Variable Flow Refrigeration Systems
Several years ago, I participated as co-presenter for a class called VRF; the Good, the Bad, and the Ugly. Presentations include the design perspective, the owner's perspective, the vendor's perspective, the installer's perspective, and the commissioning provider's perspective. I presented the commissioning provider's perspective portion.
Several years before the class, I had run into my first VRF system and had done a lot of research trying to understand what the issues were and much of that content showed up in my presentation. My bottom line was that the technology was pretty amazing and in and of itself, it worked. But there were a lot of issues with it being applied properly, including the technical details behind what it took to install the technology and the need to integrate it with things like packaged economizer systems, ventilation air systems, and building management and control systems.
A number of clients kept asking if we would share the details behind what I presented in the class, and we gladly did that, starting with a blog post I wrote about the issues that came up with integrating third party economizers with VRF indoor units. Ultimately, Jay Santos (one of our founding principles) suggested that I just write a memo that tied everything we had discovered so far together and then make that available as needed. The file below on the left is that memo.
The memo covers the following topics:
The memo includes some detailed appendixes with details on the installation issues we had seen, details regarding the flare tools and other tool issues that need to be considered when working with the Mitsubishi system, and an e-mail discussion I had with someone about the economizer integration issues.
The file below on the right is the wiring diagram and control equipment information associated with integrating the third party economizer with a Mitsubishi indoor VRF unit.