Industry professionals face a choice between a hydronic or a VRF solution for HVAC projects. Hydronic systems circulate water which is harmless if it leaks. The system overall allows the possibility of cooling, heating, simultaneous heating and cooling, heat recovery, and domestic hot water from a single unit. VRF systems have large amounts of refrigerant circulation inside the building and can be extremely dangerous if there is a leak. The many challenges with VRF systems has raised concern within the industry.
The Unified Facilities Criteria (UFC) has determined that VRF Systems will no longer be permitted in Air Force facilities and will be strongly discouraged as an HVAC solution. The following issues with VRF Systems have been raised:
- Concern of Refrigerant Concentration
The refrigerant lines are run inside buildings which are typically over office spaces. In the event of a refrigerant leak a commonly sized VRF system contains enough refrigerant to suffocate occupants.
- Refrigeration Leaks
Locating refrigerant leaks is difficult and repair is challenging as other piping and ductwork is typically installed in dropped ceilings.
- VRF Systems Have Proprietary Control Systems
These closed systems are not permitted.
Take a look at the full document here. For more information on hydronic systems versus VRF systems, check out these resources:
McCallister, Larry D. (2017). Changes to UFC 3-410-01, Heating, Ventilation and Air Conditioning Systems, with Change 3. Engineering and Construction Bulletin. 2017-7. 1-2. https://vrfrejected.org/docs/vrf_army_corp_engineers_directive.pdf