ISHS Acta Horticulturae 174: Symposium Greenhouse Climate and its Control
MICROCLIMATE, PHYSICAL PROCESSES AND GREENHOUSE TECHNOLOGY |
| Author: | B.J. Bailey |
| Abstract:
The relative importance of the greenhouse macro and microclimates is considered; although the former is the controlled quantity, it is the latter which has the more direct influence on plants. The relationships between the micro and macro climates and the plants are changed when greenhouses are insulated. Plant temperature is modified and also the greenhouse humidity is increased which reduces plant transpiration; at present the implications of this have not been fully established. The process of greenhouse natural ventilation is not well understood, although progress is now being made, this process has assumed greater importance because of its influence on carbon dioxide and water vapour exchange. Heated floors or benches influence the plant microclimate directly, and also enable energy which is available only at low temperatures, such as solar or reject heat, to be used for greenhouse heating. More information on the characteristics of these systems, particularly from the control point of view, is required before they can be fully integrated into the operation of greenhouses. Total energy systems can provide both heat and electricity for artificial lighting, despite the increased capital cost this could be beneficial for greenhouses at high latitudes where heat requirements are high and insolation is low. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
