Experimental study of a thermochemical compressor for an absorption/compression hybrid cycle

An experimental study of a thermochemical compressor with ammonia–lithium nitrate solution as working fluid has been carried out. This compressor incorporates a single-pass adiabatic absorber and all the heat exchangers are of the plate type: absorber subcooler, generator and solution heat exchanger. The thermochemical compressor has been studied as part of a single-effect absorption chiller hybridized with an in-series low-pressure compression booster. The adiabatic absorber uses fog jet injectors. The generator hot water temperatures for the external driving flow are in the range of 57–110°C and the absorber pressures range between 429 and 945kPa. Experimental results are compared with a numerical model showing a high agreement. The performance of the thermochemical compressor, evaluated through the circulation ratio, improves for higher absorber pressures, indicating the potential of pressure boosting. For the same circulation ratio, the driving hot water inlet temperature decreases with the rise of the absorber pressure. The thermochemical compressor, based on an adiabatic absorber, can produce refrigerant with very low driving temperatures, between 57 and 70°C, what is interesting for solar cooling applications and very low temperature residual heat recovery. Efficiencies and cooling power are offered when this hybrid thermochemical compressor is implemented in a chiller, showing the effect of different operating parameters.

[1]  A. Coronas,et al.  Flow boiling heat transfer of ammonia/water mixture in a plate heat exchanger , 2010 .

[2]  M. Venegas,et al.  Boiling heat transfer and pressure drop of ammonia-lithium nitrate solution in a plate generator , 2010 .

[3]  Da-Wen Sun,et al.  Comparison of the performances of NH3-H2O, NH3-LiNO3 and NH3-NaSCN absorption refrigeration systems , 1998 .

[4]  Shenyi Wu,et al.  Innovations in vapour-absorption cycles , 2000 .

[5]  N. I. Grigor'eva,et al.  Combined heat and mass transfer during absorption in drops and films , 1977 .

[6]  Reinhard Radermacher,et al.  Absorption Chillers and Heat Pumps , 1996 .

[7]  M. Izquierdo,et al.  Spray absorbers in absorption systems using lithium nitrate–ammonia solution , 2005 .

[8]  A. Ousaka,et al.  Analysis of steam absorption by a subcooled droplet of aqueous solution of LiBr , 1992 .

[9]  M. Venegas,et al.  Optimum hot water temperature for absorption solar cooling , 2009 .

[10]  M. Udayakumar,et al.  Studies of compressor pressure ratio effect on GAXAC (generator–absorber–exchange absorption compression) cooler , 2008 .

[11]  P. Riesch,et al.  A cost effective absorption chiller with plate heat exchangers using water and hydroxides , 1998 .

[12]  M. Udayakumar,et al.  Heat transfer studies on a GAXAC (generator-absorber-exchange absorption compression) cooler , 2009 .

[13]  M. Venegas,et al.  Ammonia-lithium nitrate absorption chiller with an integrated low-pressure compression booster cycle for low driving temperatures. , 2010 .

[14]  A. Z. Santiago.  Transferencia de masa y calor en absorbedores adiabáticos con aplicación de la disolución nitrato de litio-amoniaco , 2011 .

[15]  R. Lizarte,et al.  Evaluation of mass absorption in LiBr flat-fan sheets , 2009 .

[16]  A. Coronas,et al.  Vapor−Liquid Equilibrium of Ammonia + Lithium Nitrate + Water and Ammonia + Lithium Nitrate Solutions from (293.15 to 353.15) K , 2007 .

[17]  William M. Worek,et al.  Adiabatic water absorption properties of an aqueous absorbent at very low pressures in a spray absorber , 2006 .

[18]  Saman K. Halgamuge,et al.  Mathematical modeling and experimental verification of an absorption chiller including three dimensional temperature and concentration distributions , 2013 .

[19]  R. Ventas,et al.  On the recirculation of ammonia-lithium nitrate in adiabatic absorbers for chillers , 2010 .

[20]  M. Izquierdo,et al.  Heat and mass transfer during absorption of ammonia vapour by LiNO3–NH3 solution droplets , 2004 .

[21]  William A. Ryan.  Water absorption in an adiabatic spray of aqueous lithium bromide solution , 1994 .

[22]  W. Rivera,et al.  Thermodynamic design data for absorption heat pump systems operating on ammonia-lithium nitrate—Part two. Heating , 1991 .

[23]  M. Venegas,et al.  Experimental assessment of ammonia adiabatic absorption into ammonia–lithium nitrate solution using a flat fan nozzle , 2011 .

[24]  W. Beckman,et al.  Solar Engineering of Thermal Processes , 1985 .