Applications of heat transfer

Applications of Heat Transfer

CONDUCTION

CONVECTION

RADIATION

Applications of convection

• You might be surprised to know that warm-blooded animals employ convection to regulate the temperatures of the body. The human heart is a pump and blood circulation in the human body is an example of forced convection. The heat which is generated by the cells in the body is transferred to air or water which is flowing over the skin.

Land and Sea breeze

• In the afternoon, the surface of the land near the sea is warmer as compared to in the evening. Convection causes the air, which is closer to the land surface, to heat and, hence, rise. This warm air near the land is readily replaced by the cool air resulting in “Sea Breeze.”

• When its night, the tendency of land to cool down is more. However, the air above the sea water is warm and, therefore, rises up. Once this air rises, it is replaced by the cool air from the land, which is commonly referred to as “Land Breeze.”

Air Conditioning System

• The process of cooling air in air-conditioners employs the very principle of convection. The air which is cold is released by the air-conditioners. Now, this cold air is denser than the warm air, and, hence, it sinks. The warm air, being less dense, rises and is drawn in by the air-conditioner. As a result, a convection current is set up and the room is cooled

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Refrigerator

• The freezer, in case of refrigerators, is placed at the top. As mentioned above, the warm air, being less dense, rises up and, hence, it is cooled down by the freezer. Now, this cool air, being denser, sinks and, therefore, keeps the lower part of the fridge cool

Hot Air Balloon

• The reason why hot air balloons are able to rise up is because of the principle of convection. You might have seen the heater at the base of the balloon. This heater heats up the air, which moves upwards. The hot air which rises get trapped inside the balloon, and, hence, causes the balloon to rise up too. When the landing of the hot air balloon has to take place, some of the hot air is released by the pilot. The cold air replaces the hot air released; therefore, the balloon lowers.

Applications of Radiation

The old television sets emit x-ray waves which can easily be absorbed by the human body, and is harmful as well.

Microwave

• To heat food in a microwave oven, high levels of radiation are employed. Food in the microwave oven is heated when microwaves are absorbed by the water content present in the food. Absorption of the microwaves causes water molecules to vibrate and, hence, produce heat

Mobile Phone

• The exposure to radio-frequency radiation causes heating of the area of the body where a mobile phone is being held like near the ear. However, the amount of heat radiated is not sufficient to increase the temperature of the body.

Wifi Router

• wifi routers also emit electromagnetic radiations. The exposure to such electromagnetic radiations can also have consequences on human health.

Bond fire

• While sitting around the campfire, you are exposed to radiations. Same happens when you light a candle. Exposure to fire also leads to exposure to radiations.

• The heat that is radiated from the fire is due to infrared radiation which is a part of the EM spectrum. This section of the spectrum is less energetic than visible light. Our eyes are not sensitive to this type of radiation but it can be felt on our skin as heat. This is how we feel the heat from the sun, even though it is very far away.

  
  

  
  

Applications of Conduction

When a car is started on a cold day, it is best to let the engine heat up before trying to drive. This heat helps the fluids in the engine become more liquid, and helps components like the fan and drive belts be more malleable and less prone to snapping. After the engine has run for a few minutes, the hood of the car will feel warmer to the touch. Any frost or snow on the hood may begin to melt.

Ironing

• A shirt is placed on an ironing board to be ironed. Heat from the iron is conducted to the shirt, making it easy to iron out all those unsightly wrinkles and make the shirt look sharp

Ice Cube

• A cube of ice is placed into the hand of a man. Over time, heat conducted from the man's hand to the ice cube will cause the ice to melt.

Check out the video

https://www.youtube.com/watch?v=YK7G6l_K6sA