ECONOMIC GAIN FOR CUCUMBER PRODUCTION FROM GREENHOUSE COOLING IN FINLAND

This study presents the expected approximate economic performance of the cooling and drying system of greenhouse air in the production of cucumber in Finland and attempts to extrapolate the results to other climatic regions.
The system has been described earlier in Särkkä et al., 2006. The cooling capacity is high enough to run the greenhouse without ventilation in most days allowing constantly high carbon dioxide (CO₂) concentration to be maintained.
A model of greenhouse cooling requirement, crop growth and cooling system was calibrated for a single span greenhouse under cool and variable climate conditions where the cooling season lasts 3 to 5 months.
This model is used for computing cooling requirement, energy efficiency of the cooling system and the radiation sum under high (1000 ppm) and low CO₂ concentrations in an uncooled and cooled greenhouse.
A radiation use efficiency (RUE) model is used for computing the expected direct yield increase from the cooling due longer duration of high CO₂ concentration in the cooled greenhouse.
In the summer months the RUE model predicts 15 to 23% higher yield for the cooled greenhouse than in the uncooled greenhouse where temperature and humidity are controlled by ventilation and fogging.
The prediction by RUE model is only about half of the yield increase observed in the cooling experiment (Särkkä et al., 2006).

International Symposium on High Technology for Greenhouse System Management: Greensys2007

T. Kaukoranta, J. Huttunen

economy, carbon dioxide, supplemental lighting, energy efficiency

https://doi.org/10.17660/ActaHortic.2008.801.163