Thermal fluctuations

Thermal Fluctuations Evaluation with Heat Flux Sensing Technology

Thermal Influences fluctuations

This short review describes how heat flux sensing technologies can be employed to evaluate thermal fluctuations evaluation for a broad range of research and industrial applications. It will allow the reader to gain a deeper understanding about thermal influences in precision instruments.

About the importance of thermal fluctuations evaluation

Thermal Fluctuations occur when a temperature gradient is observed in a given environment over a period of time, due to natural temperature changes during the day or due to the effect of environmental conditions (Air conditioning, body heat, machinery and appliances). Consequently, thermal fluctuations are present in all systems. Thermal fluctuations can often limit the achievable precision of an instrument by inducing thermal expansion.

Thermal expansion results in an expansion of gas and materials with the addition of heat and, on the opposite, a constriction when cooled. This effect is almost invisible during everyday life, but is no longer negligible when taking nanoscale measurements. any variation in the system environment can degrade repeatability of measurements: a difference of even a few degrees can change the size and shape of a sample and also modify the calibration of the instrument. Another important application where temperature variation needs to be carefully monitored and thermal fluctuations strictly controlled, is biological applications. Indeed, biological systems are very sensitive to temperature gradient so that as temperature changes, the behavior and characteristics of the biological systems evolves.

To avoid those indesirable effects, it is important to measure, monitor or control the thermal fluctuations to compensate for those temperature gradients, and reduce the inaccuracy of a measurement.

Temperature changes occur gradually and periodically. It is therefore difficult to diagnose when thermal fluctuations lead to inaccurate measurements. Continuous thermal measurements must be performed to diagnose a thermal issue with certainty. Thus, continuous and real-time measurements of heat fluxes can be the solution to avoid thermal influences in precision instruments.

How to perform thermal fluctuations evaluation with heat flux sensors

The current approach to control thermal effects is based on multi-parameter models. These models are derived empirically, and are used to measure and predict thermal influences. The most common parameters in such models are temperatures at various locations in the system and situational information (e.g. power consumption of motor). A certain compensation of thermal effects is accomplished with this method. However, in some applications, higher measurement precision and robustness towards external factors like changing ambient temperature is required to obtain a satisfactory compensation. This is where heat flux sensors add a lot of value.

Why choosing to monitor thermal influences with gSKIN® Heat Flux Sensor vs. temperature sensor?

gSKIN® Heat Flux Sensors add value to these three areas where temperature sensors are limited:

  • Non-linear temperature profile: A large number of temperature sensors are necessary to reconstruct the temperature profile with sufficient accuracy.
  • Temperature resolution: Standard temperature sensors have a limited temperature resolution, which limits the measurement accuracy.
  • Heat flow dynamics: The change of incoming or outgoing heat flow is unknown since primarly, it is not determined experimentally. An exact statement about whether the system is heating up or cooling down is therefore difficult.

Heat Flux Sensor – gSKIN®-XI

Advantages of using gSKIN® Heat Flux Sensor for thermal fluctuations determination

gSKIN® Heat Flux Sensor is suited to evaluate thermal fluctuations in your system:

  • Miniature & compact heat flux sensor
  • Highly sensitive sensor
  • Facilitated integration into the application setups
  • Non-invasive measurement technique for determining fouling
  • Flexible, easy to mount on pipes and boilers

More R&D Uses Cases where the gSKIN® Heat Flux Sensor is employed are available here.