Jun 07, 2015 a fluid, known as a refrigerant, moves between four key stages in refrigeration cycle. The refrigeration cycle is a critical component of hvac systems and is governed by the principles of thermodynamics. Refrigeration cycle animation vapor compression cycle. If an expander had been used the line from d to a would be a vertical line. Components and working of the gas refrigeration cycle. Thermodynamics tutorial 5 heat pumps and refrigeration on completion of this tutorial you should be able to do the following. When 1 pound of ice melts, it absorbs 144 btu, as latent energy.
Vapor compression refrigeration cycle ppt xpowerpoint. The above figure shows the objectives of refrigerators and heat pumps. Vapor compression, absorption, gas cycle, steam jet and thermoelectric, of which the most popular is the vapor compression cycle. Goals of lab to get acquainted with a vaporcompression refrigeration system to be able to use pressureenthalpy diagrams and. The refrigeration cycle tells us if there is air in the central air conditioner units, what to repair after troubleshooting the refrigeration system, if there is enough air conditioner freon, or if the ac filter is dirty. Refrigeration cycle animation vapor compression cycle explained. In todays lesson on hvac training i will be covering the refrigeration cycle and the 4 main components that make the cycle work. Cycle with undercooling or subcooling of refrigerant. The change of temperature causes the refrigerant to flash or boil, and changes from a low pressure liquid to a low pressure cold vapor. Introduction a major application area of thermodynamics is refrigeration, which is the transfer of heat from a lower temperature region to a higher temperature one. Refrigeration cycle tutorial university of oklahoma.
However, in vcrs mechanical work is required as input so it is called work operated cycle and unlike vcrs the required input in vars is low grade thermal energy so, called heat. Vapour absorption refrigeration system with diagram. Zubair latif comsats institute of information technology, lahore 2. This article describes and illustrates the basics of the refrigeration cycle. A refrigerator or heat pump that acts on the reversed carnot cycle is called a carnot refrigerator and carnot heat pump respectively. Sep 23, 20 this is the beginning of the basic refrigeration cycle training. Vaporcompression refrigeration, in which the refrigerant undergoes phase changes, is one of the many refrigeration cycles and is the most widely used method for airconditioning of buildings and automobiles. For a refrigeration cycle to work, it requires five main components. Learning outcomes demonstrate understanding of basic vaporcompression refrigeration and heat pump systems. As refrigerant in the latent state or as vapor refrigerant in the process of changed state to liquid, this is the phase where it absorbs or rejects large quantities of heat. As it does so, it changes in pressure and temperature, this allows the fluid to absorb heat from one place and discharge it in another. View and download powerpoint presentations on vapor compression refrigeration cycle ppt. Of these, the reversed brayton cycle, which is also known as the gas refrigeration cycle. Hvac the refrigeration cycle hvac training for beginners.
Chapter 11 refrigeration cycles study guide in powerpoint to accompany thermodynamics. The five commercially available refrigeration cycles are. When the gas is throttled from very high pressure to low pressure in the throttling valve, its temperature reduces suddenly while its enthalpy remains constant. This rejection of heat from low level to higher level of temp. So refrigeration cycle should be known to understand the refrigeration system. Two different pressures exist in the refrigeration cycle. For an air conditioning system to operate with economy, the refrigerant must be used repeatedly. Prove that the area of inside the cycle plus the shaded. This video is part of the heating and cooling series of training videos made to accompany my websites. Irreversibility includes pressure drops in lines and heat exchangers, heat transfer. The ideal vaporcompression cycle consists of four processes.
Vars is also belongs to class of vapor cycle is similar to the vcrs. Remember refrigeration cycle diagram will always have the same basic components compressor, condenser, expansion device, evaporator, and refrigerant tube. Liquids absorb heat when changed from liquid to gas. Consider the real cycle taking place outside the two phase region using a compressor and an expander. It is also used in domestic and commercial refrigerators, largescale warehouses for. The vapour compression refrigeration cycle is classified as follows. Cycle with dry saturated vapour after compression, 2. This is what happens to keep the refrigerator cool. Devices that produce refrigeration are called refrigerators, and the cycles on which they operate are called refrigeration cycles.
The evaporator or low pressure, in the low side and the condenser, or high pressure. Cascade cycle is used where a very wide range of temperature between tl and th is. Article transcritical refrigeration systems with carbon dioxide co 2 danfoss as ra marketingmwa, july 2008 dkrci. Ppt refrigeration basics 101 powerpoint presentation.
A heat pump can be thought of as a heat engine which is operating in reverse. At this stage in the refrigeration cycle, high pressure liquid refrigerant will flow down the liquid line, through a filter drier that is designed to prevent contaminants from flowing through the system, and on to the metering device. It raises the pressure, temperature and enthalpy of the refrigerant by compressing the saturated gas, in an isentropic process, to a superheated. Purpose of refrigeration examples and applications choice of coolant and refrigerants phase diagram of water and co 2 vapor compression refrigeration system pressureenthalpy diagram for refrigerants refrigerator, air conditioner, thermoelectric cooler, heat pump designation, choice, criteria for selection, and. The bell coleman cycle also called as the joule or reverse brayton cycle is a refrigeration cycle where the working fluid is a gas that is compressed and expanded, but does not change phase. Ppt refrigeration basics 101 powerpoint presentation free. The vapor compression cycle explained is the most common type of system used in refrigeration. Ppt refrigeration free download as powerpoint presentation. While some people have viewed this method as environmentally harmful and inefficient, the cycle is still applicable in the industrial sphere.
Explains each step in a refrigeration cycle and the energy balance for each step. Compression refrigeration cycle the vaporcompression refrigeration is the most widely used cycle for refrigerators, airconditioners, and heat pumps. Fundamentals of mechanical refrigeration systems course content introduction mechanical refrigeration is a thermodynamic process of removing heat from a lower temperature heat source or substance and transferring it to a higher temperature heat sink. The refrigerator in your kitchen uses a cycle that is similar to the one described in the previous section. A simple and practical absorption system using ammonia as refrigerant and water as absorbent described in the previous articles is an example of singleeffect cycle system for vapour absorption refrigeration system. Air is the most commonly used gas, also called as refrigerant in this case, in the gas refrigeration cycles. The compressor is widely considered the engine of the refrigeration cycle. Refrigeration cycle refrigeration is the transfer of heat from a lower temperature region to a higher temperature region refrigeration cycle is the vaporcompression refrigeration cycle, where the refrigerant is vaporized and condenses alternately and is compressed in the vapor phase. A free powerpoint ppt presentation displayed as a flash slide show on id. The evaporator the evaporator is where the heat is removed from your house, business or refrigeration box. Vapor compression refrigeration system basic, working, parts of system introduction. Bahrami ensc 461 s 11 refrigeration cycle 6 cascade refrigeration cycle systems that have 2 or more refrigeration cycles operating in series. The compressor the condensing coil the metering device the evaporator 3. The refrigeration system is designed so that the refrigerant will evaporate in the evaporator at a temperature thats about 10 to 15 below the temperature setting if its a refrigerator or freezer, and the temperature will drop to around 0 in the evaporator of an ice machine or ice cream machine.
The basic refrigeration cycle is similar for many refrigeration and air. The refrigerant is a heat carrying medium which during their cycle in a refrigeration system absorbs heat from a low temp. Refrigeration cycles the vapor compression refrigeration cycle is a common method for transferring heat from a low temperature to a high temperature. In the first stage of this cycle process 12, the refrigerant absorbs heat. In this video we look at how a refrigeration cycle works and use colour coding to see how the temperature and pressure changes throughout a. Heat pump and refrigeration cycles can be classified as vapor compression, vapor absorption, gas cycle, or stirling cycle types. Cycle with superheated vapor before compression, 5. Thermodynamic system thermodynamic functions thermodynamic properties fundamental laws of. The components of the gas refrigeration cycle are very similar to the vapor compression cycle. Prove that this cycle is less efficient than the carnot cycle. Just as the vapors are used for cooling in the vapor compression cycle and vapor absorption cycle, the gas is used for cooling in gas refrigeration cycle.
To cool the refrigerant down it is passed through the expansion valve, this will reduce the pressure of the refrigerant by. The operating principle of the refrigeration cycle was described mathematically by sadi carnot in 1824 as a heat engine. In the past, this was done by collecting ice in the winter and using its specific heat to cool as the ice melted. The vapor compression refrigeration cycle is a common method for transferring heat from a low temperature to a high temperature. The cooler refrigerant in the evaporator tubes, absorb the warm room air. These components may be in difference shape, capacity and size, but it does the same thing. The vapor compression refrigeration cycle, step by step.
A refrigeration cycle explained involves the cooling system process of refrigerators and air conditioners. Referring to the illustration below, beginning the cycle at the evaporator inlet 1, the lowpressure liquid expands, absorbs heat, and evaporates, changing to. Basic refrigerator principle is reverse carnot cycle. Ph diagram representation of a dry refrigeration cycle. The process is shown in a pressureenthalpy diagram. It is then throttled to the evaporator pressure and vaporizes as it absorbs heat from the refrigerated space. Of these, the reversed brayton cycle, which is also known as the gas refrigeration cycle, is used to cool aircraft and. This video is an animation of how the refrigeration cycle. The purpose of a refrigerator is the removal of heat, called the cooling load, from a lowtemperature medium. Larger is the irreversibility in a refrigeration cycle operating with a given refrigeration load between two fixed temperature levels, larger is the amount of work required to operate the cycle. Find powerpoint presentations and slides using the power of, find free presentations research about vapor compression refrigeration cycle ppt. Unit of refrigeration the unit of refrigeration is ton of refrigeration or simply ton denoted by tr. Mechanical refrigeration is accomplished by continuously circulating, evaporating, and condensing a. The refrigeration cycle collects this heat by sending the refrigerant at a low temperature and pressure into the evaporator within that room.
The main components there are four main components in a refrigeration system. The gas flows through the compressor where its pressure and temperature becomes very high. Air refrigeration systems authorstream presentation. The concepts of the refrigeration cycle is the same concept with a car air conditioner, your homes hvac and many other applications. The vapor compression refrigeration cycle is nearly 200 years old, but it does not seem ready to leave the scene any time soon. Th movement cooling by the removal of heat the movement of heat from a place where it is notot a ted to a wanted to a. Basic refrigeration cycle nina sri maulani 121624023 tptu 2012 2.
By far the most common method of refrigeration is the vaporcompression refrigeration cycle a. In the following example, we will assume that the refrigerant being used is pure ammonia, which boils at 27 degrees f. The compressor does work on the refrigeration system consumes energy. Refrigeration cycle it is a well known fact that heat flows in the direction of decreasing temperature, i.
The basic refrigeration cycle for beginners if you are interested in learning how a refrigeration system works, it is helpful to understand from the ph pressure enthalpy chart perspective. One ton of refrigeration means amount of heat required to remove from one short ton of water at 00c to produce ice at 00c at 24 hours. Evaporator the vaporcompression refrigeration cycle eq. Transfer heat from a cold space reservoir to a hot one. Yeah, it seems complicated at first, but it will be easier to understand. Compressor basic refrigeration cycle evaporator condenser receiver expansion device. Jun 25, 2003 mechanical refrigeration is accomplished by continuously circulating, evaporating, and condensing a fixed supply of refrigerant in a closed system. Oct 12, 2012 this video is an animation of how the refrigeration cycle works, with each components function. Vapor compression refrigeration system basic, working.
When this happens, it is called a reversed carnot cycle. Vapour compression refrigeration system refrigeration vapour. If we understand how the refrigeration cycle works, well understand how any air conditioner works. Special university course for future engineers lecture notes. In the process of being compressed the cool, gaseous refrigerant is turned to. A common alternate unit is the ton of refrigeration which equals 200 btumin or about 211 kjmin. Eric nelson basics refrigeration is the removal of heat from a material or space, so that it s temperature is lower than that of it s. Some basic refrigeration cycles are discussed here through different diagrams.
Refrigeration basics and lng university of oklahoma. The vapor compression refrigeration cycle is virtually rankine cycle with the only difference that. Gases give off heat when changed from gas to liquid. Goals of lab to get acquainted with a vaporcompression refrigeration system to be able to use pressureenthalpy diagrams and tables to determine the c. The schematic sketch of doubleeffect system is shown in fig.
The refrigeration cycle explained in plain english. Air cycle refrigeration systems are employed for air conditioning the cockpit and cabin space of an airplane. Refrigerators, heat pumps, acs cycles commonly classified as. The refrigeration cycles can also be represented in a ph diagram. Refrigeration vaporcompression cycle online training. Refrigeration is used in many different residential, commercial, and industrial applications, ranging from food preservation to air conditioning to liquefaction of gases like oxygen and propane. Refrigeration cycle is the basis of all refrigeration systems. But before i get into this hvac training i want to go over the three ways that heat can be transferred, and yes there are only 3 ways that heat can be. Power and refrigeration cycles another look ppt presentation summary. Essentially, heat is taken from a body at lower temperature, say the food you want to store in the refrigerated chamber.
7 1111 1372 735 1212 1123 1486 226 832 1021 490 610 371 762 117 126 54 590 634 795 327 913 259 50 496 806 1252 135 1017 568