Click on “Download PDF” for the PDF version or on the title for the HTML version.

If you are not an ASABE member or if your employer has not arranged for access to the full-text, Click here for options.

Abstract. A greenbox horticultural system has been recently proposed and developed by VECNA (Cambridge, MA) and University of Connecticut (Storrs, CT) for intensive urban agriculture. It uses urban warehouses to house and operate many individual grow boxes, named greenboxes, and for each of boxes the climate is automatically controlled to provide the optimum growing conditions for specific plant species.

This study was conducted to analyze the energy and water use of the newly proposed greenbox system, in comparison with a specific greenhouse. Energy and mass balance equations were applied to generate dynamic simulation models for both structures. Head lettuce was selected to be the crop for our analysis. The Penman-Monteith equation was adopted to estimate the evapotranspiration rate (ET) as a function of the environment conditions at any time during the growing season. The energy uses included all the heating, cooling, lighting, irrigating, and operational usage to provide and maintain the similar growth environment for the crop in both structures for a complete growing season. Water uses for both structures were mainly the accumulative amount of ET that got lost during the growing season. Analysis then was made to compare the energy and water use between the two systems subjected to winter and summer climates for the same amount of lettuce production.

The results of this study demonstrated the water use of the greenbox system was always less than that of the greenhouse in both seasons. The energy use efficiency of the greenbox was lower in summer and higher in winter, in comparison with the greenhouse. Considering the limitations in land and water in urban areas, the greenbox system is shown to be a promising alternative facility for intensive horticultural production for people in highly populated urban areas.