Measuring the heat flow

A new heat flux measurement device called the Episensor can measure heat transfer through virtually any material surface. Developed by the US-based Vatell Corporation, and originally developed to measure heat flow through building components, the sensor has now been found to have far wider applications.

Researchers discovered that the Episensor could measure the heat flow through spacecraft skin, geothermal heat transfer, heat dissipation in electronics, or energy release in fermentation processes and micro-organism research.

The thick film sensor itself has 1600 thermocouples per square centimetre that are deposited on a thin flexible anodised aluminium substrate which can be contoured to fit flat or cylindrical surfaces with radius of curvature of 5cm. The aluminium has very low thermal resistance, reducing effects on the measured variables.

The Episensor has two options for mounting. The standard option uses specially thermally conducting double-sided tape across the back area of the sensor. The sensor is also supplied without adhesive material to allow the designer to customise it.

The manufacturing process developed for the sensor means that it can be used in previously uncharted territory: large quantity applications such as industrial control, indoor environmental controls and large-scale heat flow tests are all possibilities.

Designers interested in further information on the Episensor and other heat measurement devices can visit the company’s World Wide Web site at

{{Table 1: A new way to measure heat flow

Episensor Specifications

Standard active area 5cm x 5cmStandard substrate area 6cm x 6cmOverall thickness 0.6mm (including tape)Thermal resistance <1oK/(W/cm2)Standard sensitivity 25mV/W/cm2Rise time ~60msecFlexibility (radius of curvature) 5cmTemperature (max.) 150oCLeads 1m shielded cableCoating Colloidal Graphite and ZynolyteThermocouple Type E}}

{{Vatell CorporationTel: USA (+1) 540 961 2001Enter 403}}