The document describes an isolated air conditioning system for truck sleeper cabs. It aims to reduce fuel costs from idling trucks by containing cooled air more efficiently. The system uses a lightweight aluminum skeleton and insulated tarp to form a canopy over the cab, dramatically reducing the area that needs cooling. It is automated using a Raspberry Pi control system for monitoring and scheduling cooling. Testing showed the canopy lowered temperatures significantly faster than an uncovered cab, with potential for further improvements to airtightness and materials. The goal is to improve driver comfort while cutting fuel usage and emissions.

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

9. Canopy

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.

11. HVAC Design

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

13. HVAC Design

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.

18. Thermal Data Phase 1

19. Thermal Data Phase 2

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