1. 1 BROOKHAVEN SCIENCE ASSOCIATES NSLS – II Stability Workshop Conventional Facilities Temperature Stability Chris Channing P.E. Sr. Project Engineer National Synchrotron Light Source – II Project April 18 2007

2. 2 BROOKHAVEN SCIENCE ASSOCIATES Temperature stability goals Key temperature stability requirement is tunnel air @ +/- 0.1C (+ /-.18 F) at any given location over 1 hour Key parameter is temperature stability and repeatability vs. absolute accuracy. Tunnel temperature of 78 was selected to eliminate the concern of a temperature gradient between the experimental floor and the tunnel. The tunnel air conditioning system will be designed to accommodate tunnel temperatures between 75 and 85 F. During commissioning period, tests will be conducted to determine the optimum tunnel setpoint temperature.

3. 3 BROOKHAVEN SCIENCE ASSOCIATES Temperature stability The following will be done to achieve the requirements. Requires high resolution industrial grade instruments and controls with excellent repeatability. Will use narrow span thermistor/transmitters with.01 C sensitivity. Control scheme using programmable controllers with 14 bit resolution. We will use a control program we have written which reset the discharge air temperature in response to room temperature deviation from setpoint. The program resets and controls discharge air temperature to find the exact supply temperature required to satisfy the load requirements. This minimize the temperature fluctuation in the room. We have several application were we currently use this concept to achieve +/- 0.1C control. We will use electric reheat with SCR control to allow for fast accurate control of discharge air temperature.

4. 4 BROOKHAVEN SCIENCE ASSOCIATES Temperature Stability cont. 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. We are working with APS to modify a section of their tunnel system to prove out our concept. We will also be investigating thermal modeling of the tunnel equipment and air flows to verify our assumptions.

5. 5 BROOKHAVEN SCIENCE ASSOCIATES Tunnel Temperature Control

6. 6 BROOKHAVEN SCIENCE ASSOCIATES Tunnel Air Distribution

7. 7 BROOKHAVEN SCIENCE ASSOCIATES Example of control system stability 70 65 60

8. 8 BROOKHAVEN SCIENCE ASSOCIATES Example of control system stability 71 71. 2 70.8

9. 9 BROOKHAVEN SCIENCE ASSOCIATES Example of control system stability 65 60 DASHED CURVE IS REQUIRED DISCHARGE AIR SET POINT TO MEET LOAD ON TOP OF IT IN YELLOWIN YELLOW IS ACTUAL DISCHARGE AIR SETPOINTSYSTEM CONTROLLED TO. TEMPERATURES IN DEGREES F

10. 10 BROOKHAVEN SCIENCE ASSOCIATES Path Forward Evaluating thermal modeling software and vendors and are leaning toward Thermo Analytics Investigating thermal modeling of the tunnel equipment and air flows to verify our assumptions. Also model different supply and return flow configurations. Planning to modify a section of APS tunnel system to prove out our concept. Have included some of our concepts into the new Center for Functional Nanomaterials Building and will be using information learned from those systems to prove out and refine our concepts.