Integrated thermal improvements for greenhouse cultivation in the central part of Argentina

A system to improve winter horticultural cultivation inside greenhouses has been developed in the central part of Argentina. Previous investigators showed that it is possible to avoid the harmful freezing effects using a combination of thermal curtains and heating tubes in which warm water from a geothermal source Rows. However, in spire of these improvements, during many winter nights the ambient temperature tends to remain low inside the greenhouses, causing plant growth detention. The objective of the current work is to prevent plant growth detention by concentrating, as near the plants as possible, the energy stored in the soil during daytime and delivered by the tubes at night. This was achieved by adding a transparent and light synthetic thermal blanket to the previous improvements in order to decrease convective heat transfer effects. The results were evaluated measuring temperatures at different places of the prototype. Prototype data of winter nights were plotted and compared with temperatures from the effective greenhouse that includes thermal blankets. The system maintained satisfactory temperature levels in the surroundings of the plants, allowing their continuous growth. The raw materials necessary for these improvements are cheap common market materials, the arrangement of the whole system does not take more than a few hours, and the operation of the system is simple and nor time consuming. The system with thermal blankets maintained temperatures of over 13 degrees C most of the winter nights, which is necessary for the continuous growth and fructification of tomatoes and peppers. (C) 2000 Elsevier Science Ltd. All rights reserved.