Power compensation, differential scanning

Power-compensated differential scanning calorimetry (DSC) apparatus (S = sample R = reference). 

Figure 12.3 Schemeofa power compensation differential scanning calorimeter. A sample furnace Ar reference furnace B temperature sensor of the sample furnace Br temperature sensor of the reference furnace C resistance heater of the sample furnace Cr resistance heater of the reference furnace D cell S sample R reference.

Figure 3.3 Schematic of a power-compensated differential scanning calorimeter.

Kwon, Y.K. Andorsch, R. Pyda, M. Wunderlich, B. Multifrequency saw-tooth modulation of a power-compensated differential scanning calorimeter. Thermochim. Acta 2001, 367 (8), 203-215. 

Figure 2 (a) Power-compensation differential scanning calorimeter, (b) Heat flux differential scanning calorimeter... 

Calorific Values Obtained Using Power Compensated Differential Scanning Calorimetry... 

Kwon YK, Androsch R, Pyda M, Wunderlich B (2001) Multi-frequency Sawtooth Modulation of a Power-compensation Differential Scanning Calorimeter. Thermochim. Acta 367/368 203-215. 

Figure 5.9 Schematic cross-section of a power compensated differential scanning calorimeter (modified from Robie (1987)). R - reference S - sample. Under each sample pan is a platinum resistance thermometer and a platinum heater. The large metal block helps to keep the temperatures in the two chambers equal.

In a power compensation differential scanning calorimeter (DSC), the base of the sample holder unit is in direct contact with a reservoir of coolant (Figure 2.12). The sample and reference holders are indiv idually equipped with a resistance sensor, which measures the temperature of the base of the holder, and a resistance heater. Upon detection of a temperature difference between the sample and reference, due to a phase change in the sample, electrical power is supplied so that the temperature difference falls below a threshold value, typically <0.01 K. 

A Power Compensation Differential Scanning Calorimeter and Thermal Analysis Software, American Laboratory Magazine, January 1996. 

Another type of DSC, the power-compensated differential scanning calorimeters (see Section 7.9.4.2), follows in principle the model shown in Figure 6.15, but instead of one, there are two furnaces for the sample and the reference system, respectively. The current in the heaters (furnaces) (T) is so controlled that the average temperature of the two systems always matches the preset temperature. 

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