1. Isolated Air Conditioning System
Taylor Bontz
Josiah Bujanda
Christopher Hubbard
Adam Mengestab
Edgar Vazquez
Faculty Advisor: Dr. Yong X Tao
Industry Sponsor: Peterbilt
2. Abstract/Objective
Total fuel used by idling trucks: estimated at over 2 billion gallons/year
Currently 3.5 million truckers on the road
Each requiring 10 hours of rest per day.
To regulate comfort, drivers currently have limited options
Leave the truck on all night
Deal with the intense heat/cold
Rising costs in fuel, as well as the emphasis on green energy
Our solution:
Create a canopy system that dramatically reduces the overall area that a truck’s AC
has to cool.
Quicken cooling times while also entrapping cool air
3. Inspiration
Our approach:
Inspired by the capsule hotel designs; very popular in countries like Japan
Containing cool air while also improving the overall sleeping experience,
without interfering with the original functionality of the sleeper.
Identical wall dimensions
A retractable, portable hotel experience
4. CAD Drawing
Old Design
New Design
Old design problems:
- 2nd layer tarp difficult to keep rigid
- Rail system expensive
- Skeleton structure material expensive
5. Materials
Hollow 6061 aluminum rods for the skeleton
Rigid, strong material (yield strength 55 Mpa)
Light weight (1/16” hollow rods, 1lb./ft.)
Inexpensive
½” Thick, insulated tarp
Outer cover: 12 mm poly
½” cell foam insolation
R value: 3.25
K value: .003908
Lightweight (8 lbs.)
Total weight of material (minus bolts and screws)
32 pounds
6. Skeleton
3 hollow square rods
Minimize weight while allowing appropriate level of strength and support
Metal attaching rods to hold tarp shape
Simple door hinge attachments
Allow top skeleton system to lift vertically
Allows lower skeleton system to bend inward & out of the way
Structure should not interfere with television, lifting bed or any doors.
7. Struts
Two struts add 24 lbs. of lift each
The tarp friction of the bed prevents complete lift, but keeps the skeleton stable
and provides ease of use.
8. Magnets
Also for ease of use, a series of Neodymium mountable magnets were installed
Material: NdFeB, Grade N42
Plating/Coating: Ni-Cu-Ni (Nickel)
Magnetization Direction: Thru Thickness
Weight: 0.63 oz. (17.92 g)
Pull Force: 26.75 lbs
Brmax: 13,200 Gauss
BHmax: 42 MGOe
Ensures upper skeleton snaps into place
Eases transition to close skeleton (left)
Mounted magnets (right) snap skeleton into place
10. Velcro
We lined the skeleton and inside of the tarp with Velcro for easy removal
For safety reasons, the canopy was not allowed to interfere with the
functionality of the bed safety netting.
The easy removability of the tarp will ensure no interference with the netting,
or any other safety features inside the sleeper.
12. HVAC Design
Used a window A/C unit
Cooling Capacity: 3516 W (12000 Btu/hr)
Cooling Load Approx 500 W
Peterbilt has a 700 W A/C unit
available for use.
Exit Air Temp: 16°C
Air Speed: 4.5 m/s at vent
Volumetric Flow Rate: 0.2757 m3/s
14. Energy Analysis
The amount of energy required to cool air can by calculated by
𝑄 = 𝜌𝑉𝑐∆𝑇
𝑄𝑙𝑎𝑟𝑔𝑒 = 206kJ
𝑄𝑠𝑚𝑎𝑙𝑙 = 41.2kJ
80% difference
15. Energy Analysis
The sum of the loads when multiplied by time
can be used to replace the total energy used to
cause an updated change in temperature
𝑞 + 𝑃 𝑡 = 𝜌𝑉𝑐 𝑇𝑖0 − 𝑇𝑖
P represents the cooling load (1758 W)
assuming constant load
q represents the heat rate through the tarp
and is calculated using the instantaneous
temperatures and the properties of the tarp
by using the Equivalent Resistance Method
16. Energy Analysis
The equations can be rearranged to solve for instantaneous inside temperature
𝑇𝑖 𝑡 =
𝑇∞1 𝑡/𝑅 𝑡𝑜𝑡
𝑡
𝑅 𝑡𝑜𝑡
−𝑚𝑐
−
𝑃𝑡
𝑡
𝑅 𝑡𝑜𝑡
−𝑚𝑐
−
𝑚𝑐𝑇 𝑖0
𝑡
𝑅 𝑡𝑜𝑡
−𝑚𝑐
Works in ideal conditions
17. Testing
Temperature dropped at a significantly slower rate than in ideal situation
The practical drop from 23.5 C to 19 C took approximately 13 minutes
vs the 3 minute theoretical drop
Primary reason is escaped cool air.
Theoretically, the percent difference is still significant if not the same when
losses are considered.
20. Why Automation?
Provides functionality and flexibility
Real time monitoring system, data analysis
Improve comfort levels while reducing energy loads
Cost effective
Create a database of information, for processing, analyzing, and improving
Ease of use and high level of compatibility with existing infrastructure
21. Control System
The control system is based off of open source technologies and user generated
content, this provides a high level flexibility and adaptation
Raspberry Pi: Micro computer with micro controller inputs and outputs
Controls Relays through low voltage output, 5V coil activation
Mechanical Relays: 8 Channel 10A 250VAC relays
Switch a variety of loads, with built in circuit protection, and notification
system
Custom Webserver: Secure, versatile, and can be
modified to suit need
The webserver handles data requests and can be
used for scheduling, monitoring, and future additions
Quick to deploy
Cost Effective
Uses existing technologies and infrastructure
22. Control System
The control system is based off of open source technologies and user generated
content, this provides a high level flexibility and adaptation
Intuitive User interface: Provides familiar touchscreen functionality
Ease of use was of key importance.
Unlimited Connectivity: Any device capable of running Javascript can be a
host device
Smartphones, tablets, laptops, no internet connection required, LAN
functionality
Extremly low power consumption: 22 Watts at peak power
Remotely Accessible/Field Adjustable: Allows for user customization remotely
The system can be accessed and monitored from any location
Constantly updating software
Self diagnosing error correction
23. Expandability
Rapid Cooling
Scheduled persistent cooling
Sustained temperature control
Hysteresis to maintain efficiency and control
Reducing Comfort Priority
Based on user activity
Reduce cooling load to save power
Monitor Sleep patterns to assess comfort level
Can be coupled with existing API to develop new ways of approaching
efficiency
Increase cooling load before user wakes up
Provides added comfort when user is aware
24. Expenses
ADA Fruit Kit System
Wireless Keyboard/Mouse combo $29.95
Temperature/Humidity Sensor $15.00
5V 2A switching power supply $7.95
HDMI Cable $3.95
Miniature Wifi Module $11.95
HDMI 4 Pi: 7” Display & Audio $99.95
Raspberry Pi 2 Ultimate Starter Kit $99.95
Skeleton/Tarp System
30’ Velcro tape $33.94
1/16”x8’ Aluminum rod (3) $27.78
Aluminum rod Stiffener $9.26
Canopy support rods (3) $18.81
Hinges (6) $29.78
Nuts, bolts and screws (est) $35.00
Neodymium Magnets (5) $26.20
Total Raspberry Pi Kit: $268.70
Total with HDMI Pi Display and Hardware: $449.47
Total without HDMI Pi Display +Hardware: $349.52
Total Hardware/Skeleton Only: $180.77
25. Future Opportunities for Improvements
Remove air leakage (utilize bulb seal)
Make skeleton out of molded plastic (lighter)
More testing (with a live sleeper)
New material for the frame (custom molded for
manufacturing)
Improve strut strength
Test Raspberry Pi with an actual Peterbilt AC
unit
