The Tank 6 facility shown in Figure 1, is a 68-foot long by 25-foot diameter horizontal vacuum chamber with a liquid nitrogen cryo-wall and a solar simulator. The facility has a 10′ diameter X 10′ long test section, separated from the main chamber with a 10′ gate valve. The solar simulator uses nine 30 kW Xenon arc lamps and was designed to provide no less than 1 Sun (12″ apparent source) on a 15 foot diameter target, 56.5 feet from the source with a subtense angle of less than 1 degree. The vacuum system can provide ambient pressures as low as 0.0000001 torr. The main chamber is pumped with 12 cryopumps, and has an air pumping speed about 1,000,000 l/s, while Xenon pumping speed is about 400,000 l/s. The pumping system was upgraded in early 1999 to provide an “oil-free” pumping system and improve the pumping speed. Liquid nitrogen cryo-wall are divided into three sections and can provide wall temperatures at -320 °F which are capable of > 0.35 MW thermal power loading.
An offset concentrator, as shown in figure 1, consists of seven hexagonal panels with six reflective mirrors per panel is available for solar thermal experiments. The concentrator is 4.75 m wide by 4.55 m tall and is supported on a leaning tripod support structure. A Kendell radiometer is available to make solar flux measurements.