Building A is part of a complex of four buildings, but only the building A is subject of LEED certification. The building heating, cooling and service water heating system is served by a heat pump that supplies energy also to the other three buildings. In addition, there is a photovoltaic field that produces electricity for the complex of 4 buildings. The photovoltaic field do not produce electricity only to the HVAC generation system.
To obtain the EA-Optimize energy performance credit, option 1 is followed. It is asked which approach to follow for the modeling of the Proposed and Baseline HVAC plants and for the calculation of the photovoltaic systemcontribution.
Below is the interpretation of the work group. Please tell us if the interpretation is correct. The heating, cooling and service water heating system are considered a District Energy System.
The Option 1, Path 2 (Full DES Performance Accounting) is followed.
PROPOSED MODEL. Within the energy model it is modeled an equivalent heat pump with plant capacities (chiller, boiler capacities, circulation loop flow) "adapted" according to the percentage of peak load related to the building A. The equivalent heat pump has the same COP and EER curves of the real heat pump, but they are “offset", depending on the “adapted” chillers and boiler capacities. In addition to the heat pump COP, the efficiency of the Chilled Water Loop and the Hot Water Loop takes also into account the thermal distribution losses.
For the photovoltaics we assume to use two alternative solutions:
- The total cost offset of the photovoltaics is calculated as explained in the paragraph “Project type variation - District Energy Systems” of the credit EA-Renewable energy production. The same calculation is applied to the EA-Optimize energy performance credit.
- OR the photovoltaic energy production fraction for the building A is calculated, as follows: photovoltaic energy production for Building A = Total electricity production * (electricity demand of building A / electricity demand of the building complex)
BASELINE MODEL. According to the definition of the TABLE G.3.1.1A, the building A belongs to the following Building type: Nonresidential and and 4 or 5 floors and <25,000 ft2 [...]. The Baseline System Type 5 is selected, with Cooling type Direct expansion (fuel: electricity) and Heating type Hot-water fossil fuel boiler.
Thank you in advance for your reply!