The measurement principle and applications of calorimeters

Thread Content

　　Principles and applications of calorimetry: The heat content of steam is an important means for energy monitoring. It is related to the flow rate of steam as well as the enthalpy difference between steam and condensate. The steam flow rate can be measured using a flow meter, while the enthalpy of steam can be determined by measuring its temperature and pressure. The enthalpy of condensate depends on its temperature. Since the enthalpy value of steam is much higher than that of condensate, it is sufficient to know the heat flow rate and enthalpy value of steam in order to determine its heat content. 　　The working principle of a steam heat meter is as follows: paired temperature sensors are installed at the inlet and outlet of the heat exchange circuit, while a flow sensor is placed on either the inlet or outlet pipeline. The flow signal generated by the flow sensor, together with the temperature signals from the inlet and outlet, are used in calculations to determine the amount of heat released by the fluid as it moves from the outlet to the inlet. 　　First, it is necessary to measure the temperature difference, for which two \"temperature sensors\" are required; platinum resistors are commonly used for this purpose. Next, the flow rate needs to be measured, and for this an \"flow sensor\" is needed. For measuring steam, flow meters that can withstand high temperatures and pressures such as orifice flow meters, nozzle flow meters, and vortex flow meters can be used. The heat integrator calculates the heat energy based on the temperature difference of the fluid in the inlet and outlet pipes, the flow rate, as well as the pre-programmed heat capacity values. It then stores and records the energy consumption continuously using its internal storage device. 　　Finally, auxiliary devices with subtraction and multiplication functions are also needed so that the results can be accumulated at any time; and in this way, a heat meter is created. 　　If there is only an exhaust pipeline at the site and no return pipeline, the value measured represents the total heat released by the steam. In this case, it is assumed that the temperature of the return stream is zero, and the user absorbs all of the heat. However, in actual use, it is impossible for users to consume all the heat. 　　Flow metering is one of the components of metrological science and technology, and it is closely related to the national economy, national defense construction, and scientific research. Doing this work well plays an important role in ensuring product quality, improving production efficiency, and promoting the development of science and technology. Especially in today’s era of energy crises and increasing automation in industrial production, the significance and role of flow meters in the national economy have become even more evident.