Mathematical model of absorption and hybrid heat pump

doi:10.1016/j.cjche.2017.06.015

摘要/Abstract

摘要： Recovering waste heat from industrial processes is beneficial in order to reduce the primary energy demands and heat pumps can be used to this purpose. Absorption heat pumps are energy-saving and environment-friendly because use working fluids that do not cause ozone depletion and can reduce the global warming emissions. The hybrid heat pump processes combine the conventional vapor-compression and the absorption heat pump cycles. Studies about the simulations and modeling of hybrid heat pumps are few in literature. In this research a mathematical model for single effect absorption and hybrid heat pump is carried out with ChemCad^® 6.0.1. LiBr-H₂O is used as working fluid while electrolytic NRTL and electrolytes latent heat are used as thermodynamic model due to the better results. Binary parameters of activity coefficients are regressed from experimental vapor pressure data while default constants are used for the solubility expressions. A design of heat pumps is developed and a new modeling of generator is analyzed. The coefficient of performance of absorption heat pump and hybrid heat pump is equal to 0.7 and 0.83 respectively. For absorption heat pump a sensitivity analysis is carried out to evaluate the effect of temperature and pressure generator, the concentration of Li-Br solution on coefficient of performance, cooling capacity and working fluid temperature. For hybrid heat pump, the different coefficients of performance, the primary energy ratio, the generator heat, and the compressor power are analyzed for different values of compressor proportion. Results show that comparing the two systems the hybrid pump allows to save more primary energy, costs and carbon dioxide emissions with respect to absorption heat pump with the increasing of compressor proportion parameter. Future researches should focus on the construction of this heat pumps integrated in chemical processes as a biogas plant or trigeneration systems.

关键词: Absorption heat pumps, Hybrid heat pumps, LiBr-H₂O modeling, Energy efficiency, Process simulation, Mathematical model

Abstract: Recovering waste heat from industrial processes is beneficial in order to reduce the primary energy demands and heat pumps can be used to this purpose. Absorption heat pumps are energy-saving and environment-friendly because use working fluids that do not cause ozone depletion and can reduce the global warming emissions. The hybrid heat pump processes combine the conventional vapor-compression and the absorption heat pump cycles. Studies about the simulations and modeling of hybrid heat pumps are few in literature. In this research a mathematical model for single effect absorption and hybrid heat pump is carried out with ChemCad^® 6.0.1. LiBr-H₂O is used as working fluid while electrolytic NRTL and electrolytes latent heat are used as thermodynamic model due to the better results. Binary parameters of activity coefficients are regressed from experimental vapor pressure data while default constants are used for the solubility expressions. A design of heat pumps is developed and a new modeling of generator is analyzed. The coefficient of performance of absorption heat pump and hybrid heat pump is equal to 0.7 and 0.83 respectively. For absorption heat pump a sensitivity analysis is carried out to evaluate the effect of temperature and pressure generator, the concentration of Li-Br solution on coefficient of performance, cooling capacity and working fluid temperature. For hybrid heat pump, the different coefficients of performance, the primary energy ratio, the generator heat, and the compressor power are analyzed for different values of compressor proportion. Results show that comparing the two systems the hybrid pump allows to save more primary energy, costs and carbon dioxide emissions with respect to absorption heat pump with the increasing of compressor proportion parameter. Future researches should focus on the construction of this heat pumps integrated in chemical processes as a biogas plant or trigeneration systems.

Key words: Absorption heat pumps, Hybrid heat pumps, LiBr-H₂O modeling, Energy efficiency, Process simulation, Mathematical model

Grazia Leonzio. Mathematical model of absorption and hybrid heat pump[J]. , 2017, 25(10): 1492-1504.

参考文献

[1] R. Tozer, R.W. James, Fundamental thermodynamics of ideal absorption cycles, Int. J. Refrig. 20(1997) 120-135.
[2] V. Tufano, Simplified criteria for the development of new absorption working pairs, Appl. Therm. Eng. 18(1998) 171-177.
[3] A. Costa, B. Bakhtiari, S. Schuster, J. Paris, Integration of absorption heat pumps in a Kraft pulp process for enhanced energy efficiency, Energy 34(2009) 254-260.
[4] P. Srikhirin, S. Aphornratana, S. Chungpaibulpatana, A review of absorption refrigeration technologies, Renew. Sust. Energ. Rev. 5(2001) 343-372.
[5] J.T. Mc Mullan, Refrigeration and the environment-issues and strategies for the future, Int. J. Refrig. 25(2002) 89-99.
[6] G.A. Floride, S.A. Kalogirou, S.A. Tassou, L.C. Wrobel, Modelling, simulation 460 and warming impact assessment of a domestic-size absorption solar cooling system, Appl. Therm. Eng. 22(2002) 1313-1325.
[7] N.A. Darwish, S.H. Al-Hashimi, A.S. Al-Mansoori, Performance analysis and evaluation of a commercial absorption-refrigeration water-ammonia (ARWA) system, Int. J. Refrig. 7(2008) 1214-1223.
[8] D.S. Kim, C.A. Infante Ferreira, Analytic modelling of steady state single-effect absorption cycles, Int. J. Refrig. 31(6) (2008) 1012-1020.
[9] X. Zhang, D. Hu, Performance analysis of the single-stage absorption heat transformer using a new working pair composed of ionic liquid and water, Appl. Therm. Eng. 37(2012) 129-135.
[10] J. Sun, L. Fu, S. Zhang, W. Hou, A mathematical model with experiments of single effect absorption heta pump using LiBr-H₂O, Appl. Therm. Eng. 30(2010) 2753-2762.
[11] J.L. Rodríguez-Muñoz, J.M. Belman-Flores, Review of diffusion-absorption refrigeration technologies, Renew. Sust. Energ. Rev. 30(2014) 145-153.
[12] H.M. Hellmann, F. Ziegler, Simple absorption heat pump modules for system simulation programs, ASHRAE Trans. (1999) 780-787.
[13] O. Kaynakli, M. Kilic, Theoretical study on the effect of operating conditions on performance of absorption refrigeration system, Energy Convers. Manag. 48(2) (2007) 599-607.
[14] Z. Kravanja, I.E. Grossmann, Computational approach for the modelling/decomposition strategy in the MINLP optimization of process flowsheets with implicit models, Ind. Eng. Chem. Res. 35(1996) 2065-2070.
[15] M.S. Diaz, J.A. Bandon, A mixed integer optimization strategy for a large chemical plant in operation, Comput. Chem. Eng. 20(1996) 531-545.
[16] J.A. Caballero, D. Milan-Yanez, I.E. Grossmann, Rigorous design of distillation columns:Integration of disjunctive programming and process simulators, Ind. Eng. Chem. Res. 44(2005) 6760-6775.
[17] H. Kim, I.H. Kim, E.S. Yoon, Multi objective design of calorific value adjustment process using process simulators, Ind. Eng. Chem. Res. 49(2010) 2841-2848.
[18] R. Brunet, G. Guillen-Gosalbez, L. Jimenez, Cleaner design of single-product biotechnological facilities through the integration of process simulation, multi objective optimization, life cycle assessment, and principal component analysis, Ind. Eng. Chem. Res. 51(2012) 410-424.
[19] S.C. Kaushik, A. Arora, Energy and exergy analysis of single effect and series flow double effect water-lithium bromide absorption refrigeration systems, Int. J. Refrig. 32(2009) 1247-1258.
[20] A. Arora, S.C. Kaushik, Theoretical analysis of LiBr/H₂O absorption refrigeration systems, Int. J. Energy Res. 33(15) (2009) 1321-1340.
[21] B. Borgas, Development of the Hybrid Absorption Heat Pump Process at High Temperature Operation, Norwegian University of Science and Technology, Department of Energy and Process Engineering, 2014.
[22] D. Boer, M. Valles, A. Coronas, Performance of double effect absorption compression cycles for air-conditioning using methanol-TEGDME and TFE-TEGDME systems as working pairs, Int. J. Refrig. 21(7) (1998) 542-555.
[23] R. Ayala, C.L. Heard, F.A. Holland, Ammonia/lithium nitrate absorption/compression refrigeration cycle. Part I. Simulation, Appl. Therm. Eng. 17(1997) 223-233.
[24] G. Maurer, Electrolyte solutions, Fluid Phase Equilib. 13(1983) 269-296.
[25] E.A. Guggenheim, The specific thermodynamic properties of aqueous solutions of strong electrolytes, Philos. Mag. 19(1935) 588-643.
[26] J.N. Bronstedt, J. Amer, Calculation of the osmotic and activity functions in solutions of uni-univalents salts, J. Am. Chem. Soc. 44(5) (1922) 938-948.
[27] L.A. Bromley, Approximate individual ion values of β (or B) in extended DebyeHückel theory for uni-univalent aqueous solutions at 298.15 K, J. Chem. Thermodyn. 4(5) (1972) 669-673.
[28] K.S. Pitzer, Thermodynamics of electrolyte. I. Theorical basis and general equations, J. Phys. Chem. 77(1973) 268-277.
[29] J.L. Cruz, H. Renon, New thermodynamic representation of binary electrolyte-Solutions non-ideality in whole range of concentrations, AIChE J. 24(1978) 817-830.
[30] F.X. Ball, W. Furst, H. Renon, An NRTL model for representation and prediction of deviation from ideality in electrolyte solutions compared to the models of Chen (1982) and Pitzer (1973), AIChE J 31(1985) 392-399.
[31] C.C. Chen, L.B. Evans, A local composition model for the excess Gibbs energy of aqueous-electrolyte systems, AIChE J. 32(1986) 444-454.
[32] A. Haghtalab, J.H. Vera, A nonrandom factor model for the excess Gibbs energy of electrolyte solutions, AIChE J. 34(1988) 803-813.
[33] Y. Liu, A.H. Harvey, J.M. Prausnitz, Thermodynamics of concentrated electrolyte solutions, Chem. Eng. Commun. 77(1989) 43-66.
[34] B. Sander, P. Rasmussen, A. Fredenslund, Calculation of vapor-liquid Equilibria in nitric-acid water nitrate salt systems using an extended Uniquac equation, Chem. Eng. Sci. 41(1986) 1185-1195.
[35] E.A. Macedo, P. Skovborg, P. Rasmussen, Calculation of phase equilibria for solutions of strong electrolytes in solvent-Water mixtures, Chem. Eng. Sci. 45(1990) 875-882.
[36] J.F. Zemaitis Jr., D.M. Clark, M. Rafal, N.C. Scrivner, Handbook of Aqueous Electrolyte Thermodynamics, DIPPR, AIChE, New York, 1986.
[37] H. Renon, Electrolyte solutions, Fluid Phase Equilib. 30(1986) 181-195.
[38] K.S. Pitzer, Activity Coefficients in Electrolyte Solutions, 2nd edition CRC Press, Boca Raton, FL, 1991.
[39] M. Rafal, J.W. Berthold, N.C. Scrivner, S.L. Grise, Models for Electrolyte Solutions, in:S.I. Sandler (Ed.), Models for Thermodynamic and Phase Equilibria Calculations, Marcell Dekker, New York 1994, p. 601.
[40] J.R. Loehe, M.D. Donohue, Recent advances in modeling thermodynamic properties of aqueous strong electrolyte systems, AIChE J. 43(1997) 180-195.
[41] B.E. Conway, J.O'.M. Bockris, E. Yearg, S.U.M. Kham, R.E. White, Comprehensive Treatise of Electrochemistry, Plenum Press, New York, 1983.
[42] R.M. Mazo, C.Y. Mou, in:K.S. Pitzer (Ed.), Activity coefficients in electrolyte solutions, 2nd editionCRC Press, Boca Raton, FL, 1991.
[43] G. Grossman, K.W. Childs, Computer simulation of a lithium bromide-water absorption heat pump for temperature boosting, ASHRAE Trans. 89(1b) (1983) 240-248.
[44] G. Grossman, Modular Simulation of Absorption Systems. User's Guide and Reference Windows. Version 5.0(AbsimW), 1998.
[45] M.O. Mc Linden, S.A. Klein, Steady state modeling of absorption heat pumps with a comparison to experiments, ASHRAE Trans. 91(2b) (1985) 1793-1807.
[46] H. Perez-Blanco, M.R. Patterson, Conceptual Design and Optimization of a Versatile Absorption Heat Transformer. ORNL/TM-9841, Oak Ridge National Laboratory, 1986.
[47] G.C. Vliet, M.B. Lawson, R.A. Lithgow, Water-lithium bromide double effect absorption cooling cycle analysis, ASHRAE Trans. 88(1) (1982) 811-823.
[48] J.D. Marcos, M. Izquierdo, E. Palacios, New method for COP optimization in waterand air-cooled single and double effect LiBr-water absorption machines, Int. J. Refrig. 34(2011) 1348-1359.
[49] R. Gomri, Second law comparison of single effect and double effect vapour absorption refrigeration systems, Energy Convers. Manag. 50(2009) 1279-1287.
[50] L.M. Chavez-Islas, C.L. Heard, Optimization of a simple ammonia-water absorption refrigeration cycle by application of mixed-integer nonlinear programming, Ind. Eng. Chem. Res. 48(4) (2009) 1957-1972.
[51] L.M. Chavez-Islas, C.L. Heard, I.E. Grossmann, Synthesis and optimization of an ammonia/water absorption refrigeration cycle considering different types of heat exchangers by application of mixed-integer nonlinear programming, Ind. Eng. Chem. Res. 48(6) (2009) 2972-2990.
[52] B.H. Gebreslassie, G. Guillen-Gosalbez, L. Jimenez, D. Boer, Design of environmentally conscious absorption cooling systems via multi-objective optimization and life cycle assessment, Appl. Energy 86(9) (2009) 1712-1722.
[53] B.H. Gebreslassie, G. Guillen-Gosalbez, L. Jimenez, D. Boer, Economic performance optimization of an absorption cooling system under uncertainty, Appl. Therm. Eng. 29(17-18) (2009) 3491-3500.
[54] A. Brooke, D. Kendrick, A. Meeraus, GAMS e a User's Guide (Release 2.25), The Scientific Press, San Francisco, 1996.
[55] P.I. Barton, C.C. Pantelides, gPROMS e a combined discrete/continuous modeling environment for chemical processing systems, Simul. Ser. 25(3) (1993) 25-34.
[56] R. Fourer, D.M. Gay, B.W. Kernighan, A modeling language for mathematical programming, Manag. Sci. 36(1990) 519-554.
[57] C.R. Maya, J.J. Pacheco-Ibarra, J.M. Belman-Flores, S.R. Galván-González, C. Mendoza-Covarrubias, NLP model of a LiBr-H₂O absorption refrigeration system for the minimization of the annual operating cost, Appl. Therm. Eng. 37(2012) 10-18.
[58] M.S. Mazzei, M.C. Mussati, S.F. Mussati, NLP model-based optimal design of LiBrH₂O absorption refrigeration systems, Int. J. Refrig. 38(2014) 58-70.
[59] A. Kodal, B. Sahin, A.S. Oktem, Performance analysis of two stage combined heat pump system based on termo-economic optimization criterion, Energy Convers. Manag. 41(18) (2000) 1989-2008.
[60] A. Kodal, B. Sahin, A. Erdil, Performance analysis of a two stage irreversible heat pump under maximum heating load per unit total cost conditions, Int. J. Exergy 2(3) (2002) 159-166.
[61] A. Kodal, B. Sahin, I. Ekmekei, T. Yilmaz, Thermo economic optimization for irreversible absorption refrigerator and heat pumps, Energy Convers. Manag. 44(1) (2003) 109-123.
[62] R.D. Misra, P.K. Sahoo, S. Sahoo, A. Gupta, Thermo economic optimization of a single effect water/LiBr vapour absorption refrigeration system, Int. J. Refrig. 26(2) (2003) 158-169.
[63] R.D. Misra, P.K. Sahoo, S. Sahoo, A. Gupta, Thermo economic evaluation and optimization of a double-effect H₂O/LiBr vapour-absorption refrigeration system, Int. J. Refrig. 28(3) (2005) 331-343.
[64] R.D. Misra, P.K. Sahoo, S. Sahoo, A. Gupta, Thermo economic evaluation and optimization of an aqua-ammonia vapour absorption refrigeration system, Int. J. Refrig. 29(1) (2006) 47-59.
[65] B. Sahin, A. Kodal, Thermo economic optimization of a two stage combined refrigeration system:A finite-time approach, Int. J. Refrig. 25(7) (2002) 872-877.
[66] O. Kızılkan, A. Sencan, S.A. Kalogirou, Thermo economic optimization of a LiBr absorption refrigeration system, Chem. Eng. Process. 46(12) (2007) 1376-1384.
[67] R. Palacios Bereche, R. Gonzales Palomino, S.A. Nebra, Thermo economic analysis of a single and double-effect LiBr/H₂O absorption refrigeration system, Int. J. Thermodyn. 12(2) (2009) 89-98.
[68] C.M.R. Varani, C.A.C. Santos, R.R. Gondim, E.A. Torres, Energetic and exergetic evaluation of an lithium bromide/water absorption refrigeration system utilizing natural gas, Proc. of ECOS2003, Copenhagen, Denmark, June 30-July 22003, pp. 1597-1619.
[69] P.K. Sahoo, R.D. Misra, A. Gupta, Exergoeconomic optimisation of an aquaammonia absorption refrigeration system, Int. J. Exergy 1(1) (2005) 82-93.
[70] D.A. Al-Otaibi, I. Dincer, M. Kalyon, Thermo-economic optimization of vaporcompression refrigeration systems, Int. Commun. Heat Mass Transfer 31(1) (2004) 95-107.
[71] S. Jeong, B.H. Kang, S.W. Karng, Dynamic simulation of an absorption heat pump for recovering low-grade waste heat, Appl. Therm. Eng. 18(1998) 1-12.
[72] D.G. Fu, G. Poncia, Z. Lu, Implementation of an object-oriented dynamic modeling library for absorption refrigeration systems, Appl. Therm. Eng. 26(2006) 217-225.
[73] P. Kohlenbach, F. Ziegler, A dynamic simulation model for transient absorption chiller performance. Part I:The model, Int. J. Refrig. 31(2008) 217-225.
[74] P. Kohlenbach, F. Ziegler, A dynamic simulation model for transient absorption chiller performance. Part Ⅱ:Numerical results and experimental verification, Int. J. Refrig. 31(2008) 226-233.
[75] Y. Takagi, T. Nakamaru, Y. Nishitani, An absorption chiller model for HVACSIM+, IBPSA Conference 1999, Kyoto, Japan, September 13-15, 1999.
[76] A. Palau, E. Velo, L. Puigjaner, Use of neural networks and expert systems to control a gas/solid sorption chilling machine, Int. J. Refrig. 22(1999) 59-66.
[77] A. Myat, K. Thu, Y.D. Kim, A. Chakraborty, W.G. Chun, K.C. Ng, A second law analysis and entropy generation minimization of an absorption chiller, Appl. Therm. Eng. 31(2011) 2405-2413.
[78] G. Evola, N. Le Pierrè, F. Boudehenn, P. Papillon, Proposal and validation of a model for the dynamic simulation of a solar-assisted single-stage LiBr/water absorption chiller, Int. J. Refrig. 36(2013) 1015-1028.
[79] M. Zinet, R. Rulliere, P. Haberschill, A numerical model for the dynamic simulation of a recirculation single effect absorption chiller, Energy Convers. Manag. 62(2012) 51-63.
[80] J. Seo, Y. Shin, J. Dong Chung, Dynamics and control of solution levels in a high temperature generator for an absorption chiller, Int. J. Refrig. 35(2012) 1123-1129.
[81] A. Iranmanesh, M.A. Mehrabian, Thermodynamic modelling of a double-effect LiBr-H₂O absorption refrigeration cycle, Heat Mass Transf. 48(12) (2012) 2113-2123.
[82] A. Iranmanesh, M.A. Mehrabian, Dynamic simulation of a single-effect LiBr-H₂O absorption refrigeration cycle considering the effects of thermal masses, Energy Build. 60(2013) 47-59.
[83] V. Congradac, F. Kulic, Recognition of the importance of using artificial neural networks and genetic algorithms to optimize chiller operation, Energy Build. 47(2012) 651-658.
[84] O. Kaynakli, R. Yamankaradeniz, Thermodynamic analysis of absorption refrigeration system based on entropy generation, Curr. Sci. 92(4) (2007) 472-479.
[85] S. Aphornratana, T. Sriveerakul, Experimental studies of a single-effect absorption refrigerator using aqueous lithium-bromide:Effect of operating condition to system performance, Exp. Thermal Fluid Sci. 32(2007) 658-669.
[86] M.I. Karamangil, S. Coskun, O. Kaynakli, N. Yamankaradeniz, A simulation study of performance evaluation of single-stage absorption refrigeration system using conventional working fluids and alternatives, Renew. Sust. Energ. Rev. 14(2010) 1969-1978.
[87] K. Klein, K. Huchtemann, D. Muller, Numerical study on hybrid heat pump systems in existing buildings, Energy Build. 69(2014) 193-201.
[88] G. Bagarella, R. Lazzarin, M. Noro, Annual simulation, energy and economic analysis of hybrid heat pump systems for residential buildings, Appl. Therm. Eng. 99(2016) 485-494.
[89] F. Ziegler, G. Hammer, Experimental results of a double-lift absorption heat pump, Proc. 4th Hrernational Cotzf:On Application and Ejicieny of Heat Pump Systems in Environmentally Sensitive Times, Munich, Germany 1991, pp. 49-58(l-3 October).
[90] R. Ayala, An Experimental Study of Heat Driven Absorption Cooling Systems. Ph.D Thesis University of Salford, UK, 1995.
[91] A. Jaretun, G. Aly, New local composition model for electrolyte solutions:Multicomponent systems, Fluid Phase Equilib. 175(2000) 213-228.
[92] C.C. Chen, Y.S. Somerville, Computer method and system for predicting physical properties using a conceptual segment-based ionic activity coefficient model, US 7,809,540 B2, Oct. 5, 2010.
[93] A. Jaretun, G. Aly, New local composition model for electrolyte solutions:Single solvent, single electrolyte systems, Fluid Phase Equilib. 163(1999) 175-193.
[94] C.C. Chen, Computer method and system for predicting physical propertie using a conceptual segment model, US 8,666,675 B2, Mar. 4, 2014.
[95] C.C. Chen, Y.S. Somerville, Method of modelling physical properties of chemical mixtures and articles of use, US 8,346,525 B2, Jan. 1, 2013.
[96] J.M. Prausnitz, R.N. Lichtenthaler, E.G. de Azevedo, Molecular Thermodynamics of Fluid Phase Equilibria, third ed. Prentice Hall, New Jersey, 1999537-556.
[97] D.W. Sun, Thermodynamic design data and optimum design maps for absorption refrigeration systems, Appl. Therm. Eng. 17(1997) 211-221.
[98] G. Leonzio, Recovery of base metal sulphates and hydrochloric acid regeneration from spent pickling liquors:Process simulation, J. Clean. Prod. 129(2015) 417-426.
[99] K.E. N'Tsoukpoe, M. Perier-Muzet, N. Le Pierres, L. Luo, D. Mangin, Thermodynamic study of a LiBr-H₂O absorption process for solar heat storage with crystallisation of the solution, Sol. Energy 104(2014) 2-15.
[100] A.M.K. Bahman, Modeling of Solar-Powered Single-Effect Absorption Cooling System and Supermarket Refrigeration/HVAC System, PhD Thesis, University of South Florida, 2011.
[101] T. Berlitz, B. Cerkvenik, H.M. Hellmann, F. Ziegler, The impact of work input sorption cycles, Int. J. Refrig. 24(2001) 88-99.
[102] K.E. Herold, R. Radermacher, S.A. Klein, Absorption Chillers and Heat Pumps, CRC Press Inc., 1996
[103] B. Bakhtiari, L. Fradette, R. Legros, J. Paris, A model for analysis and design of H₂O-LiBr absorption heat pumps, Energy Convers. Manag. 52(2011) 1439-1448.
[104] W. Wu, X. Zhang, X. Li, W. Shi, B. Wang, Comparisons of different working pairs and cycles on the performance of absorption heat pump for heating and domestic hot water in cold regions, Appl. Therm. Eng. 48(2012) 349-358.
[105] Z. Hariz, Analysis of Absorption Chiller for Heat Recovery Purpose, Final Year Project, Faculty of Engineering-Branch Ⅲ-Lebanese University, Lebanon, 2003.
[106] N. Zang, K. Wang, N. Lior, W. Han, Performance study and energy saving mechanism analysis of an absorption/mechanical hybrid heat pump cycle, The 28th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, June 30-July 3, Pau, France, 2015.
[107] D. Boer, M.H. Huor, M. Prevost, A. Coronas, Combined vapour-compression-double effect absorption cycle for air conditioning:a new high performance cycle, Proc. IAHP Conf., New Orleans, LA. ASME, AES 311994, pp. 483-486.
[108] N. Sawada, K. Minato, Y. Kunugi, T. Mochizuki, T. Kashiwagi, Cycle simulation/COP evaluation of compression hybrid Heat pump:heat amplifier type, in:Proceedings of the International Absorption Heat Pump Conference (Ed.) 31, ASME AES, New Orleans 1994, pp. 471-476.