Cerberus
CU Boulder
Evan Lamson
Faisal Albirdisi
Aleksey Treskov
Wyatt Mohrman
Tegan Argo
Sarita Gautam
Project Overview
• Capture heat energy generated by the internal resisters of computer component
efficiently.
• Transfer that heat energy into electrical energy in an optimal level.
• Increase the processing power of the computer without causing to computer
components fail.
• Monitor the system functionality using an Android device and Graphical User
Interface(GUI).
• Control system temperatures and maintain optimal operating conditions
Goals
• Primary:
- Construct an effective Case
- Develop a control system to maintain the best possible temperature difference
• Secondary:
- A display which will monitor system temperatures, clock rates, and power
generation
• Final:
- Fully automated control of clock speed, flow rates, and power generation.
Preliminary Design
System Block Diagram
Power
Desktop PC
Computer
TEG Power Reclamation
DC Power
Control System
User
Display
Data Visualization
Control System
• Level 2 Functional Decomposition
Thermal Sensors
Pump Control
Flow Rate Sensor
Computer Control
Clock Speeds
User data
µController
Bluetooth
module
Current Status
• Prototype Case
• Final selection of Computer System
• Testing
• TEGS
• Power Conversion
• Microcontroller selected
• Control system schematic designed
• Functional decomposition down to level 3
• System context diagram
• Class diagram
Heat Transfer Analysis
• Heat Loss(or gain) through the walls of an insulated container
• EQ: Q=A((TO-TI)/(L/K + 1/h)) Where:
• -Q is the heat lost or gained in watts
• -L is the thickness of insulation in meters (m)
• -K is the Thermal Conductivity of the insulation material in watts/meter C
• -A is the outside surface area of the container in meters squared (m2).
• -h is the Heat Transfer Coefficient of the surface material in watts/meter2 C
• -TO is the Outside temperature in C (21 ° C for air, 15 ° C for water)
• -TI is the Inside temperature in C
Heat Transfer Analysis
VS
Heat Transfer Analysis
• Using old Design:
Heat Loss Total : Q = -188 W (with 70 ° C oil temperature)
Through TEG wall acrylic : Q = -159 W
• Using new Design:
Heat Loss Total : Q = -45 W (difference of 143 W)
Through TEG wall acrylic : Q = -0.18 W (difference of 158.82 W)
New Case Design
• SolidWorks design allows us to
laser cut each piece to the
exact dimensions needed.
• If any changes need to be
made later, they can be tested
first in software to ensure
mistakes aren’t made.
New Case Design
• Area of TEG wall reduced to
minimize the area of the acrylic
between hot and cold side.
• Power Supply is also
submerged in the oil.
• Hard Drive / CD Drive not
submerged.
Hardware
• CPU and Motherboard
• Intel I5-2500K Processor
• Quad Core Sandy Bridge 3.3GHz (3.7 GHz Turbo Boost) Processor
• Intel HD Graphics
• Fully unlocked and overclocking-enabled
• Biostar TZ77A Motherboard
• Designed for overclocking
• Unlocked BIOS
• Components chosen for robustness and long-life
Hardware
• Sensors
• DS18B20 Programmable Resolution 1-Wire Digital Thermometer
• Operating range: -55° to +125° C
• Accuracy: +/- 0.5° C
• Communicates over a 1-Wire bus
Hardware
• Pumps
• EWP-DC30A Mini DC Brushless Submersible Pump
• 3.6 L/min or 57 GPH
• Long life: > 20,000hrs
• Size: 2.0"x1.7"x1.36"
Hardware
• Thermo-electric Generators
• 1261G-7L31-04CL Power Generation Module
• Max temperature of 300° C
• Pre-applied graphite thermal interface material
• Size: 1.18"x1.18“x0.15"
Quick Recap
• How does a TEG work?
• Employ the Seebeck effect principle.
• V= S* ΔT, S : Seebeck coefficient, ΔT: Temperature differential
• Heat is carried by holes in P type, electrons in N type.
• Across each junction a small voltage is produced.
• Place many of these in series/ parallel to get useful voltage.
• Heat -> DC Volts
ΔT°C  TEG  DC Voltage!
• Can you really generate that much electricity from waste heat?
• Yes we can!
Test/Results
• Setup:
• 2 series connected TEGs where placed as part of a wall separating the hot and cold
compartments.
• Heat sinks where attached to either sides to increase thermal transfer from fluid to
TEG wall.
• PICTURE OF SETUP
Open Circuit Voltage
• Perfectly linear behavior !
• Able to log ~700mV @ 35°C ΔT
• Final design :
• 2 parallel strings of 6 series connected TEGs
• Voc = 2.4 V
Short circuit current
• Again Linearity.
• ~57mA @ 35°C ΔT
• Final desigd:
• 2 parallel strings of 6 series connected TEGs
• Isc = 120 mA
TEG resistance varies with temperature
• Typically between 1.8 to 3.3 ohms per TEG module.
• Problem with using semiconductors is the internal resistance.
Load matching
• In order to get the most power from the TEGs we must match the load resistance
to the TEG internal resistance.
• Max P equal to
• ~13mW @ 40 Delta
• ~7.5mW @ 30 Delta
For Spring
• MPPT Tracking.
• Load matching.
• Boosting output.
• Development of a back-up battery charging system.
For Spring
• MPPT Tracking.
• Load matching.
• Boosting output.
• Development of a back up battery charging system.
Class Diagram version 2
Layer 1: Data Acquisition
• Boss
• Display
• Main class
• Data manager between two user interfaces
• Updates temperature data using a Timer
Boss
- timer Timer
- int newField
+ public void run()
+ public void getOilTemp()
+ public void getWaterTemp()
+ public void getPowerReading()
+ public void analyzeCurrent()
Timer
Display
- bool checkFlag
- double Data
+ public void tempTimer()
+ public void Mpp()
+ public void displayUpdate()
+ public void UpdateAndroid()
+ public void UpdateGUI()
+ public void displayGraphs()
+ public void displayMessage()
Layer 2: Data Management
• LOG
• Alarm
• Collects data for all the sensor readings
• Analyzes data
• Sends warning to the Boss
LOG
- double hotTemp
- double clockSpeed
- double voltage
- double internalTemps
- double coldTemp
+ public void logData()
Alarm
- bool checkFlag
+ public void setFlag()
+ public void notifyBoss()
+ public void analyzeHistorical()
Layer 3: Hardware Interface(Sensors)
• Temperature
• Fluid
• CPU
• Motherboard
• Clock speed
• Voltage
MotherBoardSensorInterface
- int ambientTemp
- int CPUTemp
- int CPI
- Int Clock
+public void getTemp()
+public void getClockSpeed()
PowerInterface
- double Power
+ public void getPower()
WaterTempInterface
- double WaterTemp
+ public void getTemp()
OilTempInterface
- double oilTemp
+ public void getTemp()
Layer 3: Hardware Interface
• Control Signals
• Pump
• Motherboard
MotherBoard
- double voltage
- int Multiplier
- Int Idle
+ public void adjustVoltage()
+ public void adjustMultiplier()
+ public void adjustClock()
OilPump
-bool OnOff
+ public void PumpON(PumpNo)
+ public void PumpOFF(PumpNo)
Layer 4: User Interface
• Gives user visualization on Temperature and Power Usage Statistics
• GUI has full control of the system
Android
- double voltage
- double power
- double oilTemp
- double waterTemp
+ public void displayData()
+ public void ClockSpeed()
+ public void Temperature()
GUI
- double voltage
- double power
- double oilTemp
- int modeSelector
- double waterTemp
+ public void displayData()
MSP-430G2231
• Ultra Low Power
• standby power of 0.4μA
• Low Cost
• Dip package
• Enhanced libraries
• 1 wire library
1 wire protocol
• Dallas Semiconductors
• Speed:
• Standard: 15.4 kbps
• Overdrive: 125 kbps
-1.00E-01
1
60
119
178
237
296
355
414
473
532
591
650
709
768
827
886
945
1004
1063
1122
1181
1240
1299
1358
1417
1476
1535
1594
1653
1712
1771
1830
1889
1948
1 wire continued
6.00E-01
5.00E-01
4.00E-01
3.00E-01
2.00E-01
1.00E-01
0.00E+00
Circuit Schematic
Input Power Control with CPU
Throttling (In Windows)
This program adjusts the registers on the
CPU, either to enter idle, or to adjust
core multiplier.
In Linux MSR can set these directly…
Here I access the 0x198 register on all 4
cores, this register reports max and
current core frequency, when I try to
access 5th core (does not exist) I get
error
wrmsr 0x198 <value> would adjust the
values set to current core frequency, but
we need to find the correct <value> to
set. Luckily there is an open source tool.
CPU Tuner is a Linux open source tool
for controlling Intel CPUs with MSR
All of this allows us to control the
amount of heat going into the system.
If we fit experimental data with
known power input, P_CPU = 56 W
We get: Very basic General Model
𝜏 = 1 𝑏 = 7564.3
temp(t) = 𝑎 ∗ 1 −
−𝑡
𝐸𝜏
The model agrees nicely with
data, predicts max temp, and
time constant to get there.
𝜏 is related to input power
(assuming linear proportionality)
temp t = 𝑎 ∗ 1 −
−𝑡∗𝑃𝑖𝑛
𝐸 𝜏c
𝜏c = Pin ∗ 𝜏 = 423601
This allows us a real-time way to
adjust the heat power going into
the system.
Pumps to control the amount of
heat power leaving the system.
With this we can use make a
complete feedback control system
to maintain a nominal temperature
for safe CPU operation and TEG
power generation independently of
user process load activity.
RED = Pin-> 46W
GREEN= Pin->17W
BLUE=Pin->8W
• User would just use the computer like normal.
• At startup no pumps are running, and a good differential
temperature is built up.
• Once the TEGs have a good enough temperature differential (with
still safe CPU), we turn on/off the pumps to maintain that constant
differential.
• Our system would automatically scale back the clock speeds if our
case cannot keep up with the heat dissipation.
• Otherwise it would allow full, even overclocked clock speeds, as
long as the pumps and TEGs continue to dissipate the same amount
of heat as the CPU cores generate.
Potential Marketability
• Potential Marketability
• Close in size to regular desktop computers
• Save money on electricity
• Impact on Society
• Higher computer performance
• Reduces waste heat
• Safety
• Overheating
• Adjust clock speed
• Increase flow rate of cold oil
• Risk of ground fault
• Plug the equipment into a GFCI (Ground fault circuit interrupter) protected outlet
Parts Procured
Schedule Spring Semester
Division of Labor
Component
Primary
Secondary
Heat Reclamation System
Pump Control
Wyatt
Aleksey
Fluid Transport
Aleksey
Evan
TEG array design
Wyatt
Faisal
Case design
Evan
Aleksey
Interface /Sensor
Microcontroller
Wyatt
Sarita
On screen display
Sarita
Tegan
Software
Aleksey
Evan
PCB Design
Evan
Faisal
Safety Electronics
Tegan
Evan
Power Electronics
PCB Design
Faisal
Sarita
Circuit Design
Faisal
Evan
DC-DC Boost
Faisal
Aleksey
TEG MPP Tracking
Tegan
Wyatt
Project Management
Budget
Wyatt
Tegan
Documentation
Sarita
Tegan
System Construction
TEG Array
Sarita
Faisal
CASE
Evan
Sarita
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