D. HVAC – General
1. Calculations: As per NYC Energy Code and NYC Mechanical code the designer shall perform HVAC load calculations using an engineering software, for example Trane Trace. The loads and should be submitted as part of the DD and CD submission and the design input values should be summarized, including envelope, lighting, equipment, IT and loads per person on btu/sf. 2. Right size equipment based on efficient lighting and plug loads (as stated in the plug load section below target lighting load of 0.5 Watts per square foot and plug load of 80 Watts per workstation or less). Lighting loads in calculations shall be based on the actual lighting design. Equipment load assumptions shall be documented on a per workstation basis in individual workspace areas and on a per room basis for collaboration and break spaces.
3. Ventilation calculations shall be performed and the aggregate ventilation rate per square foot and supply air flow rate per square foot shall be reported. (ASHRAE 62)
4. The cooling coil shall be selected based upon the anticipated mixed air conditions and the ERV.
5. The design supply air flow rates should be calculated based upon the load model, and the airflow rates/sq ft shall be indicated on the drawings for each zone. Typically, the average supply air for the floor would not exceed 0.8 CFM/ sq ft excluding the IT rooms.
6. All HVAC systems design and efficiency levels shall exceed ASHRAE 90.1-2016 or IECC 2018, meet or exceed NYStretch Energy Code 2020, 2020 NYC Energy Code and relevant successor codes.
7. Air or waterside economizer to be provided on all new equipment and retrofitted to existing air- cooled DX systems serving the project area.
8. Modulating motorized outside air dampers and air flow measurement stations must be designed, installed, tied into the BMS and commissioned. Dampers must be AMCA leakage class 1A.
9. All sources of heating and cooling within a single space shall be controlled and interlocked together. For example, perimeter heating must be controlled using the perimeter heating output on a VAV box controller, air handling unit (AHU) or VRF control system etc. Any supplemental cooling systems, e.g., VRF fan coil systems, must have continuously synchronized heating and cooling setpoints with base building systems serving the same space. Having independent and uncoordinated controls for multiple systems within the same space is prohibited by this standard and energy code. Any existing systems within the project boundary shall be updated to meet this standard. All radiators must be tied into the same control system as the cooling system and fitted with modulating valves.
10. Where multiple HVAC zones exist within a single open area, the setpoints of each zone shall be synchronized to prevent simultaneous heating and cooling.
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