1. M1M3 Fan Coil Unit Status Gary Muller & Brian Johnson LSST 2017 Project & Community Workshop 8/17/2017

2. Fan Coil Unit (FCU) Overview
There are 96 FCUs inside
M1M3 Mirror Cell that circulate conditioned air through the mirror cores via >1650 vent tubes

3. FCU Location IDs in M1M3 Cell
F1, F2, F3, …, F96
Installation drawings:
Direct FCU Installation
Offset FCU Installation

4. Inlets Mount To Deck Plate
For direct ducts
For offset ducts
Captive screws
No flange for flexible duct
Flange for attaching rigid duct
Marmon clamp

5. FCU Configurations Offset duct Long duct Short duct No duct
Offset ducts are non-structural. FCU must be supported by a bracket attached to structure.
Direct ducts are structural and provide cantilever support of FCUs.
Offset FCU
Direct FCUs

6. Diffuser cone inlet with 40 w and 60 w blanket heaters
FCU Detail
Diffuser cone inlet with 40 w and 60 w blanket heaters
Heat exchanger
EGW coolant
Nozzle cone
Thermo-couples
Centrifugal fan
Inner loop Controller

7. Distribution of FCUs in M1M3 Cell
Placement of FCUs is limited by mirror support system components.
Actuators, hard points, mirror cell structure

8. EGW Coolant Loops
Supply loop
Return loop
Recirculation pump assy

9. 1650 Mirror Core Vent Nozzles

10. Mirror Core Vent Nozzles

11. Current Status
110 FCUs have been assembled, leak tested, and await acceptance testing
Conducted inlet fit check with M1M3 cell deck plate at CAID in July
EGW supply/return hoses have been procured and received
Marmon clamps and rigid ducts have been procured and received
Offset FCU mounting brackets have been fabricated and received
Need to procure flexible ducts (11X) for Offset FCUs

12. Completed FCU

13. 110 Completed FCUs Ready for Test & Integration

14. Acceptance testing (Test plan is under construction)
Future Plans
Acceptance testing (Test plan is under construction)
Fan speed / air flow rate
Vary air flow rate
Heater power
Vary heater power
50°C thermostat cutoff switch
Vibration measurements
EGW flow rate / temperature
Need to decide whether to conduct this test
Will need EGW chiller system to test (currently none)

15. Procure flexible ducts for offset FCUs Procure shipping crates
Future Plans
Drill and tap mounting holes in M1M3 cell for offset FCU mounting brackets (11x)
Procure flexible ducts for offset FCUs
Procure shipping crates
Integration into M1M3 cell
Install inlets
Install ducts and FCUs
Wire routing and electrical boxes

16. Supplemental Slides

17. Principle of Operation
Air is drawn from the mirror cores into 96 6” diameter inlets in the deck plate by low pressure in the FCU
The air passes downward through a diffuser after the inlet where blanket heaters on two diffuser cones heat the air as needed.
Temperature sensors on the mirror measure absolute temperature and thermocouples on the FCU measure the temperature change through the FCU for the thermal control feedback loop.
The air then continues downward through a heat exchanger and is cooled via chilled ethylene glycol / water mixture
A centrifugal fan draws the conditioned air from the heat exchanger and is ejected radially outward into the enclosed volume of the M1M3 mirror cell.
The conditioned air is then forced into >1700 nozzles upward into the mirror cores where they heat or cool the mirror thus, completing the cycle

18. No Duct
Inlet
Marmon Clamp
Fan coil unit

19. Short Duct

20. Long Duct
Inlet
Marmon Clamp
Long duct (rigid)
Fan coil unit

21. Offset Duct Inlet Marmon clamp Flexible duct Mounting Bracket
Hose clamp
Fan coil unit

22. Original Diffuser Design
Flow
Stagnation

23. 1st Iteration of Diffuser Design
Eliminated stagnated flow but flow is concentrated at center
Changed diffuser geometry and changed nozzle after heat exchanger

24. 2nd Iteration of Diffuser Design (Final Design)
Flow distributed over larger area of heat exchanger for maximum heat transfer
Added two diffuser cones