Performance Analysis of Absorption Refrigeration Cycles B

Home , Sodium thiocyanate

International Journal of Advanced Engineering Research and Science (IJAERS) [Vol-4, Issue-1, Jan- 2017] https://dx.doi.org/10.22161/ijaers.4.1.23 ISSN: 2349-6495(P) | 2456-1908(O) Performance Analysis of Absorption Refrigeration Cycles B. Anusha1, B. Chaitanya2

1Department of Mechanical , Gudlavalleru Engineering College/JNTU K, India 2Department of Mechanical, V R Siddhartha Engineering College/JNTU K, India

Abstract– The thermodynamic analysis of a vapor supply have made people contemplate greater use of absorption refrigeration system employing ammonia as renewable energy sources. Apart from this, use of the refrigerant are presented. The thermodynamic refrigerants with high global warming potential, CO2 analysis of these three combination of the absorption emissions from the combustion of fossil fuels in the pairs namely NH3/H2O, NH3/LiNO3, NH3/NaSCN are power generation lead to effects detrimental to the performed. The best alternative to the ammonia water environment. In such cases, alternative sustainable absorption pair are proposed as ammonia lithium nitrate technologies are desirable to attain a holistic and ammonia- sodium thiocyanate. It is very much environmental safety. important to select a prominent working substance and Absorption refrigeration systems are environment their properties have great effect on the system friendly as they use low grade nts, industrial plants and performance. Detailed thermodynamic properties of these automobile emissions, and the low global warming fluids are expressed in polynomial equations. Energy and potential. Although huge efforts have been spared over entropy balance equations are applied to analyse each of several past decades in this field, COP of the sorption the process to estimate the individual heat transfer and refrigeration system is still quite low compared to vapor entropy generation rates for all the systems. Among these compression refrigeration systems; thus there is an urgent three pairs NH3/ NaSCN yields the highest coefficient of need for further improvements in material, component performance. Cooling/Heating of the generator/absorber and overall system design to make these systems a viable results in significant entropy generation in all the alternative to vapor compression systems. systems. The solution heat exchanger significantly Absorption refrigeration system uses various refrigerant- improves the performance of the cycle and yields in the absorbent combinations known as the solution pairs, it is better cooling output. important to select the appropriate working substance the Keywords– absorption, refrigerant, evaporator, properties of which have a great effect on the vaporizes, high temperature. performance of the cycles. The absorbent acts as a secondary fluid to absorb the primary fluid which is the I. INTRODUCTION refrigerant in its vapor phase. The most widely used In recent years, growing energy needs, cooling load working fluid pairs in absorption refrigeration system demand in industrial, commercial, domestic sectors, have been ammonia-water and water-lithium bromide scarcity of fossil fuels, rise in fuel price and faulty power solutions. Assumptions used in the simulation Table.1: Working pairs for refrigeration applications 1. Simulations and analyses are performed under Liquid-gas Solid-gas Adsorption steady conditions. (Absorption/ (Absorption/ 2. Conditions of the refrigerant (ammonia) at the exits Chemical reaction) Chemical of the condenser and the evaporator are saturated. reaction) 3. The solution is at equilibrium conditions at the

CH3NH2/H2O/LiBr H2O/LiCl C2H5OH/PX21 exits of the absorber and the generator and at the

CH3NH2/LiSCN H2O/NaI C3H8/PX21 corresponding device temperatures

CH3OH/LiBr H2O/K2CO3 CH3NH2/PX21 4. Pressure losses due to friction in the heat

CH3OH/LiBr/ H2O H2O/Na2S NH3/PX21 exchangers and the connecting piping are

H2O/ H2SO4 H2O/MgCl2 SO2/PX21 negligible.

H2O/LiBr H2O/CaCl2 H2O/Silica gel 5. Heat exchanges between the systems and the

H2O/NaOH H2O/CaSO4 C2H5OH/TA90 surroundings, other than that prescribed by heat

NH3/H2O H2O/LiB CH3NH2/TA90 transfer at the generator, evaporator, condenser and absorber, are assumed negligible. www.ijaers.com Page | 149 International Journal of Advanced Engineering Research and Science (IJAERS) [Vol-4, Issue-1, Jan- 2017] https://dx.doi.org/10.22161/ijaers.4.1.22 ISSN: 2349-6495(P) | 2456-1908(O) 6. Simulations and analyses are carried out for a refrigerant mixture leaving the generator before reaching constant refrigeration capacity in all the systems. the condenser. 7. The reference environment state for the system is the average temperature of the heat rejection media and 100 K Pa. 8. Salt properties such as density and specific heat are constant.

II. WORKING PRINCIPLE The essential components of the vapor absorption system are an evaporator, an absorber, a generator, a condenser, a expansion valve, a pump, a solution heat exchanger. The compressor in the vapor compression system is replaced with an absorber, generator, pump, solution heat exchanger. Heat flows in the system at generator and it is directly added from the heat source like fuel burner, steam and work input takes place at pump for increasing the pressure and temperature what exactly compressor does in the vapor compression system. Heat rejection takes place at the absorber. The solution commonly used FIRST LAW OF THERMODYNAMICS is aqua- ammonia. For the generator mass and energy balance is given Figure 1 shows the layout of the single effect absorption m7=+ m 1 m 8 (total mass balance) …..1 refrigeration system. The single effect cycle works m7 X 7=+ m 1 m 8 X 8 (NH3 balance) ….2 between the two pressure levels, where higher pressure is Qg = m1 h 1 + m 8 h 8 - m 7 h 7 at generator and condenser and the lower pressure is at The flow rates of the strong and weak solutions are absorber and evaporator. In this cycle the refrigerant used determined from the equations (1) and (12) is the ammonia. High pressure liquid refrigerant 2 from 1- X 7 the condenser passes into the evaporator 4 through an mm81= XX78- expansion value 3 that reduces the pressure of the 1- X 8 ………..(3) refrigerant to the low pressure in the evaporator. The mm71= XX78- liquid refrigerant vaporizes in the evaporator by absorbing The circulation ratio of the system is derived from the latent heat from the material being cooled and the equation (3) as resulting low pressure vapor 4 passes to the absorber, m7 where it is absorbed by the strong solution 8 coming from f = m1 the generator through an expansion value 10 and forms The energy balance for the solution heat exchanger is as the weak solution 5. The weak solution exists in the follows absorber and its pressure is raised to the generator TETET9=ex 6 +(1 - ex ) 8 pressure by means of the pump 6 and this solution is pre m8 heated by the solution heat exchanger 7 using the heat h7= h 6 +() h 8 - h 9 released by the strong solution 8 from the generator. The m6 solution heat exchanger increases the cycle efficiency by The increase in energy by using pumping is avoiding the need to add that heat in the generator. In the h6= h 5 +() P 6 - P 5 v 6 generator a high temperature heat source is required to Wme =-() P6 P 5 v 6 generate refrigerant vapor 1 from the weak solution. This The energy balance for the absorber is given by refrigerant vapor 1 flows through the circuit and first Qa = m4 h 4 + m 10 h 10 - m 5 h 5 becomes a liquid in the condenser and rejects heat to the The energy balance for the condenser is given by cooling medium and the cycle repeats. The definition by Qc =- m1() h 1 h 2 ASHRAE to the weak/strong solution is that the ability of The energy balance for the evaporator is given by the solution to absorb the refrigerant vapor is Qe =- m1() h 4 h 3 weak/strong. If this cycle works on the ammonia water absorption pair then this had a added advantage of using The first law of thermodynamics for the basic cycle is the rectifier and analyzer to remove water vapor from the given by www.ijaers.com Page | 150 International Journal of Advanced Engineering Research and Science (IJAERS) [Vol-4, Issue-1, Jan- 2017] https://dx.doi.org/10.22161/ijaers.4.1.22 ISSN: 2349-6495(P) | 2456-1908(O)

100 QQQQg+ a + c + e = 0

The ideal COP is given by 80 NH3 - LiNO3

()TTTg- a c NH3 - H2O ideal COP = 60 NH3-NaSCN TTTg() a- c TC = 25°C

TE = -5°C 40 TA = 25°C

CirculationFactor (f) III. RESULTS AND DISCUSSION E ex = 80% 100 20

80 0 NH3 - LiNO3 330 335 340 345 350 355 360 365 370 Generator Temperature (TG, K) NH3 - H2O 60 NH3-NaSCN Fig. 4: Effect of COP on evaporator temperature TC = 25°C TE = -5°C 40 Comparison of the circulation factor values with the TA = 25°C CirculationFactor (f) E ex = 80% generator temperatures. The circulation ratio for the 20 NH3/NaSCN cycle is higher than that of the other two cycles. This is that either the solution pump needs to run 0 330 335 340 345 350 355 360 365 370 faster or a bigger pump is required. If the generator Generator Temperature (T , K) G temperature reaches its low temperature limit then Fig. 2: Effect of COP on generator temperature circulation factor increases tremondeously, but it is highly

impossible to operate a cycle at low temperature. With the increase in the generator temperature the COP 0.74 values also increases. By these comparision NH3/NaSCN 0.72 has the best performance where the generature is at its 0.7 temperature in higher limit. The NH3/LiNO3 gives the 0.68 best performance at its lower generator temperature that is 0.66 TC = 25°C by using the solar energy etc. NH3/H2O has the lowest COP 0.64 TG = 90°C performance. 0.62 TA = 25°C NH - H O 100 3 2 E ex = 80% 0.6 NH3-LiNO3

0.58 NH -NaSCN 80 3 NH3 - LiNO3 0.56 NH - H O 3 2 260 265 270 275 280 285 290 NH -NaSCN 60 3 Evaporator Temperature (TE, K) TC = 25°C Fig . 5: Effect of circulation factor with Evaporator TE = -5°C 40 temperature TA = 25°C CirculationFactor (f) E ex = 80% 20 Comparision of the COP values with the evaporator temperature for the three absorption pairs. With the 0 330 335 340 345 350 355 360 365 370 increase in the evaporator values the COP values also Generator Temperature (T , K) G increases. But for the evaporator temperature lower than Fig. 3: Effect of circulation ratio with generator zero temperature range for the refrigeration the temperature NH /NaSCN gives the better performance and the 3 ammonia/water cycle has lower COP values. However for Comparison of the circulation factor values with the the high evaporator temperatures the performance of the generator temperatures. The circulation ratio for the ammonia/water pairs gives better than NH3/LiNO3. NH3/NaSCN cycle is higher than that of the other two cycles. This is that either the solution pump needs to run faster or a bigger pump is required. If the generator temperature reaches its low temperature limit then circulation factor increases tremendously, but it is highly impossible to operate a cycle at low temperature.

www.ijaers.com Page | 151 International Journal of Advanced Engineering Research and Science (IJAERS) [Vol-4, Issue-1, Jan- 2017] https://dx.doi.org/10.22161/ijaers.4.1.22 ISSN: 2349-6495(P) | 2456-1908(O) 7 Comparison of the circulation factor with the condenser NH3 - H2O 6 temperature for all the three absorption pairs. By the NH3-LiNO3

NH3-NaSCN increase in the condenser temperature the circulation 5 factor values also increases. And among all these the

4 absorption pair ammonia/sodium thiocyanate has the better performance.

CirculationFactor (f) 3 0.7

TC = 25°C 0.68 2 TG = 90°C 0.66 TA = 25°C E ex = 80% 1 0.64 260 265 270 275 280 285 290 0.62 Evaporator Temperature (TE, K) COP Fig. 6: Effect of COP on condenser temperature 0.6 NH3 - H2O 0.58 TC = 25°C NH3-LiNO3 TE = -5°C T = 90°C The comparison of the circulation factor with evaporator 0.56 NH -NaSCN G 3 E ex = 80% temperature over the three absorption pairs. But the 0.54 circulation factor for the NH3/NaSCN cycle has best 285 290 295 300 305 310 performance and is higher than the other two cycles. AbsorberTemperature (TA, K)

0.675 Fig. 9 : Effect of circulation factor with Absorber 0.65 Temperature 0.625 0.6 Comparison of the effect of COP values with the absorber

COP 0.575 NH3 - H2O temperature for all the three absorption pairs. The effect 0.55 NH3-NaSCN TG = 90°C of the absorber temperature is as similar to the condenser 0.525 TE = -5°C temperature values. As our assumptions both the 0.5 TA = 25°C E = 80% 0.475 ex condenser and the absorber should be at the same level.

0.45 As on the absorber temperature increases there is a 285 290 295 300 305 310 315 decrease in the COP values. Condenser Temperature (TC, K) Fig. 7: Effect of circulation factor with condenser 9

temperature 8 NH3 - H2O 7 Comparison of the COP values with the change in the NH3-LiNO3 6 NH -NaSCN condenser values for all the three absorption pairs. By the 3 T = 25°C increasing in the condenser temperature results in the 5 C CirculationFactor (f) TE = -5°C decrease in the COP values. For the lower condenser 4 TG = 90°C temperature the absorption pair NH3/NaSCN pair has 3 E ex = 80% better performance and for higher condenser temperatures 2 285 290 295 300 305 310 315 the absorption pair NH3/LiNO3 has the better AbsorberTemperature (TA, K) performance. Fig. 10: Effect of external entropy with Generator 14

NH3 - H2O temperature 12 NH3-LiNO3 NH -NaSCN 3 Comparison of the circulation factor with the increase in 10 E ex = 80%

TC = 25°C the absorber temperature for all the three absorption pairs. 8 TG = 90°C The effect of the absorber temperature is as similar to the TA = 25°C 6 condenser temperature as they are working at the same

CirculationFactor (f) temperature levels. As on the absorber temperature 4 increases there is a increase in the circulation factor.

2 Among these three absorption pairs the NH3/NaSCN has 285 290 295 300 305 310 315 320

Condenser Temperature (TC, K) the higher value than the remaining two absorption pairs, Fig. 8: Effect of COP with Absorber temperature next to that NH3/LiNO3.

www.ijaers.com Page | 152 International Journal of Advanced Engineering Research and Science (IJAERS) [Vol-4, Issue-1, Jan- 2017] https://dx.doi.org/10.22161/ijaers.4.1.22 ISSN: 2349-6495(P) | 2456-1908(O) 0.18 Comparison of the effect of the total entropy with the 0.16

NH -NaSCN generator temperature for all the three absorption 0.14 3 NH3-LiNO3 pairs.For the absorption pair ammonia/water first at the 0.12 NH3-H2O initial condition it increases tremendously and then falls 0.1

0.08 suddenly to a lower value and slightly increases. By the ExternalEntropy 0.06 increase in the generator temperature the total entropy

0.04 slightly increases for the two cases that is ammonia/

0.02 NaSCN and ammonia/lithium nitrate. Here total entropy

330 335 340 345 350 355 360 365 370 is by the sum of internal and external entropy. 3.8 Generator Temperature

Fig. 11: Effect of Internal Entropy with Generator 3.6 temperature NH3-NaSCN 3.4 NH3-LiNO3 Comparison of the effect of the external entropy with the 3.2 NH3-H2O generator temperature for all the three absorption pairs. 3

By the increase in the generator temperature the external Carnot,Ext,Temps[i] 2.8 entropy slightly increases for the two cases that is COP 2.6 ammonia/sodium- thiocyanate and ammonia/lithium 2.4 nitrate. For the absorption pair ammonia/water first at the 2.2 initial condition it increases tremendously and then falls 330 335 340 345 350 355 360 365 370 suddenly to a lower value and slightly increases. This Generator Temperature external entropy is due to the heat transfer between the Fig.13 : Effect of carnot COP with Generator heat source and the generator Temperature 0.045 0.04 Comparison of the Carnot COP to the generator NH -NaSCN 0.035 3 temperature is given for the three absorption pairs. As the NH3-LiNO3 0.03 NH3-H2O generator temperature increases the Carnot COP also 0.025 increases similarly for all the three. Here Carnot COP is 0.02 considered as the base line COP and compared with them.

Internal Entropy 0.019 0.015 0.018 0.01 0.017 0.005 330 335 340 345 350 355 360 365 370 0.016 Generator Temperature 0.015 Fig .12: Effect of Total Entropy with Generator 0.014

Temperature External Entropy NH -NaSCN 0.013 3

NH -LiNO For the absorption pair ammonia/water first at the initial 0.012 3 3 NH3-H2O condition it increases tremendously and then falls 0.011 0.01 suddenly to a lower value and slightly increases. By the 290 292 294 296 298 300 302 304 increase in the generator temperature the internal entropy Condenser temperature slightly increases for the two cases that is Fig .14: Effect of External Entropy with condenser ammonia/NaSCN and ammonia/lithium nitrate. temperature 0.24

0.2 Comparison of the effect of external entropy with the NH3-H2O condenser temperature for all the three pairs that are used 0.16 NH3-LiNO3

NH3-H2O for the absorption. Here as the condenser temperature 0.12 increases the external entropy decreases for all the three Total Entropy 0.08 pairs. Among them the absorption pair ammonia/water has the highest entropy generation, next to that 0.04 ammonia/LiNO3 has the highest external entropy. The 0 330 335 340 345 350 355 360 365 370 lowest entropy generation is for the ammonia/NaSCN Generator Temperature absorption pair. Fig .12: Effect of Total Entropy with Generator Temperature www.ijaers.com Page | 153 International Journal of Advanced Engineering Research and Science (IJAERS) [Vol-4, Issue-1, Jan- 2017] https://dx.doi.org/10.22161/ijaers.4.1.22 ISSN: 2349-6495(P) | 2456-1908(O)

0.74 8

0.72 7

0.7 NH3-NaSCN 6 NH -LiNO 0.68 3 3

NH3-H2O 0.66 5 TC = 25°C COP

T = 90°C Carnot,Ext,Temps[i] 0.64 G 4

0.62 TA = 25°C COP NH - H O 3 2 E ex = 80% 3 0.6 NH3-LiNO3 2 0.58 NH3-NaSCN

290 292 294 296 298 300 302 304 0.56 260 265 270 275 280 285 290 Condenser Temperature Evaporator Temperature (TE, K) Fig.17: Effect of Carnot COP with Condenser Fig . 15: Effect of Internal entropy with condenser temperature temperature Comparison of the Carnot COP to the condenser Comparison of the effect of internal entropy with the temperature is given for all the three absorption pairs. As condenser temperature for all the three pairs that are used the condenser temperature increases the Carnot COP for the absorption. Here as the condenser temperature decreases similarly for all the three absorption pairs. Here increases the internal entropy also increases for all the Carnot COP is considered as the base line COP and three pairs. Among them the absorption pair compared with these three absorption pairs and the COP ammonia/water has the highest internal entropy that is obtained from the first and second laws is generated, and next to that ammonia/LiNO3 has the compared. highest internal entropy. The lowest internal entropy generation is for the ammonia/NaSCN absorption pair. 0.014 0.025

0.024 0.0135 0.023

0.022 0.013 NH3-NaSCN

0.021 ExternalEntropy

NH3-LiNO3 0.02

Total Entropy 0.0125 NH3-NaSCN 0.019 NH3-H2O

NH3-H2O 0.018 0.012 NH3-LiNO3 260 262 264 266 268 270 272 274 276 0.017 Evaporator Temperature 0.016 290 292 294 296 298 300 302 304 Fig.18: Effect of the External entropy with evaporator Condenser Temperature temperature Fig. 16 : Effect of total entropy with Condenser

temperature The effect of the external entropy with the evaporator

temperature for all the three absorption pairs are Comparison of the effect of external entropy with the compared. As the evaporator temperature increases the condenser temperature for all the three pairs that are used external entropy also increases. Among all these for the absorption. Here as the condenser temperature absorption pairs NH3/H2O has the highest entropy but as increases the total entropy decreases for all the three the evaporator temperature is increasing there is a sudden pairs. Among them the absorption pair ammonia/H2O has increase in the ammonia/LiNO3 at the end and increases the highest total entropy generated and next to that than NH3/H2O pair. The lowest entropy is for the ammonia/LiNO has the highest total entropy. The lowest 3 ammonia/NaSCN pair. total entropy generation is for the ammonia/NaSCN absorption pair. Total entropy is obtained from the both internal and external entropy.

www.ijaers.com Page | 154 International Journal of Advanced Engineering Research and Science (IJAERS) [Vol-4, Issue-1, Jan- 2017] https://dx.doi.org/10.22161/ijaers.4.1.22 ISSN: 2349-6495(P) | 2456-1908(O) 0.0068 Comparison of the Carnot COP to the evaporator

0.0066 NH3-NaSCN temperature is given for the three absorption pairs. As the evaporator temperature increases the Carnot COP also 0.0064 NH3-LiNO3 increases dramatically for all the absorption pairs. Here NH3-H2O 0.0062 Carnot COP is considered as the base line COP and compared with the first and second law COP. InternalEntropy 0.006

0.0058 IV. CONCLUSIONS 1. Results for all the three combinations of the 0.0056 260 262 264 266 268 270 272 274 absorption pairs such as ammonia/water, Evaporator Temperature ammonia/lithium nitrate and ammonia/sodium Fig.19: Effect of internal Entropy with evaporator thiocyanate are compared. Temperature 2. The ammonia-water absorption pair is mainly used for the refrigeration temperatures below 00c. As the evaporator temperature increases the internal 3. The thermodynamic properties of these absorption entropy also decreases. Among all these absorption pairs pairs are expressed in polynomial equations. NH3/H2O has the highest entropy but as the evaporator 4. The performances against various generator, temperature is increasing there is a sudden increase in the absorber, condenser and evaporator are compared ammonia/LiNO3 at the end and increases than for all the three absorption pairs. NH3/H2Opair. 5. The result shows that the ammonia/NaSCN and 0.02025 ammonia/LiNO3 gives the better performance than

0.02 the ammonia/H2O pair. 6. The absorption pairs have the better performance not 0.01975 NH3-NaSCN only because of the higher COP but also because of 0.0195 NH3-LiNO3 the no requirement of analyzers and rectifiers.

TotalEntropy NH3-H2O 0.01925 7. Ammonia/NaSCN cycle cannot operate at the evaporator temperature below -100c for the 0.019 possibility of crystallization.

0.01875 8. But generally speaking ammonia/ sodium 260 262 264 266 268 270 272 274 thiocyanate and ammonia/ lithium-nitrate have Evaporator Temperature similar performance but operate at higher and lower Fig. 20: Effect of the Total Entropy with Evaporator temperature limits. Temperature 9. The first law and second law analysis are carried out and the COP‘s are compared. The total entropy for the ammonia/water first increases 10. Energy and entropy balance equations are applied to and then decreases slightly. For the ammonia/lithium analyze each of the process to estimate the nitrate it increases and has the highest value as on the individual heat transfer and entropy generation rates evaporator temperature increases. As usual the entropy is for all the systems. lowest for ammonia/sodium thiocyanate absorption pair. 11. The entropy generated is higher for the 6 ammonia/water pair and least for the 5.5 ammonia/sodium thiocyanate pair. NH3-NaSCN 5 NH3-LiNO3 4.5 NH3-H2O REFERENCES 4

Carnot,Ext,Temps[i] [1] Alefeld, G. and Radermacher, R. (1994), Heat

COP 3.5 Conversion Systems, CRC Press, Boca Raton.

3 [2] Aristov, Yu. I., and Vasiliev, L. L. (2005), New

2.5 composite sorbents of water and ammonia for chemical and adsorption heat pumps, Journal of 2 260 262 264 266 268 270 272 274 Engineering Physics and Thermo-physics, vol. 79, Evaporator Temperature no. 6, pp. 1214-1229. Fig. 21: Effect of the Carnot COP with the Evaporator [3] Castaing, J.L. and Neveu, P. (1997), Equivalent Temperature Carnot cycle concept applied to a thermo-chemical www.ijaers.com Page | 155 International Journal of Advanced Engineering Research and Science (IJAERS) [Vol-4, Issue-1, Jan- 2017] https://dx.doi.org/10.22161/ijaers.4.1.22 ISSN: 2349-6495(P) | 2456-1908(O) solid/gas re-sorption system, Applied Thermal Engineering, vol. 18, pp.745-754 [4] Meunier, F. (1993), Solid sorption: An alternative to CFCs, Heat Recovery Systems and CHP, vol. 13, no.4, pp. 286-295 [5] Meunier, F., Koushik, S.C., Neven, P. and Poyelle, F. (1996), A comparative thermodynamic study of sorption systems: second law analysis. International Journal of Refrigeration, vol. 19, pp. 414-421. [6] Meunier, F. (1998), Solid sorption heat powered cycles for cooling and heat pumping applications, Applied Thermal Engineering, vol. 18, pp. 715-729. [7] Munier, D. and Goetz, V, (2001), Energy storage comparison of sorption systems for cooling and refrigeration, Solar Energy, vol. 71, no, 1, pp. 47-55 [8] Sharonov, V.E. and Aristov, Y.I.(2008), Ammonia

adsorption by MgCl2, CaCl2 and BaCl2 confined to porous alumina: the fixed bed adsorber, Reaction Kinetics and Catalysis Letters, vol. 85, pp. 183-188. [9] Farshi, L. G., Ferreira, I. C. A., Mahmoudi, S.M.S., Rosen, M.A., (2013), First and Second law analysis of ammonia/salt absorption refrigeration systems, International Journal Of Refrigeration, In-press. [10] Sargent, S.L. and Beckman, W.A., (1973), Theoretical performance of an ammonia- sodium thiocyanate intermittent absorption refrigeration cycle, Solar Energy, vol. 12, pp.137-146.