ISHS Acta Horticulturae 70: Technical and Physical Aspects of Energy Saving in Greenhouses
NEED AND DESIGN FOR A SOLAR GREENHOUSE |
| Author: | J. DAMAGNEZ | |||||||||
| Abstract:
In Europe, glasshouses or plastic greenhouses, are widely used under a number of different climatic conditions from Northern Latitude (Denmark, Germany, England, Netherlands) to, more recently, Mediterranean countries (Italy, South France, Spain, North Africa). In France, initial development was restricted to the regions located North of the Loire ; it was perhaps wrongly assumed that the regions more favored by a greater amount of sunshine and by milder winter temperatures did not need such production equipment. Now, a very rapid development of covered crops can be observed in the South of France and in all the countries of the Mediterranean belt. This very rapid development is primarily motivated by the need to protect the crops against the weather -rain, wind and frost- especially for market gardening production. Moreover, the constructions are often light to reduce capital expenditure. The introduction of plastics materials was one of the essential factors in the development of market garden crops under cover in the South of France. But, increasingly the horticulturist wishes to improve his revenue by better mastery of the details of production and a substantial increase in production. The most recent constructions in the South of France often use light structures, especially for market gardent production, and flexible plastics films as covering material. For the whole of France, the breakdown of covered areas in market gardeing is as follows : Market Garden Greenhouse Production
The gross value of these crops is about 400 M$ per year, an the cost of heating is now about 35 or 40 % of this figure. The greenhouse -which can be defined according to its outer shell (shape and covering material : glass and more recently plastics films) and its technical air conditioning facilities (heating, cooling, ventilation…) - represents a powerful means of modifying the microclimate of the crops. However, from the moment when a volume of air is separated from its exterior surroundings by a wall, which offers considerable | ||||||||||
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