Saturday, February 21, 2009

Harley Davidsons and Wind Machines


Question: What do Harley Davidson motorcycles & vineyard wind machines have in common?

Answer: They both have sub-standard mufflers for no apparent reason.
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My sister-in-law is originally from the Cupertino area. When my brother first brought her into the Napa Valley in the 60’s, she noticed the wind machines and asked what they were for. My brother told her they were just big fans that we turned on in the summertime to keep us cool. And she accepted that answer, however briefly. Now before you jump to conclusions about her intelligence, I’ll tell you that she is now the CFO of a major & prestigious winery in the valley. She may be a bit gullible at times, but she is no dummy!
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Last year we had a very cold Spring. That meant we had lots of nights that required frost protection for the vines. It had been years since I had served on this night patrol, but since we were a bit short staffed, I volunteered.

There is a network of communications around frost protection. The initial low temperature warnings can be delivered several ways. On some vineyards, there will be a vineyard foreman that lives at the vineyard and has a “hard-wired” thermometer alarm system that goes right into the bedroom. Some folks are linked into a multi-station weather tracking system on the computer. On some of our ranches, we have an automated system that calls whatever number is programmed, and in digi-speak conveys the current temperature, and other pertinent weather data.

Once the primary contact has been alerted, the frost protection “system” has been activated. While it varies from operation to operation, he/she may call someone else on the phone tree at that point, or he may just get dressed, head out and start the wind, sky and temperature monitoring process. If even a slight breeze comes up, it’s a good sign the temperature might not even get to freezing. Likewise for any type of a cloud cover that will inhibit the earths heat from radiating out into the atmosphere. But if it’s calm & clear, it’s time to start checking temperatures. Most vineyards will have one or more thermometers, and temperature indicating sensors. The thermometers are similar to the glass thermometers you may have at home, only bigger. The battery powered electronic sensors (that PVM uses) have a multi-colored light system indicating an approximate temperature range as follows:
The nice thing about these sensors is that you can monitor the temperature from a distance, usually from a nearby road. We can monitor the rough temperatures for the Kapcsandy Vineyard from the Yountville Crossroad. We can monitor our Annapurna and Gemstone vineyards from the Silverado Trail, at least as long as the sensors indicate we’re still in the upper 30’s. At these temps, one person may be able to monitor several of the PVM managed vineyards in the Rutherford, Oakville and Yountville areas. When the temperature drops into the mid-30’s its time to start monitoring the thermometers for more accurate readings. So, more phone calls are made, to get more people out of bed and patrolling the vineyards. The traffic activity level increases as the temperatures drop. As the temp approaches freezing, the wind machines start coming on. One minute I can be walking the vineyards enjoying the quiet peacefulness and intensity of the stars. And the next minute, I’m pulling out the choke and cranking up the V-8 of a rather noisy Wind Machine. And even though it may be set to idle for a while, the quiet calm has been broken. And this is when Joe Local, or Joe Visitor, or maybe even Joe the Plumber first becomes aware that it is cold outside. It starts with this low-level buzz throughout the valley. Of course if you live within a quarter mile of a wind machine, you might argue that low-level buzz description. As the temperatures drop, the buzz can eventually turn into a symphony of internal combustion engines. The decibel rating for each varies as the wind machine rotates to cover a larger area. Some might even describe the sound as a prop plane, or planes circling. There was even a story years ago (perhaps bogus) about the out-of-town visitor that called 911 to report a plane in distress that had been circling for hours.
Keep in mind there are lots of different types of frost protection systems in use, including sprinklers, misters, smudge pots and electric wind machines. Those might be discussed in a future blog.
And there are completely automated wind machines. We monitor several of those on our vineyards, too. So, why monitor them if they are automated?
The following paragraph is taken directly the operator’s manual of one of the newer machines:
“The ____ is _____’s newest member of their automatic wind machine control family. It is designed for simplicity and reliability, but no automatically controlled wind machine should ever be used as a stand alone, unmonitored, defense against frost. Automatic controls were designed to assist the grower in starting and operating his machines only.”

We have found this to be true. One night, as the temperature was dropping, we noticed that one of the automated machines wasn’t coming on as early as it should. Turns out, when the propane tank had been filled, the tank valve was closed, and the propane delivery man forgot to re-open it. And another automated machine needs to be switched over to manual mode after starting. That’s because it will get false temperature readings from warmer air sent its direction from a neighboring wind machine that gets started after that first machine (AND shut itself off). Simply stated, there is too much invested to assume these automatic machines will start & function properly.

In my next blog, I intend to explain how wind machines work to raise the temperatures in the vineyards, and also under what conditions, they don’t.

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