How the technology called environmental IoT is able to substitute knowledge for energy consumption and thus solve some of the challenges of the sustainable city.
“If you let yourself slide down a stair rail, you will increase the temperature of your posterior, however it is not by heating your buttocks that you will go up the ramp.”
The slide on the ramp illustrates quite well the second law of thermodynamics. If the energy is not lost, it becomes less and less usable. It is this increase in unnecessary energy or heat that is called entropy.
We live in a period of massive production of entropy inducing climate change which produces heat and uniformity. The environmental IoT is the management of natural resource management activities by sensor instrumentation. In this article, we share two insights that illustrate how the environmental IoT can help slow the production of entropy.
The first is that there is an equivalence between energy and information. That is to say that by bringing knowledge to an object, we actually create available energy.
The second is that when the information is used in a process of retroaction (slavery) then one is able to create a technology of intention or finality, which can make it possible to extract oneself locally from entropic laws.
We use here the term information in its etymological sense “that gives form”. We are therefore talking here only about creative information, constituted as knowledge which can produce an effect or an action.
Maxwell’s demon is able to create energy by producing knowledge
In 1867 Maxwell proposed an experiment “Maxwell’s demon” which called into question the second principle of thermodynamics. It encloses a gas in an enclosure with two compartments separated by a hatch. He imagines a demon watching and commanding the door. The opening of the hatch does not generate friction. When a hot (fast) molecule of gas from the first compartment approaches, it opens the hatch to let it pass and vice versa. The demon thus manages to separate the cold molecules from the hot molecules.
Miracle, our demon has created a potential difference between the two compartments and therefore an available reserve of energy. The demon has therefore succeeded in reducing the entropy of the system without any external energy input! It is a radical questioning of the second principle of thermodynamics which would allow us to solve all the problems of the sustainable city.
It took more than a century for Landauer removes Maxwell’s paradox by demonstrating the equivalence between Information and Energy. The demon actually brought information into the system by observing the speed of each molecule of the gas. There is creation of energy from the information introduced. The creative information introduced by Maxwell’s demon made it possible to reduce the entropy of the system. If we consider that Maxwell’s demon can be replaced by a connected sensor, we can clearly see the interest of the IoT for the sustainable city.
The power of intention
Imagine a new experience. Let’s first drop a steel ball from the top of Notre Dame. It loses all its potential energy when it crashes to the ground according to a trajectory entirely predictable by its initial state and the laws of gravity. Now let’s release a swallow from the top of this tower…
In addition to gravity, the swallow also experiences the pull of its intention. For the swallow the laws of causality combine with that of finality. The swallow can decide to maintain its potential energy by landing on a tree.
Intention or finality is the characteristic of living beings which picks up signals, analyzes them and constantly adjusts their behavior by enslaving them to this intention. This feedback loop is called feedback. A mammal’s intention may be to maintain its temperature at 37 degrees, a sunflower’s intention may be to maximize photon capture in a day.
From this point of view, the environmental IoT with its sensors, its capacities for analysis and continuous feedback is the extension of this self-regulating capacity of the living to the natural resources that sustain it. It is the means of maintaining fragile balances thanks to continuous feedback processes subject to intentions.
Examples of applications in the smart and sustainable city
To illustrate the two previous ideas, we will take two use cases deployed for the sustainable city.
The metropolis of Marseille deploys sensors in the rainwater network in order to detect the presence of waste in the network and prevent this waste from being carried towards the Mediterranean. Here, the sensors play the role of Maxwell’s demon to differentiate the drains of the network to be cleaned from the drains that do not require cleaning.
The contribution of information thus makes it possible to pass from a uniform situation (maximum entropy) to a differentiated situation (reduced entropy). This differentiation, or difference in potential, makes it possible here to reduce the number of cleaning rounds or to direct them towards an intention and thus create available work in a virtuous process of decarbonization.
The information produced by the sensor then transmitted to a decision-making body introduces organization (negentropy) into the population of gullies, which authorizes decision-making and prioritization. The entropy reduction S of the system can even be calculated precisely.
Let us now take the case of the watering of green spaces. To stay in Marseille, let’s study the one in the park of the old chapel near the Prado beaches. Until then, the city had deployed an automatic watering system as it exists in most green spaces. It is programmed at the beginning of the season and waters according to a schedule fixed in advance. The system does not exchange information with its environment. In the thermodynamic sense it is a closed system.
Such a system has no self-regulation capacity to cope with hazards: leaks from the pipes, malfunctioning of the sprinkler nozzles, drop in water pressure upstream or even climatic hazards. The old watering system in the park of the old chapel was replaced in 2021 by an “open” system. This new system continuously exchanges information with its environment (measurement of the available water reserve, pressure in the pipes, weather parameters, root development, etc.). Feedback loops allow him to continually adapt and regulate his behavior to achieve the intentions.
In this case, the intentions set are root development, water savings, detection of leaks and maximization of evapotranspiration during heat waves. Information exchange and intention loops locally reduce the entropy of the system. This translates into very significant water savings (60%) and a reduction in carbon monitoring or maintenance operations.
The smart and sustainable city is based in part on devices capable of maintaining fragile balances tending towards ecological objectives of saving resources, or energy. Environmental IoT sensor networks are Maxwell’s new demons which, by producing knowledge, will save energy, reduce carbon travel or the overuse of resources.
 Rolf Landauer, “Irreversibility and heat generation in the computing process”, IBM Journal of Research and Development, vol. 5, no. 3, 1961, p. 183-191