12/1/10

Misting Water to Protect from Cold


Here is an article I read from physorg.com written by Tom Nordlie. It is about research that Dr. Bob Stamps has been working on for the last few years looking at misters and foggers in protected structures to provide cold protection. I've copied the important stuff below.


"Now, a three-year study by University of Florida researchers suggests it would be more cost-effective to heat shade houses with water, using devices called foggers and misters that emit clouds of tiny airborne droplets.
The results were published in the current issue of the journal HortScience.
“This seems to be a very efficient way to heat in subtropical climates (in shade houses and greenhouses),” said Bob Stamps, an environmental horticulture professor with UF’s Institute of Food and Agricultural Sciences. “The systems are so much less expensive than heaters and reduce fossil fuel consumption.”
Misters and foggers are widely available and commonly used to irrigate plants and reduce air temperature in hot weather, Stamps said. Misters emit water droplets averaging about 150 microns in diameter; droplets from foggers average 90 microns. A micron is one one-millionth of a meter.
Depending on the season, well water can accomplish either heating or cooling because it has the same temperature year-round, ranging from about 70 to 80 degrees Fahrenheit.
In chilly weather, the tiny droplets quickly radiate heat into the air, because they have a large amount of surface area relative to their overall volume.
The study involved two types of misters and two foggers in commercial nurseries during three winters. They kept shade houses warm enough to protect all but one genus of plant, from at least nine tested.
With water conservation a major issue in Florida, UF researchers are eager to find ways of minimizing the amount needed to protect crops.
One fogging system evaluated in the study used only about 750 gallons per acre per hour, compared with 5,000 gallons for one of the misters. Stamps said the research team would like to investigate whether the devices can protect plants when used intermittently, which could save more water."


If you would like to read the rest of the article click on the following link: http://www.physorg.com/news/2010-11-fogging-misting-ornamental-foliage-cold.html

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