ISHS Acta Horticulturae 70: Technical and Physical Aspects of Energy Saving in Greenhouses
ALTERNATIVE PATHWAYS TO FUEL ECONOMY |
| Author: | A.E. Canham |
| Abstract:
The efficiency with which fuel is used in the heating of greenhouses depends on the limitations imposed on the growth rate of the crop by other factors. Experiments with young tomato plants have shown that a reduction in air temperature of 2.2°C can be compensated by the use of 2 to 3 klx of supplementary artificial light from high pressure sodium lamps. A greater economy can, however, be achieved by the use of higher levels of supplementary artificial light (ca. 9 klx) to give even faster growth. The results of earlier work are quoted to show that a reduction in air temperature of 5.6°C can be compensated by warming the soil to ca. 25°C while current work is suggesting that even greater benefits are possible with a fruiting crop. Both techniques offer alternative pathways to achieve the same end point but the choice will depend on the balance of energy consumption or cost involved in each one. The balance will vary widely from one country to another but under British conditions the soil warming pathway appears to offer the best chances of success. | |
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