What is Exergy, Entropy, Information, Order in relation to buildings?
Everything will turn to dust. Inevitable. Except in a subsystem where solar radiation provides just enough energy to (re)create some order.
I was once again struggling with a question: the relationship between entropy, exergy, value, and order. Yes, yes, you can ask yourself a lot of things. So, let’s think out loud again. (and maybe for a bit longer than usual…)
It actually started with me wondering whether, through our “building activities” on Earth, the total value of organized matter increases? Or are we simply gathering a lot of resources in buildings and cities and thereby impoverishing the surroundings? In thermodynamic terms (TD) that is. Thermodynamics only knows one direction: the decrease of order and the increase of entropy. So, the value would decrease anyway, and possibly even faster because we are disrupting things? How does that work again? In other words: are we creating value or not? And what kind of value? So, let’s try to get things straight.
Well, our basis is the Earth, from which we can’t escape, and it has a limited amount of matter. It doesn’t increase or decrease, but it can be reorganized, driven by a source from inside or outside the system. From within, it erodes, physical decay, call it desertification, randomly distributed particles (a thermodynamically dead reference environment). On the other hand, there’s solar-powered photosynthesis from outside, by which biological systems grow on Earth, and matter becomes organized, so to speak (“abundance”). Summed up as Life, and that creates (or stands for?) order. The sun’s energy (“external source”) is used to organize matter into complex forms like plants, animals, and entire ecosystems.
Clear. But how about us, humans, and the materials we’ve collected and turned into buildings – does the same apply?
By building, materials are brought together in a very specific and organized way to form a functional and stable structure. In other words: order arises: “because ordered structures are created from raw materials that are often in a more disordered natural state (like stones, wood, metal, glass), more diluted, dispersed forms.”
So, it’s not specifically about a building for humans, but rather a structure that captures order, physically and biologically speaking. That we happen to shelter or live in them is physically not relevant (biologically it is, but that comes later). The question is whether the ordering is more orderly than it was before: is the total matter more organized than it was before? Per building, yes, it seems, but what about at a higher level of abstraction: all buildings together, or the entire energy-mass system? Think of sand for concrete, which was originally mined in one place and now is dispersed across various buildings, where it was once concentrated in one location…
So, what about that ‘entropy’ again?
Entropy is the degree of order in a system (low entropy), or formally, the degree of freedom a system has to form order (the more freedoms, the higher the entropy). (Entropy is also sometimes seen as a measure of uncertainty, but that’s for another time [1]).
In everyday practice, we can think of it as a measure of order: high entropy is chaos, low entropy is concentration and organization. By creating a building, order has been created (the freedoms of matter are limited), and as long as the building stands, entropy on Earth decreases. Note that this is assuming the building was constructed with short-cycle solar energy or work generated by it, using an external source and restoring the resources. If it was built with an internal source, using fossil energy, then entropy has definitively increased. After all, energy and mass from within the system were used, and one part can become organized, but only at the cost of breaking down another, leading to a combined reduction. In other words, the quality within the system has decreased. (Within the timespan that modern humans have been around, that is.) So again, it’s clear from this way of arguing: we must live from the sun and its derivatives, to not destroy our environment.
Once the building is demolished, whether by deconstruction or some other means, entropy has increased disproportionately: more than it would have if no building had been created during that period! Through demolition, the original situation, with a higher entropy level, is restored, while unnecessarily wasting energy twice in the process. In other words, the shorter the lifespan of buildings, the faster entropy increases on Earth…!! And thus, a reduction in the quality of the system (for us).
Note: once again, this is a reason to make buildings last forever once built! (I previously came to the same conclusion, through another route, that everything should last at least 50 years, and preferably forever [2]).
Moreover, to keep a building “ordered,” regular energy input or maintenance is of course necessary. This means that the entropy reduction is not permanent without continuous energy input, and the less maintenance required, the greater the resulting entropy reduction. In other words, the greater the net contribution to the system’s potential, and for us, society’s potential for growth.
However, as noted, energy is needed to reduce entropy, or to create order, by investing or extracting energy. And that energy is subsequently lost, meaning it becomes useless—the capacity to do work within that system is lost.
And so, because no new energy comes to Earth from within, everything, including entropy, the amount of order or disorder, depends on how much energy we can capture from outside the system. This means that for organization here on Earth, we use solar energy from outside our own system. Regardless of Earth’s resources, which can only be depleted, creating chaos and disorder of resources. Also for materials.
Note: By “capturing,” I mean capturing as entropy reduction. For example, via trees.
“Counter-Entropy”
External energy is required to organize things. Essentially, this could be called “free exergy” on Earth: the portion of energy and mass that is usefully deployable or becomes available in the form of the capacity for ordering, change, work, and movement—without depleting the internal system (though this is not an absolute value*).
To explore and clarify this further, I often use the iron-nail example: ores contain iron, and energy must be invested to extract, concentrate, and refine it into a pure form suitable for countless applications (ideally using solar energy; otherwise, degradation and increased entropy are inevitable). The exergy—the quality of the raw material—has thus increased, from ore to iron ingots: concentrated blocks at the factory with great potential for various uses. But then comes the next step: the concentrated iron is sent to a factory where it is turned into nails, reducing mass exergy. Change occurs as iron molecules are distributed. These nails are packaged and shipped worldwide, further diluting the exergy—the potential for creation—since the material becomes more dispersed and disordered. The nails are then distributed across construction sites and eventually embedded in buildings. The once-concentrated iron supply has become extremely diluted! (Of course, as mentioned, the type and amount of energy invested in this process also matters.)
Thus, after initially being concentrated, the potential of iron has diminished. Imagine trying to collect those nails again: it requires enormous energy investment to restore the value and utility—exergy—of iron into a concentrated stock.
Disorder—entropy—keeps increasing in the process, even though we value the nail more then the original stock, from a physical standpoint the value decreases: exergy decreases, entropy rises, the potential for change diminishes, and unusability increases.
But that’s the nail. What about the resulting building?
The question then becomes: is pure material a higher form of order than a structured combination of scattered materials and molecules in a building?
I previously reasoned that disorder increases from the moment nails leave the factory—implying that buildings cannot represent hihger order. However, upon deeper consideration, it turns out differently: exergy—the potential for change—has been lost, but it has driven transformation and created a reduction in entropy, which has been fixed in place.
The key difference lies in the scale of system analysis. Looking only at material, exergy decreases, and entropy increases. But at a higher level of abstraction—that of buildings—the overall entropy has actually decreased, as collective structuring has increased the system’s value.
Alternatively, one could phrase it this way: the potential for change (exergy) has decreased, resulting in entropy reduction (ordering) within the overall energy-mass system. With the important caveat that the energetic component can be replenished by external (solar) energy—as long as we rely on short-cyclic processes.
Now, comparing a building to a human body , we see a key difference:
We, as humans, are also an assemblage of gathered molecules—structured, with low systemic entropy—but crucially, we still possess high exergy, or potential for change. Unlike a building, where exergy has been lost—it has become inert.
This takes us from physics to a higher scale: a bridge to biology—specifically evolution, assuming that, aided by solar energy, it is the ultimate driving force behind creating order on Earth*.
And this flips the perspective again—at least, that’s how I arrive at this reasoning:
The exergy of materials has been lost, sacrificed for entropy reduction in the form of buildings. However, these buildings hold no evolutionary value—they do not contribute to progressive ordering in an evolutionary sense; it stops there, they are only valuable to humans. As far as I can reason, these materials have been removed from further participation in an evolutionary process on a planetary scale.
Evolution itself is a process of counter-entropy—an ongoing reduction of entropy, achieved through a circular system (within Earth’s unique exception to the universal trend). Yet buildings make raw materials inert within this circular process. They become locked away, ceasing to play any biological role. As a result, evolutionary potential declines—what we might call “evolutionary exergy,” in contrast to thermodynamic exergy.
Unless, of course—and this is speculative—the accumulation of buildings, the city itself, represents the emergence of a new organism, an orbanism, embodying the next step in evolution! In this view, humans are merely the ordering agents, much like bacteria and other ‘transmitters’ within our bodies. I explore this speculative idea further in the chapter The Urbanoceen from my recent book [3] (also available separately as an e-book [4]).
Yet even so, there is a limit to order, for any system—there is only so much structured matter possible within a finite system. Eventually, new order can only emerge once the old collapses…
As I mentioned earlier, one can ask oneself strange questions and think out loud. There is no guarantee that I am 100% correct, though I have done my best to present the ideas according to my latest insights (to order and organize them, so to speak), in the hope that others can build upon them.
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P.S. The next stage—because this is just a transitional phase—is that it’s not about energy or matter, but about information. Everything, absolutely everything, is ultimately a matter of data organization and the information that emerges from it. Nature plays with this randomness, generating knowledge from raw information and using it consciously to drive new organisms forward. We, as humans, try to do the same—turning information into knowledge and applying it—but so far, we seem ineffective, considering the speed at which we deplete resources and disrupt organization by failing to use short-cyclic processes. In doing so, we increase entropy on the highest scale.
But perhaps… this is just the beginning of something new and beautiful.
Maybe.
Illustration : R.Nave
* Though we don’t know what exactly drives evolution.
* Exergy is in fact relative, how much can be converted depends on the knowledge of the user, or species. But that’s for another time.
[1] entropy very well explained
[2] lifspan : https://www.ronaldrovers.com/everything-that-doesnt-last-at-least-50-years-is-system-degradation/
[3] book Post Fossiel Leven (Dutch, transalation soon) : https://www.ribuilt.eu/product/post-fossiel-leven/
[4] the Urbanocene , ebook (English): https://www.ribuilt.eu/winkel/
