Optimization of Geothermal Greenhouses Design for Kenyan Fresh-cut Flowers

Abstract

Kenya is among the top countries that export fresh-cut flowers to Europe and China. The fresh-cut flower farming involves greenhouses to limit evapotranspiration and for ease of disease and pest control. Since these activities are labor-intensive, flower farming employs a significant number of farmhands which accounts for more than a tenth of employment provided by the Kenyan agricultural sector. Unfortunately, flower farms use lots of chemical pesticides, fungicides and herbicides, some of which find itself in local freshwater lakes and rivers. One farm, Oserian Development Company(ODC), situated near the Olkaria geothermal field uses brine to heat its greenhouses thus saving a lot on fungicides by raising dew-point temperatures that occur at 0100-0600 hours. The greenhouse warming reduces the chances of dew forming on leaves by reducing humidity from 100% to 85% thus limiting the growth of fungi. This research paper seeks to optimize the greenhouse design for both optimal flower growth and dew-point eradication. Besides, the paper integrates cascaded use of geothermal greenhouses with absorption chillers for cooling of fresh-cut flowers thus maximizing brine utilization and saving on electricity for running the coolers. Since a significant number of fresh-cut flower farms are located near developed geothermal prospects, coupling the two will enhance the performance of flower growing and reduce the overall cost thus making Kenyan flowers competitive price-wise in global markets.