1 BROOKHAVEN SCIENCE ASSOCIATES NSLS – II CFAC Review Conventional Facilities Briefing Chilled Water and Temperature Stability Chris Channing Sr. Project Engineer National Synchrotron Light Source – II Project October 10, 2006

2 BROOKHAVEN SCIENCE ASSOCIATES Chilled Water New 3600 ton chilled water expansion to site chilled water plant. (2400 ton load with n+1 redundancy) System will use three 1200 ton electric centrifugal chillers Existing 5,000 ton plant has 22,000 ton hour chilled water storage tank. No spare capacity available. Chilled water distributed via underground ductile iron piping system. Chilled water piped in a ring configuration to help with future load changes.

3 BROOKHAVEN SCIENCE ASSOCIATES Potential Chilled Water Plant

4 BROOKHAVEN SCIENCE ASSOCIATES Chilled Water Advantages Remote plant and pumps eliminate any contribution to vibration and noise Existing plant already manned 24/7 Excess plant capacity in winter adds to maintenance flexibility in future. Higher redundancy level in winter months

5 BROOKHAVEN SCIENCE ASSOCIATES Site Utility Routing

6 BROOKHAVEN SCIENCE ASSOCIATES Temperature stability Key temperature stability requirement is tunnel +/- 0.1C at a given location with respect to time. Requires high resolution industrial grade instruments and controls with excellent repeatability. Will use narrow span thermistor/transmitters with.01 C sensitivity. Key parameter is temperature stability and repeatability vs. absolute accuracy. Control scheme using programmable controllers with 14 bit resolution. We will use discharge air reset by room temperature. The program resets and controls discharge air temperature to find the exact supply temperature required to satisfy the load requirements. We have several application were we currently use this to achieve +/- 0.1C control.

7 BROOKHAVEN SCIENCE ASSOCIATES Temperature Stability cont. We will use electric reheat with SCR control to allow for fast accurate control of discharge air temperature. Space temp set point of 85 F is nominally equivalent to process cooling water supply set point to minimize temperature gradients Outside air ventilation will be interlocked to beam operation. We will have a unoccupied “ beam ” mode with no outside air and control to 85F. During occupied (service) periods the tunnel will be ventilated with sufficient outside air for personnel and tunnels temperatures of 75 f. It is not envisioned that the economizer will be used during beam mode to keep stable tunnel conditions. Should be readily achievable provided loads to accelerator components are relatively steady-state

8 BROOKHAVEN SCIENCE ASSOCIATES Tunnel Temperature Control

9 BROOKHAVEN SCIENCE ASSOCIATES Tunnel Air Distribution

10 BROOKHAVEN SCIENCE ASSOCIATES Example of control system stability 70 65

11 BROOKHAVEN SCIENCE ASSOCIATES Example of room stability close up

12 BROOKHAVEN SCIENCE ASSOCIATES Example of discharge air temp tracking set point