Posted on: January 20, 2020 Posted by: Rushik Gajjar Comments: 0
heat transfer
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This news is very deeply technological knowledge needed but we can understand it by easy way of some examples. Be focus, it is a very interesting material research developed by Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz and the University of Bayreuth, Germany.

First of all things to know about news technology, we will understand some basic physics concept that makes you more interesting in technical knowledge.

So, Let`s see some brief fundamental behind technical theories.

What is Heat Conduction ?

A Wonderful Hybrid Material Developed Is Both Heat-Conducting  and Heat-Insulating  at the Same Time 1
Heat Transferring from one side to another – Heat Conduction

Heat conduction (or thermal conduction) is the movement of heat from one object to another one that has different temperature when they are touching each other.

Conduction is the transfer of heat between substances that are in direct contact with each other. The better the conductor, the more rapidly heat will be transferred. Metal is a good conduction of heatConduction occurs when a substance is heated, particles will gain more energy, and vibrate more

Everyday Examples of Heat or Thermal Conduction

  • A metal spoon becomes hot from the boiling water inside the pot.
  • A radiator is a good example of conduction. Anything placed on the radiator, like an article of clothing, will become warm.
  • After a car is turned on, the engine becomes hot. The hood will become warm as heat is conducted from the engine to the hood.
  • If you are cold and someone holds you to warm you, the heat is being conducted from their body to yours.
  • An ice cube will soon melt if you hold it in your hand. The heat is being conducted from your hand into the ice cube.
  • Light bulbs give off heat and it you touch one that is on, your hand will get burned.
  • A heat exchanger uses a hot fluid to conduct heat to a cooler fluid without the two touching.
A Wonderful Hybrid Material Developed Is Both Heat-Conducting  and Heat-Insulating  at the Same Time 2

Materials that Are Good Conductors

  • Aluminium
  • Brass
  • Bronze
  • Copper
  • Gold
  • Graphite
  • Iron
  • Mercury
  • Steel
  • Silver

What is Heat Insulation ?

There are many benefits of home insulation. Insulating will add the comfort to the building, create a healthier home environment, reduce the energy bills and have a positive environmental impact. Adding home insulation to an existing home will regulate the temperature, making the living environment more enjoyable, especially in places of extreme weather. With insulation the home will become more energy efficient.

Insulation will keep the home cooler in the summer and warmer in the winter. This will reduce the amount of heating and cooling appliances that is needed to keep the house comfortable. Because of this, home insulation will reduce the energy bills and the costs of cooling and heating.

“Thermal insulators are those materials that prevent or reduce various forms of heat transfer “

Insulator resists the heat transfer from out to in or in opposite direction whether the environment temperature is high or low. There are many advantages of thermal insulation that isolates the building from the heat and reduces the energy consumption as well as the costs of air-conditioning operation. Also, it makes the indoor temperature of the building stable and non-volatile. To reduce the transmission of the heat, buildings must be isolated in order to protect it from heat loss in winter and heat gained in the summer. It is found that about 60% of heat losses directly through the ceilings and walls of the building and that about 15% through the glass and about 25% of the heat infiltrates through cracks, openings and doors.

The Advantages of Thermal Insulation

  • Reduce the amount of heat transmitted through the parts of the house.
  • Reduce the energy required for heating or cooling the house.
  • Make the internal temperature of the building stable, non-volatile.
  • Keep the temperature of the building elements stable thus long time life.
  • Reduce energy bills.
  • Reduce the burning of fuel in power plants.
  • Reduce the emission of greenhouse gases.

The most common insulators

  • Cellulose: which is made from wood or recycled paper and is characterised by its susceptibility to water and dust absorption.
  • Cork: This is taken from cork tree. It could be made industrial from petroleum product which is called the Expanded Polystyrene (EPS). It is found in the form of panels and used as thermal and acoustic insulators.
  • Glass wool: are widely used to insulate buildings, as well as boilers and reservoirs.
  • Rock wool: This material is used to isolate the buildings and storages.
  • Polyurethane: usually uses as insulated panel or foam to fill the cracks.
  • Polystyrene cork: both types, EPS and XPS.
  • Astrofoil (XPE) layers: consist of two aluminium foils and including air bubbles which are made of polyethylene materials. The aluminium layers reflect the solar radiations in the summer while the air bubbles reduce the heat transfer through the walls because of high air isolation. This material is a good insulator against the water and air leaks.
  • Poly-carbonate panels: These sheets are lightweight panels, and are composed of several layers to be able to withstand the shocks with the presence of air cavities for the purposes of thermal insulation.
  • Reflective materials: such as aluminium panels, alu-cobond and reflective paints. These materials are used to reflect solar radiation on the exterior walls.
  • Fire retardant sheets: are wooden panels characterised by their ability to delay the fire growth in addition to the thermal insulation ability.

The newly developed material conducts heat well along the layers, while at the same time providing thermal insulation vertically.

A Wonderful Hybrid Material Developed Is Both Heat-Conducting  and Heat-Insulating  at the Same Time 3

Styrofoam or copper – both materials have very different properties with regard to their ability to conduct heat. Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz and the University of Bayreuth have now jointly developed and characterised a novel, extremely thin and transparent material that has different thermal conduction properties depending on the direction. While it can conduct heat extremely well in one direction, it shows good thermal insulation in the other direction.

Thermal insulation and thermal conduction play a crucial role in our everyday lives – from computer processors, where it is important to dissipate heat as quickly as possible, to houses, where good insulation is essential for energy costs. Often extremely light, porous materials such as polystyrene are used for insulation, while heavy materials such as metals are used for heat dissipation.

A newly developed material, which scientists at the MPI-P have jointly developed and characterized with the University of Bayreuth, can now combine both properties.

“We use X-rays to illuminate the material,” says Breu. “By superimposing these rays, which are reflected by the individual layers, we were able to show that the layers could be produced very precisely.”

Prof. Fytas, member of Prof. Hans-Jürgen Butt’s department, was able to give an answer to the question why this layer-like structure has such extraordinarily different properties along or perpendicular to the individual glass plates. Using a special laser-based measurement, his group was able to characterise the propagation of sound waves, which is like heat also related to the movement of the material’s molecules. “This structured yet transparent material is excellent for understanding how sound propagates in different directions,” says Fytas.

The different sound velocities allow direct conclusions to be drawn about the direction-dependent mechanical properties, which are not accessible with any other method.

In their further work, the researchers hope to gain a better understanding of how sound and heat propagation can be influenced by the structure of the glass plate and the polymer composition. The researchers see a possible application in the field of high-performance light-emitting diodes, in which the glass-polymer layer serves on the one hand as a transparent encapsulation and on the other hand can dissipate the released heat laterally.

Good thermal insulation is observed perpendicular to the layers. In microscopic terms, heat is a movement or oscillation of individual molecules in the material that is transferred to neigh-boring molecules. By building up many layers on top of each other, this transfer is reduced: Each new boundary layer blocks part of the heat transfer. In contrast, the heat within a layer can be conducted well – there are no interfaces that would block the heat flow. Overall, the heat transfer within a layer is 40 times higher than perpendicular to it.

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