A liquid can be pumped more efficiently than a vapor can be compressed, so this technique has a decided advantage over vapor. Henley, separation process principles, wiley, 2006, pg. Pachorkar, steady state analysis of vapour absorption refrigeration system using librh2o as a refrigerant international journal of emerging technology and. At point1, 4 and 8, there is only saturated liquid.
Jun 25, 2016 vapor absorption refrigeration system vas. The purpose of the generator is to deliver the energy available to produce cooling and thus giving a high refrigerant vapor to the rest of. Discuss the properties of ammoniawater mixtures and introduce. Maximum cop cop max,vcrs cop revcarnot t e t c t e assumption. Pdf design of solar based vapour absorption system suthar. The comparison of vapour absorption system and vapour compression system with r4a as a refrigerant is done for 1 ton refrigeration capacity. Vapor absorption systems work with noncfc environmentally friendly refrigerants such as water or ammonia. Vapor compression refrigeration systema vapour compression refrigeration system is an improved type of air refrigeration system in which a suitable working substance, termed as refrigerant, is used. Nptel elearning course refrigeration and air conditioning. The vapour absorption system uses heat energy, instead of mechanical energy.
The function of compressor in the vapor compression system is to continuously withdraw the refrigerant vapor from the evaporator and to raise its pressure and hence temperature, so that the heat absorbed in the evaporator, along. Lesson 10 vapour compression refrigeration systems. 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. And the libr being a salt has a recrystallization zone when it becomes solid and hence imposes flow restrictions. The low pressure refrigerant vapour from the evaporator is fed into the absorber, which releases heat to the surroundings due to exothermic reaction. Process such as distillation, absorption and extraction bring phases of different composition. Evaporative cooling in vapor absorption refrigeration systems. After being pumped to generator, heat is supplied which gives ammonia vapour. Explain the basic principle of a vapour absorption refrigeration system section 14. Nptel video lectures, iit video lectures online, nptel youtube lectures, free video. Remaining cycle processes remain unchanged as shown. Explain the basic principle of a vapour absorption refrigeration system. Rac lecture 14 lesson 14 vapour absorption refrigeration. Schematic diagram of simple vapour absorption refrigeration system thermodynamic analysis for carrying out thermodynamic analysis of the proposed vapour absorption refrigeration system, following assumption are made.
Lecture 15 vapour absorption refrigeration system youtube. Today we will study the difference between vapour compression and vapour absorption refrigeration system in detail. In actual vapour absorption refrigeration system when heatexchanger and rectifier are used with a simple system to improve operating efficiency than it is called practical vapor absorption system. Simple vapour compression refrigeration system with. Compare vapour compression refrigeration systems with continuous vapour absorption refrigeration systems section 14. Can a vapor absorption refrigeration system be used by an. Jul 22, 2016 vapour absorption refrigeration system 1. Thermodynamic analysis of single effect vapor absorption.
Vapour absorption refrigeration system based on ammoniawater is one of the oldest refrigeration systems. However, although absorption systems seem to provide many advantages, vapor compression systems still dominate all market sectors. Draw the schematic of a ammoniawater based vapour absorption refrigeration system and explain its working principle 2. The schematic sketch of doubleeffect system is shown in fig.
Absorption systems are an alternative to vapour compression systems by being thermally activated. Explain the principle of rectification column and dephlegmator using. Joshy published research paper on vapour absorption refrigeration system using law grade energyan ecofriendly approach. As mentioned earlier, in this system ammonia is used. Discuss properties of waterlithium bromide solution and. Is an expert from iit vapour absorption refrige vapour absorption refrigeration systems slideshare may th, 2018 vapour absorption refrigeration commonly used combinations in air conditioning a textbook of refrigeration amp air conditioning 20 prof m ramgopal refrigeration and air conditioning lecture 01 nptel scribd. The vapour absorption system uses heat energy, instead of mechanical energy as in vapour compression systems, in order to change the conditions of the refrigerant required for the operation of the refrigeration cycle. This system is useful for applications where the temperature required is more than 32 degree f. Obtain expression for maximum cop of ideal absorption refrigeration system section 14. Difference between vapour compression and vapour absorption pdf. Since conventional absorption systems use natural refrigerants such as water or ammonia they are environment friendly. Absorption machines are available with capacities in the range of 101500 tons. The lowpressure refrigerant vapor nh3 from the evaporator is absorbed in the absorber by the weak solution of refrigerant. Waterlithium bromide vapor absorption system introduction vapor absorption refrigeration systems using waterlithium bromide pair are extensively used in large capacity air conditioning systems water is used as refrigerant and a solution of lithium bromide in water is used as absorbent it is used only in applications requiring refrigeration at temperatures above 00c cont.
Obtain expression for maximum cop of ideal absorption refrigeration system. Compare compression systems with absorption systems section 17. Explain the differences between ideal and real mixtures using pressurecomposition and enthalpycomposition diagrams 5. Compare vapour compression refrigeration systems with continuous. Generator absorber heat exchange based absorption cyclea. The components of vapor absorption refrigeration cooling system are as4. Absorption refrigeration system an overview sciencedirect. Hybrid refrigeration system consist of a vapour absorption cycle and a compressor. In the system the vapour refrigerant from the evaporator is drawn in to an absorption unit. A typical industrial operation for an absorption process is shown in figure 5.
It condenses and evaporates at t e m p e r a t u r e s a n d p r e s s u r e s close to t h e atmospheric conditions. Lecture 14 vapour absorption refrigeration systems youtube. Download pdf lectures on vapour absorption refrigeration system. Here are some special features of the water and lithium bromide in an absorption refrigeration. Introduction the vapour absorption refrigeration system is one of the oldest methods of producing refrigerating effect the principle of vapour absorption was first discovered by michael faraday in 1824 the first vapour absorption refrigeration machine was developed by french scientist, ferdinard carre, in 1860. But in chemical reactions and number of industrially masstransfer operations the. In the vapour absorption system the compressor is replaced by an absorber, a pump, a generator and a pressure reducing valve. The objective of this paper is to present empirical relations for evaluating the characteristics and performance of a single stage ammonia water nh3h2o vapour absorption system. The waterlithium bromide vapor absorption system is used in a number of air conditioning applications. Lecture 16 vapour absorption refrigeration systemscontd. Refrigerant enters the evaporator in the form of a cool, lowpressure mixture of liquid and vapor 4. Simple and modified vapour absorption refrigeration system. The absorption system differs fundamentally from vcr system in the method employed for.
Absorption refrigeration system, cycle, unit, how does it. At the bottom of the articles you can download pdf. Simple vapour absorption system ammonia vapour from evaporator is absorbed by water in absorber. Vapor absorption refrigeration system is the best idea regarding to cope up with energy crisis because this system is heat operated, due to which this system can be operated by using low grade of energy like solar energy, geothermal energy, waste heat from industries, etc. Simple and modified vapour absorption refrigeration. This proposed system is economical, eco friendly and also have good future scope. In order to promote the use of absorption systems, further development is required to improve their performance and reduce cost. The objective of this strive for the development of cheaper methods of paper is to design and study an environment friendly collection and storage so that the large initial vapour absorption system of unit capacity using investments required at present in most applications lithium bromide and water librh2o absorption are reduced. Introduce vapour absorption refrigeration systems based on waterlithium bromide. In the vapour absorption system, an absorber, a pump, a generator and a pressurereducing valve replace the compressor. Vapour absorption refrigeration systems 12th lecture working principle maximum cop of the ideal vars properties of mixtures simple absorption refrigeration system. Lecture 10 vapour compression refrigeration systems youtube. Lecture 12 vapour compression refrigeration systemscontd. Pdf thermodynamic analysis of lithium bromidewaterlibr.
Introduction the vapour absorption system is one of the oldest methods of producing refrigerating effect. Increasing the temperature of the system the amount of gas that can be absorbed by liquid decreases, while with increasing the pressure generally absorption increases. Vapour absorption refrigeration systems slideshare. Keywords exergy, power, thermionic cycle, vapour absorption refrigeration system, waste heat.
Pdf project report on vapour absorption refrigeration. In vapour absorption refrigerant system the lowpressure refrigerant vapor nh3 from the evaporator is absorbed in the absorber by a weak solution of. Nptel you can also checkout vapour compression refrigeration system and electrolux refrigeration system written by me conclusion. The capital cost of vam is higher compared to compression systems, but when viewed in totality of reduced electrical service size, transformer, switchgear, cabling and lack of need. The vapour is drawn in the compressor cylinder at the condition of 1. Vapor absorption systems offer many advantages like it offers flexibility to utilize any sort of low grade, low cost heat generator. Before moving further on differences lets have an overview of both the vapour compression and vapour absorption refrigeration system.
Vapour absorption refrigeration system chapter3 rac. Jul 25, 2015 vapour absorption refrigeration systems using waterlithium bromide pair are extensively used in large capacity air conditioning systems. It is based on dissolving the refrigerant vapor ammonia in a carrier liquid water and pumping this liquid to a high pressure. Find the maximum possible cop of vapour absorption refrigeration systems 4. We are here to provides you best study notes from best coachings like made easy, ace academy etc and from best institutions like mit open course, iit nptel, unep etc, which could be help you to understand concepts to crack any kind of competition exams like gate, ies. Apr 19, 2008 lecture 14 vapour absorption refrigeration systems duration. Vapour absorption refrigeration system with diagram. Although the initial cost of an absorption system is higher than that of a compression system, operational costs are much lower if waste heat is used. Heat is transferred from the relatively warm water to the refrigerant, causing the liquid refrigerant to boil. The feed, which contains air 21% o 2, 78% n 2, and 1% ar, water vapor, and acetone vapor, is the gas 1 j. Relative volatility give expression for a binary mixture.
Vapour absorption refrigeration system in vcrs, vapour is compressed directly to the condenser pressure in vars, vapour is absorbed into liquid and then pumped to the condenser pressure fig. In a vapour absorption system, the compressor is replaced by an absorber generator assembly. Such heat energy may come from the sun or even from hot exhaust gases from a particular. Now i love to hear from you, in this guide of vcc, i showed allimportant point regarding vcc. Lecture 14 vapour absorption refrigeration systems. Vapour absorption refrigeration system learn mechanical. These refrigeration and air conditioning rac study notes will help you to get conceptual deeply knowledge about it. Solar energy based refrigeration systems section 1.
This lesson discusses the most commonly used refrigeration system, i. Vapor absorption refrigeration systems for iit kanpur. Joshy department of mechanical engineering cochin university of science and technology v. The vapor absorption refrigeration uses thermal energy sources specially solar energy in the hot areas to enhance the over all efficiency. In these systems water is used as refrigerant and a solution of lithium bromide in water is used as absorbent. Because absorption systems are heat rather than work driven, their practical cop values tend to be around 1. Condensation heat released is absorbed by cooling water.
Absorption cooling was invented by the french scientist. Can a vapor absorption refrigeration system be used by an air. Ppt water lithium bromide vapor absorption system sagar. The vapour absorption system practically librwater system has bounced back with the use of solar energy and the recent emphasis on cogeneration which makes. Oct 01, 2010 the conventional single effect absorption cooling system is shown in fig. Mechanical engineering refrigeration and air conditioning nptel. Explain the basic principle of absorption refrigeration systems and describe intermittent and continuous vapour absorption refrigeration systems 3. Vapor absorption cycle absorption refrigeration systems replace the compressor with a generator and an absorber. Multievaporator systems cascade systems, optimum intermediate temperature manufacture of dry ice and supercritical co2 cycle autocascade cycle module 7. Introduce ammoniawater based vapour absorption refrigeration systems section.
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