Hi, 

We are evaluating a hotel project. It consists of the main building with about one half of the guests rooms, restaurants, gym and other amenities, while the other half of the accommodation is in 1 to 4 bedroom villas, located along the perimeter of the project. The site is located in climate zone 1B. Cooling of the main building as well as the villas is facilitated by district cooling. The source of cold are air cooled chillers with thermal energy storage, located in a separate plant-room within the LEED boundary. The chillers are fed by a PV array located outside of the LEED boundary. 

Question 1: The modeling approach we have taken is to model the whole development as one building (not campus nor group). Is this the best approach?

Question 2: Is modeling the above cooling system arrangement as a DES (purchased cold) suitable (we are not clear on this as the source of cold is within the project boundary, while it is a district system)?

Question 3: What is the suitable system type for the baseline building? As per Table G3.1.1-3, the hotel falls under Residential building type.  It is unclear what building typologies are classified under "Other Residential". If "Other residential" means "non-residential" (as used in previous versions of ASHRAE 90.1), then the Baseline should be modeled as System 2. However as per clause G.3.1.1.2 if the project, “uses purchased chilled water, direct expansion unit equipment shall not be modeled in the baseline building design”. Thus, it is unclear as to which system should be modeled in the Baseline.

Please help us to clarify the situation, any comments/help appreciated.

With many thanks,

Anna