1. Dustin R. Crouse1
Advised By: Jason Lustbader2, Cory Kreutzer2
(1) University of Virginia, Charlottesville, VA
(2) National Renewable Energy Laboratory, Golden, CO
Overview
Goals & Objectives
Materials
Approach Full Cab Solution Study Results
Conclusions & Discussion
Future Work
Acknowledgements
Reduction of Electrical Loads in Idling Long-Haul Trucks NREL is a national laboratory of the U. S. Department of Energy, Office of Energy
Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.
Rotational Study Results
This work was supported in part by the U.S.
Department of Energy, Office of Science, Office of
Workforce Development for Teachers and Scientists
(WDTS) under the Science Undergraduate Laboratory
Internship (SULI) program. I would like to thank Jason
Lustbader and Cory Kreutzer for their mentoring
support. I would also like to thank Kameron Kincade
and Ryan Langewisch for their feedback and advice.
Project Goals:
Validate CoolCalc as a cost-effective modeling
software
Achieve a national 30% reduction in annual
HVAC load
Provide fuel savings equivalent to a 1-3 year
payback period
Help meet new idling regulations
Internship Objectives:
Improve existing code, analysis accuracy, and
documentation
Develop tools to enable mapping between
thermal and electrical loads
667 million gallons of fuel are used annually by
long-haul trucks for rest period idling in the
United States
2.4 billion gallons of fuel are consumed
annually during truck workday idling
Fuel is one of the largest costs per mile at 38%
of the total cost
Reduced operation cost from idling could
make long-haul fleets more competitive
Primary reason for heavy-duty truck idling is to
heat or cool the cab
Improving the cab’s thermal performance can
reduce the need for idling, carbon emissions,
and fuel consumption
Rotational Study:
Orientation of the cab was
varied in increments of 22.5°
Simulation of 161 US cities
Soak conditions (HVAC
system not applied)
Internal cab temperature
versus orientation was
investigated
Full Cab Solution Study:
Curtains, insulation, and paint
were varied for 18 combinations
Simulation of 161 US cities
HVAC system applied
For each combination, HVAC
thermal loads were studied
Thermal loads were mapped to
electrical power for battery sizing
Step 1: CoolCalc Simulation
Step 2: Windows HPC
Step 3: MATLAB Post-Processing
Run Simulation
Generate Input FileConvert to EP
Collect ResultsUpdate Geometry
90
45
S
135
315
SE
N
180
NE
225
270 E
0
W
SW
NW
Curtain Insulation Paint
Standard Baseline White
Advanced
Half-
thickness
Insulation
National
Solar
Average
Thinsulate Black
Utilize long-haul traffic flow data for national
truck weighting calculations
Map thermal loads to fuel consumption and
evaluate potential fuel savings
Add in cost factor for payback period analysis
Unify MATLAB script and documentation
Effects of Cab Orientation:
Facing north during idling rest periods can
reduce cooling loads during sunny days.
During winter maximum heating loads occur at
night, therefore the sun and rotation have less
impact on heating
Effects of Full Cab Solution:
Truck fleets operating in northern states use
more heating energy than in southern states
Applying the advanced combination reduces
heating loads less than cooling loads
Applying the advanced combination reduces
annual battery loads to ~10 kWh
Some heavy-duty vehicles utilize an
approximate 800 Ah (9.6 kWh) battery system
Applying the advanced combination could
eliminate idling to power the AC system
Rotational Study:
Cumulative north vs. south thermal load
- Cooling: Decreased ~26.3%
- Heating: Increased ~11.1 %
Full Cab Solution:
Electrical cooling load reduction by region:
- Eastern Half: Decreased up to ~40%
- Western Half: Decreased up to ~55%
Electrical Heating load reduction by region:
- Northern Half: Decreased up to ~35%
- Southern Half: Decreased up to ~26%
 Cumulative 10 hr max battery load at 100% of
days was found to be ~10 kWh
Heating Degree Days as a Function of Orientation Normalized to South
Cooling Degree Days as a Function of Orientation Normalized to South
Cumulative Cooling Loads for One Year
Daily Thermal Heating Load in kWh
Standard Curtains, Baseline Insulation,
National Solar Average Paint
Advanced Curtains, Thinsulate
Insulation, White Paint
Heating Load (kWh)
Percent Reduction of Daily HVAC Heating Load
Heating Load Reduction (%)
Daily Thermal Cooling Load
Standard Curtains, Baseline Insulation,
National Solar Average Paint
Advanced Curtains, Thinsulate
Insulation, White Paint
Cooling Load (kWh)
Percent Reduction of Daily HVAC Cooling Load
Cooling Load Reduction (%)
Import Define Analyze Plot
~450 GB
Curtain Insulation Paint
Standard Baseline National
Solar
Average
Paint
Curtains
Insulation