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 a commercial graphical programming language, 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, plots the measured fluids
temperature. From these data, the heat transfer coefficient can be calculated. Moreover, 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. Finally,
some conclusions are presented.
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