Glenn KatzYour Design Journal entries for this module should highlight your design thinking and analysis results that influenced your decisions about:
- your overall HVAC system strategy
- your heating strategy and how you implemented it in your design
- your cooling strategy and how you implemented it
- any special HVAC system challenges that you encountered
HVAC System Strategy
The building, designed to accommodate approximately 500 visitors, is situated near Castle Clinton National Monument in NYC, a location that enjoys the comfort zone for 8.0% of the year. An analysis revealed the need for 6.4% active cooling and 44.4% active heating throughout the year. To address these requirements, the HVAC system strategy focuses significantly on active heating. This is achieved by strategically placing windows on the west side to harness solar heat, complementing the mechanical heating system and reducing reliance on artificial heating sources.
Zoning and Airflow Management
The first floor is divided into four zones (Lower South, East & West, North, and Central), with a main duct system sized at 36'' x 24'' to manage a total airflow of 6000cfm. Sub-branch ducts, designed to handle 500 cfm each, vary in size from 12" x 12" to 16" x 14". Single duct Variable Air Volume (VAV) units are installed in key areas such as exhibit spaces and educational rooms to allow for customizable air volume control, enhancing both comfort and energy efficiency. The second floor follows a similar zoning and ductwork strategy, with VAV units placed in conference rooms, offices, the cafe, and additional educational areas.
LEVEL 1 HVAC
LEVEL 2 HVAC
Space Schedule
Heating Strategy
The extensive use of glass facades and a solar glass roof capitalizes on natural sunlight to warm the interior during colder months, significantly reducing the heating load. The concrete slab flooring acts as a thermal mass, absorbing heat during daylight hours and releasing it at night, providing a natural, sustainable heating solution.
Cooling Strategy
The primary cooling is facilitated through the HVAC system, complemented by natural ventilation via exits on the east and west sides, along with the main entrance and a patio on the north side. Additionally, the green roof on the north side serves as a critical component of the cooling strategy, offering insulation and reducing heat ingress during summer, further mitigating cooling requirements.
Special HVAC System Challenges
One of the unique challenges stems from the design choice to allow unobstructed views of the solar glass roof from the second floor, eliminating ceilings in most areas on this level. This necessitates the HVAC system and ductwork to be visible, requiring careful integration with the beam support system. This design approach, while aesthetically pleasing and allowing for maximum natural light, introduces complexity in maintaining an unobtrusive and efficient HVAC installation.