We have two project pursuing the prescriptive option and each one has issues:
1. A tenant is taking all of an existing buildng and adding a VRF system to supplement the existing system (rooftop package units) because of a higher occupant load than the base building system was designed for. From previous comments, it sounds like a VRF system does not fit well into the CPG criteria because of a lack of testing procedures. I am wondering though about the last bullet in the summary of section 2.9 which says "Equipment not listed shall meet the Energy Star criteria where applicable". Energy Star does have performance criteria for VRF systems using a relatively new testing procedure - AHRI 1230. Our equipment meets the Energy Star standard and is tested in accordance with AHRI 1230. Will this work to meet the Mechanical Equipment Efficiency section?
2. The other project is a tenant taking a small portion of a large building. The only new HVAC equipment will be a WSHP to cool a server room which will tie into the existing HVAC water loop. The equipment is 8 tons and the EER is 13.7 at 85 degrees F EWT, which does not meet table 2.9.2 requirement of 14 EER. The heat pump manufacturer claims that the efficiency will actually be 14.0 EER based on the fact that our building water loop is 80 degrees F EWT. The engineer also insists that this will meet the requirement. It was my understanding that the equipment had to meet the efficiency requirement at the standard rating condition of 85 degrees EWT and since the equipment is 13.7 EER at that condition the equipment does not comply with the standard. Can someone clear this up?