Measurements of Heat Capacity and Enthalpy of Phase Change Materials by Adiabatic Scanning Calorimetry
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Citations
Phase-change material heat exchanger with coil tubes - experiment and numerical analysis
Investigation of advanced experimental and computational techniques for behavioural characterisation of phase change materials (pcms)
Determination of phase change temperature of materials from adiabatic scanning calorimetry data
Modeling of a heat capacity peak and an enthalpy jump for a paraffin-based phase-change material
References
Heat and cold storage with PCM: An up to date introduction into basics and applications
Enthalpy of Phase Change Materials as a Function of Temperature: Required Accuracy and Suitable Measurement Methods
Temperature dependence of the enthalpy and the heat capacity of the liquid-crystal octylcyanobiphenyl (8CB)
Calorimetric evaluation of phase change materials for use as thermal interface materials
Crystallisation, melting, recrystallisation and polymorphism of n-eicosane for application as a phase change material
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Frequently Asked Questions (10)
Q2. Why do the ASC measurements result in the equilibrium temperature dependence of the enthalpy?
because of the very slow rates in heating the samples, the ASC measurements result in the equilibrium temperature dependence of the enthalpy.
Q3. How many modes of operation are used in the ASC?
By keeping P or Ṫ constant, while increasing or decreasing the temperature of the sample (P and Ṫ positive or negative), four practical modes of operation are obtained.
Q4. How slow is the heating and cooling of the PCMs?
Measurements have been performed at very slow heating and cooling rates, typically three orders of magnitude slower than the ones usually applied in differential scanning calorimetry (DSC).
Q5. What is the main purpose of the paper?
In this paper the authors present adiabatic scanning calorimetry (ASC) as an interesting complementary tool to measure simultaneously the temperature dependence of the enthalpy as well as of the heat capacity near the phase transitions in PCMs.
Q6. How can the authors avoid problems with superheating or supercooling?
With ASC the problems with superheating or supercooling can in many cases be avoided and true equilibrium data can be obtained by using very slow rates as slow as 2 to 3 orders of magnitude slower than in DSC.
Q7. What is the temperature of the cell at the end of the first order?
After a long temperature stabilization time of stage 2 (shield around the sample cell) with zero power to the cell (stage 1), the cell attains the same temperature (within a few tenths of a mK).
Q8. What is the temperature of the transition between heating and cooling?
For PX 42 their transition temperatures (44.5 ◦C for heating and 43.7 ◦C for cooling) are at the upper edge of the 38 ◦C to 43 ◦C range of the manufacturer.
Q9. What is the purpose of the paper?
In this paper, ASC is introduced as a suitable tool for simultaneous measurements of the temperature dependence of the enthalpy and of the (effective) heat capacity of PCMs near their solid–liquid phase transition.
Q10. How do the authors overcome the problems of latent heat measurements?
Efforts to (partly) overcome these problems for latent heat measurements of PCMs have resulted in running a DSC in an isothermal step mode and/or by applying a T -history method [4].