(Guest article contribution by: Dan Fauth)
If you’ve ever used a Hydro Flask, you are probably as enamored with this product as I am. Hydro Flask makes the claim that their containers will keep your chilled beverage cold for up to 24 hours and your heated beverage warm for 6-12 hours. By my experience, this is not an exaggeration. Imagine the pleasure of indulging in 40 ounces of ice cold beer at the end of a six hour hike into desert wilderness. In fact, don’t imagine it, do it! So good!
In this paper, I am going to reveal the secret of the Hydro Flask. In order to do so, I must subject you to a fair bit of science.
To understand what it takes to keep things hot for 6-12 hours compared to keeping things cold for 24 hours requires a basic understanding of thermodynamics. Sadly, much of this may be new to you. This knowledge will also serve you well in understanding the natural forces which really do affect our climate.
Heat can only flow in one direction, from warmer to cooler. It’s never the other way around. To do otherwise would violate the Laws of Thermodynamics. There are four methods by which heat can flow and each method has its own efficiency and hierarchy which is dependent on the environment in which it operates. These four methods are evaporation/condensation, conduction, convection and radiation.
Evaporation is far and away the most efficient means of removing heat from a warm body. Our bodies engage in this technique constantly as we sweat to maintain our desired body temperature. This is also the primary method by which the Earth cools its surface, be it land or water. Condensation is just the inverse of evaporation or evaporation in reverse.
Evaporation is so incredibly efficient at cooling because it involves phase change, namely a liquid material converting to the gaseous form of that same material. In the cases of our bodies and the Earth’s surface, we are talking about evaporating water.
For water, which gets my vote as being the most miraculous substance in the universe, we can witness one aspect of this miracle every time we boil water. You have a pretty good idea how much heat you need to add to freezing water to increase its temperature to the boiling point, from 32 F to 212 F, a temperature increase of 180 degrees Fahrenheit. Once the water hits the boiling point, it then takes over five times that amount of heat to convert all of that water to steam (water vapor) with essentially no temperature rise at all.
Another miracle of water is that it doesn’t have to boil to evaporate. But it still takes that same amount of energy per unit volume to make the transition from liquid to vapor. Your sweat is a case in point and the same thing happens with soil moisture and the water in our lakes, streams and oceans. It is the evaporative process that carries most solar heating away from the earth’s surface. It’s very efficient. Nature loves it.
Conduction, the second choice of Nature, occurs when a warm body is in thermal contact with another body. This technique is used regardless of the phase state of the material. It may be solid to solid, solid to liquid, solid to gas or any combination of the three states of material common to planet Earth. The heat flow is always from warmer material to cooler material regardless of the phase states.
If the material receiving the heat from the other material is liquid or gas, thermal conduction usually results in convection. When added to conduction, convection greatly increases the efficiency of heat transfer. If you have a convection oven and have compared the preheating and cooking times to that of a conventional oven, you know just what this means. Before diving into the subject of convection and how it relates to Earth’s climate, we need to know a bit about air, the stuff that makes up our atmosphere.
Because water vapor has the unique ability to change phases within our atmosphere it is found in extremely variable amounts from nearly zero to over 4% by volume. For this reason it is standard procedure when discussing the composition of air to characterize it as being dry air with no water vapor. Dry air is composed of 78% Nitrogen, 20.9% Oxygen, and 1% Argon. CO2 and methane, both so called greenhouse gases, are also present in trace amounts at 0.04% and 0.0002% respectively. Again, water vapor content in the atmosphere varies dramatically ranging from very nearly zero in arid regions to more than 4% being present in powerful hurricanes and typhoons. Atmospheric water content also varies greatly with altitude as the air within the troposphere (the portion of our atmosphere from surface to around 40,000 feet) becomes cooler with height and water vapor condenses out to form clouds and precipitation.
It is important to note here that all matter has the capacity to store thermal energy, even our atmosphere. This concept of heat capacity is a fundamental property of all matter. Nitrogen for instance has a specific heat capacity of 0.25 btu/lb 0F at sea level pressure. As you may remember from science class, a btu is defined as the amount of heat required to raise the temperature of 1 pound of liquid water 1 degree Fahrenheit. At one quarter of this value, four pounds of nitrogen in our atmosphere can store the same amount of heat as one pound of liquid water. The total mass of our atmosphere is estimated at around 5.5 quadrillion tons. This is a lot of heat storage.
Water vapor has a specific heat capacity of 0.36 btu/lb 0F at sea level pressure, so 2.8 pounds has the same heat storage capacity as 1 pound of liquid water. With water though we should never forget that in making the change in phase state from liquid to gas, each pound of water vapor is storing an additional hidden 970 btu of thermal energy that is not evidenced by temperature. This energy storage associated with phase change is called Latent Heat. This latent heat can be released should the water vapor condense to form clouds or precipitation as it does typically high up in the atmosphere.
Let’s now take a look at how much heat on a percent basis is contained within the constituents of our atmosphere.
Average water vapor content in the troposphere is somewhere between 1% and 2%. If we assume 1% water vapor and we take the specific heat capacities, the latent heat in water vapor and the proportional makeup of the atmosphere, we wind up with the following distribution of heat storage in the troposphere, ranked first to last: Nitrogen: 72%; Oxygen: 17%; Water Vapor: 10.5% ; Argon: 0.5%; CO2: 0.04%; Methane: 0.000%.
So in air containing 1% water vapor, Nitrogen contains 72% of the heat, oxygen is second with 17%, water vapor is third with 10.5% and so on. CO2 and Methane are insignificant. Forget them. They are of no consequence in influencing atmospheric temperatures within the troposphere where life resides. This basic physical fact may be contrary to what you have been told. You have likely been told that CO2, methane and other so called greenhouse gases trap heat in our atmosphere. This is not possible. Given that each CO2 molecule is surrounded by 1,950 nitrogen molecules and 522 oxygen molecules (based on air containing 78% nitrogen and 20.9% oxygen) which are in thermal contact with the CO2 molecule, CO2 has no ability to trap heat beyond the proportions previously listed. Thermal contact requires that should they somehow be heated independent of their neighbors, they must instantly begin sharing that heat with the neighbors. This in turn would induce convection which moves heat away from the Earth’s surface toward space. It can be no other way.
On dry areas of the Earth’s surface, evaporation is absent due to the lack of moisture. Nature’s second favorite means of heat transfer is active here. The air at the surface is in thermal contact with the ground and once the ground is heated relative to the air, the heat must flow to the air as nature always strives to equalize the temperature of adjacent matter.
Warming the air causes it to expand and it becomes less dense relative to the cooler air above it. Like a hot air balloon, the warmer air becomes buoyant and rises above the surface thus being replaced with cooler air that in turn accepts heat from the warmer ground. This process of rising warm surface air with replenishment by cooler air is called convection. Conductive heat transfer from the solid or liquid surface to the air layer with which it makes thermal contact initiates this convection. So long as the sun is shining, the solar radiation impinging the ground will continue to keep the ground warmer than the air above it and the conduction/convection heat transfer process will keep the air circulating with the temperature gradient moving heat away from the surface. At night the convection process will eventually equalize surface and air temperatures and the air will become calm as convection grinds to a halt.
It is important that you understand that greenhouses work by allowing light rays to enter the inside of the greenhouse where the electromagnetic energy from the sun is converted to thermal energy within the molecular composition of the surfaces and air within the greenhouse. The walls and roof of a greenhouse present a barrier to convection, just like your car with the windows closed, and this restriction allows the greenhouse temperature to rapidly rise to the point where thermal conduction between the glass and outside air equalize the energy flows and stop the temperature rise. Even at greenhouse temperatures over 100 0F, radiant heat loss is not significant. Because our atmosphere is completely open to convection within the troposphere, the term “Greenhouse Effect” is a complete misnomer. The term is not just inaccurate, it is deceptive.
Radiation is the least efficient method of heat transfer and generally requires a very high temperature for the radiating source. Radiation is of utmost importance in terms of getting heat to transfer across a vacuum. The sun and light bulbs are good examples of high temperature radiating sources. Light bulbs are vacuum tubes and since the sun is surrounded by the vacuum of space, you may view it as a naturally occurring vacuum tube. It is the fact that the presence of the vacuum precludes more efficient methods of heat transfer that allows the light bulb filament to achieve the high temperatures necessary to emit bright visible light.
Since as described earlier, the Earth’s surface is in thermal contact with the atmosphere and the surface of the Earth is not at a high temperature as compared to the sun or a light bulb, radiation can be ignored in terms of cooling the Earth’s surface. Radiation is nature’s last resort when it comes to equilibrating temperatures. It is far, far less efficient than the other forms of heat transfer.
Now back to the Hydro Flask.
The Hydro Flask container is constructed of two stainless steel containers, one inside the other with the only point of contact being at the upper rim where they are connected. The space between the two containers is filled with nothing meaning that a vacuum has been pulled on this space such that almost no air molecules are present. As with the vacuum of space, there is no temperature present in this cavity between the inner and outer containers. Temperature requires matter. No matter, no temperature. This space is neither cold nor hot. This is a mysterious concept because you can’t measure the absence of temperature. To do so would require the insertion of some instrument, but since a vacuum is defined as the absence of matter, inserting something into a vacuum renders it no longer a vacuum. It’s a mind bender. You must use your imagination. Nonetheless the heat transfer properties of a vacuum are very special.
As described, the Hydro Flask’s only thermal contact point is at the upper rim and of course the hollow stopper which is made of plastic with poor thermal conductivity. This design, with the stopper in place and firmly sealed, eliminates evaporation and greatly reduces conduction / convection. At the temperatures desired for hot and cold beverages, radiant heat transfer is nearly non-existent.
With hot coffee inside the Hydro Flask at 140 degrees Fahrenheit, and with room temperature at 70 degrees, the heat wants to get out and bring the coffee to room temperature. The sides of the inner container are also at 140 degrees, but because of the vacuum next to the outside surface of the inner container, conduction is impossible and 140 degrees is too low for significant radiation of heat. The only way for conduction to work is to pass through the contact points at the rim and stopper of the Hydro Flask. The smallness of this area of thermal contact at the rim combined with the insulative properties of the stopper greatly limit conductive heat transfer. The temperature of the coffee is sufficient to allow some heat to traverse the rim and stopper, but it is a slow and inefficient process taking 6-12 hours. As the coffee cools, the rate of heat transfer slows as the temperature differential between the coffee and outside air diminishes. The power of a vacuum to stop conductive heat transfer is truly amazing.
With a chilled IPA at 40 degrees inside the Hydro Flask and outdoor temperatures at 100 degrees, the desert heat would love to warm up your beer. As with the coffee example, conductive heat transfer is pretty much limited to the top of the flask. Now the interesting question here is why the beer stay cold does for 24 hours but the coffee only stays hot for 6-12 hours?
Liquids are less dense at higher temperatures, so with coffee, the hottest coffee is at the top. As the coffee cools from heat conduction at the top of the flask, this cooling effect causes the top layer of coffee to become denser, so it moves toward the bottom of the flask. Convection has been induced in the coffee. As described previously, this convection enhances the heat transfer efficiency dramatically by always keeping the hottest coffee at the top.
With the cold beer, the warmest part of the beer is at the top as with the coffee, but the “warm” beer is becoming warmer, so it doesn’t sink and initiate convection. The warmest part of the beer stays put and doesn’t enhance cooling of the beer. Thus the beer stays cold much longer than the coffee stays hot.
The implication here is that if you turn your coffee flask upside down, so that the hottest least dense coffee is at the top, which is now the bottom of the flask next to the vacuum, the coffee should stay hot for much longer because you have stopped convection in its tracks. Using this technique, you may get many more hours of hot coffee available to you. The physics says this will work. Try it and see!
Now that you have a better understanding of the thermodynamics of heat transfer than 99% of the people on the planet, let’s conduct a brief examination of the radiative greenhouse effect (RGHE).
The Powers That Be (TPTB) want you to live in fear that catastrophic human induced climate change is at your doorstep. Excessive burning of fossil fuels has been vociferously identified as the culprit. We are all guilty, especially Americans, and we must change our evil ways. Since this is a global problem, we will have to give up our national sovereignty and work together with all other humans on planet Earth. No holdouts allowed!
The case for carbon based climate change, previously known as anthropogenic global warming (AGW), has at its foundation the Radiative Greenhouse Effect. Every school child knows that the greenhouse effect is what allows the Earth to maintain the moderate temperatures which allows for life as we know it. All of the fear mongering government agencies and university science departments whose funding is dependent on this climate of fear will give you their particular version of the greenhouse effect. Let’s start with the agency with the forked tongue on their logo.
“When they absorb the energy radiating from Earth’s surface, microscopic water or greenhouse gas molecules turn into tiny heaters— like the bricks in a fireplace, they radiate heat even after the fire goes out. They radiate in all directions. The energy that radiates back toward Earth heats both the lower atmosphere and the surface, enhancing the heating they get from direct sunlight.
This absorption and radiation of heat by the atmosphere—the natural greenhouse effect—is beneficial for life on Earth. If there were no greenhouse effect, the Earth’s average surface temperature would be a very chilly -18°C (0°F) instead of the comfortable 15°C (59°F) that it is today.”
There you have it. The sun heats the Earth’s surface, the surface radiates to the atmosphere and the “bricks” which compose 0.04% of our atmosphere radiate back to the surface adding more heat than the sun did initially. This is the radiative greenhouse effect and every purveyor of climate alarm uses some variant of this deception. The deception as you now can see works by substituting radiant heating for evaporation and conduction / convection. Back heating of the Earth’s surface is clearly impossible with evaporation and conduction / convection, but somehow “climate scientists” are able to make the case that back-radiative heating doesn’t violate the Laws of Thermodynamics. It does, but it’s not as obvious as with the other heat transfer methods. It fools most of the people all of the time. And yes, this makes those people FOOLS.
Now you may ask the question: “Why isn’t Hydro Flask smart enough to make a new and improved version of the Hydro Flask coffee mug that fills the vacuum space with carbon dioxide, methane, water vapor or even better, sulfur hexafluoride which has, as reported by EPA, a global warming potential on the order of 12,000 times that of CO2. Surely it would keep the coffee hot for at least a year. In fact, if we can back-radiate more heat than we started with, as the radiative GHE implies, we should be able to heat the coffee to boiling. In fact, if you think this out logically, you should be able to warm yourself in front of a mirror just using your radiative body heat. How’s that for NASA science?
Now that you know real thermodynamics and you are smarter than all of the astrophysicists at NASA, you understand that the Earth is surrounded by an atmosphere which has both mass and large thermal storage capacity. This fact alone completely explains the moderate temperatures found on planet Earth. Not only is a greenhouse effect not necessary, but it is impossible given the extent of thermal contact within the troposphere and nature’s preferred methods of heat transfer.
So where does radiant heating or cooling become important in moderating temperatures on planet Earth? Only in the upper reaches of the atmosphere where the vacuum of space abuts the thinness of our outer atmosphere. This is the area where thermal molecular contact is lost and the only option for planetary cooling is radiant emissions. Theoretically, greenhouse gases which are more radiatively active than nitrogen and oxygen, could enhance this cooling, but that would first require additional heat to get to this part of the atmosphere and that amount of heat is set by the mass and composition of the troposphere. Additional greenhouse gases cannot upset the balance of heat flow from the Earth’s surface to space. More CO2 means more plant food and that is a wonderful thing.
Within the troposphere, evaporation/condensation, conduction and convection rule our climate, and no greenhouse effect is remotely possible or needed. That’s Real Science!
The secret of the Hydro Flask reveals the deception hidden within the Anthropogenic Global Climate Change scam. The truth is out!
-By Dan Fauth,
Independent Scientist and Engineer
April 6, 2016