The Initial Tests for Performance Evaluation of Closed Plant Experiment Facility (CPEF) of Closed Ecology Experiment Facilities (CEEF)

The Closed Ecology Experiment Facilities (CEEF) have been under construction in northern Japan since 1994. These facilities contain the Closed Plant Experiment Facility (CPEF), as well as other facilities, in all of which, Controlled Ecological Life Support Systems (CELSS) research and development can be conducted. The CPEF includes two Plant Cultivation Modules (PCMs), which contain a PCM consists of three 30m² closed cultivation rooms illuminated solely by lamps and a 165.1m³ preparation room, and a PCM consists of a 60m² closed cultivation room illuminated by natural light and supplemental lamps and a 88.8m³ preparation room, and a Material Circulation System (MCS). Measured rate of air exchange between a 30m² cultivation room and the preparation room was 0.48% hour^-1, and that for a 60m² cultivation room was about 0.11% hour^-1. Air leak rate of the PCM as a whole was less than 0.01% hour^-1 under isothermal and equal pressure condition. Ethylene and isoprene concentrations in a 30m² cultivation room increased from 5nmol mol^-1 to 32nmol mol^-1 and 13nmol mol^-1 to 50nmol mol^-1 during 35 days closed rice cultivation. Accumulation of methane, NO, NO₂, SO₂ and ammonia during the closure could not be detected and could not arouse any problem. Changes in photosynthetic CO₂ uptake rates of rice and soybean stands in each 30m² cultivation room with PPFD change in tiers could be monitored satisfactory using [CO₂] decline rate after each intermittent CO₂ supply. Changes in transpiration rates of them could be monitored satisfactory using dew point difference before and after the room and air circulation rate. PPFD in 30m² cultivation rooms at the height 1.2m above cultivation beds was ca. 1.93m mol m^-2s^-1, when all lamps were turned on. Standard setting range of air temperature in cultivation rooms during light phase is 18 - 30 °C, but actual temperature raised from the setting point by ca. 3.4 °C, when temperature was set at 25 °C, 75% of lamps were turned on and rice (leaf area was about 3 times of the cultivation area) was planted.