Heat Footprint

Our Polluting
Waste Heat

Posted on August 10,2011

We could be like the planet Venus. Venus has a 40-mile high blanket of CO2 for an atmosphere. The atmosphere on Venus is so thick and heavy that very little convection takes place to help cool the planet.

So what about the Earth? The Earth has plenty of Carbon and Oxygen, so why doesn’t CO2 blanket the Earth like it does on Venus? The answer is life! It is life that has made use of CO2 and stored the excess carbon as the hydrocarbons that we commonly use as fuel. It is safe to say that we could not exist if different life forms, over time, hadn’t stored all of that carbon and kept it out of the atmosphere. Locking all of that carbon away has taken millions of years while we seem Hell-bent on re-releasing it in a span of only a couple of hundred years. Are we crazy or what?

Stored carbon is found in the form of coal, oil, and natural gas that we use for fuel. Using this fuel releases CO2 back into the atmosphere. But releasing CO2 back into the atmosphere is not the only consequence from using those fuels. No, as we use energy, we also release heat. Heat may prove to be an even a worse pollutant than the CO2 we release.

Heat is the product sought after from fuels by humans. Ignition of fuel cooks our food, propels our automobiles, heats our homes, cools our homes, enables our industries, and even allows us to smoke cigarettes. Without the use of heat, we couldn’t survive. Human generated heat is not the largest source for planetary CO2, but we do contribute to the overall quantity of the gas.

Although CO2 is a minor greenhouse gas, it is far from being the bad guy as proposed by others. But CO2 could become the bad guy if enough of it accumulates. At high enough levels, CO2 could start accumulating in lower levels because of its weight. At the present, our atmosphere is homogenous as convection currents keep the air mixed up. It is convection currents that are most responsible for releasing heat to the cooler regions at the higher levels of our atmosphere. Atmospheric layering like we see on Venus could be in our future unless we find a way to control CO2 release into the atmosphere.

But this piece is not principally about CO2, but rather about heat. It is our ‘heat footprint’ rather than our ‘carbon footprint’ that we need to reign in to more manageable levels. The Sun provides most of the Earth’s heat, but recently, man has been using that stored energy at a rate that may be altering the balance enough to increase the Earth’s temperature.

Heat is not a zero sum game from the Sun. By that I mean that the heat received from the Sun is not equal to the heat returned into space. If the heat leaving the Earth is equal to the heat received and generated on Earth, then Earth’s temperature remains constant. However, if the total of heat on the Earth from all sources exceeds the earth’s ability shed heat, the Earth warms.

Since we can do nothing about the radiation we receive from the Sun, we need to look at those things that we can control. Population expansion is one of those offenders that rank high when it comes to heat generation.

Just the presence of humans produces a lot of heat. Even if we didn’t use energy, the human basal metabolic rate is 50-75 watts per/person. Without cooking, cooling, heating, transporting ourselves or exercising we each produce roughly 1800 watts per/day. For more on basal metabolic rate you can go here -- http://en.wikipedia.org/wiki/Basal_metabolic_rate

If a human is doing nothing he emits the same heat as a 50-75 watt light bulb or 255.97 BTU/hour. In the 1950’s there were approximately 2 billion humans on Earth. That translates into 150 billion watts. But since the 50’s our population has soared to over 6 billion with an output of power equal to about 450 billion watts or 603 million horsepower.

Not to get too far off into the weeds, suffice it to say that just to keep you alive and doing nothing but breathing with a heartbeat and bodily functions you emit between 43 to 64 large-calories/hour. Dieting or food calories use the ‘large calorie’ definition. One large calorie is the heat required to raise the temperature of one kilogram one degree C. The large calorie is 1000 times the scientific calorie which is the heat required to raise the temperature of one gram by 1 degree C.

The purpose of explaining the power usage by people is important. Our population matters when it comes to energy. Whether a human lives in a modern electrified dwelling or a grass hut, cooking is a staple of existence. Burning wood to cook produces heat as well as an electric or gas range. Most of our teeming masses also transport themselves about burning fossil fuel. The heat load in our atmosphere increases with each gallon of fuel burned. Every gallon of gasoline we burn gives off 114,000 BTU of heat. A 20 gallon tank of gasoline literally pumps 2,280,000 BTU into the atmosphere when used. There are literally millions of cars and trucks on the roads burning fuel at any given time. The heat we need to dissipate increases with every added person to our population. Each additional person means one more person to cook for, keep cool, warm, transport, and produce more food.

More people translate into an increased need for energy. Energy increases means more waste heat to pollute the planet. At present our need for energy is increasingly out pacing the Earth’s ability to lose the waste heat without increasing in temperature.

Electricity production by any method that uses steam as the prime mover disperses heat and a lot of it. The waste heat discharged by most power plants goes into the air using cooling towers or directly through smoke stacks. Some power plants discharge the heat directly into rivers. There is no way to deny the increases of waste heat generated because of the needs of an expanding population.

At the present time we cannot sustain our electrical needs without steam plants, but wind, solar cell, tidal flow, and hydroelectric generators produce far less heat than generation by the steam process.

The rate of heat transfer from Earth to space remains fairly constant. As we generate more heat, guess what? The Earth becomes a little warmer. As mentioned, CO2 is a minor greenhouse gas and causes slight delays in the process of expelling heat from the Earth.

The past century has almost been the perfect storm for gains in heat. I documented the assault on the Earth by the Sun and the document is still available here: http://www.robfg.com/sunspots_and_the_earth.html -That article documents the increases in solar radiation in the 20th century.

Our waste heat pollution is a much larger threat than CO2. Human generated CO2 is a red flag and a symptom of our careless use of energy. A friend that I asked to pre-read this article pointed out numerous points that I skirted or omitted. All were good points and will be addressed in a future article. This article only represents the thrust of my thinking about heat in general. The logic feels right but as pointed out to me by my friend, there are a lot of variables unaccounted for.

Addendum

CO2 gains over the past century have been 97% attributable to an increase in Ocean temperature. Cold sea water absorbs CO2 while warmer sea water releases CO2. There is not much we can do to change that process, but our activities are detrimental to the overall health of the ocean environment. Whether by God’s design or the luck of the draw, we find crustaceans such as krill, crabs, and others in great abundance in the cold water at the poles. They play an important part in maintaining the Ph level of the ocean.

As CO2 gets absorbed back into the colder waters, chemical reactions convert some of the gas into carbonic acid. Neutralizing that acid is important. An ocean with a low or acidy Ph, wants to eat at corals. The corals are an integral part in the chain of life in the oceans and their destruction would have major consequences on humans. So we have shell fish.

Those shells on the crabs and other crustaceans are made of calcium carbonate and act as giant antacid for the oceans. The human part in this cycle interrupts this process by removing large quantities of those shellfish for human consumption. Instead of the calcium carbonate being returned to the ocean to help neutralize the acid, the remains wind up in landfills far removed from where they can do the most good.

Of course the oceans are prolific enough to stand some taking of shellfish, but as we increase our demand for shellfish, we increase the strain on the oceans ability to prevent acidification.

Robert welcomes your comment to this or any other of my commentaries.

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