The techno-economics of growing high-value temperate crops under controlled soil temperature on tropical climate lowland.

Abstract

Demand for high-value temperate fruits and vegetables such as lettuce, cabbage, and berries have increased with population growth despite decrease in available space for cultivation due to urbanisation. These crops particularly grow well under low soil temperature, hence their cultivation pose huge challenge in the hot tropics except on a few cool highlands and via greenhouse farming. Outputs from these methods are always complemented with importation to meet the demand. Studies have however shown that low soil temperature gives the right conditions for microbes that promote development of these crops. This study presents application of solar thermal chilled water for agricultural soil cooling, and the economic analysis of the cooling process. The analytical and experimental models show the cooling process is technically feasible. However, to ascertain its financial viability, additional scenarios with 1 kW, 5 kW and 10 kW cooling capacities were analysed together with the experimental size of the developed system of cooling. This shows that the viability of the system improves from 5 kW cooling capacity. In addition to all other widely cultivated crops, implementation of the proposed system would promote local production of temperate crops hence diminish heavy reliance on importation of these crops in tropical climate countries and enhance food security.