Energy
We discuss energy as it is key to anything we do. Humanity has moved from the use of the energy of the animals to energy generated from fossil fuels. Realizing the negative impact of energy generated from fossil fuels, man is striving hard to switch to renewable sources of energy.
In that context, we present a brief description of the energy scene via the Morphological Analysis below here.
In that context, we present a brief description of the energy scene via the Morphological Analysis below here.
Morphological Analysis of Energy Systems
A presentation made at IIT, Gandhinagar, India in 2015 is presented below here.
It enumerates many alternative energy systems possible.
| morphoenergyiitgn2015.ppt |
You can see the presentation here.
Quality of Energy
Quality of Energy
Energy takes different forms and all forms of energy are not of the same quality. For example, mechanical energy can be converted with one hundred percent efficiency to thermal energy (heat). But thermal energy cannot be converted one hundred percent to mechanical energy. Therefore, the quality of mechanical energy can be considered superior to that of thermal energy (heat).
We use thermal systems (engines, turbines, and rockets) to convert thermal energy to mechanical energy. In these processes, thermal energy at a higher temperature is used and when some of that energy is converted to mechanical energy, there is a requirement that the rest of the thermal energy is rejected to another body, which is necessarily at a low temperature.
That all thermal energy cannot be converted to mechanical energy and some of that thermal energy must be rejected to another body at a low temperature are observed in nature. In Thermodynamics, such requirements are defined as the Laws of Thermodynamics.
If we have thermal energy in a body at a low temperature and if we wish to transfer it to another body at a higher temperature, it is not possible unless aided by another device with mechanical energy. This case is what we observe with items in a refrigerator. The food is kept at a low temperature and the thermal energy from it is taken out and transferred to outside air (at a higher temperature) with the use of an electric motor that requires the expense of mechanical energy. It may be noted that mechanical and electrical energy are of the same quality.
Chemical energy can be converted to electrical energy in a battery with one hundred percent efficiency in a theoretical sense. Thus, Chemical, electrical, and mechanical energy are of the same high quality.
Let us look at two hypothetical constructs.
Let us assume that we have a certain amount of energy in a body at an infinitely high temperature. We will require no mechanical energy to transfer it to a higher temperature because it is already at the highest possible temperature (Infinity).
Let us assume that a certain amount of energy is at a temperature Zero degrees absolute (Kelvin). Such energy cannot be converted to mechanical energy as there is no other body at a temperature below it to take rejected heat when we try to convert that thermal energy (heat) to mechanical energy (work).
Absolute Zero degrees temperature is defined thusly.
These two scenarios can be used to state that thermal energy (heat) can have a quality depending on the temperature at which it exists.
a) The quality of thermal energy (heat) can be as high as that of mechanical (or chemical or electrical) energy when thermal energy is at temperature, Infinity.
b) Thermal energy is of quality Zero (lowest) when it is at Zero degrees absolute (Kelvin).
c) When, thermal energy is at any temperature between these two limits (Infinity and Zero), its quality is in between the highest and lowest.
Combustion:
Let us consider the case of chemical energy in a fuel. When a fuel is burned, the chemical energy in the fuel is converted to Thermal energy in the products of combustion. Invariably, we get temperature of products much less than Infinity and greater than Zero degrees absolute. Hence, combustion degrades the quality of energy. The degradation depends on how low the temperature of the products of combustion is. This is the reason why in engines we try to obtain temperatures that are as high as practically possible.
Friction:
Friction will be there whenever there is motion caused by force. Frictional forces oppose motion. Friction causes mechanical energy to be converted to thermal energy (heat).
Since friction converts mechanical energy to be converted to thermal energy, it degrades the quality of energy. Friction does not cause thermal energy to be converted to mechanical energy.
We try to minimize friction so that energy degradation is minimized.
Heat transfer:
We know that thermal energy (heat) moves from a body at a higher temperature to a body at a lower temperature when the two bodies are allowed to come in contact. Say, certain amount of thermal energy is transferred from a body at a higher temperature to another body at a lower temperature. Since that thermal energy (heat), which got transferred, is now at a lower temperature, its quality has degraded. So, we state that heat transfer across a temperature gradient degrades energy.
Summary:
Thus, while designing and operating engineering systems, we try to make sure that the quality of energy is not unduly degraded.
Energy takes different forms and all forms of energy are not of the same quality. For example, mechanical energy can be converted with one hundred percent efficiency to thermal energy (heat). But thermal energy cannot be converted one hundred percent to mechanical energy. Therefore, the quality of mechanical energy can be considered superior to that of thermal energy (heat).
We use thermal systems (engines, turbines, and rockets) to convert thermal energy to mechanical energy. In these processes, thermal energy at a higher temperature is used and when some of that energy is converted to mechanical energy, there is a requirement that the rest of the thermal energy is rejected to another body, which is necessarily at a low temperature.
That all thermal energy cannot be converted to mechanical energy and some of that thermal energy must be rejected to another body at a low temperature are observed in nature. In Thermodynamics, such requirements are defined as the Laws of Thermodynamics.
If we have thermal energy in a body at a low temperature and if we wish to transfer it to another body at a higher temperature, it is not possible unless aided by another device with mechanical energy. This case is what we observe with items in a refrigerator. The food is kept at a low temperature and the thermal energy from it is taken out and transferred to outside air (at a higher temperature) with the use of an electric motor that requires the expense of mechanical energy. It may be noted that mechanical and electrical energy are of the same quality.
Chemical energy can be converted to electrical energy in a battery with one hundred percent efficiency in a theoretical sense. Thus, Chemical, electrical, and mechanical energy are of the same high quality.
Let us look at two hypothetical constructs.
Let us assume that we have a certain amount of energy in a body at an infinitely high temperature. We will require no mechanical energy to transfer it to a higher temperature because it is already at the highest possible temperature (Infinity).
Let us assume that a certain amount of energy is at a temperature Zero degrees absolute (Kelvin). Such energy cannot be converted to mechanical energy as there is no other body at a temperature below it to take rejected heat when we try to convert that thermal energy (heat) to mechanical energy (work).
Absolute Zero degrees temperature is defined thusly.
These two scenarios can be used to state that thermal energy (heat) can have a quality depending on the temperature at which it exists.
a) The quality of thermal energy (heat) can be as high as that of mechanical (or chemical or electrical) energy when thermal energy is at temperature, Infinity.
b) Thermal energy is of quality Zero (lowest) when it is at Zero degrees absolute (Kelvin).
c) When, thermal energy is at any temperature between these two limits (Infinity and Zero), its quality is in between the highest and lowest.
Combustion:
Let us consider the case of chemical energy in a fuel. When a fuel is burned, the chemical energy in the fuel is converted to Thermal energy in the products of combustion. Invariably, we get temperature of products much less than Infinity and greater than Zero degrees absolute. Hence, combustion degrades the quality of energy. The degradation depends on how low the temperature of the products of combustion is. This is the reason why in engines we try to obtain temperatures that are as high as practically possible.
Friction:
Friction will be there whenever there is motion caused by force. Frictional forces oppose motion. Friction causes mechanical energy to be converted to thermal energy (heat).
Since friction converts mechanical energy to be converted to thermal energy, it degrades the quality of energy. Friction does not cause thermal energy to be converted to mechanical energy.
We try to minimize friction so that energy degradation is minimized.
Heat transfer:
We know that thermal energy (heat) moves from a body at a higher temperature to a body at a lower temperature when the two bodies are allowed to come in contact. Say, certain amount of thermal energy is transferred from a body at a higher temperature to another body at a lower temperature. Since that thermal energy (heat), which got transferred, is now at a lower temperature, its quality has degraded. So, we state that heat transfer across a temperature gradient degrades energy.
Summary:
Thus, while designing and operating engineering systems, we try to make sure that the quality of energy is not unduly degraded.
Entropy Explained
Battery Operated Vehicles
Let us say that a body has a certain amount of thermal energy (heat) at temperature T1. If we take some thermal energy from that body, and put it through an engine and have a low temperature sink, it will produce some mechanical energy (work).
On the other hand, let us say that we took that same quantity of thermal energy from the body at temperature T1 and allowed it to transfer it to another body at a lower temperature T2 without producing any mechanical energy (work).
Now, if we take that thermal energy from the second body at temperature T2 and put it through an engine and have the same low temperature sink, it will produce less work than in the first case. (We explained elsewhere that higher the source temperature, greater will be the work produced.)
What happened is that when some thermal energy moved from the body at temperature T1 to the body at temperature T2 (where T2 lower than T1), we lost some capability to produce mechanical energy (work). Or in other words, we degraded the quality of energy.
They had invented the property called Entropy to explain this degradation of the quality of energy.
We would say that the first body has Entropy S1 (along with its temperature T1) and that Entropy is decreased when a certain amount of thermal energy moved away from it. The second body has entropy S2 (along with its temperature T2) and that Entropy has increased when it received the thermal energy from the first body. The increase of Entropy of the second body is greater than the decreased value of entropy in the first body.
But, in the universe, which has the first body and the second body, one has decreased its entropy and the other has increased its entropy for the same amount of heat that transferred from the first body to the second body. The increase is greater than the decrease. Hence, in the universe, the Entropy has increased.
So, we conclude that while we have not lost any energy in the universe, its quality has decreased. Such increase can be measured (observed or indicated) by the increase in the Entropy of the universe.
Thus, Entropy is a good measure to indicate the degradation of the quality of energy.
Combustion, friction, and heat transfer degrade the quality of energy and there will be increase in Entropy (of the universe).
The property, called Entropy, can thus be used to measure if a system that we are designing or operating is keeping up the quality of energy or degrading it.
Please note that it is different from wasting energy.
An observation:
Bring boiling water and frozen butter together (without actually mixing them) and you will find that the boiling water would give some of its heat to melt the frozen butter. The entropy of the universe increases. The entropy of the boiling water decreases and the entropy of the butter increases (more than the amount of decrease of entropy of the boiling water.)
Analogy:
Let us say, we have a heart surgeon and a first aid worker. The heart surgeon can do heart surgery as well as provide first aid. The first aid worker can provide first aid but cannot perform heart surgery. Now, if a first aid case comes up, it is best to assign that task to the first aid worker and not to the heart surgeon. If we use the heart surgeon for first aid work, we are degrading her capabilities. We could say that we are increasing the Entropy of the system. Again, please note the difference between wasting one’s time versus degrading one’s capabilities.
In popular conversation, we say that the Entropy has gone up when we do something to degrade the quality of someone’s capabilities.
Cosmic Energy System
Cosmic Energy System
This energy system description is only a thought. There may be no scientific or engineering support for it. Please read it with caution.
The core of the Sun is said to be at a temperature of 15 million degrees Celsius, and the temperature of the sun’s photosphere is about 5,500 degrees Celsius. (We get degrees Kelvin by adding 273 to the Celsius value. At these large values such addition is not important for our discussion here.)
We, on earth, get thermal energy (heat) by radiation from the Sun. As we discussed earlier in another posting, this heat is used to evaporate sea water, to cause clouds, to move them up into the sky and all over the globe. In the night time (at various points on the earth), the heat is radiated from the clouds to deep space and the clouds become water and water will come down to the earth as rain or snow.
It is interesting to realize that here is a heat engine. It has a source (Sun) at a high temperature, a sink (Deep space) at a low temperature, water acting as the working medium converting thermal energy into mechanical energy (work), and space serving as the apparatus or equipment.
It is also interesting to realize that the thermal radiation from the Sun is also heating air and moving it up while the Deep space is cooling it at night time. Thus, there is another heat engine generating mechanical energy in the form of kinetic and potential energy of the air.
We thank the Sun (the donor), but we should also thank the Cold Deep space (the donee) and the elements water and air, which act as the working media. Otherwise, without the done and the elements, we would have gotten heat and not mechanical energy (work).
We should wonder if on some other planets, a similar energy to work conversion would take place if those planets have fluids such as water and air. It may be worthwhile conducting an experiment by taking water to some planets with no atmosphere there and see if rains occur.
Even a larger Energy System:
Astronomers explain that the angular momentum allows the earth and other planets in the solar system to continue to spin and orbit. It is perhaps so!
But, there may be a larger energy system that causes the rotations and movements of all the planets in our universe.
The thermal cycle taking place on the earth (namely, solar energy evaporating water, deep space causing that water vapor to condense as rain, and generating mechanical energy) should prompt us to ask if there is a bigger heat engine going on in the cosmos. It may not use water and air as the working substances but may use other energy conversion mechanisms and still using the thermal cycles.
In the cosmos, there may be a body at a temperature at infinity degrees and a body at zero degrees spinning all the planets in the solar system. The body at a temperature at infinity degrees can only give away heat but cannot receive heat, while the body at zero degrees can only receive heat but cannot give away heat unaided with mechanical energy from another body. The body at zero degrees can be a Black hole as far as thermal energy is concerned.
We know that the Sun (just) is there with internal sources generating energy from materials to sustain life on earth with energy. One could hypothesize that there is some infinite thermal energy source continuing to radiate looking for a body either to absorb it or reflect it. Someone has to search the whole cosmos and show the absence of the Infinite temperature source and the Zero temperature sink.
Please note that according to our observations of the nature and as enunciated by the Laws of Thermodynamics, heat can flow only from a body at a higher temperature to a body at a lower temperature unaided by external forces. These laws do not say anything about other forms of energy and whether the other forms of energy can flow from and to the bodies at any temperature.
The Laws of Thermodynamics also do not say anything about other universes as we have no knowledge about them. Other universes and what happens in these extreme bodies (Infinity and Zero) will be interesting to imagine and study.
This energy system description is only a thought. There may be no scientific or engineering support for it. Please read it with caution.
The core of the Sun is said to be at a temperature of 15 million degrees Celsius, and the temperature of the sun’s photosphere is about 5,500 degrees Celsius. (We get degrees Kelvin by adding 273 to the Celsius value. At these large values such addition is not important for our discussion here.)
We, on earth, get thermal energy (heat) by radiation from the Sun. As we discussed earlier in another posting, this heat is used to evaporate sea water, to cause clouds, to move them up into the sky and all over the globe. In the night time (at various points on the earth), the heat is radiated from the clouds to deep space and the clouds become water and water will come down to the earth as rain or snow.
It is interesting to realize that here is a heat engine. It has a source (Sun) at a high temperature, a sink (Deep space) at a low temperature, water acting as the working medium converting thermal energy into mechanical energy (work), and space serving as the apparatus or equipment.
It is also interesting to realize that the thermal radiation from the Sun is also heating air and moving it up while the Deep space is cooling it at night time. Thus, there is another heat engine generating mechanical energy in the form of kinetic and potential energy of the air.
We thank the Sun (the donor), but we should also thank the Cold Deep space (the donee) and the elements water and air, which act as the working media. Otherwise, without the done and the elements, we would have gotten heat and not mechanical energy (work).
We should wonder if on some other planets, a similar energy to work conversion would take place if those planets have fluids such as water and air. It may be worthwhile conducting an experiment by taking water to some planets with no atmosphere there and see if rains occur.
Even a larger Energy System:
Astronomers explain that the angular momentum allows the earth and other planets in the solar system to continue to spin and orbit. It is perhaps so!
But, there may be a larger energy system that causes the rotations and movements of all the planets in our universe.
The thermal cycle taking place on the earth (namely, solar energy evaporating water, deep space causing that water vapor to condense as rain, and generating mechanical energy) should prompt us to ask if there is a bigger heat engine going on in the cosmos. It may not use water and air as the working substances but may use other energy conversion mechanisms and still using the thermal cycles.
In the cosmos, there may be a body at a temperature at infinity degrees and a body at zero degrees spinning all the planets in the solar system. The body at a temperature at infinity degrees can only give away heat but cannot receive heat, while the body at zero degrees can only receive heat but cannot give away heat unaided with mechanical energy from another body. The body at zero degrees can be a Black hole as far as thermal energy is concerned.
We know that the Sun (just) is there with internal sources generating energy from materials to sustain life on earth with energy. One could hypothesize that there is some infinite thermal energy source continuing to radiate looking for a body either to absorb it or reflect it. Someone has to search the whole cosmos and show the absence of the Infinite temperature source and the Zero temperature sink.
Please note that according to our observations of the nature and as enunciated by the Laws of Thermodynamics, heat can flow only from a body at a higher temperature to a body at a lower temperature unaided by external forces. These laws do not say anything about other forms of energy and whether the other forms of energy can flow from and to the bodies at any temperature.
The Laws of Thermodynamics also do not say anything about other universes as we have no knowledge about them. Other universes and what happens in these extreme bodies (Infinity and Zero) will be interesting to imagine and study.
Charging vehicles equipped with batteries takes an impractically long time. By using battery capsules, loading charged batteries and unloading discharged batteries takes seconds. Battery vending machines can be located at key points on highways. This concept can become a reality when the infrastructure from charging the batteries to loading them into vehicles in seconds is developed. Pictures of logistic chain from grid to battery capsules and wall plug to battery vendor are shown here.
