Sometimes you need to get everyone in the same room!

May 23, 2019

A cool story about one of our projects: we were brought on-board at the tail end of this project during the construction period and were to perform functional testing and verification services. 

 

As soon as we got started on the project and began reviewing the design documents and proposed sequence of operations we started having concerns with the way that the design sequences were written for the geothermal heat recovery chiller system. We brought these concerns up to the Engineer of Record and team and were told that the sequences would work as written. We continued with writing the test sheets and once the Contractors had finished their work and performed their tests and check-outs we began functional performance testing and verification. 

 

From the start of testing we observed and documented that the geothermal modular heat recovery chiller system was having issues and not functioning properly or efficiently.

 

Some of the issues we observed and documented included:

  • Flow faults

  • Unit faults and alarms

  • System locking-up and not maintaining water set points

  • Excessive hunting of pumps, chiller, system bypass valves, etc.

  • Problems maintaining stable system differential water pressures

We documented all of this during our testing and verification and alerted the team. We then stepped back to allow them to correct the issues. After months of failed attempts by the Contractors, manufacturer and design team to get the system operating properly with repeated follow-up testing/verification by our staff we called an on-site meeting with the entire project team.

 

The goal of this meeting was to get everyone in the same room and looking at the device at the same time. Prior to this, it was a revolving door of people coming individually to try to figure the system out. This ultimately led to an increasingly frustrated Owner with a system that was not reliably working and a warranty period quickly coming to an end. 

 

During the meeting we ended up offering some suggestions on what we thought would be a more appropriate method for controlling the various components in the system and got buy-in from the design team and Owner to go ahead and try these proposed changes. 

 

Long story short, as you can see in the following trending graph, we made a significant impact! While the trend graph is pretty complex with 8 different variables overlaid throughout a 3 month time span, you can see a clear line of change from the original programming to our intervention. There is still some tweaking to be done, but we are happy to say that for the last month the system has been operating reliably and much more smoothly than previous to our 'all hands on deck' meeting. 

Now that the system is running without alarms and trip-outs, we can start fine-tuning PID loops to reduce hunting and make the system more efficient.

 

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