HVAC Design Case Equivalent of VRF systems

Achelles DSouza

Sustainability Engineer

Freelance Building Simulator

LEEDuser Basic Member

7 thumbs up

March 16, 2014

I am working in an Office block project (conditioned area- 8500 sqft). VRF systems have been considered for it. The modelling software that we are using is Visual DOE which unfortunately cannot model VRFs. The HVAC baseline for the project is System 4- PSZ HP (Appendix G, Table 3.1.1a). Is it acceptable if in the design case, I consider PSZ system but EER of 13? As VRF is far efficient than PSZ systems, even one with EER of 13 may not match VRF's efficiency. Please provide me suggestions. Thanks.

Post a reply

Marcus Sheffer

LEED Fellow

7group / Energy Opportunities

LEEDuser Expert

4454 thumbs up

Sun, 03/16/2014 - 20:04

Since you will be using a work around you are required to explain it per G2.2. You would need to provide justification for any efficiency improvement you are claiming. Making sure that you model is conservative and demonstrating that is the case will improve your chances of getting the work around approved by the reviewer. See also 90.1-2010 which added VRF systems to the 6.8.1 tables.