The second law of thermodynamics claims that it is impossible for heat to spontaneously flow from a cold body to a hot body, but it can move in that way if some form of work is done. This is how the refrigeration process works, and an example can be seen in Figure 1.
What is the working principle of refrigerator?
EXPLANATION: The basic principle is that whenever a liquid coolant is passed through things at a higher temperature, it absorbs the heat; gets evaporated and the cooling effect is produced. The Refrigerator works on the principle of evaporation.
What is a refrigerator in physics?
A refrigerator is a heat engine in which work is done on a refrigerant substance in order to collect energy from a cold region and exhaust it in a higher temperature region, thereby further cooling the cold region.
What is a refrigerator in thermodynamics?
A refrigerator is a device which is designed to remove heat from a space that is at lower temperature than its surroundings. The same device can be used to heat a volume that is at higher temperature than the surroundings. In this case the device is called a Heat Pump.
Which gas is used in refrigerator?
Modern refrigerators usually use a refrigerant called HFC-134a (1,1,1,2-Tetrafluoroethane), which does not deplete the ozone layer, unlike Freon. R-134a is becoming much rarer in Europe. Newer refrigerants are being used instead.
What are the three laws of refrigeration?
- Heat causes refrigeration in vapor absorption refrigeration.
- On decrease of pressure, the boiling temperature decreases.
- Heat naturally flows higher temperature to low temperature.
- Clausius statement of second Law of Thermodynamics.
What is a refrigerator Class 11?
A refrigerator is a device which works on the principle that evaporation of a liquid gives a cooling effect.
What is the process of refrigeration?
refrigeration, the process of removing heat from an enclosed space or from a substance for the purpose of lowering the temperature.
What are the 5 parts of refrigerator?
The main working parts of a refrigerator include a compressor, a condenser, an evaporator, an expansion valve, and a refrigerant.
What is unit of refrigeration?
Unit of refrigeration: Unit of refrigeration is TR (Ton of refrigeration). It is the amount of heat which is required to extract from one tonne of water at 0°C in order to convert it into equivalent ice at 0°C in a day.
What type of energy is a refrigerator?
Answer and Explanation: Refrigerators use electricity, which is then turned into kinetic energy by fans.
Why is it called a refrigerator?
The word refrigerator originates from the Latin verb refrigerare which was derived from the Latin adjective frigus, meaning cold.
What is refrigerator and its uses?
A refrigerator is an open system that dispels heat from a closed space to a warmer area, usually a kitchen or another room. By dispelling the heat from this area, it decreases in temperature, allowing food and other items to remain at a cool temperature.
What is the first law of refrigeration?
The underlying physics principle of mechanical refrigeration is the first law of thermodynamics. This law states that energy — or heat in this case — cannot be created or destroyed, only transferred from one place to another, and that it requires work to cause the transfer of energy.
Why is heat pump called refrigerator?
A heat pump is simply a refrigerator where the inside of the refrigerator is outside the house. In other words, a heat pump attempts to cool down the air outside the building, and in the process heats up the air inside the building.
Who invented refrigerator?
In 1913, American Fred W. Wolf invented the first home electric refrigerator, which featured a refrigeration unit on top of an icebox. Mass production of domestic refrigerators began in 1918 when William C. Durant introduced the first home refrigerator with a self-contained compressor.
Is CFC used in refrigerator?
CFCs have recently been phased out and newer refrigerators will not contain CFCs. In the 1980s it was a concern that fridges and freezers containing chlorofluorocarbons were destroying the ozone layer. The use of CFCs was phased out by 2000 under the Montreal Protocol.
Who discovered refrigeration?
Carl von Linde, a German scientist, invented a portable compressor refrigeration machine using methyl ether in 1873, and in 1876 switched to ammonia.
What is entropy in refrigeration?
Entropy is the work performed during the phase change. It is the quickening and separation of the molecules as they adopt a gaseous form. The opposite is true for the condenser.
Does a refrigerator decrease entropy?
Entropy inside a refrigerator decreases (at least while cooling down).
How does refrigerant get cold?
When the Freon gas is compressed, its pressure rises, making it very hot. Next, the hot Freon gas moves through a series of coils, which has the effect of lowering its heat and converting it to liquid. The Freon liquid then flows through an expansion valve, which causes it to cool down until it evaporates.
What is the efficiency of a refrigerator?
Refrigerators can use 2.5 percent more energy for each 1 degree over normal ambient room temperature (70 degrees). This means your refrigerator could use 22 to 25 percent more energy in an 80-degree room, and 45 to 50 percent more in a 90 degree room.
What is difference between heat pump and refrigerator?
A refrigeration system cools the external fluid flowing through the evaporator, whereas a heat pump heats the external fluid flowing through the condenser. The main difference between a refrigerator and a heat pump is in the manner of operation regarding cooling or heating.
What is the principle of refrigerator or heat pump?
Heat pumps move thermal energy in the opposite direction of spontaneous heat transfer, by absorbing heat from a cold space and releasing it to a warmer one; however, a refrigerator is a household appliance that is passed a cooler temperature than the external environment.
What are the 4 process of refrigeration?
A refrigeration cycle has four major components: the compressor, condenser, expansion device, and evaporator. Refrigerant remains piped between these four components in the refrigerant loop.