Presented at the June 2009 IDEA Conference - Rebuilding the World Trade Center Central Chiller Plant

1. Rebuilding ofthe District Cooling Plantat theWorld Trade Center Hemant Mehta, P.E. and Christopher Tso, P.E. WM Group Engineers, P.C. CRC Engineering, P.C.

2. Executive Summary Project highlights and challenges: 12,500 ton central chiller plant, river water systems and site chilled water distribution system design Provides ten (10) stakeholders with CHW for cooling Uses river water from the Hudson River for condensing Rehabilitation of the existing river water pump station Compliance with environmental permit (SPDES) for river water use Salt water (river water) systems design Chiller plant energy modeling and configuration study Site chilled water distribution system design passing through other stakeholder areas Extensive coordination with other projects onsite at varying stages of design / construction

3. Project Highlights 12,500 ton chiller plant and distribution system Five 2500 ton electric centrifugal chillers Five 300 hp chilled water pumps with VFDs Two 1000 ton free/pre-cooling plate & frame heat exchangers (chilled water / river water) River water pump station rehabilitation Environmental permit requirements Four 500 hp vertical turbine river water pumps with VFDs Replacement/rehabilitation of traveling screens and sluice gates

4. Stakeholders Served National September 11 Memorial & Museum Freedom Tower retail Transportation Hub Performing Arts Center East Bathtub retail Vehicle Security Center Master Manager MTA Cortland Street ‘1-train’ Subway Station North Access South Projection

5. Project Challenges Rigging of equipment Coordination with many other projects onsite at varying stages of design/construction Central chiller plant is located below grade inside the National September 11 Memorial & Museum Site chilled water distribution passes through other stakeholder spaces Phased stakeholder loads Construction staging/logistics Site wide systems integration

6. World Trade Center Site

7. World Trade Center Site Chiller Plant Below Memorial Plaza

8. Chiller Plant Configuration Study Detailed energy and operating cost modeling Hourly weather data Hourly river water temperature data Equipment part-load performance VFDs vs constant speed drives for the chillers Free cooling operation Utility rate schedule Procurement considerations Multiple bidders required

9. Cooling Load Profile

10. River Water Temperature

11. Free Cooling Operation

12. River Water Systems Design Condition survey River water pump station equipment River water pump station diver inspection River water pump station ductbank condition survey Interior piping inspection of 60 and 66 inch underground river water mains Environmental permit requirements (SPDES) VFDs for river water pumps Metering/logging of flows and temperatures

13. River Water Pump Station

14. Existing River Water Piping Inspection

15. River Water Systems Design Salt water system design Materials and coatings Cathodic protection Dual headered piping system for seasonal interior river water piping inspection Replacement/refurbishment of traveling screens and sluice gates

16. Interior River Water Piping Inspection

17. Stakeholder Chilled Water Interface Interface at each stakeholder mechanical room Flow meter, temperature & pressure transmitters Monitoring of interface at chiller plant

18. Phased Stakeholder Loads Phased loads Memorial: September 2011 (partial opening) Freedom Tower: October 2011 Transportation Hub: November 2012 East Bathtub Retail: November 2012 Two chillers with hot gas bypass to serve the Memorial partial opening

19. Construction Logistics Chiller plant is below grade inside the Memorial The Memorial plaza at grade must be completed for partial opening (September 2011) Plant access through equipment rigging hatch and shared freight elevator Site access from Route 9A River water pump station Located below grade, under a pedestrian plaza Equipment access via hatches in plaza Pedestrian plaza owned by Battery Park City

20. Construction Logistics Coordination with other projects onsite National September 11 Memorial & Museum Freedom Tower Vehicle Security Center West Vent Structure South Projection Route 9A Relocation

21. Construction Logistics

22. Construction Logistics

23. Site Wide Systems Integration Fire Alarm Radio systems Telecommunications BMS

24. Contact Information Hemant Mehta, P.E. President WM Group Engineers, P.C. 370 Seventh Avenue, Suite 701 New York, NY 10001 (646) 827-6500 hmehta@wmgroupeng.com http://www.wmgroupeng.com Christopher Tso, P.E. President CRC Engineering, P.C. 1261 Broadway, Suite 608 New York, NY 10001 (212) 889-1233 ctso@crc-eng.com http://www.crc-eng.com