On the First Principles of Heat Transfer: A Note from Alan Siddons
CLIMATE concerns look surreal when you examine modern assumptions (“the settled science”) on the basis of first principles like conductive, convective and radiative heat transfer, specific heat (where water is king) and density. To me, they paint a picture 180° contrary to the greenhouse theory consensus.
In my view, the earth’s surface can do nothing except heat the air molecules that surround it, and thus be cooled in turn (convective transfer follows, of course, but the surface must heat the air first). Yet the prevalent gossip is all about how air molecules heat the surface. That alone is surreal.
Listed below is mostly a collection of what various academic and engineering sources say about heat transfer, i.e., the conditions by which Body A is able to raise Body B’s temperature. While they don’t explicitly refute the IPCC’s notion of back-radiation, they DO insist that if A is radiating 100 watts per square meter at B and B is radiating 50 at A, heat transfer follows a one-way path from A to B. That is, B alone gets hotter and no “mutual heating” occurs. By contrast, observe what the IPCC depicts: mutual heating.
One-way heat transfer renders null and void the repeated assertion that A (the earth’s surface) gets hotter by thermally exciting B (IR-reactive gases). The unalterably more-to-less flow of thermal energy is the very essence of the second law of thermodynamics and it prohibits “mutual heating,” meaning that “radiative forcing” by IR-reactive gases is entirely a product of the imagination, a complete reversal of cause and effect.
Moreover, if earth’s surface temperature then shifts focus to heat RETENTION rather than heat GAIN, the FIRST thing to investigate is a substance called water, which covers 70% of our planet, is 800 times denser than sea-level air, and is FAMOUS for retaining heat! Solids are roughly 2000 times more dense than air and must also be considered.
In any case, hinging the whole affair on trace gases that intercept a small portion of the earth’s IR spectrum is so outlandish a premise I’m amazed that anyone can offer it with a straight face. Gases are the runt of the litter, the least able to hold onto heat and the first in line to confront the vacuum of space. Light passes through air at 99.97% of its optimum speed and yet we propose that a few of the gases it contains CONTROL the earth’s emission to space? As I say: surreal.
1. Professor M. Quinn Brewster, University of Illinois: Thermal Radiative Transfer and Properties
Like conduction, thermal energy is in harmony with the second law of thermodynamics such that, in the absence of work, thermal energy is radiated spontaneously from higher temperature to lower temperature matter.
2. Heat transfer
Thermal energy flows from higher temperature to lower temperature. This process is called heat transfer.
There are three ways heat flows:
3. Department of Physics and Astronomy, Vrije University, The Netherlands
If the two bodies are in thermodynamic equilibrium no net heat transport takes place and the two bodies are at equal temperature
4. Pyrotechnic Chemistry, by Kurt Kosanke, I. von Maltitz, B. J. Kosanke, Ron A. Hancox, B. Sturman, R. J. (2004)There are three mechanisms by which energy can be transferred from reacting to pre-reacting layers: conduction, convection and radiation. [...] In radiation, thermal energy is passed from hotter to cooler regions as long wavelength light (infrared).
5. Heat Transfer
Heat will always be transferred from higher temperature to lower temperature independent of the mode.
6. Heat is transferred from high temperature areas to low temperature areas by conduction, convection and radiation.
7. Heat transfer is the net change in energy as a result of temperature differences. This energy is transferred in the direction of decreasing temperature until thermal equilibrium (equality of temperatures) is achieved. The basic mechanisms involved in this process include radiation (the transfer of energy in the form of electromagnetic waves) and conduction (the transfer of kinetic energy).
8. Radiation heat transfer takes place when bodies with temperature gradients are separate in space. All bodies emit radiant heat continuously, and the intensity of the emission depends on the temperature and the nature of the surface. Heat transfer by radiation becomes increasingly important as the temperature of an object increases.
9. Thermal radiation is electromagnetic radiation that consists of quanta and waves, to be precise, photons and waves, like light’s propagation. Thus, the radiative heat transfer can take place through vacuum. The energy always moves from a warm system to a colder system.
10. Radiation heat transfer is concerned with the exchange of thermal radiation energy between two or more bodies. Thermal radiation is defined as electromagnetic radiation in the wavelength range of 0.1 to 100 microns (which encompasses the visible light regime), and arises as a result of a temperature difference between 2 bodies.
11. Temperature is a measure of the amount of energy possessed by the molecules of a substance. It is a relative measure of how hot or cold a substance is and can be used to predict the direction of heat transfer.
What is Heat Transfer? “Energy in transit due to temperature difference.”
12. Heat transfer is a study of the exchange of thermal energy through a body or between bodies which occurs when there is a temperature difference. When two bodies are at different temperatures, thermal energy transfers from the one with higher temperature to the one with lower temperature. Heat always transfers from hot to cold.
13. As a result of heat transfer, hotter objects tend to become cooler and cooler objects become hotter, approaching thermal equilibrium.
…There are three modes of heat transfer: conduction, convection, and radiation. All heat transfer processes occur by one or more of these three modes. Infrared thermography is based on the measurement of radiative heat flow and is therefore most closely related to the radiation mode of heat transfer.
…Radiative heat transfer is unlike the other two modes in several respects:
1. It can take place across a vacuum.
2. It occurs by electromagnetic emission and absorption.
3. It occurs at the speed of light.
4. The energy transferred is proportional to the fourth power of the temperature difference between the objects.
14. Heat is thermal energy that is transferred between two bodies due to a difference in temperature. Heat transfer is the process of increasing the kinetic energy of a material’s particles from a material of high temperature to one of lower temperature. It can also be thought of in the opposite direction of cooling an object by slowing down its particles. Heat can be transferred to other materials through conduction, convection and/or radiation.
15. HEAT TRANSFER: form of energy transfer due to temperature difference
higher temperature —-> lower temperature
stops when two mediums reach the same temperature
Dr. Saziye Balku
16. Heat Transfer, in physics, process by which energy in the form of heat is exchanged between bodies or parts of the same body at different temperatures. Heat is generally transferred by convection, radiation, or conduction.
17. Winthrop University, South Carolina
Temperature difference: Energy always moves from higher temperature regions to lower temperature regions
Energy-form conversion: Transfer of heat by doing work
Three mechanisms for heat transfer due to a temperature difference
Natural flow is always from higher temperature regions to cooler ones
18. Heat Transfer: Transmission of energy from one region to another as a result of a temperature difference between them. Energy transfers from high temperature region to low temperature region. (2nd law).
19. Heat transfer in engineering consists of the transfer of enthalpy because of a temperature difference. Enthalpy is the name for heat energy, to distinguish it from other sorts, such as kinetic energy, pressure energy, useful work. There has to be a temperature difference, or no heat transfer occurs. (If we insist on moving enthalpy from a cold body to a hotter one, we will have to do extra work, as in the case of a refrigerator. This invariably involves some other process, such as mechanical work, and cooling by expansion of gases, but within the overall activity heat transfer always goes from the hotter to the cooler.) The temperature difference is called the driving force. Other things being equal, a greater temperature difference will give a greater rate of heat transfer.
20. Heat is energy or more precisely transfer of thermal energy. As energy, heat is measured in watts (W) whilst temperature is measured in degrees Celsius (°C) or Kelvin (K). The words “hot” and “cold” only make sense on a relative basis. Thermal energy travels from hot material to cold material. Hot material heats up cold material, and cold material cools down hot material. It is really that simple. When you feel heat, what you are sensing is a transfer of thermal energy from something that’s hot to something that is cold. http://www.g9toengineering.com/resources/heattransfer.htm
21. Modes of Heat Transfer
Heat transfer can be defined as the transmission of energy from one region to another as a result of temperature difference. Heat conduction is due to the property of matter which causes heat energy to flow through the matter. Heat convection is due to the property of moving matter (naturally or under force) to carry heat energy from higher temperature region to low temperature region. Heat radiation is due to the property of matter to emit and absorb different kinds of electro-magnetic radiation.
22. Fundamentals of Heat Transfer
1st and 2nd Laws of Thermodynamics
The 1st Law of Thermodynamics involves the conservation of energy. It states that – within a closed system where no other energy material can enter or leave – energy can neither be created nor destroyed. Although energy cannot be created or destroyed, it can be transferred to work other forms of energy.
Transferring heat energy is subject to the 2nd Law of Thermodynamics. The 2nd Law (again applying to a closed system) says that – for a spontaneous process – there is a net increase in entropy (i.e., a measure of the disorder that exists in a system).
Three alternate but equivalent ways to describe the 2nd Law are:
1. Heat flows spontaneously from a hot body to a cool one. (Example: A hot microprocessor or laser diode is cooled by flow of heat into heat sink or cold plate.)
2. It is impossible to convert heat completely into useful work. (Example: In a combustion engine, a certain heat component must always be exhausted without performing work.)
3. Every isolated system becomes disordered in time. (Example: In conduction when hot and cold bodies first contact each other, the system is somewhat ordered. Hotter molecules move faster than cooler molecules. But, once the entire system attains a uniform temperature, this order is lost.)
Expressed in mathematical terms, any of the above statements imply the other two.
The 1st and 2nd Laws of Thermodynamics govern the various modes of heat transfer: conduction, convection and radiation.
In radiation, heat flows from a higher temperature body to a lower temperature body when the bodies are separated in space, even across a vacuum.
23. University of Nebraska, Physics Department
When an object is in equilibrium with its surroundings, it radiates and absorbs at the same rate. Its temperature will not change.
24. Valdosta State University, Georgia
Heat is a form of energy whose magnitude depends on the total energy of motion of the molecules within a substance or object.
Temperature is a measure of the average energy of motion of the molecules within a substance or object. It is an indicator of the tendency of a substance to transfer heat energy since heat energy always moves from higher temperature to lower temperature.
25. Students will understand that, on its own, heat travels only from higher temperature object/region to lower temperature object or region. Heat will continue to flow in this manner until the objects reach the same temperature.
Heat energy is the disorderly motion of molecules. Heat can be transferred through materials by the collisions of atoms or across space by radiation. If the material is fluid, currents will be set up in it that aid the transfer of heat. To change something’s speed, to bend or stretch things, to heat or cool them, to push things together or tear them apart all require transfers (and some transformations) of energy. Heat lost by hot object equals the heat gained by cold object.
26. Boston University, Physics Department
Heat transfer in general
We’ve looked at the three types of heat transfer. Conduction and convection rely on temperature differences; radiation does, too, but with radiation the absolute temperature is important.
27. National Oceanography Centre, University of Southampton UK
Heat flows from a region of high temperature to a region of low temperature. Heat transfer occurs by three main methods: Conduction and convection, which require matter (atoms/molecules) to provide a pathway for heat transfer, and radiation, which does not.
28. California Institute of Technology, Infrared Processing and Analysis Center
How Does Heat Travel?
Heat can be transferred from one place to another by three methods: conduction in solids, convection of fluids (liquids or gases), and radiation through anything that will allow radiation to pass. The method used to transfer heat is usually the one that is the most efficient. If there is a temperature difference in a system, heat will always move from higher to lower temperatures.
…Objects emit radiation when high energy electrons in a higher atomic level fall down to lower energy levels. The energy lost is emitted as light or electromagnetic radiation. Energy that is absorbed by an atom causes its electrons to “jump” up to higher energy levels. All objects absorb and emit radiation.
When the absorption of energy balances the emission of energy, the temperature of an object stays constant. If the absorption of energy is greater than the emission of energy, the temperature of an object rises. If the absorption of energy is less than the emission of energy, the temperature of an object falls.
IN summary, I can no longersee how we got it into our heads that the earth’s surface temperature is due to the IR-response of a few trace gases, a response which immediately ceases when the stimulus is turned off! Via conduction and convection, an atmosphere merely makes a heated surface cooler than it would be otherwise. In addition, a planet’s liquids or solids lose heat over a 2-dimensional area, whereas a gas radiates in 3 dimensions. This geometrical factor alone handicaps the ability of a gas to conserve thermal energy, irrespective of how relatively massless it is.
Detail of UN/IPCC illustration http://www.ilovemycarbondioxide.com/FAQ.html