HEAT CAPACITY DETERMINATION LABORATORY
Objective: To
determine the heat capacity of a given material.
Concepts: Data acquisition using
LabVIEW software, Heat content and sensible enthalpy of materials, energy
conversion, and energy losses
Method: A LabVIEW software program will be utilized to record the dynamic
responses of thermocouples to heating of selected materials by an immersion
heater. A schematic of the set-up is
attached.
Materials and equipment:
Water
and oil
Beakers
Thermocouples
Voltmeter
Plate
heater
Procedure:
Start
with a material at thermal equilibrium (record the initial temperature)
Turn
the immersion heater on.
Record
the voltage at 30 second intervals
Heat
the material for 3 minutes and turn the immersion heater off.
Temperature
of the material will be recorded with LabVIEW software.
Calculations: You will be asked to work in
groups of 3 to do the following calculations:
1)
Determine
the resistance of the immersion heater
2)
Calculate
the energy given by the immersion heater
3)
Use
the Excel Spreadsheet program to prepare temperature versus time graphs for oil
and water systems.
4)
Determine
the rate of heating for oil and water systems using the Excel program
5)
Determine
the temperatures of oil and water systems after heating with a immersion heater
for 1, 2, and 3 minutes
6)
Calculate
the energy received by the water if the heat capacity of water is equal to 4.18
kJ/kg oC at the end of 1, 2, and 3 minutes
7)
Assuming
the same amount of heat energy was delivered to the oil system at corresponding
times, calculate the heat capacity of oil using the energy amounts at 1, 2, and
3 minutes.
8)
Calculate
the ratio of energy received by the oil and water systems to the electrical
energy delivered by the immersion heater
Report: You will be asked to work
in groups of 3 to prepare your report.
You are expected to type your report neatly and clearly. Handwritten reports will not be accepted.
Your
report will include:
1)
Temperature
versus time graphs for oil and water systems
2)
The
calculations described above and the results of the calculations
3)
A
discussion about:
a)
the
factors influencing the conversion of electrical energy to heat energy
b)
recommendations
to improve the design of the system to improve the conversion of electrical
energy to heat energy