Fueling the Future
Project undertaken in course year 2022-23 with Verne and the Stanford Precourt Institute for Energy
Project Goal
Develop a rack system to hold 8 tanks of cryo-compressed hydrogen fuel for everyday mining operations of large scale class 7 and class 8 mining trucks.
Project Motivation
The goal of this project is to help the mining industry transition to hydrogen fuel as an alternative to fossil fuels
Heavy duty transportation accounts for 11 percent of the total greenhouse gases emitted around the world yearly. Hydrogen fuel can be a replacement for common fuels employed by larger construction equipment.
Background
Transportation in the US accounts for 27 percent of the total greenhouse gases emitted yearly. Heavy duty transportaiton, which includes large scale mining operations plays a large role in this. Hydrogen fueling of large scale mining operations is an alternative for the current fossil fuels that these trucks run on.
Hydrogen can be difficult to work with, and in gas form requires a significant volume to store sufficient amount of energy to power vehicles. Verne are developing a means to cryo-compress hydrogen to make it more volume efficient to carry on vehicles, requiring 8 tanks to hold sufficient energy to power Class 7 and 8 mining vehicles.
High Priority Requirements
The rack shall fit within an envelop of 1.6m x 2.2m x 3.0 m
The rack shall have the capacity for 8 filled storage vessels (tanks)
The rack shall be able to withstand a maximum load of 8g on all sides.
Ethical Considerations
Ensuring adequate safety while designing for cost efficiency supporting the overall loads
Creating a system that will go into an industry that has harmful environments
Solution
Designed a rack consisting of fours rows of two tanks, each row above the other. The end of each tank is necked down to a smaller diameter that is clamped by the rack system.
Rack system
CAD image of full-size solution. Each tank is held at both ends by clamps, which are fastened to the horizontal bars above and below them. The horizontal bars have hollow square cross sections and are made of steel. The four vertical bars are T-beams, also made of steel.
Assembly sequence
The rack is built up in steps, with the tanks being built in to the rack. The tanks do not need to be removed easily, as they are refilled while the tanks are mounted to the truck.
Stress and deflection analysis
Finite Element Analysis for horizontal beams on rack. Top view shows the stress bearing the weight of the tank, and the bottom view shows the displacement. Both resulted in a safety factor >3.
Test setup for horizontal beam test
To validate the FEA, the team conducted beam deflection testing and compared to predicted from FEA. Top view shows the Test setup, and bottom views are the results of testing and FEA.
Other testing conducted
Buckle analysis of vertical beams
Side panel deflection and stress analysis
Different cross sectional geometries for each test
Student team
Future Work
Reduce weight of rack from 1500 kg to 1200 kg
Cyclic load testing
Test/design to support 8g
Establish mounting location for the rack to the truck