Vapour Absorption Refrigeration System By Using Solar Energy

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I JSRD - I nternational Journal for Scientifi c Research & Development| Vol. 3, I ssue 11, 2016 | I SSN (onli ne): 2321-0613

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Vapour Absorption Refrigeration System by using Solar EnergyProf. Narale Pravin 1 Mr.Pisal Pravinkumar 2 Mr.Shende Kiran 3 Mr.Shende Onkar 4 Mr.Sawant

Rahul 5

1Assistant Professor 2,3,4,5 B.E. Student1,2,3,4,5 Department of Mechanical Engineering

1,2,3,4,5 S.B. Patil College of Engineering, Indapur Abstract — As the energy is the backbone of the technologyit affects the price of product as well as the overall economyof the industry. Energy is the most important factor inindustrial production as well as in the domestic useecofriendly system as it uses solar power. Assun is the hugesource of energy solar energy is the perfect alternative forsome energy sources such as electricity, petroleum .In Indiathe large part of the solar energy is wasted because of lackawareness about the solar energy. Mostly the solar energy isused to dry the food grains and mostly to dry the cloths. Butlast few years are the most memorable years for the Indiafrom the last few years most of the peoples decide to installthe solar units. We are focusing on the need of thealternatives for the conventional energy source. we are usingthe vapour absorption refrigeration system operated by usingsolar power, in this we are using R-717 as refrigerant andwater as working fluid. system consist of collector,evaporator, absorber the refrigerant in the system whencome in contact with the water the cold water absorbs mostof the ammonia in it after that the strong solution isconveyed up to the collector where the strong solution isheated to form a vapour then this vapours are condensed incondenser and then passed to expansion valve wheretemperature falls down then it is passed to the evaporatorwhere the refrigerant absorbs the heat from the surroundingof the evaporative section.Key words: Absorber, Aqua-Ammonia Vapour, Coefficientof Performance, Generator, Solar Energy, Tonnage ofRefrigeration

I. I NTRODUCTION

Refrigeration is the process of removing heat from enclosedsystem or space and rejects it to the another system orsurrounding. The refrigeration is used to lower thetemperature of the enclosed system. A vapour absorptionrefrigeration system is similar to a vapour compressionrefrigeration system. The vapour absorption systemcomprises of all the processes in the vapour compression

refrigeration system like compression, Condensation,expansion and evaporation. In the vapour absorption systemthe refrigerant used is ammonia-water or lithium-bromide.The refrigerant gets condensed in condenser and evaporatedin evaporator. The refrigerant produces cooling effect in theevaporator and release the heat to the atmosphere throughthe condenser. The difference between the two systems isthe method of the suction and compression of the refrigerantin the VARS cycle. In the vapour compression system, thecompressor sucks the refrigerant from the evaporator andcompress it to the high pressure. The compressor is alsoenables the flow of the refrigerant through the completerefrigeration cycle. In the vapour absorption cycle the

process of suction and compression are carried out by twodifferent devices called as absorber and generator. Thus the

absorber, generator and the pump replace the compressor inthe vapour absorption cycle.

The absorbent enable the flow of refrigerant fromthe absorber to the generator by absorbing heat. In thevapour absorption system the energy input is in the form ofheat this can be from the excess system from the process orhot water. The heat can be created by another source likenatural gas, kerosene, heater etc .Though these sources areonly in the small system.

The above sources are conventional and are beingused extensively in such way that their known reserves have

been depleted to a great extent. At same time it is becomingincreasingly difficult to find and exploit their new depositsof petroleum on our country will get exhausted by the fewdecades and their reserves are expected to last for anothersome years. But here we are using the solar energy to heatthe water. Because the solar energy the abundant source ofenergy. Solar energy systems allow you to absorb freesunlight and convert it into usable power in your system.Unlike conventional power, solar produces no harmfulemissions that hurt the environment. Solar energy will saveyour money each month. In addition, the investment thatyou made in solar, will improves property value. Vapourabsorption system is basically uses the low grade energysuch as waste heat and solar energy coming in the naturefrom thousands of years.

II. LITERATURE SURVEY

V.K. Bajpai designed and studied vapour absorptionrefrigeration system. which is environment friendly. thesystem used by the V.K. Bajpai is having unit capacity.therefrigerant used is R-717 and water is used as absorber orthe working medium, he used the flat plate collectors forheating the strong solution to vaporise and separateammonia vapour from the water. He also described the

performance of the system component and overall systemfor various working conditions.

Abhishek Sinha,S.R.Karale are studied and

described the various methods to use the solar energy. Inwhich solar electrical method, Solar Mechanical Methods,Solar Thermal Method, Desiccant, Cooling Thermal EnergyStorage (CTES) System, Chilled Water Storage (CWS), IceThermal Storage (ITS) ,Ice Harvesters ,External melt ice-on-coil storage systems are studied And tested for various

parameters and conditions.K Karthik has designed the model of vapour

absorption system having 0.0168TR Capacity and tested itfor various operating conditions and parameter. according tohis study and calculations he proved that the solar poweredvapour absorption system is feasible.

Nirajkumar Sharma, Mr. Pradip Singh, Dipak Gaur

described and presented the 3.5 ton lithium-bromide andwater refrigeration system, as well as they determined the



Vapour Absorption Refrigeration System by using Solar Energy(IJSRD/Vol. 3/Issue 11/2016/120)


cop of the system. They also studied the whole system forvarious working parameters and various working conditions. They also describes that the above systems how efficientlyworks and among which some are more feasible.

Dillip Kumar Mohanty, Abhijit Padhiary developedand described the vapour absorption refrigeration system,they also investigated the cop for various workingconditions. the error analysis also taken to investigate the

justifications of the system outcomes. And with the help ofstudy they determined that optimal performance of thevapour absorption system is obtained for absorber of40 0C(degree celcious) and generator temperature of 90 0C.

Tarik A. Shaikh, Yogesh J. Morabiya done themathematical modelling and study of the solar operatedvapour absorption system and with the help of their studyand analysis they also confirmed that the vapour absorptionsystem is also a feasible way to finish the use of CFC’s andHFC’s ,They also developed the Li -Br model of vapourabsorption system and determined the cop of the system.Satish Raghuwanshi ,Govind Maheshwari has developedand studied the relation characteristics And performance ofthe single stage ammonia water vapour absorption systemand confirms that the vapour absorption refrigeration byusing solar power is feasible alternative for the conventionalrefrigeration system which are using the conventional powersource.

M A Mehrabian and A E Shahbeik was developeda computer program for design and thermodynamic analysisof a single effect absorption chiller by means of LiBr – H 2Osolution as working fluid. The condition of hot waterentering to the desorber and leaving the desorber, coolingwater entering to the absorber and leaving from thecondenser, chilled water entering to the and leaving fromthe evaporator, as well as the approach temperature rangesin condenser, evaporator, and absorber, the effectiveness ofheat exchanger, the chiller refrigeration power consumption,and the ambient temperature are used as input data. The

program code gives the thermodynamic properties of all phase state points, the design details of of all heatexchangers in the cycle and the complete cycle performance.The results from the computer program are used for studyand analyze the effect of design parameters on cycle

performance. It is observed that the temperature of hotwater, cooling water, and chilled water respectively, at theinlet of the desorber, condenser, and evaporator have a greatvariations on cycle coefficient of performance. The resultsof this program can be used either for sizing a newrefrigeration cycle or rating an existing system. It can also

be used for optimization purposes. The predictions of the present program are compared with other simulating programs and qualitative agreement is achieved.K Muhammad Imran had done the irreversibility analysis ofdouble effect Li-Br water vapour absorption chiller. He

performs the analysis for four different operating conditionsof chiller. he calculated the mass flow rates, specificentropies, specific enthalpies, energy balance, andirreversibility changes are also studied and calculated. Theresults of this author reveals that irreversibility changes incondenser, evaporator, and heat exchanger are less as

compared to the irreversibility changes in the generator andabsorber. He also determined the cop of his own designedsystem. results are found as cop increases with increase in

temperature of the high temperature generator, howeverirreversibility changes also increases with this increase intemperature thus reducing the availability of energy.

A. Ponshanmugakumar, M. Sivashanmugam and S.Stephen Jayakumar concen¬trated dishes and Vapourabsorption machine (VAM). The storage tank was usedinstead of an Electrical AC compressor, by which therenewable energy can be utilized to its full extent.

Numerical Simulation is done and the Total Heat output,Temperature distribution along the bed, Pressure, chargingtime, discharging time, Mass flow rate are calculated. Thestorage system contains Erythritol as PCM in HDPEspherical capsule, having the storage capacity 345,121 KJ/hr(for the tank capacity considering the latent heat andsensible heat of the heat transfer fluid)

III. HISTORY OF SOLAR VAPOUR ABSORPTIONREFRIGERATION

Attempts have been made to run vapour absorption systems by solar energy with concentrating and flat plate solar

collectors. Several small solar absorption refrigerationsystems have been made around 1950s in several countries.Professor G.O.G. Lf of America is one of the pioneers in thearea of solar refrigeration using flat plate collectors. A solarrefrigeration system that could produce 250 kg of ice perday was installed in Tashkent, USSR in 1953. This systemused a parabolic mirror of 10 sq m area for concentrating thesolar radiation. F. Trombe installed an absorption machinewith a cylindro-parabolic mirror of 20 sq m at Montlouis,France, which produced 100 kg of ice per day.

Serious consideration to solar refrigerationsystems was given since 1965. Due to the scarcity of fossilfuel based energy sources. LiBr-water based systems have

been developed for air conditioning purposes. The firstsolar air conditioning system was installed in anexperimental solar house in University of Queensland,Australia in 1966. After this several systems based onsolar energy were built in many parts of the worldincluding India. In 1976, there were about 500 solarabsorption systems in USA alone. Almost all these were

based on LiBr-water as these systems do not require veryhigh heating temperatures. These systems were mainlyused for space air conditioning.

Intermittent absorption systems based on solarenergy have also been built and operated successfully. Inthese systems, the cooling effect is obtained during the

night time, while the system gets “charged” during theday using solar energy. Though the efficiency of thesesystems is rather poor requiring solar collector area, theymay find applications in remote and rural areas wherespace is not a constraint. In addition, these systems areenvironment friendly as they use eco-friendly refrigerantsand run on clean and renewable solar energy.

IV. COMPONENTS OF VAPOUR ABSORPTION REFRIGERATIONSYSTEM

The Components of vapour absorption refrigerationsystem are

1) Absorber2) Generator3) Condenser





4) Expansion valve5) Evaporator6) Aqua pump

A. Absorber:It is used to store the mixture of water and ammonia in

particular proportion. Function is to produce the requiredaqua ammonia solution.Low pressure NH 3 vapour is

absorbed by the weak solution of NH 3 which is stored in theabsorber.

Inside the absorber of a vapour absorption system,the refrigerant vapour is absorbed by the solution. As therefrigerant vapour is absorbed, it condenses from a vapourto a liquid so that the heat it acquired in the evaporator is

being released.The cooling water circulating through theabsorber tube bundle carries away the heat released from thecondensation of refrigerant vapours by their absorption inthe solution.

B. Generator:It is used to heat the strong aqua ammonia solution up to the

boiling temperature of ammonia solution to produceammonia vapours. Function is to separates the dissolvedammonia solution from the water ammonia solution.

In the generator, the solution vertically falls overhorizontal tubes with high temperature energy sourcetypically steam or hot water flowingthrough the tubes. Thesolution absorbs heat from the warmersteam or water,causing the refrigerant to boil (vaporize) andseparate fromthe absorbent solution. As the refrigerant is boiled away, theabsorbent solution becomes more concentrated. Theconcentrated absorbent solution returns to the absorber andthe refrigerant vapour migrates to the condenser.

C. Condenser:Condenser is a device or unit used to condense a substancefrom its gaseous to its liquid state.Application areas includeair conditioning, industrial chemical processes such asdistillation, steam power plantsand other heat exchangesystem.

The purpose of condenser is to condense therefrigerant vapours. In the condenser, heat is extracted fromrefrigerant at constant pressure. The phase of the refrigerantchanges from vapour to liquid state. As heat transfers fromthe refrigerant vapour to the water, refrigerant condenses onthe tubesurfaces. The condensed liquid refrigerant iscollected at the bottom of the condenser before proceeding

to the expansion valve. D. Expansion Valve:It is used to control the amount of refrigerant flow into theevaporator. It cause a pressure drop (isenthalpic) of theworking fluid. It cause sudden drop in temperature.From thecondenser, the liquid refrigerant flows through an expansiondevice into the evaporator. The expansion device is used tomaintain the pressure difference between the high-pressure(condenser) and low-pressure (evaporator) sides of therefrigeration system. As the high pressureliquid refrigerantflows through the expansion device, itcauses a pressure dropthat reduces the refrigerant pressure tothat of the evaporator.

E. Evaporator:The refrigerant at very low pressure and temperature entersinto the evaporator and produces the cooling effect. In thevapour absorption refrigeration cycle, refrigerant flows tothe absorber that acts as the suction part of the refrigerationcycle.

At a lower pressure in the evaporator, therefrigerant gets evaporated by absorbing heat from thecirculating water and the refrigerant vapours thus formedtend to increase the pressure in the vessel. With increase in

pressure, the boiling temperature increases and the desiredcooling effect is not obtained. Therefore the refrigerantvapours are removed from the vessel into the lower pressureabsorber. Most commonly the evaporator and absorber arecontained inside the same shell, allowing refrigerant vapoursgenerated in the evaporator to move continuously to theabsorber.

F. Aqua Pump:When the absorbent absorbs the refrigerant strong solutionof refrigerant-absorbent(ammonia-water) is formed. Thissolution is pumped by the pump at high pressure to thegenerator. this pump increases the pressure of the solution.

Fig. 1: Schematic Diagram of Vapour AbsorptionRefrigeration System.[7]

In a simple vapour absorption system ammonia isused as refrigerant and water is used as absorbent. It should

be noted that solubility of ammonia in water is higher at low pressures and temperatures.Ammonia – water vapourabsorption system consists of generator, condenser,expansion valve, evaporator coil , absorber, ,aqua pump,analyser, a rectifier, heat exchangers.

Ammonia vapour is extracted from the NH3 strongsolution at high pressure in the generator by an externalheating source. In the rectifier, the water vapour whichcarried with ammonia is removed and only the driedammonia gas enters into the condenser, where it’scondensed.

The pressure and temperature of cooled NH3solution is then reduced by a throttle valve below thetemperature of the evaporator. The NH3 refrigerant at lowtemperature enters the evaporator and absorbs the requiredheat from it, then leaves it as saturated vapour.

The low pressure NH3 vapour is then passed to theabsorber, where it’s absorbed by the NH3 weak solutionwhich is sprayed also in the absorber as shown in Fig.6.7.After absorbing NH3 vapour by the weak NH3 solution(aqua – ammonia), the weak NH3 solution becomes strong





solution and then it is pumped to the generator passingthrough the heat exchanger.

In the pump, the pressure of the strong solutionincreases to generator pressure. In the heat exchanger, heatform the high temperature weak NH3 solution is absorbed

by the strong NH3 solution coming from the absorber.As NH3 vapour comes out of the generator, the

solution in it becomes weak. The weak high temperature NH3 solution from the generator is then passed through thethrottle valve to the heat exchanger. The pressure of theliquid is reduced by the throttle valve to the absorber

pressure.

.Fig. 2: Schematic Diagram Of Solar Absorption

Refrigeration System[2]

V. SOLAR VAPOUR ABSORPTION REFRIGERATION SYSTEMMETHODOLOGY

The absorption cycle powered by solar energy is illustratedin fig.2 Low-pressure refrigerant vapour from the evaporatoris absorbed by the liquid strong solution in the absorber.The

pump receives low-pressure liquid weak solution from theabsorber, elevates the pressure of the weak solution anddelivers it to the generator. By weak solution (strongsolution) is meant that the ability of the solution to absorbthe refrigerant vapour is weak (strong). In the generator,heat from a high-temperature source by solar energy(solarcollector)drives off the refrigerant vapour in the weaksolution.

A. Solar Collector:

Solar Collectors are either non-concentrating orconcentrating. In non-concentrating type, the coolector are isthe same as the absorber area. In this types the whole solar

panel absorbs light. Concentrating collector have a biggerinterceptor than absorber.

A solar thermal collector collects heat by absorbingsunlight. A collector is a device for capturing solar radiation.solar radiation is energy in the form of electromagneticradiation from the infrared (long) to the ultraviolet (short)wavelengths. The term “Solar Collector” commonly refersto solar hot water panels, but may refer to installation suchas solar parabolic troughs.

The liquid strong solution returns to the absorberthrough a throttling valve whose purpose is to provide a

pressure drop to maintain the pressure difference between

the generator and the absorber.The high-pressure refrigerantvapour condenses into liquid in the condenser and enters theevaporator through a throttling valve, maintaining the

pressure difference between the condenser and theevaporator. In order to improve cycle performance, asolution heat exchanger is normally added to the cycle.

VI. CONCLUSION

Vapour absorption refrigeration system with R-717 asrefrigerant and water as working fluid have been studiedtheoretically. Consistently increasing CO2 emission andozone depletion from CFC’s are serious environmentalissues challenging scientific community. In conventionalrefrigeration system, compression machines are employed,which requires high-grade energy as input and this is in theform of electricity. Therefore it is better to use the Vapourabsorption refrigeration system which gives scope ofutilizing low grade energy source i.e. solar panel forgenerating cooling effect which is dominated by high gradeenergy driven compression technology. Absorption

refrigeration system provides large potential for reducingheat pollution of the environment. Therefore, in future it isdecided to compare the performance between conventionalsystems and vapour absorption system using solar thermalenergy.

VII. SCOPE FOR THE FUTURE WORK

It is obvious from the introductory part of this paper, that the basic absorption refrigeration systems can be based either onlithium bromide-water (LiBr-H 2O) where water vapour isthe refrigerant and ammonia-water (NH 3-H2O) systemswhere ammonia is the refrigerant. The future trends ofresearch in this area would be on other refrigerant pairswhich will be more effective and their main advantage isthat they do not cause ozonedepletion. Any change can bedone that can bring an overall improvement in the systemCOP or material saving or more simple design procedure.The methodology described in this work can be adopted todesign and develop a suitable system that can be mosteffectively and efficiently used maximum utilization of thesolar power.

The major limiting factor at present is theavailability of solar energy whenever it is required, forexample at nights and extended cloudy days we cannotattain a high enough temperature and hence refrigeration is

poor. Modifying the design of solar collector for wideracceptance angle and making generator tubes with materialof higher thermal conductivity yield can be improved. Thereare many other achievements carried out by researchers,nevertheless, further improvements should be made to thesolar powered refrigeration systems in order to competewith the conventional refrigeration systems.

It is hoped that these results could serve as a sourceof reference for designing and selecting new absorptionrefrigeration systems, developing new working fluid pairsand optimizing suitable operating conditions.

R EFERENCES

[1] K Karthik, “Design, Fabrication a nd Analysis of SolarVapour Absorption Refrigeration System”International Journal of Emerging Technology and





Advanced Engineering, Website: www.ijetae.com(ISSN 2250-2459, ISO 9001:2008 Certified Journal,Volume 4, Issue 9, September 2014).

[2] Dillip Kumar Mohanty, Abhijit Padhiary,“Thermodynamic Performance Analysis of a SolarVapour Absorption Refrigeration System”International Journal of Enhanced Research in ScienceTechnology & Engineering, ISSN: 2319-7463 Vol. 4Issue 4, April-2015, pp: (45-54).

[3] Sachin Kaushik, Dr. S. Singh, “ThermodynamicAnalysis of Vapor Absorption Refrigeration Systemand Calculation of COP” International Journal forResearch in Applied Science and EngineeringTechnology (IJRASET)), Vol. 2 Issue II, February2014, ISSN: 2321-9653.

[4] V.K.Bajpai, “design of solar powered vapourabsorption system”, proceeding of the world congresson engineering, 2012 vol-3.

[5] Tarik Shaikh, Prof. Yogesh J. Morabiya, “Review ofSolar Absorption Refrigeration System Using Libr-Water and Simulate The performan ce Of the System”International Journal of Advanced EngineeringResearch and Studies E-ISSN2249 – 8974.

[6] Ajay Sankar N R, Dr. S. Sankar, “Design andPerformance Analysis of a Solar Thermal AssistedVapour Absorption Air Conditioning System”International Journal of Innovative Research inScience, Engineering and Technology (An ISO 3297:2007 Certified Organization), Vol. 4, Issue 4, April2015.

[7] Tarik A. Shaikh,Yogesh J. Morabiya, “MathematicalModelling And Analysis Of Solar AbsorptionRefrigeration System” In ternational Journal ofEmerging Trends in Engineering and DevelopmentIssue 3, Vol.2 (May 2013), ISSN 2249-6149.

[8] V.D.Patel, A.J.Chaudhari, R.D.Jilte, “ Theoretical andExperimental Evaluation of Vapour AbsorptionRefrigeration System”International Journal ofEngineering Research and Applications (IJERA) ISSN:2248-9622 National Conference on Emerging Trendsin Engineering & Technology (VNCET- 30 Mar’12).

[9] Satish Raghuvanshi, Govind Maheshwari, “Analysis ofAmmonia – Water (NH 3-H 2O) Vapor AbsorptionRefrigeration System based on First Law ofThermodynamics” International Journal of Scientific &Engineering Research Volume 2, Issue 8, August-2011, ISSN 2229-5518.

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Vapour Absorption Refrigeration System By Using Solar Energy