Hello all,
We have a C&S office project where the owner prepares technical infrastructure for VRF heating cooling system in tenant area. All tenants are obligated to use VRF system since the base building infrastructure only allow it. However, VRF units will be bought by tenants according to their needs.
We've added system efficiency requirements in tenant lease and modeled the building with VRF. However, the reviewer didn't accept it since the lease is not signed by tenants. It is not possible to get it signed since the project is still in design phase and only a few of the tenants are determined.
In this case, do we have to model all tenant area same as baseline? If we do so, we cannot pass the prerequisite since the improvement in the CS area is very low.
Can we get the lease signed by some of the tenants we know?
Are there any alternative compliance paths for this situation.
Thank you!
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5867 thumbs up
May 5, 2017 - 9:45 am
Since the building infrastructure only allows for a VRF system I think you could propose to model a VRF system in the tenant spaces with some provision for ensuring that it is modeled conservatively. A conservative estimate of fan power and system efficiency for the VRF heat pumps could be the worst-case values from manufacturers (Watts / cfm and EER), or the worst-case fan power and efficiency used in similar projects in the past five years. Or alternatively the default VAV system to be modeled in the Baseline case; the Proposed case to be modeled with VRF heat pumps having constant volume fans at ASHRAE 90.1 Appendix G default fan power and system efficiency. In either case i would propose something to the reviewer via a project team inquiry before submitted for the final review.