Development and evaluation of an advanced water-jacketed high intensity discharge lamp

During the period July 2001 to March 2002, the performance of a water-jacketed high intensity discharge lamp of advanced design was evaluated within a lamp test stand at The University of Arizona (UA), Controlled Environment Agriculture Center (CEAC) in Tucson, Arizona. The lamps and test stand system were developed by Mr. Phil Sadler of Sadler Machine Company, Tempe, Arizona, and supported by a Space Act Agreement between NASA-Johnson Space Center (JSC) and UA. The purpose was for long term testing of the prototype lamp and demonstration of an improved procedure for use of water-jacketed lamps for plant production within the close confines of controlled environment facilities envisioned by NASA within Bioregenerative Life Support Systems. The lamp test stand consisted of six, 400 watt water-cooled, high pressure sodium HID lamps, mounted within a framework. A nutrient delivery system consisting of nutrient film technique re-circulation troughs and a storage tank was also included, but plants grown in the system were not evaluated in this time period. The performance of the lamps was quantified in terms of photosynthetic photon flux (PPF), and spectral irradiance during the 9-month testing period. In addition, an energy balance and a series of short term tests were completed on the lamp system. The lamps were operated on a 16 hour 'on' and 8 hour 'off' duty cycle each day. The total operation time for the lamps during the test period was 4208 hour. The following report describes a series of tests performed on the water-cooled high pressure sodium (HPS) lamp system.