Multiple Sensor Based Autonomous Monitoring and Control for Energy Efficiency Liyanage C. De Silva1,2, Titty Dewana1, M. Iskandar Petra1, and G. Amal Punchihewa2 1
Faculty of Science, University of Brunei Darussalam, Brunei Darussalam
[email protected],
[email protected] 2 School of Engineering and Advanced Technology (SEAT), Massey University, Palmerston North, New Zealand
[email protected],
[email protected]
Abstract. Recently the importance of autonomous monitoring has become an essential part of the society. Autonomous monitoring and control in a home environment can lead to energy savings. Also autonomous monitoring can serve as an alerting mechanism when something is out of the norm so that the controlling mechanism can rectify the problem. In this paper we present a system we developed using multiple sensors for autonomous monitoring and control with relatively low cost components. The sensors we integrated together in to one central operation unit can monitor room temperature, humidity, human motion activity etc. We present a prototype implementation of an energy efficient home environment using our proposed centralized monitoring platform. Using a sample scenario we show that the energy consumption in a smart home is about 15kWh while that of a normal home is about 35kWh. Keywords: Multiple Sensors, Energy Efficiency, Autonomous Monitoring, Smart Homes, Sensor Integration, Environment Monitoring.
1 Introduction Use of multiple sensors for autonomous monitoring and control is applicable in a wide area including the environment monitoring, health monitoring, commerce and industry. In fact many sensors are used in our home environment such as inside refrigerators to control inner temperature, in the water pump assembly to control the water flow etc. However one should note that the number of sensors used in a motor car is much more than one might see in their own home. This leads us to the thinking of a Smart Home with multiple sensors to monitor and control the home environment. In autonomous monitoring and control of a home environment one may employ many sensors to continuously monitor the activities in the home. There are various techniques available which can be used in smart homes such as temperature and humidity measurement and light intensity measurement etc. Due to the ever increasing energy price and scarcity of the resources the cost of energy bills plays an important role in our household expenditure. Hence we need to find a way of constantly monitor the usage and reduce the waste. Energy is used to operate most of the appliances such as cooling, heating, lighting, and many more. P. Vadakkepat et al. (Eds.): FIRA 2010, CCIS 103, pp. 361–368, 2010. © Springer-Verlag Berlin Heidelberg 2010
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There are many ways to reduce the energy consumption they use. One of the best ways is to use sensor technology which helps to monitor and control the energy usage as well as make the user aware of the usage using display technologies or graphical user interfaces (which will help the user to observe the energy usage and control) which in turn persuades them to change the pattern of their energy usage.
2 Related Research Autonomous monitoring and control has been used in many research works for monitoring environmental conditions using smart sensors. The research work presented by De Silva et al. 1 is a technique based on smart monitoring, control and communication to improve energy efficiency and provide eldercare. In their research, they also looked into the use of multiple of different sensors to monitor activities in a smart home and the result of the monitoring was used to control the home environment to reduce energy usage and provide eldercare. The application of the smart monitoring to a prototype system of audio based sensor was also presented in the paper. Chao Chen et al. 2 proposed a monitoring system to monitor human movements at a home environment using wearable wireless sensors. This project designed and developed a wearable wireless sensor system called a waist-mounted tri-axial accelerometer unit to obtain data concerning physical activities of a person in need of medical care. The unit was used to record human movements. And the Sampled data are transmitted using an IEEE 802.15.4 wireless transceiver to a data logger unit and passed to a PC for analysis. In the paper by Cameron Lach et al. 3 the authors proposed a graphical user interface to monitor and control home appliances to reduce energy usage. They have presented data from their prototype implementation. Diane J. Cook et al. 4 proposed a technique of monitoring environmental conditions in a home called MavHome (Managing An Intelligent Versatile Home). The aim of the MavHome project was to create a home that acts as an intelligent agent. In their paper, they introduced architecture for an intelligent home and demonstrated the effectiveness of some monitoring and controlling algorithms on observed smart home data. In the papers 5 and 6 the authors describe human activity detection techniques in home environments. This information can be used for home automation to control the level of lighting used at a given time. In the literature review we looked at many research work that are being carried out to provide better insight and awareness towards the methods of increasing the quality of the daily life at the same time addressing the energy efficiency. In this paper we propose a centralized multiple sensor based platform for environment monitoring to reduce the energy usage in a typical home.
3 Autonomous Monitoring for Energy Efficiency In a given home there are many appliances. But all of them run independently and at present no effort is being used to centralize the monitoring of their operation. Appliances such as air conditioning systems, heating systems require a large amount of energy to run but they tend to operate irrespective of the activities of the householders. This makes the homes one of the environments that waste precious
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energy. Hence the design of smart home environments using sensor network has a great potential to reduce the energy consumption by actively monitoring the household activities and controlling the related appliances. If you have an active sensor network at home they can monitor and automatically control the appliances. For example the motion sensors can sense human presence and it can allow keeping the appliances for example television, air conditioner running as desired. Then when the sensor does not detect movement for long time within the detection area, it will start to power down and reduce energy wastage. Also motion sensors can help in saving energy by switching off the lights if no one passes by the sensor or detection zone. Another advantage of a centralized system is that it is a way to keep occupants aware of their energy efficiency. Laptop screen or mobile phone could set up in a home to track electricity use, water use and other metrics and fed into an online interface or text messages can be sent via mobile phones. The occupants will get updates on their home's energy usage, children’s and elderly conditions at any time. Hence if you have a sensor driven smart home people are constantly made aware of the energy they're using and are more conscious about their affect on the environment.
4 Motion and Temperature Sensor Based Air-Conditioner Control Among the home appliances air conditioners are the equipments those contribute to high energy consumptions. In our platform the air conditioner system was designed and programmed in such a way that it can maintain temperatures given to each room in a house and able to improve the energy efficiency by monitoring the availability of occupants in each room by using distance measuring sensors (PING sensors 7) in addition to temperature sensors. The controlling steps of the air conditioner are given in the flow chart in the Figure 1. ACsystem
Yes
No If PINGdetectspeopleenter the room ACswitch off
Check the room temperature If Room is cool
Wait until the room warms up
Is the roomreacheshigh temperature threshold?
If Room is warm
Acswitch on
No
Yes Is the roomreacheslow temperature threshold?
Yes
No ACTURNS off
Fig. 1. Motion sensor and temperature sensor based air-conditioner control
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Air conditioning is the process of maintaining comfortable conditions inside a closed space. In country like Brunei Darussalam, the surrounding temperature is higher and hence air-conditioners act as a cooler to keep the room cool. Figures 2 and 3 show our prototype implementation of a distance measuring sensor and temperature sensor based air-conditioner control arrangement.
Fig. 2. The temperature sensing and controlling circuits of an Air-conditioner operated by a pair of distance measuring sensors
Fig. 3. Two PING type distance measuring sensors to detect enter and exit of a person to the Smart Home
5 Motion Sensors Based Lighting Control Although lighting consumes less energy, similar to the air-conditioning control we can control the lighting in the house using sensors. For this purpose we have used Passive Infra-Red (PIR) Sensors 7. The PIR sensors are motion detectors that senses infrared radiation emitted by any warm-bodied object through a Fresnel lens and infrared-sensitive element. Infrared Radiation is the electromagnetic spectrum that has wavelength longer than visible light and it is invisible but it can be detected. Human body and animals that generate infrared radiation is maximum at a wavelength of 9.4µm. Infrared radiation will not pass through types of material such as window glass and plastic. However it will penetrate through material with some attenuation
