Archive for January, 2010

An SNU lunch at Cabela’s in Verdi

The SNU managed a get together between winter storms in Verdi. Cabela’s has a nice meeting room and a grill that offers food like from the hunt.

Check out the photo gallery!

Next month is Carson City.

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When it gets cold

Marks RV has an interesting page about the properties of LP gases including both propane and butane. Near the bottom of the page is a table that provides information about the BTU per hour as a function of temperature and tank type. It tells the story of why keeping warm in cold weather gets difficult from many directions.

For the typical RV with 30# propane bottles and a 30 kBTU/hr furnace, the furnace is going to be fuel starved when temperatures get below 10F or your tank gets below 20% full. The factors behind this include the surface area of the liquid in the tank and the fact that it is tougher to get from liquid to vapor when the temperature decreases. A chart on the page puts propane vapor pressure at 0F at only a quarter of its value at 70F. If you have a lot of Butane in the mix, which might happen if the tanks were filled in warm climes, then getting vapor will be even more difficult as butane has to get to 100F to have the same vapor pressure propane has at 0F.

The bottle size is one reason for getting a large, rented, bottle when parked for the winter. From the tables, a 20# tank nearly full could just barely fuel the furnace at 20F and a 65# under mounted tank could be 30% full and keep the furnace going down to 0F.

The website also has a good rundown on troubleshooting your RV furnace that will help you learn how it works.

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Winter humidity

Lifehacker suggests that you Humidify Your Home for Increased Winter Comfort.

If it seems like your skin is dryer, you get zapped with static shocks more often, and you wake up frequently with a stuffy nose, you’re not just imagining things—you’re experiencing the effects of low humidity.

In an RV, winter humidity can be a control issue. The walls are often poorly insulated and there is a lot of wall surface compared to the inside air volume. One of the comments linked to Humidity and the Indoor Environment at the Minnesota Blue Flame Gas Association. That website has a lot of good information.

The basic problem is that cold air cannot hold much water. That means that when outside air with a very high relative humidity (that means it is hold about as much water as it can) is brought inside and heated, the humidity is significantly reduced as the amount of water in the air is the same but the warmer air can hold a lot more.

If the outside air temperature in winter is 0°F and the relative humidity is 75 percent, that same air inside your 70°F home will have a four percent relative humidity. That’s dry! The Sahara Desert has an average relative humidity of 25 percent.

One way to gauge indoor humidity is to “Drop three ice cubes into a glass, add water and stir. Wait three minutes. If moisture does not form on the outside of the glass, the air is too dry; you may need a humidifier. (Do not perform this test in the kitchen, because cooking vapors may produce inaccurate results.)”

But the problem in an RV is that many things you do add water. Just breathing can add a quarter cup per hour. Cooking for a family of four will add 5 pints a day. A shower can add a half pint. A catalytic heater or stove burner also adds significant amounts of water to the air. What that means is that you can get condensation on windows and walls in the RV and that can lead to mold and mildew and rot. That means poor air quality which can lead to musty smells, head or chest colds, stuffiness, headaches and other ills?

How do you balance the ‘too little’ and ‘too much’ humidity? They call it ACH or air changes per hour. This means ventilation that replaces inside air with outside air. Your RV probably needs more than one complete air change every hour. For a thirty foot RV, that means more than a thousand cubic feet of air every hour or 20 cubic feet per minute. For contrast, a high end vent fan on high will move nearly a thousand cubic feet of air per minute.

Generally, an RV will ‘leak’ 2% of the volume a vent fan can move so the problem is usually reducing air changes per hour unless you are preparing dinner or running a catalytic heater or showering. Balancing air exchange with inside humidity can conflict with the energy budget for keeping warm. Perhaps that is why Quartzite is popular in January and February – except that they are having significant rain problems so keeping warm and reasonably dry might be more of a challenge this year than usual.

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Fresh batteries saves lives?

Winter is hard on batteries. The RV storage batteries need to be properly maintained to assure that they are healthy come spring. The batteries for flashlights and other gadgets also need some consideration although they tend to do well sitting in cool temperatures. This hasn’t always been the case.
Gizmodo says “FACT: Stale Batteries Are THE Leading Cause of Fatal Snake Encounters“. It shows a 1936 Everready battery newspaper ad with an interesting story.

For your lead acid storage batteries you need to make sure that they are kept fully charged and that the electrolyte is not allowed to stratify (see Zephyrs Basic battery guidelines).

If you have gadgets with built in rechargeable batteries, give them a charge every month or two and make sure they don’t run flat.

For gadgets with replaceable batteries that aren’t being used, take the batteries out and check for any indications of corrosion in the battery compartment. If these are the inexpensive non-rechargeable alkaline type then it might be worthwhile to replacing them with new ones as a part of your preparation for a new season. This is like the general advice to replace smoke alarm batteries every year.

Temperature extremes and discharged states are hard on batteries. Make sure you are prepared for emergencies by taking care of your batteries, especially when ‘out of sight out of mind’ might apply. Who knows, maybe you’ll wake up in the middle of the night wondering what is making that strange noise …

see also Wikipedia and Powerstream Battery Storage Recommendations for more ideas and background.

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Keep watch for EVIL cameras

That’s Electronic Viewfinder Interchangeable Lens as Wired has it. The story is a head’s up on what in on the horizon in digital cameras.

The traditional choice going back to film days is that you could aim your camera with a viewfinder or you could use a reflecting mechanism to actually see what the film would see. Digital cameras have provided LCD screens to view pictures and control the camera but these screens have not been used so much as a replacement for the old standby’s.

The key with EVIL is the ‘IL’ or interchangeable lens. That is a step up from the fixed lens usually found in cell phones or snapshot cameras. When you can change lenses, you have options to make the best choice for distance, light, and other factors that you can adapt to differing circumstances.

The ‘EV’ or electronic viewfinder provides ‘what you see is what you get’ capabilities without the bulky mirrors and complex mechanisms needed for SLR viewfinders.

These days you can see a lot of folks holding a camera out at arm’s length trying to use the screen on the rear as a viewfinder. It is difficult to hold a camera steady that way. The EV needs to be one that can be held close to the eye yet still provide a clear focus for presbyopic old eyes.

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About winter and ice and snow and heat

The Reference Frame has a good rundown on what goes on in winter temperatures with ice and snow in the post Warming induced by the latent heat of snow. If you can handle basic math, even the formulas could be interesting. The ideas apply not only to atmospheric temperature conditions when there is ice and snow but also in how you keep your RV warm and the energy budget for a hot shower.

You only need 1/2 of the water’s thermal energy to heat up the same amount (mass) of ice or snow. And melting of 1 kilogram of snow/ice into water needs as much energy as warming 80 kilograms of water or 160 kilograms of snow by 1 degree Celsius.

Moreover, ice is three times as good thermal conductor as liquid water (in the units of W/(m.K) – so that it enters Fourier’s law for heat conduction). So in general, I do expect that the temperature swings become much easier below the freezing point as long as there is any ice around.

One point being made is that making snow takes heat out of the water and gives it to the atmosphere. That can warm up the air where it is being frozen. The calculations indicate that 4 cm water equivalent can make something like 1C in temperature change in the atmosphere above it. That’s why wet snowstorm temperatures usually hang around freezing.

What this also means is that every inch of water equivalent snow, maybe six inches to a foot of snow, blanketing the ground warms up the atmosphere by a degree Fahrenheit when its made and cools the atmosphere by that much when it melts. Once freezing temperatures have taken hold, it is easier to get really cold because ice can only hold half as much heat as water and it conducts heat only a third as fast as water does.

The fact that ice has only a third the conductivity for heat as water plus the fact that snow tends to mix in a lot of air which has even less heat conductivity is why building a skirting for your RV with snow can help you keep down your living space heat budget inside the RV.

If you want numbers for these phenomena, check out the post. They have much to do with our climate and with the biosphere of our planet. You can find out more about the Anomalous properties of water that we depend upon for life and comfort beyond this global temperature regulation.

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Insulate windows with bubble wrap

Way back, like just after the medieval warm period when the little ice age took hold, they used quilts to warm up the stone walls in the castles. Airstream does that nowadays by using padding to add an insulating layer to the inside aluminum skin. But that leaves the windows.

You can use something like Prodex, a foil-foam-foil insulation for the Windows but that is expensive and would not let light in. The office supplies blog has another suggestion: Bubble Wrap Keeps You Warm.

You can find bubble wrap with big bubbles or little bubbles. You can buy it at office supply stores or you can troll places like furniture stores that might receive stuff wrapped in it and be willing to pass it along to you rather than throw it out.

Bubble wrap is cut to fit. It attaches to the window by using only a thin film of water. Put the bubble side to the window and the smooth side to the inside. It will fuzz up the view but should still let light through. It is an easy and inexpensive and temporary way to help reduce winter heat loss through the windows and that may help keep you comfortably warm while reducing the fuel bill.

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Travel, Arctic Tern style

Peter calls it An astonishing migration at Bayou Renaissance Man. A research team attached 1.4 gram geolocators on several birds to find out exactly how they made their pole to pole yearly migrations. The geolocators worked by detecting light intensity which were used to determine local day length and time of sunset and sunrise. From that information, the researchers could figure out where the birds were. That’s a bit over 1% of the bird’s weight being carried on an annual round trip of over 44,000 miles so the researchers could track them.

Let’s see, 1% of a typical person’s weight would be ten to twenty pounds. If you were hiking at a typical rate of 3 mph, the bird’s trip would take you nearly 2 years of steady hiking. For a typical RV daily jaunt of 250 miles, that’d be 176 days of traveling. At highway speeds, 44000 miles is 800 hours of travel.

The research findings revealed that the Arctic Terns trip south was different from that going north. It appears that food supply and winds were the major factors. That sounds a lot like the kind of things cross country RVers consider.

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How old are the mountains?

New research suggests Sierra Nevadas older than previously thought. 50 million years ago:

The western United States would have looked very different back then, filled with lush forests of vines and magnolias. The Pacific Ocean would have lapped the foot of the Sierras.

“The work, which was published in the journal Geology, also provides a more accurate tool for exploring the elevation of ancient landscapes.” It looked at leaves and things washed out of the mountains and figure that they “were sitting at their current height 30 million years earlier than anticipated” when it was more than ten degrees warmer.

Can you break open a rock and find 50 million year old leaves and figure out the story they tell?

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State parks and budget crunches

Coyote Blog has Total Frustration With Arizona Parks. He runs a business of privatizing public recreation and knows how to keep state parks and similar recreation areas financially viable yet cannot convince the authorities to act on his knowledge.

Of course, I am not completely naive. I know there is a tried and true kabuki dance here where parks departments threaten to close down the Washington Monument in a bid for public sympathy that will either deflect budget cuts or spur new taxes. I also know that state parks directors have sworn a blood oath together never to let private concessionaires run whole parks, even if the parks have to be shut down

The places we like to visit in our RV’s make for good symbols because they are ‘recreational’ and, hence, luxuries that are not critical to the state and they are visible. When times are good, that is why they get a lot of extras and fancy geegaws and RV spaces with utilities and fancy trails and facilities. When times are not so good, …

The observations in the commentary are worth considering. They touch on how government and social ideology influence our access to outdoor opportunities with our RV’s.

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Baking soda plus grease is soap

Marine catering at Global Sea Services has some best practices that might be helpful in keeping your RV kitchen in top shape. For instance, the tip about dealing with greasy dishes or plates suggests soaking in hot water with baking soda. The rationale makes sense to anyone who has made their own soap.

Browse the website- it is an interesting business

We also believe that that the way to anyone’s heart is through the stomach. To our sensibility, life at the sea not only builds great character, but a wonderful appetite as well!

Whether you agree with Joseph Conrad that “The true peace of God begins at any point 1,000 miles from the nearest land” think maybe some wilderness will do, good food well prepared and enjoyed with friends will make an experience away from home a much more enjoyable enterprise.

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