12th International Symposium on District Heating and Cooling

The <strong>12th</strong> <strong>International</strong> <strong>Symposium</strong> on District Heating and Cooling,September 5 th to September 7 th , 2010, Tallinn, EstoniaINTEGRATION OF AN IP BASED LOW-POWER SENSOR NETWORKIN DISTRICT HEATING SUBSTATIONSJ. Gustafsson, H. Mäkitaavola, J. Delsing and J. van DeventerDiv. of EISLAB, Dept. of Computer Science and Electrical EngineeringLuleå University of Technology, 971 87 Luleå, SWEDENABSTRACTIn this study, the implementation of a wireless, lowpower,sensor network with IP capabilities in a districtheating substation was evaluated. The aim of thestudy was to show that an open standard solution istechnically feasible. Low-power wirelesscommunication was established using IPv6/6LoWPANon an IEEE 802.15.4 wireless network. Anexperimental district heating substation was equippedwith sensor platforms in vital devices located within ornear a district heating substation. As a result, allconnected devices could obtain a direct internetconnection.A system with open standards facilitates theintroduction of new energy services such as individualmeasurements and improved space heating control.In this study, we found that resource-limited batterypowereddevices possess a life expectancy of over10 years, using small batteries while participating inIPv6 compatible communication.INTRODUCTIONEmbedding low-power wireless devices in districtheating substations and surrounding equipment suchas temperature sensors could provide useful servicesto consumers and producers. Currently, manydifferent substation control systems on the market canconnect to the internet and have various wirelesssensor reading systems. However, these systemstend to be specialized and are only compatible withequipment from the same manufacturer. Moreover,internet-compatible control systems are often alsorelatively expensive, and provide bad scalability.In general, commercially available heat meters cannotcommunicate through the current infrastructure; thus,specialized communication methods such as mbus,pulse, and infrared readings must be employed.Therefore, poor communication standards limit thecurrent usage of heat meters and other equipment inthe substation. However, by sharing information withother devices in the substation, the heat meter couldprovide useful feedback and sensing information,which can be used to improve the substation controlfunctionality.Fig. 1 provides an overview of the development ofsensor networks over the last 20 years. Unfortunately,most equipment currently used in district heatingsubstations is antiquated.Fig. 1. Evolution of wireless sensor networks. Althoughthe scalability of the sensor network has increased, manyindustries still use vendor-specific cable solutions. (Thefigure was obtained from the literature [1])If heat meters, control systems, and other non-districtheating equipment could communicate, new servicesthat have impact on both economy and theenvironment could be developed.The infrastructure required to achieve wireless devicecommunication may be attained with low-powerwireless technology. Small sensor platforms withdirect internet access through standardized wirelesstechnology can provide a solid platform for newservices.A lack of standardized communication protocols iscommonly encountered when connecting electronicdevices from different vendors. In general, devicesmanufactured by different companies use differentcommunication protocols, which limits the functionalityof the substation.District heating substations can be divided intosections based on metering, space heat control, andtap water control. For a visual overview of a commonparallel connected district heating substation, seeFig. 2, this is also the substation type used in thestudy. Typically, information is not shared betweenthese sections; thus, each system can only be locallyoptimized. To achieve complete substationoptimization, information must be shared betweensections. To this end, wireless sensor-platforms wereinstalled in temperature-sensors, heat-meters,circulation pumps, and control valves, and new controlmethods and services were tested. This empowers us4