Nimbus Power Systems

Nimbus Power Systems is a hydrogen fuel cell company utilizing its technology for many possible sectors including being on track to produce a diesel engine replacement. Being a small company I fulfilled many roles there as an intern. I collected data, built lab equipment, increased capability, sourced parts, managed projects, improved safety, and completed many other tasks.

Skills Developed:

LabView:

In order to add new capability to the cart that tests the fuel cells, I learned how to program in LabView. I added an external heater, oxygen sensor, and filters for inconsistent data. LabView is a program used to create testing apparatus, it is a National Instruments product so plays nicely with all of its hardware, LabView is used extensively in R&D departments everywhere.

In this example I added a safety mechanism where if the oxygen senor is plugged in the computer will not let you go into the mode where hydrogen could contact it. If hydrogen contacts that auxiliary oxygen sensor it would ignite.

Wiring and Plumbing:

Many of my projects involved aspects of wiring and plumbing. I learned how to design and wire complex power distribution units starting with 120 and 240vac, 24-volt relays with reset buttons and indicator lights, and CAN cables. I used Deutch connectors, screw terminals, CAN connectors, and push-in connectors.

Documentation:

I took notes throughout all of my projects making a detailed bill of materials, a wiring diagram, and supplemental instructions or checklists when needed. In addition to documenting my own projects, I also added documentation to prior projects if I ran into undocumented wiring, plumbing, or lab protocol.

Projects:

New 20 Cell Cart:

Power Distribution Unit:

I sourced, purchased, assembled, and wired the new power distribution box for the 20-cell cart. This wiring included wiring for 240vac, 120vac, and 24vdc components. Sourcing components with acceptable lead times with a budget was especially challenging, many components had 20+ week lead times from the manufacturer and had to be sourced second-hand or refurbished.

8020 Frame:

I planned, sourced, purchased, and assembled the physical cart weighing factors such as budget, lead time, and required man hours. All decisions and reasoning were documented in detail through a series of bills of materials.

Hydrogen Safety System:

I designed, sourced parts for, constructed, wired, and tested a hydrogen safety system that utilizes E-stops at every exit, hydrogen sensors, and a switch to turn on and off the valve that lets hydrogen into the lines. If it detects hydrogen or an Estop is pressed the hydrogen valve outside turns off and an alarm with a flashing light goes off to alert every employee of the issue. I also instituted a technically less complicated hook system where you hang the keys to the hydrogen storage on a hook to determine if the hand valve has been opened that day.

Load Bank Cart:

I designed, sourced parts for, constructed, wired, and tested a cart that cools a 12kW load bank. A load bank is a component that, in a controlled and measured manner, accepts amperage from the hydrogen fuel cell in order to test its capability under load. This type of load bank turns all of the power it absorbs into heat, this means it must have a sizable cooling mechanism to dissipate that heat. I designed this cooling loop that utilizes an inexpensive mustang radiator, shroud, and fans that, with the help of a powerful pump, can keep the load bank cool.

Anti-smell plug:

One piece of machinery in the shop uses tap water to cool down and the wastewater goes into the sewer. Initially, this was done with a hose going into an open sewage pipe, this did not smell pleasant. I designed and printed at home this adapter that seals off the open pipe, I looped the hose so water would pool and not allow gasses to push their way back out (like a toilet).

Safety Tag System:

I instituted a flag system where components that cannot remain on the hydrogen fuel cell's test cart for certain operations are tagged with a large orange flag (borrowed from our friends in aerospace) so it is visible and can be removed. This solved an issue where a safety mechanism was mistakenly bypassed with a jumper that is meant to only be used when the cart is left on over night with no hydrogen on. It also protects instruments such as the oxygen sensor to the right which heats up in order to sense oxygen and if it came into contact with hydrogen it would ignite. Seeing that flag the operator knows not to run any tests that could put hydrogen near the sensor.

5 Cell Test Cart Improvements:

Oxygen Sensor:
This oxygen sensor allows Nimbus to verify its data by measuring the oxygen content on either the inlet or exhaust of the cell. I Implemented it in the plumbing, wiring, and LabView code.

Hydrogen Sensor:

I designed, CAD'ed, CAM'ed, and machined this block to bolt to this hydrogen sensor so it can be used with SAE fittings and integrated on the test cart

Heater:
The test cart needed more heating capability, I plumbed in this heater (under the insulation) and DI water refill valve.

Feet:

The fuel cell has to rest on a non-conductive surface, these feet I made are a pretty elegant one.

Insulating Jacket:

This insulating jacket I made helps keep heat in so the heaters don't

have to work so hard, it also helps keep the temperature more even throughout the stack.

Workbenches:

I made a set of work benches for the shop based on some plans that were found online.

Crates for Carts:

I fabricated custom protective plywood shields for these two test carts so they could be shipped to our customers.