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P3K Palomar Infrastructure

P3K Palomar Infrastructure. Balance Adaptations Larger Cass weight load Electrical Service Upgrades Higher electric service loads at Cass, Computer Room and AO lab Cooling of Cass Electronic Racks Removal of ~6kW of heat from below primary mirror. Cass Mounted System Weights.

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P3K Palomar Infrastructure

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  1. P3K Palomar Infrastructure • Balance Adaptations • Larger Cass weight load • Electrical Service Upgrades • Higher electric service loads at Cass, Computer Room and AO lab • Cooling of Cass Electronic Racks • Removal of ~6kW of heat from below primary mirror J.Zolkower

  2. Cass Mounted System Weights • Current AO Cass System Weights • AO Bench 3820 lb • AO Rack 1 (Loc 3) 415 lb • AO Rack 2 (Loc 2) 345 lb • Cables 85 lb (est) Total 4665 lbs • P3K AO Cass System Weights • P3K Bench 3900 lb • P3K DM rack 1 (Loc 3) 525 lb • P3K DM rack 2 (Loc 2) 525 lb • P3K Ctrl rack 1 (Loc 5) 258 lb • P3K Ctrl rack 2 (Loc 4) 348 lb • Cables 475 lb • Glycol system hardware 260 lb Total 6291 lb (~1600 lbs > current AO) J.Zolkower

  3. Balance Adaptations J.Zolkower • P3K Cass mounted component weights exceed current balance adjustments via moving counterweights • New balance adaptations required: • Additional 506 lbs of lead added to weight boxes on Tube upper ring • Implementation of up to three ‘dummy’ electronic cabinets: • 2 cabinets loaded with 475 lbs of weight, the third with ~200-300lbs • To be applied with lower weight Cass instrument / electronic configurations

  4. Electrical Service Upgrades Power Requirements • Computer Room Electronics (2 Racks) • Total Rated Power : 11,870 W • Total measured continuous measured: 3500 W • Continuous + Intermittent measured: 5400 W • Cass Cage mounted Electronics (4 Racks) • Total Rated Power: 8900 W • Total continuous measured: 6250 W • Continuous + Intermittent measured: 7210 W • Current AO system measured: 1035 W • Highest power AO instrument P1640 ~ 500W • P1640 Cal power TBD • Chiller in Coude • 220 V / 3 Phase / 30 amp service J.Zolkower

  5. Electrical Service Upgrades J.Zolkower Required Electrical Upgrades • Computer Room Electronics • Add 3x 120V / 30 Amp Receptacles • Cass Cage • Add 3x 120V / 30 Amp Receptacles • Add Load Center in Cass Cage • Insufficient paired conductors available in exiting wrap-up to provide required power (electromagnetic field cancellation concerns) • A new, auxiliary wrap-up will be used to bring required power to Cass • This auxiliary wrap-up will also be used to transport glycol to Cass Cage • AO Lab • Add 3x 120V / 30 Amp Receptacles • Coude (Chiller location) • Add Breakers, Disconnects, and Junction Box

  6. Power Dissipation / Mirror Temperature Current AO power ~ 1000 W J.Zolkower

  7. Maximum Heat Dissipation Requirement Specification released May 5, 2010: • For all Cassegrain mounted instruments, the maximum heat dissipation shall not exceed 300W under the primary mirror, and 1 kW into the dome air away from the primary mirror.  If this requirement is met, it is assumed that the following requirements will also be met except under extreme circumstances. • The heat dissipated by any Cassegrain mounted instrument shall not increase the temperature of the primary mirror, locally or globally, by more than 0.75ºC relative to the mirror baseline temperature.  • The heat dissipated by any Cassegrain mounted instrument shall not induce a temperature gradient in the mirror of more than 0.5ºC measured between any two points on the mirror. • Evaluation of items 1a. and 1b. to be made by comparing values using a 12 point moving average of data taken at a 5 minute sampling rate. • The baseline temperature is defined as the average of the primary mirror temperature measured at the north and northeast temperature sensor locations. J.Zolkower

  8. Cass Rack Power Allocation These racks to be cooled ~6100 W J.Zolkower

  9. Cooling System Functional Parameters • Basic Functional Requirement • Provide system for cooling of Cass mounted electronics in order to minimize the heat dissipated to environment below the primary mirror and dome air • Operating parameters: • Ambient temperature range: -10ºC to +30ºC • Target Coolant temperature: 3ºC below ambient • Cooling fan air flow: Constant speed • Coolant Mix: 35% Propylene Glycol • Coolant Temperature Range: -13ºC to +27ºC • Heat expelled to facility chilled water 5ºC to 10ºC (seasonal range) • Facility chiller total capacity 10 ton ( 35 kW) • Facility chiller current heat load ~ 1 ¾ ton (~6.2 kW) • Thermal modeling of electronic rack heat exchangers by Thermatron to confirm heat exchanger design within proposed operating parameters J.Zolkower

  10. Electronic Rack Heat Exchanger J.Zolkower

  11. Heat Exchanger Thermal Model Results J.Zolkower

  12. Heat Exchanger Thermal Model Results J.Zolkower

  13. Heat Exchanger Thermal Model Results J.Zolkower

  14. Heat Exchanger Thermal Model Results J.Zolkower

  15. Chiller Specification • Total heat load: 6100 W • Max. coolant flow rate: 16 GPM • DM Racks: 3x 2 gpm x 2 Racks = 12 gpm • Cass 1 Rack: 2x 2 gpm x 1 Rack = 4 gpm • Coldest required supply coolant temp: -13ºC • Warmest required supply coolant temp: +27ºC • Chiller Construction / Installation Options for Cass: • Air cooled unit: exhaust chiller warm air directly out dome by most direct route on dome floor. • B) Air cooled unit: exhaust chiller warm air through Buffalo Blower exhaust. • C) Air cooled unit: Split system with refrig condenser outside. • D) Water cooled unit: exhaust chiller heat through facility chilled water. • E) Water cooled unit: exhaust chiller heat through connection to 2nd closed cycle coolant system via outside heat exchanger. • Chiller Construction / Installation Options for AO Lab: • Acquired Neslab System III & IV Liquid to Liquid Heat Exchangers • Cooling requirements are less stringent when operating in AO lab, so refrig of process coolant not req’d • No need to move chiller from dome floor to AO lab of long plumbing runs J.Zolkower

  16. Chiller Selection J.Zolkower

  17. Chiller Selection J.Zolkower

  18. Chiller Selection Optitemp Chiller J.Zolkower

  19. Chiller Selection J.Zolkower

  20. Cooling System Control Motivation: • The P3K power dissipation in the Cassegrain environment will introduce thermal gradients into the primary mirror. The long time constant of the primary mirror and cell will extend the induced thermal effect to instruments that follow possibly degrading the performance of Non-compensated system. • Containing the thermal waste of the system in closed cabinets requires the heat transport away from the telescope environment. The solution proposed requires the enclosure of the sources of heat to be confined to three cabinets. The heat must be transferred away from this closed environment to prevent damage to the electronic systems. • The P3K system may be operated at times unattended locally and a failure of the cooling system must be detected and acted upon before damage occurs. • In addition, the cooling of the electronics requires a liquid under pressure to be circulated in the proximity of the electronics. Leaks or condensation are possible adding yet another risk to the system that must be detected and acted upon. • The operation of this system may require the precise understanding of the cooling systems performance and the secondary function of this system is to provide a telemetry stream for analysis.

  21. Cooling System Control Basic functions: • Closed loop temperature control • Control of Air temperature within the rack environment to prevent the shell temperature of the electronics from exceeding a temperature of 3 degrees C below the ambient temperature. • Fan speed optimization • To minimize the fan vibration, a fan speed control is proposed to run the fan array at the slowest possible speed. In a fault state such as condensation, the fans may be used at high speed to assist in the evaporation of the leak or condensate. • Over temperature shutdown • A failure of a system within the electronics cabinets such as the DM driver temperature control, blocked or diverted coolant flow, or loss of air circulation can quickly raise the internal temperature to unacceptable levels. • Coolant leak or condensation. • Cooling liquid or the result of condensation may result in damage to the electronics.

  22. Cooling System Control • Chiller fault shutdown • A failure of the main chiller will cause the internal cabinet temperature to rise to unacceptable levels. To prevent damage the cooling system supervisor will need to power off the electronics. • Emergency Stop • In the case where it is desired to do a manual immediate shutdown we propose that three emergency shutoffs, E Stops, located in the Cassagrain cage, 200 inch data room, and coude room or where the main chiller is located. • Cabinet door state • Monitors cabinet doors incase of a configuration error. • System overrides • If it is determined that it is necessary to bypass a sensor, we propose a bypass switch panel that allows the controller to do so without changing jumpers or software. • Remote access • The Chiller supervisor will be accessible remotely for control and telemetry data

  23. Cooling System Control Chiller supervisor concept • Parameters to be monitored: 1) Ambient air temperature and dew point at cabinet location. The read should note that the system is capable of operation in two locations, Cassegrain and AO lab. 2) Cabinet Skin temperatures 3) Cabinet coolant flow rate 4) Cabinet internal air temperature 5) Cabinet wetness 6) Cabinet Door state 7) E stop status 8) Sensor Bypass configuration (overrides)

  24. Cooling System Control Supervisor electronics: • At present we propose the consideration of two possible solutions. • Campbell Scientific 3000 data logger/controller • Industrial Programmable Logic Controller (PLC) • The Campbell data logger and control system has a versatile set of analog and digital inputs and outputs that are programmed with a simple interface and is in use at 4 location already at Palomar Observatory. • Due to the possible number of inputs and outputs combined with the Varity of communication protocols to and from the system it may be necessary to use a programmable logic controller instead. Only after the scope of this control system is accepted, will the many details be explored.

  25. Cooling System Control • Modes of operation: • We envision three modes of operation. • Constant set point • Controller maintains a constant internal air temperature • Tracking • Controller maintains a temperature relative to the ambient temperature • Dew point avoidance • Controller maintains a temperature relative to dew point. • Anticipated performance: • We expect that the Campbell scientific logger will be capable of monitoring temperatures to better than 0.1 C and that the control loop cycle time will be less than 1 second. • Telemetry Data and remote commands: • We expect that all parameters and the resulting control signals are provided at the loop rate via serial or network connections. In addition the control mode and state will be remotely accessible.

  26. Cooling System Control Block Diagram The Block Diagram is simplified to show the locations of the main components. Items to note: Main Power contactors for Cassegrain electronics and Chiller are controller by hardwire to contactors that do not depend on control electronics Chiller fault and Estop signal to use existing telescope patch panels

  27. Plumbing/Electric to Cass - Drag Line Option Evaluation of using a drag line to bring coolant and electric to Cass 2x Cooling Lines 1x Electric Cable 2x Cryotiger lines? Risk of adverse effects on pointing and balance. Decision made to pursue a fixed plumbing arrangement; a.k.a. Auxiliary Wrap-up J.Zolkower

  28. Auxiliary Wrap-up Routing South Polar Axis Routing Turning Guide Attached at yoke bottom center To Coude J.Zolkower

  29. Auxiliary Wrap-up Routing Dec Axis Tube East Arm J.Zolkower

  30. Dec Axis Wrap-up Concept East Arm Spool Attached To Tube (Tube not shown) Dec axis Igus Cable Carrier Guide trough (cutaway) Attached to East Arm

  31. Cass Plumbing & Electric Routing Electric Load Center Cooling distribution manifold South side

  32. Cass Plumbing & Electric Routing Liquid cooled rack locations Southwest side

  33. Pressure Drop of Coolant Plumbing • Compared flow velocity of main supply/return lines with 1” and 1 ¼ “ dia plumbing. • At 16 gpm 1”→ 6.5 ft/sec; 1 ¼” → 4.2 ft/sec • Calculate viscosity of 35% Propylene Glycol / water mix at -13ºC (lowest coolant temp) • 5.67 cSt , Using blended viscosity equation • Calculate Reynolds Number: for 1 ¼ Re= 7120→ Turbulent flow • Using D’Archy-Weibach eq., Calc pressure drop for 100 ft of pipe • 1” pipe dP = 10.5 psi / 100ft • 1 ¼ “ pipe dP = 3.5 psi / 100ft → 30% less than 1” pipe • Repeat process for ½” Cass Cage plumbing J.Zolkower

  34. Pressure Drop of Coolant Plumbing J.Zolkower

  35. Pressure Drop of Coolant Plumbing J.Zolkower

  36. Pressure Drop of Coolant Plumbing Optitemp Chiller 5 HP pump 2 HP pump 3 HP pump Telescope & Rack plumbing dP ~ 32 psi @ 16 gpm Chiller internal dP ~ 11 psi @ 16 gpm J.Zolkower

  37. DM Rack Cooling System Layout Cage inside Cage outboard inside J.Zolkower

  38. Cooling Fan Speed Control J.Zolkower Cooling system operating strategy requires constant speed fan control of the each 9-fan tray Xinetics DM drivers control fan speed by a stepped function based on temperature We do not have access to the Xinetics software required to control fan speed An alternate fan speed control system is required to operate the fans according to our cooling system strategy

  39. Cooling Fan Speed Control Proposed solution from Degree C • Accepts up to nine fans • ·Synchronizes rotational speeds of 4-wire fans to • eliminate “beat” noise and vibration • · Monitors speed of 3-wire fans • · Simultaneously controls up to two types of fans • · I2C and RS232 communication interfaces • · Field configurable through serial interface • · Programmable alarm thresholds & fan curve • · Open collector alarm output • · One onboard/ two external temperature sensors • · Non-volatile memory to store configuration • · Power & Alarm LEDs with external connections • · Software selectable 3.3/5V logic operation • · Isolated Fan and Logic power domains • · Single/Dual power input • · Inrush current limiter for “hot swap” • · Fan failure detection and prediction J.Zolkower

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