were made from copper tubes. Water was selected for the heating
and cooling. Temperatures were controlled so that the temperature
measured at the adiabatic section was constant at 400 ± 4 C,
50 ± 4 C and 60 ± 4 C. The sizes of three aspect ratios (Le/di) were
of 5, 10 and 20. The evaporator, adiabatic and condenser sections
represent the three sections of the thermosyphon. Ten thermocouples
were installed to collect data (Yokogawa DX200 with ±0.1 C
accuracy, 20 channel input and 200 C to 1100 C measurement
temperature-range) and were used with type K thermocouples
(OMEGA with ±0.1 C accuracy) attached to the inlet and outlet
of the heating jackets and cooling jackets. The thermocouples were
attached to the TPCT and data were recorded using a data logger.
There were three points on the condenser, three points on the
evaporator and three points on the adiabatic section. A hot bath
(TECHNE TE-10D with an operating range of 40 C to 120 C
and ±0.1 C accuracy) system was used to pump hot water into
the heating jacket in the evaporator section and the cold bath (EYELA
CA -1111, volume 6.0 l with an operating, temperature range of
20 C to 30 C and ±2 C accuracy) system was used to pump the
cooling water into the cooling jacket in the condenser section. The
inlet temperature of the cooling water was maintained at 20 C
then a floating Rota meter (PLATON PTF2 ASS-C for a flow rate of
0.2–1.5 l/min) was used to measure the flow rate of water. During
the experiment, the mass flow rate was set at 0.25 l/min in order to
calculate the heat-transfer characteristics of TPCT using the calorific
method. The following equations were used to calculate the
heat-transfer rate and check error analysis.