Thermal ConductivityThermal conductivity (λ with the unit W/(m•K)) describes the transport of energy – in the form of heat – through a body of mass as the result of a temperature gradient (see fig. 1). According to the second law of thermodynamics, heat always flows in the direction of the lower temperature.Thermal Conductivity

GHP 456 Titan®

Innovative Guarded Hot Plate System GHP 456 Titan® for Determination of Thermal ConductivityThermal conductivity (λ with the unit W/(m•K)) describes the transport of energy – in the form of heat – through a body of mass as the result of a temperature gradient (see fig. 1). According to the second law of thermodynamics, heat always flows in the direction of the lower temperature.Thermal Conductivity of Insulations

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Highlights

Guarded Hot Plate - The Absolute Method for Testing Insulation Materials

Insulation materials are growing in significance in a number of applications, including the insulation of buildings. Improved insulation reduces energy use and consequently heating costs for each individual household or industrial operation.

The NETZSCH GHP 456 Titan® is the ideal tool for researchers and scientists in the field of insulation testing. Based on the well‐known, standardized guarded hot plate technique, the system features unrivaled performance over an unmatched temperature range. 

The GHP principle is based on an absolute measurement method and therefore requires no calibration standards. Combining cutting‐ edge technology with the highest quality standards, NETZSCH has designed a robust and easy‐to‐ operate instrument, featuring unparalleled reliability and optimum accuracy over a wide temperature range.

The Guarded Hot Plate is an absolute method

The great advantage of the GHP method is that it is an absolute method; i.e., no calibration or correction is required at all. The Thermal ConductivityThermal conductivity (λ with the unit W/(m•K)) describes the transport of energy – in the form of heat – through a body of mass as the result of a temperature gradient (see fig. 1). According to the second law of thermodynamics, heat always flows in the direction of the lower temperature.thermal conductivity values result in the stationary state simply from the: 

  •  precisely measured total power input into the hot plate, Q
  • average sample thickness, d,
  • measurement area, A, and
  • mean temperature difference, ΔT, along the sample or the two samples, as the case may be (the factor 2 results for two samples).
GHP 456 Titan® in open position. The samples are placed between the hot plate (1) with guard ring (2) and the lower (3) and upper cold plates (4), respectively. Additionally shown are the three‐part sectional furnace (5), insulation (6), feed‐throughs (7), hoisting device (8), and gas connection (9).

Guarded Hot Plate - Principle of Operation 

The hot plate and the guard ring are sandwiched between two samples of the same material and approximately the same thickness, d. Cold plates are placed above and below the samples. All plate temperatures are controlled such that a well‐ defined, user‐selectable temperature difference, ΔT, is established between the hot and the cold plates – and thus across the sample thickness. The guard ring is maintained exactly at hot plate temperature in order to minimize lateral heat losses.

NETZSCH offers more exciting products that support you in measuring Thermal Conductivity:

Specifications

 GHP 456 Titan®
Technique/Design
  • Absolute method (no calibration or reference materials required)
  • Symmetrical arrangement
  • Fully automated operation
StandardsBased on standards such as ISO 8302, ASTM C177, DIN/EN 12667, DIN/EN 12939, etc
Mean specimen temperature range
  • Low‐temperature version: ‐160°C to 250°C
  • High‐temperature version: ‐160°C to 600°C 

Both versions require LN2 cooling for the sub‐ambient temperature range

Cooling systems

Liquid nitrogen (LN2): ‐160°C to 250°C

Compressed air: 50°C to 300°C

Chiller: 20°C to 85°C 

→ No active cooling from 300°C to 600°C

Plate dimensions
  • 300 mm x 300 mm
  • Motorized plate hoist
Plate material
  • Low‐temperature version: Aluminum alloy
  • High‐temperature version: Tungsten alloy
Plate temperature range
  • Standard version: ‐180°C to 270°C
  • High‐temperature version: ‐180°C to 620°C
Vacuum‐tightnessBy design, 5 x 10‐4 mbar (0.05Pa)
Defined pressure levelsControlled between 0.1 mbar and 100 mbar
Specimen thickness
  • Up to 100 mm (typically 10 ... 50 mm)
  • Max. difference in thickness for the two specimens to be measured: 2%
Atmosphere/ pressure level
  • Oxidizing up to 300°C
  • Inert
  • Vacuum
  • Defined pressure levels
Thermal conductivity range0.003 to 2 W/(m·K)*
Minimum measurable thermal resistance0.02 m2·K/W*
AccuracyTypically 2%*
ReproducibilityTypically < 1%*
Software specialties

SmartMode, including:

  • Method‐based, easy operation (e.g., user and predefined methods)
  • Support of controlled, adaptive cooling
  • Report generator
  • Results including combined standard uncertainties according to GUM**

* Depending on the measurement conditions and specimen properties 
** GUM = Guide to the Expression of Uncertainty in Measurement

GHP 456 Titan® – Technology

The vacuum-tight GHP 456 Titan® combines the latest developments in material science and electronics with state-of-the-art design and technology.

Accessories

  • Various pump systems (rotary pumps, turbo molecular pumps) are available for the GHP 456 Titan®. The system can be easily extended later on by add the appropriate pump to the connections of the system.
  • Standard materials: Various kinds of certified (NIST, NPL) standard materials (fiber insulations, foam insulations) are available for the system.
  • Cooling of the heat sinks: The heat sinks can be cooled with forced air (for mean sample temperatures above 40°C) with a chiller (for mean sample temperatures above 0°C) or with liquid nitrogen. The liquid nitrogen is supplied from a feeding system via a software controlled supply system.
  • For measurements of powders and flakes special calcium silicate frames are available, fitting exactly to the plate dimensions.

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Proven Excellence in Service

At NETZSCH Analyzing & Testing, we offer a comprehensive range of services globally to ensure the optimal performance and longevity of your thermoanalytical equipment. With a track record of proven excellence, our services are designed to maximize the effectiveness of your devices, extend their lifespan, and minimize downtime. 

Unlock the full potential of your equipment with our tailored solutions, backed by years of industry expertise and innovation.

Software

All software highlights at a glance

The Highlight of Proteus® Software - SmartMode

The convenient SmartMode allows for the prompt start of a measurement via Wizard, via methods which were defined by the user beforehand (known as User Methods), or via Predefined Methods supplied for the NIST 1450D, IRMM 440 and SilCal1100 standard reference materials. 

Integrated Stability Criteria Management

When should the measurement points be recorded? The Stability Criteria Manager within the Setup & Control section of SmartMode allows conditions to be defined before a measurement starts and even while it is in progress. The stability criteria ensure optimum reliability and reproducibility for the test results. Of course, the default stability criteria of the instrument work well for most specimens

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