Energy will not flow spontaneously from a low temperature object to a higher temperature object..the Second Law of Thermodynamics states that heat will spontaneously always flow from a hot region to a cold region. REFRIGERATOR . Fruits juices are also require refrigerators to maintain their nutrition value and taste. Some major application of the refrigerator are given as follow. The system maintained at lower temperature is known as refrigerated system. 2 nd Law of Thermodynamics; The second law of physics you need to know is the 2 nd Law of Thermodynamics: If you paid attention in school, you might remember that the second law of thermodynamics states that heat flows from hotter to colder bodies naturally. heart pump blood in whole body same as compressor regulate the refrigerant in whole unit by increasing the pressure of the working fluid i.e. When we keep something on the refrigerator, the evaporator tube … A Condenser rejects the heat from working fluid (refrigerant) by means cooling coils made up of copper into the atmosphere used in case of domestic refrigerator. 1. These types of devices are used to control the temperature in the refrigerator. As a result of the cyclical repetition of this process, the load is cooled. 2. Like a heat engine, refrigerators are cyclic devices. A typical Refrigerator working principle. In a refrigerator, the working substance absorbs an amount of heat Q 2 from the cold reservoir at temperature T 2.An amount of work W is done on it by some external agency (a compressor pump driven by an electric motor) and rejects a larger quantity of heat Q 1 to the source at temperature T 1 as shown in the fig. Nowadays refrigerators are used to preserve food. Ice can be easily manufactured by using domestic refrigerators for domestic use. A Copyright © 2018-2021 BrainKart.com; All Rights Reserved. Ice was manufactured in plants by dipping water containers in chilled brine for some time. The compressor constricts the refrigerant vapor, raising its pressure, and pushes it into the coils on the outside of the refrigerator. It is shown in the figure 8.49. A portable air conditioner (i.e. When the refrigerant enters into the evaporator, it absorbs heat from the storage space and evaporates. In the same way a liquid (called as refrigerant) at low temperature is allow to pass through the fridge compartment. refrigerator has COP of 3. this equation into equation (8.70) we get. In fixed opening type the flow area remains fixed, while in variable opening type the flow area changes with changing mass flow rates. The term heat pump is usually reserved for a device that can heat a house in winter by using an electric motor that does work W to take heat Q cold from the outside at low temperature and delivers heat Q hot to the warmer inside of the house. Working of Refrigerator and Refrigeration Principle. By the first law of thermodynamics, the denominator of the expression is Q 2 − Q 1, and for a reversible Carnot cycle, the entropy in equals the entropy out, so that Q 2 /Q 1 = T 2 /T 1. We can regulate and control the temperature of refrigerator using expansion devices by varying the opening as per our requirements. There are four parts (Expansion Valve, compressor, evaporator, condenser) and all are connected with copper or steel tubes. The growth of bacteria is reduced at low temperature. The vapour compression refrigeration system (VCRS) is most commonly used in refrigeration. Thermodynamic cycle is essentially a closed cycle in which the working substance undergoes a series of processes and is always brought back to initial state. The general working principle of a magnetic refrigerator is as follows: the working material (refrigerant) absorbs heat from the load at a low temperature (the cold heat exchanger) and transfers it to the high temperature source (hot end heat exchanger). A wide variety of refrigerants can be used in these systems as per different applications and capacities. Read More » Earlier food was preserved by traditional methods like salting and pickling which were not always practical. Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. This process includes a phase change process which maximizes the cooling effect. Air Conditioning 101: The … Some perishable items like fruits and vegetable are rotten on high temperature because some kinds of bacteria are grow very rapidly in them. Long-term storage requires storage at -25oC. The vapor-compression refrigeration cycle is the most common cycle. Refrigerant comes from throttling device enters into the evaporator at very low temp and pressure. A good refrigerant must have some qualities like it should be non-toxic, non-explosive, non-corrosive; non-inflammable and leakage should be non-inflammable etc. at a lower temperature TL. The basic functions of an expansion device used in refrigeration systems are to reduce the pressure of working fluid which comes from condenser and goes into the evaporator. The working fluid is colder than the refrigerator air at one point and hotter than the surroundings at another … to maintain a system or body at a temperature lower than that of its surrounding (atmospheric temperature). In the refrigeration cycle, there are five basic components: a fluid refrigerant; a compressor, a condenser coil, an evaporator coil, and an expansion device. is ejected to surrounding air and total entropy of (refrigerator + surrounding) The law states that if a cold object is placed next to a hot object, the cold object will become warmer and the hot object will become cooler. these are examples of two principles addressed by the 2nd law of thermodynamics: 1. some processes can occur spontaneously only in one direction. After condensing refrigerant goes into the expansion devices. Refrigerant absorbs heat from the food items. Study Material, Lecturing Notes, Assignment, Reference, Wiki description explanation, brief detail. 0. Our home and work environments are unthinkable without the many devices that are powered by electricity: light, microwave and stove, freezer and refrigerator, television and radio, DVD and bluray, CD and MP3 player, smartphone and telephone landline, computer and printer, washer and dryer, air conditioning and (sometimes) heat, power drill and lawn mower; the list goes on. refrigerant. Another important application of second law of thermodynamics is found in refrigerators and heat pumps, which are based on the principle of reversed Carnot cycle or reversed Carnot theorem. You can only transfer heat from a colder body to a warmer body through some kind of external work. To maintain good quality of other dairy products like butter, curd and ice cream they also require refrigerators. Thermodynamics’ first law explains that energy cannot be neither created nor destroyed, but can be changed from one form to another. The vapour compression refrigeration system (VCRS) is most commonly used in refrigeration.