IMPLEMENTATION OF A REAL TIME MONITORING SYSTEM FOR A HEAT EXCHANGER VIA THE INTERNET: DESIGN, CONSTRUCTION AND TESTING OF THE EXPERIMENTAL EQUIPMENT

摘要

The development of a digital laboratory based on the Internet can be very beneficial, as these systems are inexpensive, easy to install, and allow communication of video and data in real time with a remote computer. We here report the design and construction of experimental equipment which allows remote monitoring of the thermodynamic variables of a cross flow air - water heat exchanger. The experimental equipment and the principal parts are described. Water flow rate is measured with a rotameter; temperatures are measured for both the cold fluid (water) and the hot fluid (air) with thermocuples, and transmitted via internet, in real time to each remote client linked to the digital lab. For this project the graphical programming language from National Instruments LabView, using the USB port for communication between computer and experimental equipment, was used. Programs were implemented to linearize the thermocouple readings, and filters were placed to remove noise from temperature sensors. The front panel of the system, showing important data of the heat exchanger, shows the changes of temperature of the fluids with time. From these data the heat transfer coefficient U can be calculated. The system displays the experiment (video) and the front panel data from a web page to every computer that is linked to the laboratory, so that the remote client can take control, partial or total, of the experiment in real time from any computer. The paper documents the experiments, sample measurements and analyzes results. Finally, laboratory experiments with their corresponding work guidelines for students are presented.