Career Excerpts

1. Career Excerpts
Mark C. Woods
M.S. Mech. Engineering
Heat Transfer Specialist
Product Development
Project Management

2. Marlow (2004 – 2012)
A vendor of thermoelectric coolers (TECs) and systems.
TECs are semiconductor devices which employ the
Peltier effect to move heat/refrigerate. Many applications
require highly custom designs.
Common single-stage TEC

3. Marlow (2004 – 2012)
Since trillions of TEC designs are possible and performance is
highly design-dependent, modeling is required to arrive at the best
design for customer applications. Defense/NASA and other high-end
applications are usually custom product. New high-volume
applications are generally custom as well.
Types of Modeling Tools used at Marlow
1-D Codes (MathCAD, Qfin (3-D Flow Network Ansys/Icepak (Detailed
Excel/VB, Proprietary) Solver & Conduction) Modeling, CFD)
Heat Spreading (e.g. telecom Stress predictions in coolers
Steady-State TEC bulk performance
laser diodes, chips, TECs on sinks) (relative comparisons)
Heat Sink/Fan Performance Submount Design/Control Point
Stress/deflection in an assembly
(Extrusions & Similar) Thermal Uniformity
TEC Air-to-Air Cooling System ALO/ALN/BEO decisions
Flow patterns inside an enclosure
Performance Anisotropic Material Selection
Transient Modeling of TECs Multi-Stage lumped TEC modeling
and Systems (especially co-planar)
Quick Cold Plate, Heat Pipe,
Heat Exchanger Modeling
Pinfin Heat Sink Assessment

4. Marlow (2004 – 2012)
First critical step is to adequately characterize the customer’s system and do a good 1-D
model. I’ve found that a “fill-in-the-blanks” approach is the best way to communicate with
a customer (who may not fully understand his system from a thermal perspective).
Thermal Network Model for Active Component(s)
mCp ~ 0 J/K; q = ? W
Total Radiative Load
(Scene and Incident)
SS and Transient Response ~ ??? mW
??? K/W (solder?) Tsurr
at ???K
Device being cooled
??? K Control Point ??” x ??” x ???” Material = ?
mCp = ??? J/K
0.?? K/W (0.?? K/W device RQ + 0.?? K/W epoxy)
TE Cooler Twalls
Leads to Package Temp
Qc, total = ??? mW at ??? K
(~ ?? mW )
~?? K/W (TEC ceramics + solder)
Submount??
Notes: ~0.XXX K/W (Submount spreading + normal resistance)
1 Component: Mass is negligible???
(I/F Resistance ~ 0.??? K/W)
2 Steady-state TEC heat load: Al Sink???
QSS,TOTAL = ?? mW from leads mCp = ??? J/K
+ ?? mW active
+ ?? mW total convective load ??? C/W (Heat Sink Resistance)
+ ?? MW total radiative load)
T ambient held at ??? K

5. Marlow (2004 – 2012)
Working with the customer and managing expectations
• Ideally the customer approaches you early in the design process
• If they are flexible, there may be better materials, mounting
techniques, heat sink designs, or flow schemes they may not have
considered.
• For ill-defined specs, try to bracket the best-case and worst-case
condition (heat load, HSR, ambient temp, etc.)
• Balance/prioritize specs (example: SS COP vs. transient response).
• Don’t sign on to endless model iteration; time is money.
• If available, test customer target package to determine precise design
conditions. Can also import customer solid model of package into
ANSYS or Solidworks and run a model to find design conditions.
• Get feedback from the floor (lab techs, mfg. personnel, process
engineers); push back at customer (tactfully) if necessary.
• For small orders/small fish, use product database to see if ANY
catalog product can meet design requirements.

6. Marlow (2004 – 2012)
Qfin – a flow network modeler with a 3-D conduction solver, offers a
good, quick 3-D estimate (can also toggle it to full CFD, like Icepak).

7. Marlow (2004 – 2012)
Qfin 3-D Parametric Simulation

8. Marlow (2004 – 2012)
ANSYS Simulation on Imported Solid Models

9. Marlow (2004 – 2012)
ANSYS Parametric Simulation on a PCR Wellblock driven by TECs

10. Marlow (2004 – 2012)
Product development example: researched, developed,
and patented the SLIC enclosure cooling system

11. Marlow (2004 – 2012)
Project Management: successfully developed products/
systems for the following demanding customers
Raytheon Lockheed-Martin
Teledyne Imaging Systems SAIC
JPL (Mars Rover) BAE Systems
Coherent General Dynamics
Swales (Mars Rover) Air Force Research Lab
MIT Lincoln Laboratory INO
Thales Alenia Aerospace Hamilton Sundstrand

12. 3M (1998 – 2004)
Led Effort on FTTx / DSL Remote Cabinet
Modular skin-over-frame design with
custom heat exchanger system
Patented battery cooling system
Telcordia GR-487 compliant

13. 3M (1998 – 2004)
Custom door-mounted Hx system also marketed as a field
upgrade for existing OSP cabinets.
Alcatel LSC-2030 Electronics Cabinet with 3M Hx

14. 3M (1998 – 2004)
8800W Remote FTTx Cabinet
Patented small-footprint design
Construction enabled pad-
mount, pole-mount, and thru-
wall interface.
Multiple cooling system options:
custom heat exchanger, OEM air
conditioner, filter fan.
Targeted application: remote
FTTx installations.

15. 3M (1998 – 2004)
CFD Modeling for Upfront Design Verification

16. 3M (1998 – 2004)
Other Projects/Activities
• Laboratory investigations / R&D.
• Analysis and testing in support of legacy products.
• Patent research/authoring, technical report writing,
field documentation authoring.
• Proposal development.
• Customer visits/presentations/demos
• Field trial installations