Friday, January 14, 2011

Negentropy from an ESD perspective and its imperative

This topic is a bit extensive to put and completely justify in a blog post, what I would like to do however is to make an introduction into this as I believe that this aspect a critical, fundamental and core to what is both a central to the source and effect of Environmentally Sustainable Design.

Of the literature that currently exists on this topic, most of it revolves around the periphery of how to achieve Sustainable Design, mainly basing it on concepts of renewable resources, both of material and energy, as well as delving into the aspects related to the environmental impact, it should not have.

From a historical perspective there has been some amount written on this topic, a search on Google for "entropy sustainability" return several papers written on the topic, however what is interesting to note is that most of these make reference to the Bruntland Report published in 1987 and make a start from there, some assuming the definitions of sustainability therein described, which was commissioned by the UN. After some papers that appear at the beginning of the 1990s, the topic largely disappears, except for some sporadic papers and constant contributions of Prof. Timothy Gutowski of MIT (Publications).

What I have found though, except those that directly address the topic, is that most of them miss the central base point of how sustainability is achieved. Those that directly address the topic, normally go as far as establishing the nexus between the aspect of Thermodynamics or Entropy and Sustainability, though they do not really elaborate on how to go about designing sustainably with this in mind.

As this is not an academic paper, and my idea is to provide practical and viable contributions to society, not that academic papers do not also do that, but they have another focus I will and give a more practical focus to what is being presented. Another observation is that for everyday purposes, I believe that concepts have to be synthesised so that they are easier understood, as such I prefer to use the word "Negentropy" meaning the inverse or in opposition to what is entropy.

So to summarise, in my view, this is achieved be designing systems that are, or tend towards, establishing Negentropy, from the acception of ESD.

To be able to elaborate on this it is necessary to trace back one's steps though and start with explaining what is Entropy, which is associated with the Second Law of Thermodynamics as a corollary.

To explain entropy succinctly is not simple, this is my attempt to do so in lay man's terms and how I connect it to ESD: Entropy is manifested when heat flows from hot to cold regions, this heat is molecular agitation and in the measure that we have more agitation there is more disorder in our systems and as such degradation.  

One of the most common examples of entropy is ice melting in a warm room.
source: wikipedia
How do we apply this concept them to ESD? Well, an easy way to do this is in the concept of an urban environment, in a building that uses air conditioning. It is very good as it shows how entropy can be accelerated and what is the alternative as a solution invoking sound ESD principles.

A definition of air conditioning that can be used is: is the removal of heat from indoor air for thermal comfort. Now comes an interesting question where does this heat that was removed go to? Well outside obviously, this hot air, summed to other aspects such as the albedo of reflecting surfaces in urban landscapes, provide a feedback loop that has the effect increasing the temperature difference, making it ever hotter outside due to the increased demand on the air conditioning system to remove "heat from indoor", as the environment indoor is necessarily affected by the outside temperature. This effect is called the Urban Heat Island.

So what can be done about this? How can we introduce the concept of Negentropy to create a sustainable design in this environment which can be said is a very typical one where there is human population.

Plants or Flora as Negentropic elements
(please not that the intent of this is to be as illustrative as possible, to go into to details such as excepting archaea, or using terms like autotrophs and heterotrophs extensively, might defeat the purpose of reaching a wider audience.)
Vegetation can be considered as negentropic for several reasons. From the basis of the description of entropy, plants we could say have an effect that is "opposite" of entropy. Among the reasons plants grow we can find, for our purposes, two main ones which would be photosynthesis and the requirement of "heat". When referring to heat we mainly want to imply 2 or 3 conditions. Heat refers to a manifestation of molecular movement, hence one could theoretically say that anything over 0 degrees Kelvin, would be "heat", this is any the formal definition from a physics or chemical perspective. In colloquial terms though heat is a relative term, heat or something being hot could be considered above what has been defined as thermal comfort which is 21 deg C or 70 deg F, and then again it could be whatever anyone wants to define it.

Autotrophs, life forms that "create their own food", need heat to metabolise, this heat is transformed into organic compounds, what today has fashionably been called "carbon sunk" if you wish. This means that in a closed system heat is for practical effects being "absorbed" in an endothermic reaction. This constitutes, we could say and negentropic situation.  

In the case of photosythesis, implying phototrophs, light and in this case we would mean sunlight, we also have a situation where light energy is being transformed again organic compounds. The presence of light is for our purposes associated with the presence of heat, in the measure that heat can be absorbed, photosynthesised, metabolised, is once more for practical effects a negentropic situation.

So as we have elaborated a bit on this basically what are we aiming for here? We have identified 2 aspects that we can work with, heat and light, both of these are forms of energy or E.

Albert Einstein put very well and succinctly quite a few years ago in his formula E=mc². When I was at high school and even later, when I was study to get my degree in engineering, it was a concept a bit difficult to grasp saying that if I have, matter (m) and make it travel at the speed of light (c) squared, then I end up with energy (E). What if we look at it another way, energy can become matter, which is what happens, for our simple purposes, in negentropy. The energy that is heat, is "sunk" in to the carbon structures that these autotrophs metabolize.  

Going back to our air conditioning example, if we were to have plants surrounding the building, on the sides and on top as well as inside, we could do substantially to reduce then the entropy as the plants will be having several effects to break the feedback loop of ever heating the environment.

Water quality
This is another one of the cases that I find interesting. Water is tremendously complex, interestingly enough temperature is not given enough importance as characteristic of water quality, some people do however. The presence of dissolved oxygen (DO) is obviously a critical aspect of water quality, this goes down in the measure that we have more BOD or COD, but also temperature, we could mention some other aspects, but that would possibly be too much detail for the purpose of illustrating a point. "Coincidentally" all of these points are interdependent and related. However the point here is that in the measure that water enters an entropic cycle, where it is heated, it is degraded, remember heat is associated with molecular disorder, it also becomes a more suitable environment for anaerobic lifeforms, which can only further degrade the quality of water, further increasing the BOD and reducing the DO.

What is to be done then? Well water has to be given conditions where it can exist in a negentropic situation. How is that done? Well that is another point that depends on every situation in a different manner.

There are many more aspects that could be discussed that would have relation to how negentropy can positively affect ESD. I look forward to receiving any observations, corrections or questions on this topic.

More reading and references:
Preliminary Thoughts on the Application of Thermodynamics to the Development of Sustainability 
Criteria Entropy and Its Implications for Sustainability
Economics,  entropy  and  sustainability
Entropy and Energy: Toward a Definition of Physical Sustainability

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