The Coudé Lab Environment
Boulder18 March 2009
The Coudé Lab
Air Curtain Interface
Instrument Foundations
Instrument Foundations
Air Curtain Interface
Dust Control Requirements
0.002 %/hr ≈ 264 ppm per 24 hrs
Scatter w ith Accumulation
0.0E+00
2.0E-05
4.0E-05
6.0E-05
8.0E-05
1.0E-04
1.2E-04
1.4E-04
1.6E-04
1.8E-04
1.0 1.2 1.4 1.6 1.8 2.0
Distance from Sun Center (solar radii)
Rat
io to
On-
Dis
k Irr
adia
nce
Microroughness
0.01% Coverage
1 Day (0.063%)
1 Week (0.38%)
Figure 15. The figure shows the effects of dust accumulation on the primary mirror after one day and one week, assuming the UKIRT accumulation rate of 0.002 percent per hour. [TN-0013]
… we can tolerate about … 0.3 percent total coverage…we will exceed the stray-light budget after only 132 hours (about five days). [TN-0083]
Photosphere: The scattered light from telescope and instrumentation from angles > 10 arcsec shall be 1% or less.
Cleanrooms
Class
# 0.5mmparticlesper ft3
# 5.0mmparticlesper ft3
airchangesper hour
ceilingfiltercoverage(%)
airvelocity(fpm)
max.vibration(min/s)
temp.tolerance
RHtolerance
approx.capital costper ft2
office 12-18 ? $10
100,000 100,000 650 18-30 10 $50
10,000 10,000 65 40-60 30 10 ±3.0°F ±5% $200-250
1,000 1,000 6.5 150-300 50 30-50 ±2.0°F ±5% $350-400
100 100 0.65 400-540 80-100 75-90 500 ±1.0°F ±5% ~$1200
10 10 0.065 400-540 100 75-90 250 ±0.5°F ±3% ~$3500
1 1 0.0065 540-600 100 90-100 250 ±0.3°F ±2% ~$10,000+
0.5 0.5 0.0033 540-600 100 100-110 125 ±0.1°F ±1% ~$25,000+
Cleanrooms fall under the following FED-STD-209E classifications:
Note: Dunn environment approximates Class 100,000 (ISO 7) with existing filtration in use
The Downflow Concept
Environmental Rooms
• Clean Room – has a controlled level of contamination that is specified by the number of particles per cubic meter at a specified particle size, but it also implies many other parameters.
• Environmental Room - temperature and/or humidity level is controlled at a single set condition within specified tolerances regardless of activity in the room.
• In any case - tight temperature control requires flow that is free of recirculation zones.
The Coudé Lab
END
from “The Harris Guide to Environmental Room Design”
Design Parameters•Temperature and Velocity
•Design set-point (0.5 m/s and 20 or 21 or 22 (0.5 m/s and 20 or 21 or 22 C)C)•Temperature Uniformity @ work surface (0.25(0.25 C)C)•Temperature Gradient through room (0.5(0.5CC))•Velocity (0.5 m/s @ optics)(0.5 m/s @ optics)
•Heat Loads (sensible & latent)•Design allowance (lights, ventilation, instruments, equipment, etc.)•Vagrant Loads (people, laptops, equipment?)(people, laptops, equipment?)
•Humidity•35-50% for comfort, 45% for ESD (45%(45%±5%)±5%)•Low to prevent hygroscopic adhesion of dust
•Dust Control•Filtration vs. cleaning•Contamination control (personnel, construction materials, etc.)
•Pressure Control (positive pressure) •Service Access (access to filters, etc.)•Vibration (fans, equipment locations)
CROSS FLOW mechanical packaging
Air Handling Unit
Return Air
Supply Air
CROSS FLOW results
CROSS FLOW boundary conditions
SUPPLY
RETURN
•Air properties for 3000-m
•16ea – 4’x4’ openings supplying 4 m3/s @18˚C
•16ea – 4’x4’ openings for return @ P=0 Pa
•Thermal properties set up, but never run