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 sh owed that it is possible to avoid the harmful freezing effects using a comb ination of thermal curtains and heating tubes in which warm water from a ge othermal source Rows. However, in spire of these improvements, during many winter nights the ambient temperature tends to remain low inside the greenh ouses, 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 synthe tic thermal blanket to the previous improvements in order to decrease conve ctive heat transfer effects. The results were evaluated measuring temperatu res at different places of the prototype. Prototype data of winter nights w ere plotted and compared with temperatures from the effective greenhouse th at includes thermal blankets. The system maintained satisfactory temperatur e levels in the surroundings of the plants, allowing their continuous growt h. The raw materials necessary for these improvements are cheap common mark et 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 consumin g. The system with thermal blankets maintained temperatures of over 13 degr ees C most of the winter nights, which is necessary for the continuous grow th and fructification of tomatoes and peppers. (C) 2000 Elsevier Science Lt d. All rights reserved.