Estimation of Efficiency of the Vitamin Conveyor-Type Plant Growth Facility “Phytocycle” from Ground Tests 2001-01-2424
Plants of the celery cabbage (Brassica pekinensis (Lour) Rupr.) were grown in a Vitamin Conveyor-Type Plant Growth Facility (PGF) “Phytocycle” with a cylindrical planting surface being the ground prototype of a vitamin greenhouse for the International Space Station. We offered a global criterion of an overall efficiency, Q, of space plant growing units as a maximum of the product Q = MV·ME, where MV and ME are specific productivity of the PGF per unit of volume and per unit of consumed energy. For each step of conveyor crop in “Phytocycle” this criterion is proportional to value: QT = Pi2·Si/Wi; i = 4, 5, … n, where Pi – an yield of the shoot dry mass at the i-th step of the conveyor, Si - the illuminated area on the i-th step of the conveyor, Wi - amount of energy of PAR fallen on the crop for conveyor step number i. Values of QT were determined for each step at the steady regime of conveyor crop. The optimal number i0 was chosen appropriate to the maximal meaning of the criterion. The age of plants at the end of the optimum conveyor step was assumed equal to the optimum length of plant growth cycle, T0, for the first approach. The tests must be repeated for the conveyor crop with length of plant growth cycle equal i0T/n. The optimal number i01 at the second test iteration was determined as the optimum plant growth cycle. For the same plant illumination energy spent, crop on the convex cilindrical planting surface allows to receive more specific productivity than crop on a flat one due to the plants auto-extending effect. The plants extending effect reduced a shading inside crop during the growth period. During the VCPGF “Phytocycle” tests MV was equal 0.8 kg/m3day, ME – 0.053 kg/kW·hr. Correspondingly, that are 30% more and almost twice more in comparison with similar values for the most economical Russian conveyor-type PGF with a flat planting surface.