1 brookhaven science associates nsls – ii stability workshop conventional facilities temperature...
DESCRIPTION
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.TRANSCRIPT
1 BROOKHAVEN SCIENCE ASSOCIATES
NSLS – II Stability Workshop
Conventional FacilitiesTemperature Stability
Chris Channing P.E.Sr. Project Engineer
National Synchrotron Light Source – II ProjectApril 18 2007
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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 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 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.
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Tunnel Temperature Control
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Tunnel Air Distribution
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Example of control system stability
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Example of control system stability
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70.8
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Example of control system stability
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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
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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.