Lawrence Street Center Case Study

1. Lawrence Street CenterCase Study Craig Griffiths Merrill Lynch

2. Lawrence Street Center • Steel & concrete structure • Concrete & glass wall construction • 14 floors, 140,000 sq.feet • Commercial offices & radio stations • 6 am to 6 pm operation

3. Inefficient cooling system oversized chiller running at low part load efficiencies 15 year old electric chiller, CFC refrigerant R-11 Public Service Company utility rebate program currenlty in effect Lawrence Street Center Project Scenario

4. Lawrence Street Center Internal Loads • Lighting with standard fluorescent fixtures • Office equipment - PC’s, copiers, fax machines • Telecommunications equipment for four radio stations

5. Lawrence Street Center Project Challenges • Space constraints on chiller make replacement very difficult • Quick turnaround time necessary • only 3 weeks for retrofit work before spring startup

6. Lawrence Street Center Original Chiller • 400 ton Carrier electric chiller • R-11 refrigerant • 0.72 kW/ton full-load efficiency • Only operating at 60% capacity • In third floor mechanical room

7. Lawrence Street Center Chiller Driveline Retrofit • Replaces the driveline, including starter, motor, compressor, purge unit and controls • New parts compatible with new refrigerant • HCFC-123 used in Lawrence Street Center • Kept old heat exchanger • checked the shells & tubes condition with eddy current testing of the condenser and evaporator • Retrofit work by York International

8. Lawrence Street Center Other Chiller Enhancements • External oil pump installed • allows chiller operation at a lower condenser water temperature • more energy savings when ambient conditions permit • New chiller control panel • Refrigerant monitoring system and high-efficiency purge unit

9. Lawrence Street Center Retrofitted Chiller • Capacity reduced from 400 tons to 290 tons • Full load electricity use down to 0.59kW/ton from 0.72 kW/ton • Payback period of 7.5 years without rebate

10. Lawrence Street Center Project Timeline • Chiller retrofit work generally takes 1-2 months, this was a rush job, done in 3 weeks

11. Lawrence Street Center Energy Savings Results • Occupancy increased significantly during and just after the retrofit occurred • from ~ 75% occupancy to ~ 95% • Utility bills stayed about the same as during the last cooling season • Chiller downsizing and efficiency gains offset the occupancy increase

12. Lawrence Street Center Project Results • Significant energy savings from more efficient, correctly sized chiller • Switch to HCFC refrigerant • no longer have to deal with escalating R-11 prices • Fairly short payback period, thanks to utility rebate

13. Lawrence Street Center Extension of Project Results • Most chillers are incorrectly sized • measure energy use carefully to see how much downsizing and/or staging of chillers can save • Load reductions and system improvements could have been done with chiller work • save even more energy and $$$ • potential to downsize chiller even further • help finance chiller and reduce payback period • correct any building problems