Refrigeration system an overview sciencedirect topics. A refrigeration cycle explained involves the cooling system process of refrigerators and air conditioners. Vapor compression refrigeration systems are used for a variety of coolingrefrigeration applications. Vapor compression 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.
In a vapor compression cycle, the refrigerant immediately after expansion valve is a liquid b subcooled liquid c saturated liquid d wet vapour e dry vapour. Jan 11, 2018 basic vapor compression cycle, the carnot cyclefour main elements are required to complete the basic refrigeration cycle, a compressor, a condenser, a metering device expansion valve in this case, and an evaporator, all labeled below in the system diagram along with connecting components. Absorption cycle vapor compression cycle during the compression cycle, the refrigerant passes through four major components within the chiller. Evaluate the performance of innovative vaporcompression. Vapor compressionexpansion absorption steam jet watervapor compression by using the pressureenthalpy ph diagram, the refrigeration cycle can be broken down into four distinct steps. Refrigeration cycle is the basis of all refrigeration systems. Actual vapour compression cycle watch more videos at. The vapor compression cycle in aircraft airconditioning. The vapor compression cycle is most widely used for the refrigeration purposes. The vapor compression cycle is made possible because the refrigerant is a fluid that exhibits specific properties when it is placed under varying pressures and temperatures. Schematic diagram of simple vapor compression refrigeration system 14. The prospects of alternatives to vapor compression technology.
The vapor compression refrigeration cycle is nearly 200 years old, but it does not seem ready to leave the scene any time soon. In this paper exergetic approach is used to analysis the performance of theoretical vapour compression refrigeration cycle using r404a, r407c and r410a. The vapor compression cycle circulates a fluid through a compressor, condenser, expansion valve, and evaporator, in order to absorb heat from a refrigerated space at a low temperature and give off heat at a higher temperature to the surroundings, thus keeping the refrigerated space cool. The equations of exergetic efficiency and exergy destruction for the main system components such as compressor, condenser expansion device. Experimental study and mathematical modeling of a vapor. Refrigeration cycles the vapor compression refrigeration cycle is a common method for transferring heat from a low temperature to a high temperature. Expansion from 41 results in a very wet refrigerant, causing erosion of turbine blades. A chiller is a machine that removes heat from a liquid via a vapor compression or absorption refrigeration cycle. In this paper, the case study was extended to include an expanded search space, inclusion of utility streams and practical design criteria.
The vapor compression refrigeration cycle, step by step. Basic vapor compression cycle, the carnot cyclefour main elements are required to complete the basic refrigeration cycle, a compressor, a condenser, a metering device expansion valve in this case, and an evaporator, all labeled below in the system diagram along with connecting components. Refrigeration is the process of heat removal from a low temperature sink and added to a high temperature reservoir to. Analyze the ideal vaporcompression refrigeration cycle.
Pdf various criteria in optimization of a vapor compression. The design problem concerns the replacement of r4a refrigerant. Figure 1 typical schematic of a vapour compression refrigeration vcr cycle. A common alternate unit is the ton of refrigeration which equals 200 btumin or about 211 kjmin. 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. The prospects of alternatives to vapor compression. Vapour compression refrigeration or vapor compression refrigeration system vcrs, 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. The vapor compression uses a circulating liquid refrigerant as the medium usually r4a which absorbs and removes heat from the space to be cooled and subsequently rejects that heat elsewhere. Vapour compression cycle definite guide with video. Dynamic modeling and control of single and multievaporator.
This case study demonstrates the modeling of a vapour compression refrigeration system using r22 as refrigerant. Gandhinagar institute of technology subject applied thermal and hydraulic engineering2140907 branch electrical topic refrigeration vapour compression refrigeration system 2. Vapor compression refrigeration system basic, working, parts of system, advantages, and disadvantages introduction. Compressor basic refrigeration cycle evaporator condenser receiver expansion device. Vapor compression is currently the incumbent technology for the vast majority of space cooling and food refrigeration applications. Different types of process chillers fall under two main categories. In this cycle, the two isothermal processes of the carnot cycle is replaced by two isobaric process these changes decrease the refrigerating effect and increase the work done. The operating principle of the refrigeration cycle was described mathematically by sadi carnot in 1824 as a heat engine. The vapor compression cycle explained is the most common type of system used in refrigeration and air conditioning. Vapor compression chillers are the most common and include 1 air chillers and 2 waterfluid chillers.
System description the layout of the system is shown in figure 1. The vapor compression cycle circulates a fluid through a compressor, condenser, expansion valve, and evaporator, in order to absorb heat from a refrigerated space at a low temperature and give off heat at a higher temperature to the surroundings, thus keeping the. The purpose of a refrigerator is the removal of heat, called the cooling load, from a lowtemperature medium. The cop of a carnot vapor compression cycle is given by. Saturated mixture 100 % vapor there is no a mixture of vapor and liquid. The fonner is most commonly used and is known to carnot cycle, conceived by nicolas carnot in 1824. Layout of the r22 vapour compression refrigeration system. Both these control schemes showed good results on implementation on the validated system models. The most common types of refrigeration systems use the reverserankine vaporcompression refrigeration cycle, although absorption heat pumps are used in a minority of applications. A typical vapor compression cycle system is a closed loop system and includes a compressor, a condenser, an expansion device and an evaporator. Figure 1 is a schematic representation of the vapor compression cycle. First, evaporation is simply the process of vaporization these two terms are essentially synonymous.
The above figure shows the objectives of refrigerators and heat pumps. Refrigeration may be defined as a process of removing heat from a substance and pumping it to the surroundings. A comparative study has been carried out of r12, 22, 125, 4a, 152a, 218, 245, 500, 502, 507 and 717 as working fluids in a vapour compression refrigeration system. The vapor compression cycle in aircraft airconditioning systems.
Energy in the form of heat is required to change a substance from a liquid to gas i. Vapor compression refrigeration an overview sciencedirect. Heat pump and refrigeration cycles can be classified as vapor compression, vapor absorption, gas cycle, or stirling cycle types. The actual vapour compression cycle differs from the standard cycle due to the following reasons. Cycle with superheated vapor before compression, and 5. Chillers are further categorized by the type of compressor technology used. It is used in household refrigerators, airconditioners, water cooler, ice and ice cream makers, deep. Vapourcompression refrigeration or vaporcompression refrigeration system vcrs, 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. Layout of the r22 vapourcompression refrigeration system. The different types of cooling compressors executive summary there is much confusion in the marketplace about different compressor types and their characteristics. A chiller is a machine that removes heat from a liquid via a vaporcompression or absorption refrigeration cycle.
Evaporator compressor condenser expansion valve most common refrigeration cycle in use today all energy transfers by work and heat are taken as positive in the directions of the arrows on the schematic and energy balances are written. A heat pump can be thought of as a heat engine which is operating in reverse. Its cop is less than that of the vapor compression cycle. Comparison of vapor compression cycle and gas cycle. This liquid can then be circulated through a heat exchanger to cool air or equipment as required. The figure depicts a typical, singlestage vapor compression system. The vapor compression refrigeration system you need to know some basic rules of physics to understand the vapor compression cycle. It also includes the process of maintaining and reducing the temperature of a body below the general temperature of its surroundings. Review the factors involved in selecting the right refrigerant for an application. Vocabulary background in the thermodynamics and refrigeration literature, several words are used interchangeably that can cause confusion. Description of the vaporcompression refrigeration system. Both a steadystate and a transient simulation will be considered.
The refrigerant as a mixture of liquid and vapour corresponding to state point 1 enters the compressor where isentropic compression takes place. What is vaporcompression cycle refrigeration cycle. Basic refrigeration cycle fundamental refrigeration. This was done to demonstrate the efficacy of the modeling structure for system. Ideal vapour compression refrigeration cycle the impracticalities of the reversed carnot cycle can be eliminated by. So refrigeration cycle should be known to understand the refrigeration system. The vapor compression cycle works on the reverse brayton cycle, while the gas compression cycle works on reverse rankine cycle. Vapor cycle refrigeration can further be classified as.
Carnot cycle there are only two temperatures in the carnot cycle heat is added at t h heat is rejected at t l there are four temperatures in the otto cycle heat is added over a range of temperatures heat is rejected over a range of temperatures. Analyze the actual vaporcompression refrigeration cycle. This heat vaporizes liquid refrigerant in the evaporative cold plate. Process description mechanical vapor compression distillation of saline water is a process in which mechanical energy is used as the main driving force. The vapor pressure of refrigerant should be a lower than atmospheric pressure b higher than atmospheric pressure. Thirdly, the component models developed in this research were used to simulate the system response to varying component parameters. However, it does not exactly match a carnot cycle, so its potential coefficient of performance cop is less than the maximum possible.
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. The most common types of refrigeration systems use the reverserankine vapor compression refrigeration cycle, although absorption heat pumps are used in a minority of applications. The main types of air conditioners and refrigerators are a vapor compressionrefrigeration cycle, and b adsorption systems. In this paper, each of these compressors is defined, benefits and limitations are listed, and practical applications of each are discussed. The vaporcompression refrigeration system uses a circulating liquid refrigerant as the medium which absorbs and removes heat from the space to be cooled and subsequently rejects that heat elsewhere. Vapor compression refrigeration cycle engineering essay. In the early years of the twentieth century, the vapor absorption cycle using waterammonia systems was popular and widely used, but after the development of the vapor compression cycle it lost much of its importance because of its low coefficient of performance about one fifth of that of the vapor compression cycle. It is also used in domestic and commercial refrigerators, largescale. Vaporcompression refrigeration cycle there are four principal control volumes involving these components. Cycle with dry saturated vapor after compression, 2. We will try to present below the basic characteristics of vcr cycle. Natural gas plants, petroleum refineries, and petrochemical plan. At the top of the loop, heat is introduced to the system by the device being cooled.
Vapor compression cycle thermodynamic cycle of heat pumps. The vapor usually leaves the evaporator is superheated to prevent droplet of liquid within the compressor. Gas cycle refrigerationdefinition, advantages, disadvantages. Videos you watch may be added to the tvs watch history and. Jun 25, 2018 different types of process chillers fall under two main categories. Cycle with under cooling or sub cooling of refrigerant, advantages of vapour compression system.
While some people have viewed this method as environmentally harmful and inefficient, the cycle is still applicable in the industrial sphere. Vapor compression refrigeration system basic, working. It is also used in domestic and commercial refrigerators, largescale warehouses for chilled or frozen storage of foods and meats. A comparative study has been carried out of r12, 22, 125, 4a, 152a, 218, 245, 500, 502, 507 and 717 as working fluids in a vapourcompression refrigeration system. Various criteria in optimization of a vapor compression refrigeration system. If playback doesnt begin shortly, try restarting your device.
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