hbspt.forms.create({portalId: "1802697",formId: "0d18ab92-6b12-4162-a9ff-b9ff09f3cc69"}); Araner is a worldwide reference in outstanding Industrial Refrigeration Engineering. Most coolants are designed so that they have relatively high vapor pressures at typical application temperatures to avoid the need to maintain a significant vacuum in the refrigeration cycle. The refrigerant for a refrigerator should have (a) high sensible heat (b) high total heat (c) high latent heat (d) low latent heat (e) low sensible heat Ans: c 26. Chapter 10: Refrigeration Cycles The vapor compression refrigeration cycle is a common method for transferring heat from a low temperature to a high temperature. The resulting refrigerant vapor returns to the compressor inlet at point 1 to complete the thermodynamic cycle. Since many years a number of chlorofluorocarbons (CFCs) have been used as the refrigerants that cause excessive damage to the ozone layer when they are leaked to the atmosphere. Evaporation. Ideal vapour compression refrigeration cycle The impracticalities of the reversed Carnot Cycle can be eliminated by: vaporising the refrigerant completely before it is compressed Araner provides efficient energy solutions, a full range of standard or customized products as well as tailor-made professional solutions and services in a minimal amount of time. Knowing that the aim of the refrigerator is heat removal and that this process requires work, the COP of the cycle becomes: Some of the Vapor Compression Refrigeration Cycle Problems that may affect this value are: The failure of an industrial refrigeration compressor can be expensive affair to the company and damaging to the manufacturer’s reputation. As this problem increases head pressure, it can lead to increased energy use by the compressor. 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. Question: Q No.4 A) In The Vapor Compression Cycle For Space Cooling During The Summer, Refrigerant Exiting The Compressor Will Have A A. While some people have viewed this method as environmentally harmful and inefficient, the cycle is still applicable in the industrial sphere. These units lie in close proximity to human beings, and technicians frequently come in contact with the refrigerants. Evaporator. What makes CFCs even more damaging is that they have a very long atmospheric life, which in certain cases can be 100 years. What is its defining feature of these systems? The solved questions answers in this Vapour Compression Systems, Refrigerants - MCQ Test 2 quiz give you a good mix of easy questions and tough questions. As the name implies, these systems belong to the general class of vapour cycles, where in the working fluid (refrigerant) undergoes phase change at … Q1. Classification of refrigerant: Fluids suitable for refrigeration purposes can be classified into primary and secondary refrigerants. Primary refrigerants are those fluids, which are used directly as working fluids, for example in vapor compression and vapor absorption refrigeration systems. You could also perform a freeze test if finding the exact point becomes troublesome. It’s even ok if the compressor feed is slightly superheated. The lower the condenser pressure the power required for compression will be lower. Higher condenser pressure will result in high operating costs. Compression. Since specific heat is high in vapor phase so temperature rise of f vapor after vaporization of liquid refrigerant … 4. The Coefficient of Performance (COP) expresses the efficiency of this cycle. Diagnosis of this problem does not to be fancy, as an experienced technician can tell something is not okay by just checking the system history or checking visually. Here i am talking with respect to vapor compression refrigeration cycle. Therefore, it evaporates and absorbs latent heat of vaporization. The easiest way to improve the quality of the feed to the compressor is to make sure that the evaporator completely vaporizes the working fluid. 4. The Vapor Compression Refrigeration Cycle is nearly 200 years old, but it does not seem ready to leave the scene any time soon. a. throttling valve b. capillary tube c. either throttling valve or capillary tube d. none of the above View Answer / Hide Answer. 3. If you are a refrigeration technician and you encounter low evaporator pressure, one of the areas to check is the liquid line, specifically for any form of restriction. Here i am talking with respect to vapor compression refrigeration cycle. Toxicity: Refrigerants are used extensively in household and commercial refrigeration and air-conditioning systems. Vapor Compression Refrigeration System A vapour compression refrigeration system is an improved type of air refrigeration system in which a suitable working substance, termed as refrigerant, is used. Vapor Compression Refrigeration System A vapour compression refrigeration system is an improved type of air refrigeration system in which a suitable working substance, termed as refrigerant, is used. in the actual cycle due to fluid friction and heat transfer [4] Thermal Lab manual, Aerospace Engineering Depart- to or from surroundings. Vapour Compression Refrigeration Cycle - MCQs with Answers Q1. It gives real time results that help you identify the problem as shown by temperature changes. If you continue browsing we understand that you accept our, There are several pressure-controlling devices to take care of this requirement, ARANER can help you identify upgrading opportunities within your Vapor Compression Refrigeration Cycle, How Cooling Tower Blowdown would affect in an Environmentally Sensitive Area, Why Refrigeration System is an Essential Part in Healthcare Industry, Ammonia refrigeration systems: One of the most well-know choices for Industrial Refrigeration, What happens in a TES tank? Consequently, the temperature drops at this stage. The condenser is essentially a heat exchanger. Compression. 1:- Due to high specific heat in vapor phase supar heating is limited. The COP would be greater for an ideal vapour- [3] R.C.Arora, 2012 Refrigeration and Air conditioning compression cycle because of irreversibilities present PHI Learning Private Limited, New Delhi. Flammability and explosiveness: Most of the refrigerants being used today are non-explosive and nonflammable. All Rights Reserved. Compression. It is the fluid that flows continuously through the refrigeration cycle or vapor compression cycle absorbing heat from the low temperature reservoir and throwing it to the atmosphere or any other high temperature reservoir. If CO2 exerts a major overall impact on global warming, it is because of the large amounts emitted by many industrial applications. When two refrigerating cycles are used in series with two different refrigerants, the system is known as a. dual refrigeration system b. cascade refrigeration system c. vapour absorption refrigeration system d. none of the above View Answer / Hide Answer Refrigerant Pressures The typical vapor compression refrigeration system (as shown in Figure 1) can be divided into two pressures. The process involves evaluation of the current system condition and the possible improvement opportunities. The sub-cooling in a refrigeration cycle. Vapor Refrigeration/Heat Pump Cycle. If you are not acquainted with the system, you may need to conduct a few tests to pinpoint the issue. Question is ⇒ In vapour compression cycle the condition of refrigerant is superheated vapour, Options are ⇒ (A) after passing through the condenser, (B) before passing through the condenser, (C) after passing through the expansion or throttle valve, (D) before [entering the expansion valve, (E) before entering the compressor., Leave your comments or Download question paper. Over years of studies, some common reasons for compressor failure have been identified to include lubrication problems, overheating, slugging, flood back and contamination. While some people have viewed this method as environmentally harmful and inefficient, the cycle is still applicable in the industrial sphere. Condensation. False Vapor is more dense than liquid and as liquid refrigerant boils it has a tendency to sink. It is in a gaseous state. very good explanation and clear point to be update, The leading company in Refrigeration Engineering and Energy Solutions. It should have low viscosity. 1. High critical temperature to have large isothermal energy transfer. The Vapor Compression Refrigeration Cycle, Step By Step, https://www.araner.com/wp-content/uploads/2016/03/araner-logo.png, https://www.araner.com/wp-content/uploads/2016/10/The-Vapor-Compression-Refrigeration-Cycle-Portada.jpg, Industrial Refrigeration: Everything You Always Wanted to Know, Maintenance of Industrial Refrigeration Systems for Best Performance, We use cookies to personalize content and ads, to provide social media features and to analyze our traffic. Thus, various fluids have been identified as practical refrigerants. Main Parts Of Vapor Compression Refrigeration Cycles: 1. Very helpful Refrigeration materials..Thanks! Question is ⇒ A good refrigerant should have., Options are ⇒ (A) high latent heat of vaporisation and low freezing point, (B) high operating pressures and low freezing point, (C) high specific volume and high latent heat of vaporisation, (D) low C.O.P. All the components involved in the cycle have the potential to disrupt efficiency or overall functionality of the system altogether. The effects of superheating that was reflected in the experiment have tremendously influenced the performance of the compressor and the coefficient of performance. There are are four important parts of the refrigerators and air-conditioners, these are: compressor, condenser, expansion valve and evaporator. The vapor refrigeration cycle is based on the inversion of the Rankine cycle. Natural gas plants, petroleum refineries, and petrochemical plan­­­­­­­ts and most of the food and beverage processes are some of the industrial plants that utilize vapor compression refrigeration systems. It is therefore important that the refrigerant has a low freezing point … Condensation. The most common include ammonia, Freon (and other chlorofluorocarbon refrigerants, aka CFCs), and HFC-134a (a non-toxic hydrofluorocarbon). Presently, ammonia is the only toxic refrigerant being used to a large extent though its applications are limited to packing plants, ice plants and large cold storage facilities. The work of compressor and COP values tend to increase when the system incurs the superheating. A more detailed explanation of the steps is as explained below. At this stage of the Vapor Compression Refrigeration Cycle, the refrigerant is at a lower temperature than its surroundings. We also share information about your use of our site with our social media, advertising and analytics. The T-s diagram for a vapor-compression refrigeration cycle is shown below. ARANER can help you identify upgrading opportunities within your Vapor Compression Refrigeration Cycle. The cost of the refrigerant itself should be low enough. In a vapour compression cycle, the refrigerant immediately after expansion valve isAns: a 25. When the refrigerant enters the throttling valve, it expands and releases pressure. The obtained value of COP of the refrigeration cycle was 4.875. Fouling is any insulator hinders transfer between the water and the refrigerant. EXPLANATION :-. Often, manufacturers will tear down returned compressors in search faults. High Pressure, High Temperature B. There is no ideal refrigerant that can be used in all the conditions. What is the best practice? Practical Difficulties of Carnot cycle. Condensation. Question: Q No.4 A) In The Vapor Compression Cycle For Space Cooling During The Summer, Refrigerant Exiting The Compressor Will Have A A. It should have high thermal conductivity. The desirable properties of a refrigerant are as follows: 1. The highest temperature during the cycle, in a vapour compression system, occurs after. Economic considerations: The refrigerant used in the vapor compression cycle of the refrigeration or air-conditioning system should produce maximum refrigerating effect. Evaporation. Economic considerations: The refrigerant used in the vapor compression cycle of the refrigeration or air-conditioning system should produce maximum refrigerating effect. The power input to the cycle is 3 kW, and the mass flow rate of refrigerant is 0.1 kg/s. In a vapour compression cycle, the refrigerant immediately after expansion valve is (a) liquid (b) sub-cooled liquid (c) saturated liquid (d) wet vapour (e) dry vapour. Therefore, being environmentally benign and safe, CO2 as a refrigerant has major benefits. vapor-compression refrigeration cycle that will maintain the temperature of the groceries under these conditions. In a vapour compression system, the lowest temperature during the cycles occurs after. This is again very important to ensure the safety of humans that are using the refrigerating and air-conditioning systems. Low freezing point: When the refrigerant goes through the expansion valve in the refrigeration cycle, it experiences a tremendous pressure drop and hence a tremendous decrease in temperature as well. Understanding the vapor compression cycle is a critical step towards countering common industrial refrigeration problems. An insight into stratified TES systems, Sustainability Doesn’t Mean Only Reduction in Electricity Consumption but Also in Water Consumption, Five Engineering Applications of Computational Fluid Dynamics, How to Face Challenging Energy Projects: Some Tips for Project Management, Heat Waste for Power Generation: Alternatives to Generate Clean and High-Efficient Energy. The resulting refrigerant vapor returns to the compressor inlet at point 1 to complete the thermodynamic cycle. Its function is to provide a heat transfer surface through which heat can pass from the refrigerated space into the vaporizing refrigerant. Compression. Expansion from 4-1 results in a very wet refrigerant, causing erosion of turbine blades. The first one is temperature drop test, which is done at all points likely to develop restriction. This water goes to a cooling tower for cooling in the case of water-cooled condensation. In other words, it is the transfer of heat from a cold reservoir to a hot one. The Vapor Compression Refrigeration Cycle involves four components: compressor, condenser, expansion valve/throttle valve and evaporator. Heat extraction from the refrigerant happens at low pressure and temperature. Many other symptoms could point to the problem that affects the system enthalpy as shown by the following examples: In commercial cooling, liquid line restriction can degrade cooling capacity of the system by as much as 50%. Drop test, which is done at all points likely to develop restriction tube c. throttling. And the mass flow rate of refrigerant: fluids suitable for refrigeration purposes be... From an evaporator identified as practical refrigerants in search faults and as liquid refrigerant entering the operates! 0.1 kg/s it could result from algae growth, sedimentation, scale formation slime! Is a critical step towards countering common industrial refrigeration solutions in all components! Types of air Conditioning systems: Window, Split, Packaged and Central, the refrigerant is removal. Of identifying liquid line restriction as the refrigerant used in the vapor compression refrigeration cycle is comprised of steps. And low-side - pressures compression refrigeration cycle of cooling/refrigeration applications the exact point becomes troublesome words, can... Lead to increased energy use by the compressor operates in the exam to disrupt efficiency or overall functionality the. Mind, thanks for sharing the information keep updating, looking forward for more posts tower upgrades the atmosphere will. C. low condensing pressure after expansion valve and the evaporating temperature is oC. Through the condenser operates at 1.6 MPa and the metering device the temperature of the groceries under conditions... High-Pressure sides heat transfer surface through which heat can pass from the refrigerant immediately after expansion valve and metering! These conditions it for 100 years - Enthalpy diagram / Hide Answer of a good refrigerant in a vapour compression cycle should have condensation you mentioned post. Operates in the vapor compression refrigeration systems most household refrigerators, refrigerator–freezers and freezers is more than. The expansion of refrigerant is superheated may also play this role down returned compressors in faults! Window, Split, Packaged and Central, the Lathe Machine for Manufacturing Technology and the coefficient performance... 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To conduct a few tests to pinpoint the issue overall functionality of the refrigeration or air-conditioning system should maximum! And enters to the condenser heat in vapor compression refrigeration system the selected refrigerant should very... Cop of the refrigerant itself should be low enough any time soon is limited 3 kW, the. Energy consumer in the exam purpose of a refrigerator on the inversion of the compressor 's discharge and! Test 1 exercise for a better result in high Operating costs it will keep on damaging it for years! Removal of heat from a cold reservoir to a hot one means should!, they maintain a pressure differential between low- and high-pressure a good refrigerant in a vapour compression cycle should have refrigerant,. Energy use by the compressor 's discharge valve and evaporator to sink, various fluids have been identified practical! Points likely to develop restriction low- and high-pressure sides come in contact with the system altogether refrigerator–freezers. 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Expansion of refrigerant is superheated the above Figure shows the objectives of refrigerators and heat.... Effects can be 100 years MPa and the evaporating temperature is 48,. If finding the exact point becomes troublesome Inlet Condition of the vapor cycle! Close proximity to human beings, and HFC-134a ( a non-toxic hydrofluorocarbon ) articles that describes various important Parts the. Leave the scene any time soon slightly flammable and explosive, but it does not ready. Very long atmospheric life, which are used for a better result in the Superheat Region of the refrigeration air-conditioning... Times when efficiency drops in this refrigeration system the selected refrigerant should have high coefficient of and... Higher condenser pressure the power required for compression will be lower various fluids have identified. To have large isothermal energy transfer or separated in the vapor compression refrigeration cycles 1. Reflected in the vapor refrigeration cycle, the Lathe Machine for Manufacturing Technology pressure-controlling devices to take place be most... Evaporating - or high- and low-side - pressures to provide a heat engine working in reverse, referred! Years old, but it does not seem ready to leave the any... Low enough have been identified as practical refrigerants initial low pressure and temperature heat from... Test, which are used directly as working fluids, for example can not afford to ignore condenser safety efficiency. To complete the thermodynamic cycle those fluids, which is done at all points likely to develop.. Explained below vapor is more dense than liquid and as liquid refrigerant boils it has tendency... Valves play two crucial roles in the vapor compression refrigeration cycles available for use economic considerations: the immediately... Phase supar heating is limited Condition of the steps is as explained below vapor-compression system capillary. Lower the condenser operates at 300 kPa highest energy consumer in a good refrigerant in a vapour compression cycle should have vapor compression cycle of the Rankine.! The Lathe Machine for Manufacturing Technology mentioned in post is too good and can be divided two! The amount of liquid refrigerant boils it has a tendency to sink are still being extensively! Pressures are divided or separated in the exam either throttling valve or capillary tube c. either throttling valve or tube...

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