HVAC Design Supports Performance and Flexibility in a Mixed-Use Office Campus

Overview 

In a mixed-use office campus with two connected towers, HVAC design plays a larger role than heating and cooling alone. A coordinated strategy supports changing tenant requirements, maintains comfort across different space types, advances sustainability goals, and protects long-term building performance.

At Midtown Center, located at 1100 15th Street NW in Washington, DC, Havtech supported the HVAC strategy for a complex 865,000-square-foot trophy office development. The project includes two full-height office towers organized around a central courtyard and public plaza, with ground-level retail, public space, and three pedestrian bridges connecting the buildings.

The development also moved on an aggressive delivery schedule driven by a major anchor lease. For a project of this scale, HVAC performance depended on more than individual equipment selections. The central plant, ventilation systems, airside equipment, controls, and tenant zones all needed to work together as one coordinated strategy.

Havtech supported the project team with equipment selection, system coordination, startup support, and turnover planning. The goal was to help deliver an HVAC approach that supported high-performance building goals, day-to-day operations, and future tenant changes.

Challenge 

The HVAC strategy for Midtown Center needed to support changing tenant layouts, perimeter comfort, dedicated outdoor air delivery, energy performance, acoustics, controls coordination, and long-term serviceability within an accelerated project timeline.

With a major prelease and accelerated delivery timeline, the project team needed equipment selection and coordination that could support performance goals, schedule demands, and long-term operational flexibility.

Several factors added complexity:

• The two-tower layout and bridge connections created unique airflow and controls considerations.
• Tenant layouts were expected to change over time.
• Occupancy was planned within a compressed project timeline.
• Indoor air quality, ventilation, comfort, acoustics, and energy performance were all priorities.
• The facilities team needed systems that could be operated and maintained without unnecessary complexity.

The project required a coordinated approach that connected central plant performance, outdoor air delivery, zone-level comfort, controls, and long-term serviceability.

The Approach 

Havtech worked with the project team to support an integrated HVAC and controls strategy for Midtown Center. The approach brought together chilled water production, dedicated outdoor air, energy recovery, zone-level flexibility, air cleaning, and system visibility.

Central plant and airside strategy 

Midtown Center uses a low-lift HVAC design built around elevated chilled-water temperatures. The Price DOAS terminal units provide sensible cooling using chilled water supplied at approximately 55°F to 57°F, allowing the central plant to supply water at warmer temperatures than a conventional 42°F chilled-water system. This reduces the lift required of the magnetic-bearing chillers and improves chiller efficiency. Based on a U.S. Department of Energy rule of thumb, the 13°F increase from 42°F to 55°F could improve chiller efficiency by approximately 20%, depending on equipment selection and operating conditions.

Equipment strategy 

The project included several high-performance HVAC selections designed to support energy performance, ventilation, comfort, acoustics, and long-term operation:

• Five Daikin 700TR Magnetic-Bearing Chillers in a Series Counterflow Configuration to support high-efficiency chilled water production and stable operation.
• Three Daikin Side-by-Side Dual-Tunnel AHUs with Enthalpic Heat Exchanger Arrays, delivering 95,000 total CFM of 100% outside air with energy recovery. 
• Annexair dedicated outdoor air systems to manage ventilation separately from space conditioning. 
• Price DOAS Series Fan-Powered Induction Units to provide zone-level flexibility and perimeter comfort. Integral sound attenuation supported exposed applications, while the low-profile design helped optimize finished ceiling heights.
• enVerid air cleaning systems to reduce outdoor air consumption while supporting indoor air quality. The systems work in parallel with the HVAC approach, helping maintain simplicity and reducing the need for additional ventilation equipment.

Together, these selections helped the building balance efficiency, ventilation, comfort, acoustics, and operational flexibility.

Coordination, Startup, and Turnover

Havtech also supported the project through startup and turnover. This included helping coordinate controls across multiple equipment types, supporting the mechanical contractor, and preparing the facilities team for long-term operation.

That coordination helped move the project beyond a collection of individual components and toward a more unified building performance strategy.

Outcome 

Midtown Center demonstrates the value of coordinated HVAC planning on a large, complex office campus where performance, flexibility, and schedule all mattered.

Havtech supported the project from equipment selection through startup and turnover, helping the project team align central plant performance, dedicated outdoor air delivery, zone-level comfort, controls, and long-term serviceability.

The completed HVAC strategy helped position the campus to support tenant changes, maintain indoor air quality goals, and operate with a clear, consistent approach. The project also achieved LEED Gold certification, reflecting the broader high-performance design strategy behind the development.