Wireless sensor network architectures as a foundation for efficient district heating

Sammanfattning: Our expanding modern society demands more and more energy, and with diminishing fossil fuel supplies and threats of global warming, it has become imperative that we use our energy efficiently. For decades, district heating has proved to be a stable and energy-friendly way of supplying space- and hot-water heating to connected customers. In this thesis, methods to make the technology of district heating (and cooling) even more efficient and competitive are presented and investigated. Most installed district heating substations today do not work at their full potential, meaning that energy is short-circuited and hence wasted. By integrating wireless Internet-enabled embedded devices into district heating substation components, e.g., circulation pump, heat meter and temperature sensors, a Wireless Sensor Network (WSN) is formed. With a Internet enabled WSN in place, the possibility is given to interact and communicate with the substations worldwide. It also enables information sharing between devices that traditionally have not been able to communicate and exchange data, e.g., heat meter and control valve. Frustration is often associated with the introduction of new IT solutions, including their implementation, maintenance and proprietary protocols. To make the embedded devices (sensor platforms) context-aware and support plug-n-play features, an information architecture based on service-oriented architecture (SOA) has been experimentally tested with promising results. When looking at efficiency in district heating systems, ∆T (difference between supply- and return-temperature) is a key indicator, as a large ∆T contributes to lower distribution, fuel and installation costs. A large ∆T can also increase electricity production if the heat is produced in a combined heat and power plant. Using the Internet-enabled WSN architecture described in the thesis, it is possible to increase system ∆T through improved substation control. It is also possible to support a range of new services for both customers and producers that will enhance the quality of service and functionality, both from a system-wide and subsystem perspective.