Posted in | Calorimeters

Netzsch Accelerating Rate Calorimeter 254

The Accelerating Rate Calorimeter 254 (ARC® 254) provides adiabatic calorimetry data in a safe, controlled laboratory environment. The Accelerating Rate Calorimeter 254 (ARC® 254) simultaneously measures temperature and pressure.

Gaseous reaction products may be analyzed at the end of an experiment to help identify and understand the reaction mechanisms involved.

The Accelerating Rate Calorimeter 254 (ARC® 254) is designed to model the course of a large-scale reaction on a small scale. A test material is externally heated in a fixed volume until exothermic activity is detected. Keeping that sample in an adiabatic environment where no energy is lost, the calorimeter then measures and records the sample temperature and pressure.

A single experiment provides data for use in the following:

  • Thermal Hazard Evaluation
  • Pressure Hazard Evaluation
  • Thermokinetic Analysis

User safety is a key objective in the design of Accelerating Rate Calorimeter 254 (ARC® 254). The user is protected by a series of safety systems that are completely independent of the control system. These safety systems work to protect the user in the event that the primary control system fails. Fully computer-controlled and highly automated, the Accelerating Rate Calorimeter 254 (ARC® 254) features a graphical interface that is easy to learn and use.

Accelerating Rate Calorimeter 254 (ARC® 254) is totally integrated into clean, modern designs in which all routinely used equipment is easily accessible.

Key Technical Data

  • Minimum Detectable Slope: < 0.01 K/min
  • Temperature Range: RT to 500°C
  • Operating Test Cell Pressure Range: 0 to 200 bar
  • Pressure Accuracy: 0.35% of full scale
  • Sample container volume: 0.5 ml - 8.5 ml
  • Tracking rate at adiabatic operation up to 200 K/min
  • Test cell materials:
  • Stainless steel
  • Inconel
  • Hastelloy
  • Glass
  • Stirring, injection, and vent capability (options)
  • ASTM standard: E1981

Netzsch’s Accelerating Rate Calorimeter heaters offer a controlled near-adiabatic environment for the VariPhi®, bomb, and sample system. This makes it easy to test the sample in the normal Accelerating Rate Calorimeters (ARC®) operational modes such as Iso-Track, Iso-Fixed, or Heat-Wait-Search.

VariPhi®s key features in Accelerating Rate Calorimeters mode include:

  • The heat lost to the sample bomb throughout an exothermic reaction is offset by the internal heater.
  • The PHI (F) or thermal inertia for the test can be defined by users. All or part of the heat lost to the bomb wall to the sample is returned by the heater. Users can even define the actual thermal inertia at which to perform the test.
  • The heat capacity of the sample is determined as a function of temperature.
  • Users can run the tests at the actual thermal inertia at which they will run in a storage container or the plant.
  • Kinetics that relies on thermal inertia, like competing reactions, cannot be compensated mathematically. Now, such issues are completely eliminated.
  • It is possible to correct thermal inertia without extrapolating kinetics from multiple and overlapping reactions.
  • The data, thus acquired, will correlate directly to the exact run or storage conditions, thereby making it much easier to pass the data to non-calorimetry specialists.

VariPhi® in Scanning Mode

Users can utilize the VariPhi® technology as an additional heater and can run ramp tests with the ARC®. The ARC® provides enhanced information regarding a sample’s activity. When VariPhi® operates in scanning mode, it can determine pressure, heat capacity, endothermic and exothermic activity sample in a faster and more cost effective way compared to traditional differential scanning calorimeter.

The following features are provided by VariPhi in scanning mode:

  • Heat capacity is directly determined as a function of temperature
  • Data can be collected quickly on exothermic activity when compared to Heat-Wait-Search tests
  • Better measurements and capabilities over standard DSC analysis
  • Data related to pressure can be recorded
  • Endothermal activity can be monitored
  • Thermal inertia can be set for direct, real-world comparison
  • Samples can be stirred and injected

VariPhi® in Isothermal Mode

Users can utilize the VariPhi® technology to run the exact isothermal calorimetry on ARC254 for battery cells and chemical samples. In this mode, VariPhi® offers the following features:

  • Both exothermic and endothermic events
  • True isothermal operation
  • Isothermal charging and discharging of batteries

VariPhi® in Fire-Exposure Mode

By using VariPhi®, power may be added to offset to phi = 1.0, and the fire energy influx thus measured can be directly added to the sample at a steady speed. In this mode, VariPhi® offers the following features:

  • Measures kinetics
  • Measures heat of reaction
  • Highly precise fire exposure test case


  • Used as a controlled variable DC heater in ARC®, the VariPhi® provides the exact simulation of real-world thermal environment.
  • The advanced calibration software in VariPhi® controls and records the quantity of energy supplied by the internal heater.
  • By using VariPhi®, pressure, heat, and activity within a sample can be accurately determined, and complex mathematical corrections can thus be prevented.
  • VariPhi®’s patent number is US 7,021,820 B2

Diagram of the VariPhi®

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