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GPG OUTBRIEF 14
Variable Refrigerant Flow
If you missed our last webinar, “Variable Refrigerant Flow,” you can now access a recording of it on YouTube. You can also view the presentation slides. A schedule of upcoming webinars and links to past webinar recordings are available on the GPG Outbrief page.
Thanks to all the presenters and to participants for their excellent questions, some of which are answered below.
Q&A
Q: Does VRF need to be installed in an entire building?
A: No, GSA has found VRF to be a good solution for spaces that benefit from independent temperature control, such as courtrooms and dispersed IT closets.
Q: Does ASHRAE have guidelines for VRF?
A: ASHRAE 2016 Systems and Equipment Handbook chapter 18 provides some guidance. Additional VRF guidance has been drafted and is open for public comments until June 25, 2018: GPC 41P, Design, Installation and Commissioning of Variable Refrigerant Flow (VRF) Systems.
Q: Refrigerant leaks are a common concern with VRF. How do you detect and/or guard against them?
A: VRF system designers are asked to comply with ASHRAE 15/34 requirements for Designation and Safety Classification of Refrigerants. GSA requires that compliance calculations be placed on all drawings. It is also important for drawings to note where joints in refrigerant piping are located. Once insulation is installed, it can be difficult to trace leaks. A new EPA rule going into effect in January of 2019 will regulate a common refrigerant used in VRF systems, R-410A, and lower the threshold leak rate to 10% annually.
Q: In climates where heat recovery function is seldom used, would non-VRF heat pumps be a better option?
A: Yes, heat-pump-only systems have less complex refrigerant piping and are less costly.
Q: How do you deal with the "Buy American Act"?
A: GSA installations of VRF have received waivers.
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