50 percent of the energy consumption compared to the fluorescent lighting device. Recently, an intelligent lighting control system using various sensors and communication modules are actively studied and developed in both university and industry [6]. The intelligent lighting control system can reduce energy consumption as automatically controlling the intensity of illumination through situation awareness, such as awareness of user movement or brightness of surroundings. The technical report from the U.S. Department of Energy shows that about 15 percent of total energy consumption can be reduced through light control according to user's living pattern. However, since the existing lighting control systems can support only simple on/off or dimming control according to user movement or brightness of surroundings, it is hard to be applied to complex environments such as house or office. The complex environment means that there is a variety of control requirements, because of the presence of a variety of users. Because of this limitation of existing systems, they are mostly installed in the places such as the front door or the hallway. Furthermore, since the existing systems are designed without considering user satisfaction, it is not appropriate to the places such as house and office where user satisfaction is more crucial factor than cost benefits due to energy saving; thus a new intelligent lighting control system should be designed considering both energy efficiency and user satisfaction. All things considered, design goals of the new intelligent lighting control system are as follows: designed to maximize the utilization of an LED. designed to have the communication capability. designed to control based on the situation awareness. designed to enhance both energy efficiency and user satisfaction. Therefore, this paper proposes an intelligent household LED lighting system considering energy efficiency and user satisfaction. The proposed system utilizes multi sensors and wireless communication technology in order to control an LED light according to the user s state and the surroundings. The proposed LED lighting system can autonomously adjust Contributed Paper Manuscript received 01/01/13 Current version published 03/25/13 Electronic version published 03/25/ /13/$ IEEE

2 J. Byun et al: Intelligent Household LED Lighting System Considering Energy Efficiency and User Satisfaction 71 the minimum light intensity value to enhance both energy efficiency and user satisfaction. This paper is organized as follows: in Section II we discuss the works related to the existing intelligent lighting control system; in Section III we discuss the problems of the existing system; then we present the proposed intelligent household lighting control system along with system architecture and an important algorithm; in Section IV we present the system implementation and test bed; in Section V we discuss some case studies and experiment; finally we draw our conclusions in Section VI. II. RELATED WORK There are many researches on the lighting control system. Pan et al [7] proposed a wireless sensor network-based intelligent light control system for indoor environments. This light control system manages lighting devices according to user's activities and profiles. Two algorithms (Illumination decision algorithm and device control algorithm) are proposed to meet requirements of the user and to save energy. Uhm et al [8] proposed an LED light system with light sensors, motion sensors, and network interfaces. This light control system can control illumination intensity of an LED light based on brightness of surrounding and movement of residents. Park et al [9] presented lighting control system based on a building automation and control network (BACnet). Matta et al [10] proposed a light control system with detailed design for energy saving by controlling the intensity of illumination. In this paper, a logical low cost design is introduced to conserve electrical energy taking daylight illumination into consideration by using a controller area network (CAN) bus as the media for communication. Bellido-Outeirino et al [11] presented building lighting automation system using digital addressable lighting interface (DALI) devices with wireless sensor networks. There are some researches about street lighting control systems. Leccese [12] proposed remotecontrol system can optimize management and efficiency of street lighting systems. It uses ZigBee communications which enable more efficient street lamp-system management. There are some researches about evaluation of energy-efficiency of lighting systems. Delaney et al [13] proposed a wireless sensor network as a evaluation tool that can help in analysing and evaluating the energy-efficiency of an existing lighting control system in a low-cost. Denardin et al [14] presented an intelligent street light controlling and monitoring system based on a wireless data network. This system add communication capabilities to the existing street lighting systems through the integration of a ZigBee compatible transceiver in order to turn each street lighting system in to a node of a large wireless network. The lighting control system for energy savings in current markets can support on-off and dimming control as managing lighting devices after detecting an object or intensity of illumination, or controlling with time setting. Furthermore, although most existing systems have variable control parameters, it is difficult for users to modify these parameters, so that it is not appropriate to be applied in various places. In addition, although the lighting control system using central management server or sensor networks was studied recently, it was not commercialized or industrialized, and even the commercialized products were excessively concentrated to the central management server. III. PROPOSED INTELLIGENT HOUSEHOLD LIGHTING SYSTEM We design the intelligent household LED lighting system with a motion detection sensor, illumination sensor, and wireless communication interface. Before presenting the proposed system with system architecture and important scheme, we discuss the problem of the lighting system. A. Problem Description Fig. 1 illustrates the basic operating principles of the proposed system. The system control and state variables are: Lmin Lmax T r T m T f minimum light intensity; maximum light intensity; rise time period of the light intensity; time period between no movement detection and that the light intensity begins to falls; fall time period of the light intensity; Fig. 1. Basic operating principles of the proposed system. The proposed system basically controls illumination intensity of a lighting device according to user movement and brightness of surroundings. That is, when the maximum value of illumination intensity of a lighting device is Lmax and the minimum value is Lmin, the illumination intensity becomes Lmax, if user movement is detected and becomes Lmin, if user movement is not detected for certain period time. As shown in Fig. 2, it can be confirmed that as T r is longer, T m and T f are shorter, and Lmax and Lmin are smaller, the energy saving effect becomes larger. However, it implies the possibility that inconvenience of users can be bigger because of frequent light on/off, and dark indoor environment, etc. whereas the energy saving effect becomes larger. Therefore, it is necessary to properly set the value according to space environmental characteristics (frequent or rare user movement, work type, etc.).

3 72 IEEE Transactions on Consumer Electronics, Vol. 59, No. 1, February 2013 Collective control using a wireless technology Control and system setting through a wireless controller and a mobile phone application The proposed system can reduce energy consumption via interaction with the information about user s state and surroundings (e.g. brightness of a room). The autonomous control could lead to disturbance to residents. Thus, the proposed system autonomously optimizes the system control and state variables, especially Lmax, Lmin, T r, T m, and T f in order to enhance both energy efficiency and user satisfaction. Fig. 2. Comparison of the amount of energy reduction according to Lmax, Lmin, T r, T m, and T f. C. Minimum Light Intensity Control Algorithm Fig. 4 illustrates a flowchart of a minimum light intensity control algorithm that requires a signal of inconvenience and a countdown timer. The signal of inconvenience is received from residents through a smart phone when they feel the brightness of the lighting with inconvenience. The countdown timer can interrupt the system after a given amount of time has expired. The proposed minimum light intensity control algorithm automatically adjusts Lmin based on the signal of inconvenience of users, which are inputted via smart phones. The value of illumination intensity of the lighting that has been felt with inconvenience at the latest is Lmin incon, whereas the value of illumination intensity that has not been felt with inconvenience for a certain period of time, T at the latest is Lmin con. The initial Lmin 0, and Lmin incon is set to zero, and the initial Lmin con is set to Lmax. The procedures are composed of five steps. Step 1. First, check whether a signal of inconvenience has occurred. If a signal of inconvenience has occurred, then Lmin n = (Lmin con +Lmin n-1 )/2, Lmin incon = Lmin n-1, n = n + 1, and timer = T. And then check again whether a signal of inconvenience has occurred. Step 2. Check whether a signal of inconvenience has occurred. If a signal of inconvenience has occurred, then Lmin n = (Lmin con +Lmin n-1 )/2, Lmin incon = Lmin n-1, n = n + 1, and timer = T as in Step 1. If a signal of inconvenience has not occurred, then check whether timer is equal to zero (i.e. the expiration of a given amount of time, T). Fig. 3. Overview of the proposed system. B. Overview of IHLS We propose an intelligent household LED lighting system using various sensors and wireless communication technology. Fig. 3 shows an overview of the proposed lighting system. The main features are as follows: Autonomous control based on user movement Autonomous control based on brightness of the room Autonomous optimization of system control and state variables. Step 3. Check whether timer is equal to zero, if timer is equal to zero, then Lmin n = (Lmin incon +Lmin n-1 )/2, Lmin con = Lmin n-1, n = n + 1, and timer = T. And then, check whether Lmin con minus Lmin incon is less than 5 or not. If timer is not equal to zero, check again whether a signal of inconvenience has occurred. Step 4-1. After check whether Lmin con minus Lmin incon is less than 5, if Lmin con minus Lmin incon is less than 5, then terminate this flowchart. If Lmin con minus Lmin incon is not less than 5, then perform the process of Step 4-2.

4 J. Byun et al: Intelligent Household LED Lighting System Considering Energy Efficiency and User Satisfaction 73 Step 4-2. Check whether a signal of inconvenience has occurred. If a signal of inconvenience has occurred, then Lmin n = (Lmin con +Lmin n-1 )/2, Lmin incon = Lmin n-1, n = n + 1, and timer = T. If a signal of inconvenience has not occurred, then perform again from Step 3. which manages a variety of data used for context awareness and LED control. Fig. 5 shows an adaptive middleware platform of the proposed system. Fig. 5. Adaptive middleware platform of the proposed system. Fig. 4. flowchart of a minimum light intensity control algorithm. It is possible to derive the value of Lmin, which can save energy at the maximum without causing inconvenience for users through the proposed algorithm. D. Middleware Architecture As for the conventional LED lighting products, they should be developed using the low-cost MCU in order to reduce the production unit price; thus, they have a disadvantage of having the limited availability of the computing resources or storage resources. To solve this problem, we design the platform of adaptive middleware that can update an internal program through the automatic control or the remote control by an administrator in accordance with the external environmental changes. The adaptive middleware platform is composed of the LED control module group, which performs the role of controlling LED, the adaptive middleware group, which can change through the external environment or the remote command of the administrator, and the table group, 1) LED Control Module Group - Network Module: It is the module related to the ZigBee and RS485 serial for communication with the external control system. This module processes interrupts and message for communications. - Manager Module: It internally processes the control command, which is transferred from the manager of the adaptive middleware group and converts it into a form for communications and control, and has the role of managing the conflict or loss of the transferred messages. - PWM Module: It performs the role of generating and stabilizing the PWM signal for LED control. It also performs the role of generating the signal to control an actual LED based on the data transferred from the adaptive middleware and retrieved from the table group. 2) Adaptive Middleware Group - Core Middleware: It is the module to possess the core function of the adaptive middleware. Basically, it is mainly used for the manager management, scheduling for managers, and access control of the table used by the managers. It registers and activates the managers upon receiving the control messages from the external management server. It also performs the role of deleting the existing managers in accordance with the commands transferred from the management server. In addition, it performs the role related to authentication for external management server. - Manager Group: This group can registers and deletes the managers in the adaptive middleware group in real time. The illumination sensor manager performs the roles of gathering the value of intensity of illumination from the sensor or making the rule table for control upon receiving the data sensed from the sensor module, the neighboring lighting system, or the management server. In addition, this group is

5 74 IEEE Transactions on Consumer Electronics, Vol. 59, No. 1, February 2013 used for managing the value of illumination intensity of the internal parameter table. The time sync manager is the manager related to the time-based control. It plays a role in time synchronization with the external control system and making the rule table for time-based control or updating time information in the share table. The motion sensor manager plays the role in managing the information collected from the motion sensor in the same way as the illumination sensor manager. 3) Table Group: - Rule Table: It stores the rule, which is the information for control. It is composed of the time-based and sensor-based rule, and it is connected with the PWM module. - Share Table: It is the table to store the information to be shared between the modules. It stores the necessary information to share, such as real-time sensing information or connection information with the management server. - Variable Table: It is the table to store the data of the variables to transfer information between the modules. - Parameter Table: It is the table to store the control and network status. It stores a variety of parameters such as network address, transfer schedule, transfer buffer, etc. Fig. 5. Implementation of the proposed system; (a) prototype, (b) installation, (c) hardware block diagram. Fig. 6. PCB layout of the proposed system. The proposed intelligent LED lighting system has eight switches as shown in Fig. 6, and it is possible to adjust the variable system control parameters, i.e. Lmax, Lmin, T r, T m, T f, and countdown timer. When the switch g is On and the h is On, the switch a, b and c are used to adjust the maximum value of illumination intensity (Lmax), and the switch d, e, and f are used to adjust the setting of the minimum value of illumination intensity (Lmin). When the switch g is On and the h is Off, the switch a, b, and c are used to adjust the rise time period (T r ), and the switch d, e and f are used to adjust the fall time period (T f ). When the switch g is Off and the h is On, the switch a, b, and c are used to adjust the countdown timer (T m ). If the switch g is Off and the h is Off, the proposed system operates as a general LED lighting without intelligent lighting control. B. Testbed Fig. 7 shows a floor plan of a test bed with the illumination simulation result. There are 44 LED lights (42-watt light) with the proposed system. A. Implementation IV. IMPLEMENTATION AND TESTBED Fig. 5 shows the prototype and hardware block diagram of the proposed system. The main processor part uses 8 bit microprocessor. This part plays a role in situation analysis, event processing, and learning. This part optimizes the control and state variables to adapt itself to the various environments. The sensor part is composed of various sensors. To provide energy saving services mentioned above, two kinds of sensors, that is a motion detection sensor and illumination sensor are needed basically. A ZigBee (250 kbps/2.4 GHz) module is used for communication with other LED lighting system and networked devices. LED driver part consists of current controller modules for driving LEDs. There are two ports that are controllable and are able to control for 255 levels of brightness. The power part is composed of a power regulator and SMPS. Fig. 7. Floor plan of a test bed with the illumination simulation result. V. CASE STUDY AND EXPERIMENT A. Case Study 1) Home and office building There are many people in a home and office building; thus, user satisfaction is an important factor in the light evaluation.

6 J. Byun et al: Intelligent Household LED Lighting System Considering Energy Efficiency and User Satisfaction 75 In these places, Lmin is set according to the proposed minimum light intensity control algorithm. Generally, Lmin is set to the high value in these places. 2) Warehouse There are a few people in a warehouse; thus, user satisfaction is a less important factor than the case of a home or office building. Generally, in the warehouse, Lmin is set to the low value. In this case, a significant amount of energy consumption can be reduced. 3) Parking lot Like the warehouse, in the parking lot, user satisfaction is an less important factor than the case of a home or office building as in a warehouse. A car that enters the parking lot will move a vacant parking space; thus, when a car enters the parking lot, Lmin is set to the high value only from the entrance of the parking lot to a vacant parking space. Then, when a user gets out of a car, Lmin is set to the high value only from user's current position to the entrance of the building. B. Experiment and Results In an experiment, we measured total power consumption for 14 days. Fig. 8 shows the result of an experiment. The proposed lighting control system reduces energy consumption up to approximately 21.9%. Fig. 8. Floor plan of a test bed with the illumination simulation result. VI. CONCLUSIONS AND FUTURE WORKS Saving energy has become one of the most important issues these days. A light accounts for approximately 20 percent of the world s total energy consumption; thus, a lot of studies and development related to energy saving of a light have been done by various researchers all over the world. However, since there are no products considering both energy efficiency and user satisfaction, the existing systems cannot be successfully applied to home and office buildings. Therefore, we propose an intelligent household LED lighting system considering energy efficiency and user satisfaction. The proposed system utilizes multi sensors and wireless communication technology in order to control an LED light according to the user s state and the surroundings. The proposed system can autonomously adjust the minimum light intensity value to enhance both energy efficiency and user satisfaction We designed and implemented the proposed system in the test bed and measured total power consumption. The proposed lighting system reduces total power consumption of the test bed up to 21.9%. REFERENCES [1] S. Tompros, N. Mouratidis, M. Draaijer, A. Foglar, and H. Hrasnica, "Enabling applicability of energy saving applications on the appliances of the home environment," IEEE Network, vol. 23, no. 6, pp. 8-16, Nov.- Dec [2] Tao Chen, Yang Yang, Honggang Zhang, Haesik Kim, and K. Horneman, "Network energy saving technologies for green wireless access networks," IEEE Wireless Communications, vol. 18, no. 5, pp , Oct [3] J. Byun and S. Park, "Development of a self-adapting intelligent system for building energy saving and context-aware smart services," IEEE Trans. on Consumer Electron., vol. 57, no. 1, pp , Feb [4] J. Han, C.-S. Choi, and I. Lee, "More efficient home energy management system based on ZigBee communication and infrared remote controls," IEEE Trans. on Consumer Electron., vol. 57, no. 1, pp , Feb [5] Ç. Atıcı, T. Özçelebi, and J. J. Lukkien, "Exploring user-centered intelligent road lighting design: a road map and future research directions," IEEE Trans. on Consumer Electron., vol. 57, no. 2, pp , May [6] A. A. Siddiqui, A. W. Ahmad, H. K. Yang, and C. Lee, "ZigBee based energy efficient outdoor lighting control system," in Proceedings of the International Conference on Advanced Communication Technology, pp , [7] M.-S. Pan, L.-W. Yeh, Y.-A. Chen, Y.-H. Lin, and Y.-C. Tseng, "A WSN-Based Intelligent Light Control System Considering User Activities and Profiles," IEEE Sensors Journal, vol. 8, no. 10, pp , Oct [8] Y. Uhm, I. Hong, G. Kim, B. Lee, and S. Park, "Design and implementation of power-aware LED light enabler with location-aware adaptive middleware and context-aware user pattern," IEEE Trans. on Consumer Electron., vol. 56, no. 1, pp , Feb [9] T.-J. Park and S.-H. Hong, "Experimental Case Study of a BACnet- Based Lighting Control System," IEEE Trans. on Automation Science and Engineering, vol. 6, no. 2, pp , Apr [10] S. Matta and S. M. Mahmud, "An intelligent light control system for power saving," in Proceedings of the Annual Conference of the IEEE Industrial Electronics Society, pp , [11] F. J. Bellido-Outeirino, J. M. Flores-Arias, F. Domingo-Perez, A. Gil-de- Castro, and A. Moreno-Munoz, "Building lighting automation through the integration of DALI with wireless sensor networks," IEEE Trans. on Consumer Electron., vol. 58, no. 1, pp , Feb [12] F. Leccese, "Remote-Control System of High Efficiency and Intelligent Street Lighting Using a ZigBee Network of Devices and Sensors," IEEE Trans. on Power Delivery, vol. 28, no. 1, pp , Jan [13] D. T. Delaney, G. M. P. O'Hare, and A. G. Ruzzelli, "Evaluation of energy-efficiency in lighting systems using sensor networks," in Proceedings of the First ACM Workshop on Embedded Sensing Systems for Energy-Efficiency in Buildings, pp , 2009 [14] G. W. Denardin, C. H. Barriquello, R. A. Pinto, M. F. Silva, A. Campos, and R. N. do Prado, "An Intelligent System for Street Lighting Control and Measurement," in Proceedings of the IEEE Industry Applications Society Annual Meeting, pp. 1-5, BIOGRAPHIES Jinsung Byun received his B.S and M.S. degree in the School of Electrical and Electronics Engineering from Chung-Ang University, Seoul, Korea in 2008 and He is currently a Ph.D. candidate at Chung-Ang University. His current research interests include ubiquitous computing, situation-aware middleware technologies, wireless sensor network, MAC and routing protocols, and embedded system design.

7 76 IEEE Transactions on Consumer Electronics, Vol. 59, No. 1, February 2013 Insung Hong received his B.S and M.S degree in Electrical and Electronics Engineering from Chung-Ang University, Seoul, Korea, in 2009 and He is currently a Ph.D. candidate at Chung-Ang University. His current research interests include ubiquitous computing, embedded system, and intelligent system and home network. Byoungjoo Lee received his B.S. degree in Electronic and Electrical Engineering from Hong-ik University, Seoul, Korea and M.S. degree in Electrical and Electronics Engineering from Yon-sei University, Seoul, Korea, in 2000 and He received the Ph.D. from in Electrical and Electronics Engineering from Chung-Ang University, Seoul, Korea, in He is currently a vice president of the Aurora Design Lab, Seoul, Korea. His current research interests include embedded system, home network, energy saving system, power management. Sehyun Park (M 01) received the B.S. and M.S. degrees in electronics engineering from the Chung-Ang University, Seoul, Korea in 1986 and 1988, respectively, and the Ph.D. from University of Massachusetts, Amherst in From 1988 to 1999, he was a senior research staff at ETRI, Korea. He is currently an Professor of School of Electrical and Electronics Engineering at the Chung-Ang University, where he has established the Ubiquitous Computing and Cipher Internet Laboratory. He is the head of Chung-Ang University HNRC (Home Network Research Center)-ITRC (Information Technology Research Center) supported by the MKE (Ministry of Knowledge Economy), Korea. His major research interests include home networks, ubiquitous computing and network security.