Study And Design On Urban Heat-Supplying Metering And Management System

As the reform of urban heat-supplying system is being further promoted in China, the household metering and charging of concentrated heating represents an irresistible trend. Large quantities of heat meters are to be put into operation in future, and the market demand and potential is enormous. A heat meter featuring of simple structure, low cost, high measuring precision and great suitability of the concrete heat-supplying situation in our country was designed in this paper. Besides, the urban heat-supplying metering and management system based on the new-style heat meter was represented.The design proposal for combined heat meter was adopted. Pt1000 platinum resistors served to collecting the temperatures of supply water and return water. Ultrasonic flow sensors were chose to collect the flow of supply water. The time-to-digital converter TDC-GP21 was introduced to measure the transit-time difference of ultrasonic pulses propagating in and against flow direction, and then the water flow was obtained by the ultrasonic transit-time difference method. Moreover, the high-accuracy temperature measurement was completed by the Newton iteration method using the resistances of Pt 1000s measured by TDC-GP21. As the main controller of the heat meter, the 16-bit ultraslow-power-consumption microcontroller MSP430F4481 figured out the calorie value using the enthalpy method, which is more suitable for the concrete situation in our country than the heat coefficient method.The M-BUS interface circuit was designed so that heat meters in an intelligent building could construct a network. In that case, the meters and a building concentrator formed a data terminal, GPRS wireless network and Internet built the remote communication channel, the control center served as the core, and then the urban heat-supplying metering and management system was successfully established. To reduce cost, the M-BUS interface circuit composed of discrete components. The infrared communication realized the local meter reading by a hand-hold device once the remote meter reading failed.The urban heat-supplying metering and management system could provide the accurate and convenient household metering and charging service, meeting requirements of intelligent buildings. Besides, the intelligent management of urban heat-supplying system was realized.