Coaxial Tubular Heat Exchanger

Using the trainer, the characteristic properties of heat transfer in pipe flows can be demonstrated. The heat transfer takes place in a coaxial tubular heat exchanger. The hot water is fed through the inner tube.
Using the trainer both parallel flow and counterflow operation with their different temperature profiles can be demonstrated. The non-linear temperature profile along a heat exchanger can be demonstrated by measuring temperatures at the inlet, outlet and halfway along the pipe. After the experiment the key parameters such as heat flux, heat transfer coefficient and heat loss are determined.
The closed hot water circuit includes a tank with electrical heater and a pump. The hot water temperature is kept constant using a thermostat. The cold water is drawn from the water mains and is fed to a drain after use.
The flow rate and relevant temperatures are recorded by sensors. A display panel for the measured values is located on the instrument panel next to the copper pipework.
Learning Objectives / Experiments
plotting temperature curves
in parallel flow operation
in counterflow operation
determination of mean heat flux for
parallel flow and counterflow operation
determination of mean heat transfer coefficient
Specification
trainer with a tubular heat exchanger
closed hot water circuit, insulated with pump
and heater with thermostat
copper piping
all valves in the cold water circuit to select the
operation mode parallel flow or counterflow
temperature measurement with 6 sensors
flow rate measurement with sensor