The Coudé Lab Environment Boulder 18 March 2009
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] Dust Control Requirements Photosphere: The scattered light from telescope and instrumentation from angles > 10 arcsec shall be 1% or less. … 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] 0.002 %/hr ≈ 264 ppm per 24 hrs
Cleanrooms Cleanrooms fall under the following FED-STD-209E classifications: Note: Dunn environment approximates Class 100,000 (ISO 7) with existing filtration in use
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 C) • Temperature Uniformity @ work surface (0.25 C) • Temperature Gradient through room (0.5C) • Velocity(0.5 m/s @ optics) • Heat Loads (sensible & latent) • Design allowance (lights, ventilation, instruments, equipment, etc.) • Vagrant Loads (people, laptops, equipment?) • Humidity • 35-50% for comfort, 45% for ESD (45%±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 Supply Air Air Handling Unit Return Air
CROSS FLOW boundary conditions SUPPLY • 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 RETURN