It has been just over a year since we shipped out our first paid pilot to Oxnard, California and an update is in order. Before I get to that, I want to take a moment to thank the lineage engineering and analytics teams for helping get this Pilot installed along with the entire Oxnard staff for helping us operate it.
Now, let’s get to some results, with more than 5000hrs of operation, the Oxnard pilot was a success. After reviewing its performance, Lineage Logistics agreed to deploy the first, full-scale IcePoint® unit. Additionally, the pilot was used to as a showcase for investors. To summarize pilot performance, lets go over some high-level numbers:
Total Runtime [hr]
Strawberries Accelerated [lb]
Largest Burst of Cooling [kWt] (TR)
Tank Temperature [C] (F)
* The COP calculation was complicated, as I will describe later. This value is an adjusted COP taking into account a condenser issue that, for practical purposes, was left unsolved.
The overwhelming majority of the pilot system performed well over the entire operating period
1. There were no major pump failures, tank ruptures, or spills.
2. The unit never negatively impacted the performance of any on-site equipment or caused any lost time.
3. The controller, cloud-based user interface, and remote-control features never failed to respond.
For all these reasons, the pilot was a success. That being said, the most valuable aspect of the pilot were the many lessons learned. I think it is valuable to discuss a few of the key findings here.
Vapor compression isn’t easy: There is the perception out there that because Freon and Ammonia refrigeration is so ubiquitous it must be simple. That couldn’t be further from the truth. By far the least reliable, and most difficult to control, component was the off-the-shelf condensing unit. Why? Because vapor compression is extremely mechanically complicated. We dramatically underestimated this and thus were never able to operate at the ice maker’s designed suction temperature. As such, we had to adjust our COP values for the extremely low suction temperatures encountered. For the past year, ice maker suction temps have been a primary development focus and the few people we have shown our new top secret ice maker to are… excited.
Waste heat isn’t economically worth it: This one ended up being pretty simple. We can mechanically separate our freeze point suppressant for a fraction of the cost of capturing waste heat. In the end, capturing waste heat is just too expensive. While running a refrigeration cycle at -22°F using 140°F waste heat is a thermodynamic marvel, the economics just don’t line up. Luke and Alex are hard at work building out our mechanical vapor recompression separator at this very moment.
In-house commissioning is key: One of the hard lessons we walked away with is how much easier it is to fix a problem in your own shop before shipping a product. We ran into a lot of small issues with this pilot. All of these issues would have been a 1-2 day fix in our shop but diagnosing them remotely and fixing them on-site took months. For the full-size deployment, we set aside significantly more in-house commissioning time and Chance is hard at work preparing the facility’s infrastructure for the task. Some of the small problems we spent a lot of time fixing in the field were:
1. the water recuperator froze often
2. managing lubricant oil levels in the ice maker was difficult
3. the check valve seals on the ice maker water lines failed
4. the vacuum pump required a soft-start relay to startup under some ambient conditions
5. the column solenoid caused illusive water hammer issues
6. the ice maker lubricant caused materials compatibility issues with seals throughout the system.
It is great to walk away from a pilot with a customer making follow on purchases and investors excited to help us scale. However, from a strictly technical development perspective, the satisfaction, despite those long hours cramped in the hot container, was pushing this technology forward and learning what it takes to create a reliable, large-scale, industrial refrigeration technology.
I want to close with a host of photos covering the pilot. This was a huge undertaking for our small team and I want to share that journey as honestly as possible.
Fig9. The system arrives in Oxnard!!! Kevin did a great job managing the on-site relations during the install while the tech team prepared to commission the system.
Fig10. The separation system is installed. It will start to become obvious to anybody who has ever worked with hot pipe why waste heat capture isn’t economically viable.
Fig13. The system went live Feb 13th!! It actually wasn’t that exciting. The system just starts getting cold. Here is some video of the ice makers dropping ice into the tank. Sorry for the terrible video quality, this shot is very difficult to take… After this point we started commissioning the system and troubleshooting problems.