Simulated effects of dynamic row spacing on energy and water conservation in semi-arid Central California greenhouses.

摘要

Considerable effort is expended to conserve energy and water in current greenhouse systems, and look for alternative energy sources, especially passive heating and cooling strategies. Proper environmental management systems can significantly change the energy and moisture dynamics of greenhouse production systems. In this study, specifically, influences of dynamic row spacing on energy and water conservation were investigated. A dynamic computer simulation model was used to compare different row spacings, plant heights, and leaf dimensions to draw a conclusion about energy and water conservation. The results showed that using smaller spacings between cucumber crop rows (for instance, 0.5 m instead of 0.75 m) reduced energy consumption per unit floor area in average of 14.4%. With a decrease in row spacing, the total amount of surface for radiation exchange decreases, and plant canopy shading within the canopy increase consequently. This leads to less radiational and evaporative cooling in smaller row spacings, hence lower heating requirements during the heating season. By changing the row spacing from 0.75 m to 0.5 m, average water savings (adjusted to the whole greenhouse area) of 27.8% occurred. A complete system analysis is necessary to be able to make a viable conclusion in total energy and water conservation.