User Interfaces Team
Team Members (Left to Right):
Tucker Stone – Michael Towne – Drew Christian – Jeff Bauer – Lachlan Sinclair
Hydrogen technology and fueling is the future of sustainable energy, and our interface is designed to welcome people to that future. In addition to providing the user with a fueling experience similar to that of a Sci Fi movie. our safe, efficient, and intuitive station will make the transition from traditional, carbon based fuel to hydrogen as smooth as possible. Our team has designed a system that is as familiar as it is exciting while still meeting the following criteria:
Must:
- Meet SAE standards and criteria for fueling, vehicle connection, and pump nozzle storage (SAE J2601 and SAE J2799)
- Safely and securely connect to the vehicle
- Fuel at pressures between 5,000 and 10,000 psi
- Securely collect payment via card reader
- Display relevant information to the consumer
Should:
- Be user friendly
- Have an appealing design
- Be durable and weather resistant
- Require maintenance that is cost effective
Background
What’s out there?
Most hydrogen fueling stations being used today look similar to standard gas stations; they have a hose housed in the open with a card reader and screen, mounted on a small island. However, due to the need for our station to be portable, we had to to rethink how our system would be set up.
We are aiming to design our system with the following in mind, taken from Jakob Nielsen’s “Usability Engineering” and Robert Hoekman, Jr’s “Designing the Obvious“:
- Information displayed and options need to be cut down to the essentials
- Take the little things into consideration when designing the system
- System is easy to learn, efficient once learned, and minimizes user and system error
- Safety information and solutions for common errors must be properly displayed
- Survey the consumer to get suggestions for improvement
Applicable Standards: There are many safety standards that are applicable to a hydrogen refuelling station, but the most applicable to the user interface are SAE J2601 and SAE J2799.
SAE J2601-
- Fueling must take place between -40°C and 50°C
- The flow rate cannot exceed 60g/s
- The initial pressure when refueling must be between .5 and 35Mpa or .5 and 70 Mpa, depending on the vehicle
- The pressure sensor must be no further than 1 meter from a break away in the hose
SAE J2799-
- The nozzle will communicate with the car via an infrared signal
- Data must be communicated in ASCII format
- The nozzle must have at least 3 infrared receivers
- The vehicle will transmit many things to the receiver including:
- The volume of the tank in liters
- The nominal working pressure of the tank.
- The pressure of the hydrogen in the fuel tank in MPa.
- The temperature of the hydrogen in the fuel tank in Kelvin
Design Comparison
A house of quality (HOQ) is a practical way for engineers to systematically evaluate the potential performance of multiple design features. This provides us with a simple, highly effective way of insuring that our design will preform safely and efficiently while also being cost efficient.
For the user interface, we focused our HOQ around variables such as the ease of use, customer experience, and interface installation, weighing these variables based off of factors such as manufacturing cost, life cycle, and ease of maintenance. With this HOQ, we are able create relationships between the factors and variables, allowing us to analyze the potential performance of our design.
- The Simplistic Design has cheaper components than the other two options, which increases the chances for failure and decreases security. In this design, the hose would be housed on the outside of the container. The computer would be more susceptible to damage due to moisture and vibrations and would not come equipped with sufficient RAM and storage capacity.
- The Technologically Advanced Experience involves an automated door that would house the hose assembly and open once the payment is received, providing extra protection to the hose. The computer in this design is more modular, allowing it to be progressively updated and has more RAM and storage capacity than the simplistic design.
- The Hybrid Design utilizes the advanced computer system, but uses the same security as the simplistic design, which created the high risk high reward situation represented in the below HOQ.
Our Simplified HOQ:
Design Specifications
Technologically Advanced Experience
- WEH fueling assembly capable of dispensing hydrogen at 10000 psi (70 Bar)
- Fueling hose housed on inside of the container
- Access to system granted via automatic door after payment is collected
- Screen interface with keypad
Hybrid Design
- WEH fueling assembly capable of dispensing hydrogen at 10000 psi (70 Bar)
- User interaction elements on outside of container
- Screen interface with keypad
Simplistic U.I.
- WEH fueling assembly capable of dispensing hydrogen at 5000 psi (35 Bar)
- User interaction elements on outside of container
- Screen interface with keypad
Our Recommendation:
To allow for the user to have the most efficient experience while keeping the system easy to maintain, we recommend using the Technologically Advanced Design. It uses a more robust and modular computer to decrease maintenance and increase the life of our system to the required 10 years. The automatic door system will consist of a 4 foot wide roll up, which will be opened with an electric motor and locked in the closed position with a servo at either side.
To ensure the safety of the user and the system, an instructional video will play for each new user. To avoid consumers having to watch the video each time a rueful is needed, we recommend a simple registration system that will recognize users that have already used the system successfully. After viewing the video, the new user would be prompted to create a 5 digit PIN number that they can use to bypass the video in future visits to the station. When a user visiting the station has input their payment and PIN, using the Rugged Back-Lit Metal Keypad USB System, the station door will open and allow the user to begin fueling, which adds to both the ease of use and the security of the station.
In order to create a highly modular system, the computer we will be implementing will be a HP 8000 Elite Desktop which comes equipped with a motherboard that has all the necessary components to continually add ram and storage capacity as needed. Due to the potential failure resulting from a prolonged life cycle and environmental effects, this systems cheap and replaceable parts make it an excellent machine for long term use. In order to insure the safety of the computer monitor, a custom, high strength glass panel manufactured by Dulles Glass and Mirror will be used to cover the screen.
Economics
- Approximately $38,000 should be set aside today in order to cover the total cost of the subsystem.
- Initial Cost = $20,000
- Annual maintenance cost of about $150 due to periodic inspection
- Annual interest rate of 6%
- A = $150, therefore A(P/A,6%,10)=($150)(7.3601) = $1104
- Total cost = $20,000 + $1104 = $21,104
- Future total cost = G(F/G,6%,10)=($21,104)(1.7908) = $37,793
- Our subsystem will depreciate to approximately $7,170 after 10 years. This calculation is based off an original cost of $20,000 and an iterative depreciation at a 10 year recovery period.
What’s Next
To begin building the user interface of a working hydrogen refueling station, we need to purchase the following components:
- Computer: HP 8000 Elite Desktop Package
- Nozzle assembly: WEH nozzle
- Keypad: Rugged Back-Lit Metal Keypad USB
- Screen Protector: 19”x19”x0.5” glass panel
With these, construction and system testing can commence.