Feedback Application Notes Product
Thermoelectric Cooler Super Coolers for Chip
Solid State Heat Pump to cool your device below freezing !
· Apply Voltage ( + to red, - to black ) Top side will be cooled · Reverse polarity Top side will be heated
|
DTmax: maximum temperature difference achievable when no heat source at cold side (Q=0W) Qmax : max. heat moved from cold to hot side (DT=0oC) Imax : current needed to reach maximum DT or Q Vmax : DC voltage needed for Imax |
|
| P/N | Imax | DTmax | Vmax | Qmax | L | W 30 | H |
| C1-07103A* | 3.3 | 60 | 8.1 | 16.4 | 30 | 30 | 4.7 |
| C1-07104A* | 3.9 | 60 | 8.6 | 18.7 | 30 | 30 | 4.7 |
| C1-07105A | 4.6 | 60 | 8.5 | 22.8 | 30 | 30 | 4.0 |
| C1-07106A* | 6.0 | 62 | 8.6 | 28.7 | 30 | 40 | 3.8 |
| C1-12704A* | 3.9 | 60 | 15.4 | 33.4 | 40 | 40 | 4.7 |
| C1-12705A | 4.6 | 60 | 15.4 | 33.4 | 40 | 40 | 4.0 |
| C1-12706A* | 6.0 | 62 | 15.4 | 51.4 | 40 | 40 | 3.8 |
| C1-12708A* | 8.5 | 60 | 15.4 | 68.8 | 40 | 40 | 3.3 |
|
P/N |
Imax |
DTmax |
Vmax |
Qmax |
L |
W1 |
W2 |
H |
|
S1-00701A* |
1.0 |
62 |
0.8 |
0.6 |
4 |
4 |
4 |
2.7 |
|
S1-03102A* |
2.0 |
62 |
3.8 |
4.0 |
12 |
12 |
12 |
3.2 |
|
S1-06303A* |
3.0 |
62 |
7.6 |
12.7 |
30 |
15 |
15 |
3.6 |
|
S1-07103A* |
3.0 |
62 |
8.6 |
14.4 |
23 |
23 |
23 |
3.6 |
|
S1-12704A* |
3.9 |
62 |
15.4 |
33.4 |
30 |
30 |
30 |
3.2 |
S1-03201 |
0.80 |
67 |
3.87 |
1.72 |
special |
|
|
2.4 |
|
S1-1801C |
1.50 |
67 |
2.18 |
1.82 |
4.2 |
6.2 |
4.2 |
2.4 |
|
S1-1701K |
1.50 |
67 |
2.06 |
1.72 |
6.2 |
6.2 |
6.2 |
2.4 |
|
S1-0401C |
1.50 |
67 |
0.48 |
.40 |
4.2 |
4.2 |
2.2 |
2.4 |
|
S1-3102M |
2.1 |
67 |
3.75 |
4.4 |
12 |
12 |
12 |
3.4 |
|
S1-3103O |
3.0 |
67 |
3.75 |
6.3 |
15 |
15 |
15 |
3.6 |
Multistage to maximize the cooling.
|
P/N |
Imax |
DTmax |
Vmax |
Qmax |
L1 | L2 | W1 | W2 | H |
|
S2-2401 |
TBD |
5.9 | 3.9 | 5.9 | 3.6 | 3.5 | |||
|
S2-5604 |
25.0 | 9.7 | 25.0 | 9.7 | 7.2 | ||||
|
S2-8402 |
28.8 | 22.4 | 21.6 | 8.9 | 7.3 | ||||
|
C3-17704 |
39.9 | 19.8 | 39.9 | 9.8 | 10.7 |
* These are Popular Models and are readily available. · Proper Heat sink always needed for the hot side
Max. Operating temperature 85oC. Modules for higher temperature ( > 125 oC ) are also available.
Other Models available & custom design welcome. Call ACK for details.
Cool to below ambient or even freezing !
Heat Pump Assembly -- It consists of a Heat Pump ( Thermoelectric Cooler), heat sink, and cooling fan. These assemblies can provide cooling for Laser Diodes, Detectors, CPUs, small samples, small box & etc. The heat from one side will be pumped away thru the Heat Pump to the heat sink and then to ambient air with the help of the cooling fan. Cooling to below freezing can be achieved and the cooling powers are from ~ 2 W to ~ 40 watts and up. Apply the DC power, these units are ready to cool your device. No complicated assembly is required.
Chip Cool Chip to below ambient Miniature ( ~ 1" x 1" x 1")
Super Coolers for Chip Custom design welcome.
| P/N Super Cooler | TEC Power Req. | Cooling | W x L x H (mm) | Price |
| SC-3 | 5 V, ~1 A | ~ 2 W | ~ 30 x 30 x 30 | $45 |
| SC-5C (Pentium) | 5 V, ~2 A | ~ 25 W | ~ 55 x 62 x 30 | $39 |
| SC-P2 (Pentium 2) | 5 V, ~2 A | ~ 35 W | ~ 65 x 140 x 35 | $50 |
Super Cooler Box
Box Cool Box to below ambient
Cool Box Custom design welcome.
| P/N Super Cooler | TEC Power Req. | Cooling | W x L x H (mm) | Price |
| SB-10 ( for small Box) | 12V, ~3.2 A | ~ 15 W | ~ 90 x 70 x 100 | $80 |
| SB-12 ( for small Box) | 12V, ~5 A | ~ 25 W | ~ 90 x 70 x 130 | $90 |
For all SC models - the fan requires 8- 12 VDC power. For SB series - Box is not included.
Cold Stations for Lab Applications Custom design welcome.
| P/N Cold Station | TEC Power Req. | Cooling | W x L x (mm) | Price |
| CS 5A ( 4.5-5.5 Volt) | 4.5-6V, ~1.5 to 2 A | ~ 5 W | ~ 45 x 45 x 30 | $40 |
| CS 6A ( 5-5.5 Volt) | 5-6V, ~3 to 4 A | ~ 10 W | ~ 65 x 70 x 70 | $45 |
| CS 10A ( 8-12 Volt) | 8-12V, ~1.8 to 3 A | ~ 10 W | ~ 90 x 70 x 70 | $55 |
| CS 12A ( 8-12 Volt) | 8-12V, ~2 to 4 A | ~ 20 W | ~ 140 x 90 x 70 | $65 |
Other Models available & custom design welcome. Call ACK for details.
Application Note
ThermoElectric Cooler (TEC) Also called TE cooler or Peltier cooler or electronic heat pump,
is a semiconductor device and functions like a heat pump. · By applying a DC current to the
TEC, heat will be moved through the module from one side to the other. One
module face will be cooled while the other side is heated. Seebeck Effect an electric current would flow continuously in a
closed circuit if heat is applied to the thermocouple junction. This principle
was discovered by Thomas Seebeck, a German scientist.
Peltier Effect If a voltage is applied to the semiconductor junction an electrical current will flow in the circuit. As a result of the current flow, a cooling effect will occur at one junction and a heating effect will occur at the other junction.
· The cooling or heating is proportional to the magnitude of current.
· Thjs effect is reversible. If the direction of current is changed, the original cooling side will become heating side and heating side becomes cooling side. Joule heating (1X R), R is the electrical resistance also occurs in the semiconductors as a result of current flow.
ThermoElectric Material
·
Made of Bismuth Telluride Semiconductors· Couple - pair of N & P bars connected in series
· Bar areas are from 0.2mm2 to 25mm2
· Pumping capacity is about 40 mW/mm2
· Roughly one amp/mm2 produces 3 00C temperature difference Technology up to
254 couplesMean Time Before Failure (MTBF)
TEC, a solid state device, is highly reliable with MTBF 200K to 300K hours at room temperature.
· At
800 C, MTBF are estimated about 100K hours. Yet, actual field results are 2 to 3 times higher. Failure return rate is less than 0.1% with over 90% of these returns are due to improper uses such as too much mechanical force or overheating.· Less than 0.01% is due to the production defect.
Mechanical Mounting: Uneven compression forces induced by improper torque, bolting patterns, and uneven surface of heat sink should be avoided.
· Recommended compression is 150 pounds/sq. inch. TEC is relatively weak in the shear direction.
· Avoid any shear force due to un~ven torque.Shock and Vibration: TEC has been used for military applications. However, it can handle sever shock and vibration in compression mode only.
Moisture: Prevent moisture from penetrating into the TEC. The presence of moisture will cause corrosion and degrade the TEC, conductors and solders. Moisture can also cause electrical and thermal shorts between the hot and cold sides.
· Sealing or dry atmosphere should be provided.
Overheating: Above 800 C, copper diffuses into the TEC. At 100-1 100C it could result in about 25% loss of device performance within 100 hours.
· Also above 850 C, a solid state reaction occurs between TEC and bismuth4in solder. In extended time this may result in failures of the interface.
· For high temperature applications be sure to use ACK's industrial & military grades.
Installation There are three methods:
adhesion, compression, or soldering.
For smaller area (<1 9mm) adhesion or soldering works fine since the thermal stress due to expansion mismatches of solder or epoxy and the TEC ceramic plate is not much.
· For area larger than 1 9mm, the compression with thermal grease is recommended. Thermal grease can provide a more flexible interface to relieve the stress.
Preparin~ Surfaces The surface should be flat of less than 0.08mm over the TEC mounting area. The surface should be clean and free from oil, nicks and burrs. For multiple-stage application, the TEC thickness should vary no more than 0.05mm
Typical TEC Applications
for cooling:· Infrared Detectors
e Charge Couple Devices· Liquid Exchangers · Laser Diodes
· Air to Air Exchanger. Black Body References
ThermoElectric Cooler (TEC) Selection
· Use the ACK rule of thumb on the inside of back cover for a quick selection and the following detail guides to verify the selection
Active Heat Load - Q = V x I. The heat load is the voltage, applied to the device, times the current through the device. Typical Intel 586 CPU generates about 15W in active mode. A photo diode with bias of 50V and resistance of 0.5 mega-ohms generates only 0.005 watts.
Parasitic Heat Loads- Heat loads due to:
Convection - When the air (Tair) flows over an object of different temperature (T~), heat transfer takes place. Convective heat load on TEC can be result of natural convection or induced by a fan.
This loading, the most significant loss, is a function of
the exposed area and the difference in temperature (Tair -T~). It is computed:
Q = h A (T air - T) , where h is heat transfer coefficient
(w/m2 0C) 21.7 for a flat, horizontal plate in air at 1
ATM, A is the exposed area in m2
Example: A 0.01 m2plate (0.006m thick) is cooled from
25 0C to 5 0C. The heat load is about 5.4 watts.
· It is important to avoid condensation when cooling below the dew point. This can be achieved by enclosing the cooling system in a dry gas or a vacuum environment.
Conduction -Conductive loads occur through lead wires, mounting screws, etc., which form a thermal path from the device being cooled to the heat sink or ambient environment. The loading can be expressed as:
Q=k A AT I L, where k is the thermal conductivity of the material (w/m 0C), A is the cross section (m2), L is the heat path length (m), and AT is the temperature difference (0C). The thermal conductivity for a few commonly used materials. Unit: w/m 0C
AL(1100) 238 AL(6035) 205 CU 386 Epoxy 0.8 Grease 0.87 Air 0.026
Radiation -Heat load through the electromagnetic radiation between two objects of different temperatures. This load is not significant when the system is operated in a gaseous environment.
Coefficient of Performance (C.O.P. ) defined as the heat removed at the cold junction, divided by the input electrical power for the TEC.
· Operating at higher C.O.P. has the advantages of using less input power and therefore generating less heat on the hot side. In turn a smaller heat sink is required. To achieve higher C.O.P. it requires larger or additional TECs. This should be examined closely to reach a optimal design in terms of overall cost and reliability.
Heat Sink Selection
· Keep TEC hot side temperature as low as possible with proper heat sink.
Power Supply - Keep AC ripple <20%TEC is a low impedance device. After a TEC has been selected, the required current and voltage can be used to determine the wattage of power supply needed. Power supply ripple filtering is not critical for TEC than for other typical electronic applications.
· TEC performance, AT, will degrade by 5% for a 20% AC ripple.
From the 115 VAC source, a simple full-wave bridge rectifier and a filter capacitor ( 4000 mf) can be used. A switching power supply, with small size and light weight advantage over a linear unit, should also be considered.
Temperature Controller - Determine temperature
accuracy needed, then use one of the followings:
Open Loop (f 10C) - Simple temperature control can be achieved by a variable DC power supply if the thermal load is relatively constant.
· By manually adjusting the DC power supply output a temperature of 1 1 0C can be maintained for over several hours.
Closed Loop ( +/- 0. 10C) - Feedback system is needed for 1 0. 10C accuracy or it the heat load fluctuates. Special PID control loop is used to maintain 1 0.0 10C. TEC exhibits about 0.5% per 0C increase in its electrical resistance.
Installation
Directions
Cold Station
1. Connect the Red terminal
to +Black terminal to -.
DC Voltage ONLY
2. Check that the two flat head screws on cold plate
( holding TE to heat sink) is hand
tight. Never
apply too much force ! It
may break the TE.
3. Make sure: a)
fan rotating properly & b)
no blockage of air flow.
*
The heat sink may get warm, but never too hot to touch.
4. If a sample holder is placed on top of the cold
plate, apply a thin layer of the thermal grease (included) to the interface.
For better cooling, use brackets, 4-40 screws (not included) and tapped
holes to press down the sample holder for good contact.
SuperCooler
a. Turn off the Computer and open the computer case.
b. Mounting Method: Clamp or clip
1. Apply
a very thin layer of thermal compound on the TEC surface.
2. Position the
package on top of the CPU ( press, slide left & right for good TEC & CPU
contact),
3. Use the clamp to tighten
the SuperCooler to the CPU.
c.
Connect the SuperCooler to DC power.
Cautions:
Max. Voltage for
Fan is 12 VDC.
Max. Voltage for the TEC is ~ 10 VDC,
nominal 5 V for CPU applications.
( use voltage > 5 V, the
hot side - heat sink may overheat and damage the TEC. )
Super Cooler - Box
On
your box it Requires
A.
a cut-out of ~ 65 mm x 65. For
cooling module.
B.
Two holes ( spaced x distance apart across the square cut out, make sure it
matches the spacing of two holes on the large heat sink) to allow at least #4
screw to go thru). For fastening the large heat sink & fan package
C.
One hole ( 0.25 dia.) ~ 1
away from the edge of cut out. For
wires. ( a proper grommet is recommended.)
Installation
-
a.
put the
small fan package thru the cut- out on the box
b.
align the
two holes on the box with the two hole on the large heat sink
c.
use two #
4 screws and nuts to fasten the heat sink on to the box,
put
adequate insulating material between the two heat sinks.
d.
pull
wires ( inside box) thru the wire-hole to the out side
e.
screw
back the larger fan on to the heat sink, make sure the fan wire is close to the
heat sink (the air should blow down to heat sink).
Both
fans require 12VDC.
Heat
pump (thermoelectric module) can operate from ~5VDC to ~ 12VDC.
You may adjust it to achieve optimal cooling for your applications.