Dear All,
we’re currently working on LEED certification projects with the following characteristics:
- two independent buildings located in the same campus. This will imply 1 LEED certificate per building;
- 1 new HVAC system designed to serve both buildings and located on the roof of one of them.
In what relates with Energy Performance, we have some doubts related with the methodology we shall follow to simulate these buildings. We are planning to use the following strategy:
- consider the HVAC system as a DES serving both buildings;
- follow Path 1 (ASHRAE 90.1-10 Appendix G) or Path 3 (Streamlined DES modelling) described in Reference Guide to calculate DES performance. Please note that since the system is not already installed, Path 2 will not be possible because records of actual performance are not available;
- in what relates with Path 3 (Streamlined DES modelling):
- Proposed building: both buildings will be simulated together, to better calculate energy performance of the HVAC system (accounting for thermal needs of both buildings);
- Baseline building:
- each building will be simulated independently, being the HVAC system defined according to ASHRAE 90.1-2010, Appendix G (fans, pumps, chillers, boilers, etc);
- thermal energy cost (chilled and hot water) shall be calculated for each building;
- an average weighted cost is then calculated considering the efficiency of HVAC system both buildings. This cost shall be used in baseline system of both buildings.
Do you validate this approach?
Thanks in advance
Afogreen Build
www.afogreenbuild.comGreen Building Consultant
214 thumbs up
October 8, 2020 - 11:36 am
Dear Ricardo,
Baseline shall use building plant with conventional equipment using performance parameters and efficiencies per ASHRAE 90.1–2010, using energy sources corresponding to the DES.
You can consider that way for proposed model. However, since you will submit each building separately (for obtaining 1 LEED certificate per building), you need to think of how to divide the plant energy for each building. You can consider using cooling load of each building to prorate the plant energy.
Tyler Thumma
7GroupLEEDuser Expert
60 thumbs up
October 20, 2020 - 2:09 pm
For the Proposed building, I recommend using the combined building model you describe to determine the average annual efficiency of the DES, then applying that efficiency to separate models for each building since they are separate LEED certifications.
For the Baseline building, there is no need to calculate an average weighted cost considering the efficiency of the HVAC system for both buildings. You treat each building independently for the Baseline.