Greenhouse matters
A new series of articles started in the New Zealand Grower in May 2008 aiming at presenting snippets of technical information from the international greenhouse industry. The topic will vary from month to month.
(1) Greenhouse matters in the Netherlands
..... Some new products are on the marked now that address the issue of plant stress in summer. Plants benefit from abundant light from the sun, but the amount of heat that comes with sunlight is often too much for plants. In summer it would be good if light could be let in, while heat could be blocked out of a glasshouse. The new .....
....... At a seminar on (semi-)closed greenhouses, the key note speaker stated that the production in semi-closed greenhouses is now 15 % higher than in a normal greenhouse (thanks to locking in CO2) and this will rise to 30% in 2018. Energy use is currently reduced by 25 %, but in ten years time the (semi-)closed greenhouse will be an energy producer. ......
Two new greenhouse areas in the vicinity of Amsterdam have come into production recently. ...... Six growers here have just started their 200 MegaWatt gas-fired CHP (combined heat power or co-generator). This produces heat, CO2 and electricity. A part of the electricity is used by the grower (e.g. for lighting) but the major part of the electricity is sold to the grid. ......
An overwhelming 185,000 people visited the open days of the Dutch greenhouse industry held on 5 and 6 April 2008. About 300 growers in 24 regions in the Netherlands opened their greenhouse to showcase their production process and products ....
See the full article on Greenhouse matters - part 1 (2008), Grower, May 2008.
(2) Solar heating in greenhouses in Kenya
It is an obvious fact that all greenhouses are heated by the sun. But extra heat input is required when it is dark, cold and/or windy. Solar heating of greenhouses in cold periods is the dream of every greenhouse grower. This was considered uneconomic and unfeasible, if not impossible. However, what was impossible in the past may come true in the future. At present solar collectors are being used for greenhouse heating in various places including Kenya and the Netherlands. However, the costs are huge, and these projects only came of the ground thanks to substantial subsidy.
See the full article on Greenhouse matters - part 2 (2008), Grower, June 2008.
(3) Combined heat and power, renewable energy and CO2
See the full article on Greenhouse matters - part 3 (2008), Grower, July 2008.
(4) Greenhouse growers worldwide face despairingly high energy costs
See the full article on Greenhouse matters - part 4 (2008), Grower, September 2008.
