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| Energy saving in greenhouses | |
| Almost all production costs in ornamental horticulture are rising and it is often not possible to pass on these costs by way of increased prices for the plants. A guide to some energy saving possibilities are described. Proper heater maintenance can result in up to 12% savings. Any maintenance work that has been overlooked over the last 3-4 years should be carefully checked, especially to see that boilers and heaters are properly tuned. If not their efficiency can fall to as low as 80%. Make sure that all doors and vents in the greenhouse close properly and that there is no obvious means of loosing heat. Focus on the weather stips on doors and fan louvers, lap seals in glass covered houses and any holes in the cladding. The sensor that controls greenhouse temperatures is worth an inspection. The sensor is subject to the effects of dust, dirt, irrigation water and pesticides all of which can reduce a few degrees of accuracy. This might result in greenhouse temperatures being a few degrees too hot or too cold with respect to the calibration of the sensor. This can have a big impact on plant quality and watering. Greenhouse ridges should be properly sealed which can save 5% of heating costs. The ridge vents in greenhouses rarely close tightly, particularly in older structures. Leaking vents can loose 5-10% or more of total energy use. Long-term investments can save up to 40% of energy use. Improvements that take longer and cost more should be taken seriously on the basis of the percentage of sales revenue spent on fuel. Typically a grower does not want to spend more than 5-6% of revenue on fuel. Internal curtains can provide savings of 25-30%, new boilers (10-20%). Bob Johnson GrowerTalks See also http://ohric.ucdavies.ed/study on reducing energy costs in California greenhouses. |
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