Articles
THE VERTICAL SOUTH ROOF MULTISPAN GREENHOUSE
Article number
170_21
Pages
193 – 200
Language
Abstract
A novel shape of roof for an east-west multispan greenhouse is described in which the south facing surface is vertical and the north surface is inclined at 20° to the horizontal.
As a consequence sunlight reflected at the southern surface is directed downwards into the greenhouse, rather than upwards as with conventionally shaped houses.
Computer simulations of the light transmissivity during winter showed this roof transmitted 6% more light, and the same amount of light when double glazed, as a single glazed conventional roof.
Under clear and completely cloudy skies the overall heat transfer coefficients for the new roof, expressed per unit floor area, were 8% and 11% higher than for a conventional roof.
The heat transfer coefficient for a double glazed vertical south roof was 33% lower than for a single glazed conventional roof.
This suggests a double glazed greenhouse with this shape of roof would have a similar light transmission but require one-third less energy than current multispan greenhouses.
As a consequence sunlight reflected at the southern surface is directed downwards into the greenhouse, rather than upwards as with conventionally shaped houses.
Computer simulations of the light transmissivity during winter showed this roof transmitted 6% more light, and the same amount of light when double glazed, as a single glazed conventional roof.
Under clear and completely cloudy skies the overall heat transfer coefficients for the new roof, expressed per unit floor area, were 8% and 11% higher than for a conventional roof.
The heat transfer coefficient for a double glazed vertical south roof was 33% lower than for a single glazed conventional roof.
This suggests a double glazed greenhouse with this shape of roof would have a similar light transmission but require one-third less energy than current multispan greenhouses.
Publication
Authors
B.J. Bailey, D.L. Critten
Keywords
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