Perma Pure BALDWIN 225CE, Instruction Manual

Page: 5 / 44

Section C: Principle of Operation 5
C: P
RINCIPLE OF
O
PERATION
Thank you for purchasing a Baldwin Model 225 Thermo-Electric Cooler. Baldwin’s
Thermo-Electric Coolers are specifically designed for high ambient temperature &
high water volume applications. Each model features an oversized heat sink and
high performance thermoelectric devices for high heat removal capacity. Heat sinks
used in Baldwin Thermo-Electric Coolers are made out of high heat transfer
extruded aluminum with large 3/4" thick end plates. Each model also incorporates a
special controller specifically designed to run at high ambient temperatures.
The process of sampling combustion product stack gas or exhaust from internal
combustion engines requires a method to remove the moisture from the sample,
without removing the gas components of interest. The Baldwin Thermo-Electric
Cooler is an ideal way to decrease the dew point of combustion gases to a
repeatable, stable, constant low dewpoint. The Baldwin cooler prevents water
condensation in sample pre-filters, sample pumps, and gas analyzers. For gas
analyzers where water vapor is an interferant, a stable, repeatable dewpoint
becomes a part of the gas analyzer performance specification. Baldwin coolers
provide this constant low water concentration, resulting in an accurate component
gas measurement.
All Baldwin coolers use thermo-electric elements (Peltiers) to cool the sample gas to
the desired dew point temperature. A thermo-electric cooler is best illustrated as a
small heat pump with no
moving parts. The Peltiers
operate on direct current and
may be used for heating or
cooling by reversing the
direction of current flow. This is
achieved by moving heat from
one side of the module to the
other with current flow and the
laws of thermodynamics. A
typical single stage Peltier
(Figure 1) consists of two
ceramic plates with p- and n-
type semiconductor material
(bismuth telluride) between the
plates. The elements of
semiconductor material are
connected electrically in series and thermally in parallel.
Figure 1: Thermo-electric element (Peltier)