Chapter 1: Introducing The Peltier Plate; Overview - TA Instruments DHR Series Getting Started Manual

Chapter 1:

Overview

The standard Peltier Plate (schematic shown in the figure below) is the most widely used temperature con-
trol system for the rheometers. It uses the Peltier thermoelectric effect to control the temperature accu-
rately, with rapid heating and cooling. The plate consists of a copper disc, with hard chrome plating on the
upper surface. A Pt100 temperature probe is embedded in the disc, in thermal contact with it and close to
the surface. Copper is used as the disc material for its very high thermal conductivity, ensuring negligible
temperature gradients across the surface of the plate. The hard chrome plating prevents mechanical or
chemical damage to the plate.
The basis of the Peltier effect is this: When an electric current passes across the junction between two dis-
similar metals or semiconductors, a temperature gradient across the junction results—the temperature will
rise on one side and fall on the other. The direction of the current determines on which side the temperature
rises.
On the DHR rheometer plates, a set of Peltier elements is placed below and in thermal contact with the
copper disc. The desired level of active heating or cooling can be achieved by controlling the direction and
magnitude of the current supplied to these elements.
Figure 1 Peltier Plate schematic diagram.
Since a temperature gradient can only be maintained by the input of energy, the Peltier plate requires a heat
sink to remove any waste heat. This is provided by a coolant fluid, normally water, passing through a fluid
jacket situated below the Peltier elements. If the fluid circulating through the fluid jacket is from a closed
reservoir, then its temperature will rise unless it is actively cooled, particularly when the Peltier plate is
operating at temperatures far from ambient.
DHR/AR Series Peltier Plate Getting Started Guide
Introducing the Peltier Plate
80 mm diameter copper
with hardened chrome
surface
Peltier heating elements
Platinum Resistance
Thermometer (PRT)
Smart Swap™ base
Heat sink fluid jacket
Heat sink connections
Page 9