Faculty

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Research interests

• Development of Low GWP Refrigerant mixtures
• Improvement of efficiency of Refrigeration and Air conditioning Systems
• New refrigeration and liquefaction processes operating with mixtures
• Heat exchangers – Modelling, additive manufacturing, testing
• Thermodynamics of mixtures

Courses taught

• ME1100 Thermodynamics (Undergraduate)
• ME3250 Refrigeration and Air Conditioning (Undergraduate)
• ME4100 Design Project (Undergraduate)
• ME6003 Refrigeration and Cryogenics (Graduate)
• ME5134  Process Simulation (Graduate)

Patents Granted

• Venkatarathnam, G., Refrigerant composition and process for preparation thereof, US Patent No. 7722780 (2010)
• Venkatarathnam, G., Refrigerant composition for refrigeration systems, US Patent No. 7582223 (2010)
• Venkatarathnam, G., A refrigerant composition for refrigeration systems, India Patent No. 211627 (2007)
• Venkatarathnam, G., A refrigerant composition for a single stage refrigeration system, India Patent No. 205644 (2007)
• Venkatarathnam, G., A refrigerant composition for refrigeration systems, India Patent No. 197997 (2006)

Patents Applications Pending

Three Indian, One PCT Applications pending

Technologies developed and available for commercialisation

1. Battery coolers
2. Perforated plate matrix heat exchangers
3. Biofreezers
4. Mixed refrigerant cycle refrigerator operating between -40 °C and -100 °C
5. Mixed refrigerant cycle refrigerator operating between 70 and 150 K
6. Mixed refrigerant cycle nitrogen liquefier with a liquefaction rate of 0.7-0.9 l/hr and a power input of about 1.5 kW

Thermodynamic Methods and Routines

Our phase identification parameter is actively used in the fitting of Helmholtz energy equations of state of a number of fluids at NIST and elsewhere. Similarly, our Density marching methods for phase envelope calculations are used in a number of process simulation and thermodynamic programs. Here are some of the well known software that use our methods and routines:

• NIST Refprop property program – Phase identification method, phase envelope routine, true mixture critical point routine
• Aspen Plus Process simulation software – Two and Three Phase envelope calculation methods
• Aspen Hysys Process simulation software – Phase identification method
• Coolprop property program – Phase identification method, Phase envelope calculation method

Selected Publications

Books & Handbook Chapters

1. G. Venkatarathnam, Cryogenic Mixed Refrigerant Processes, Springer, NY, 2008
2. G. Venkatarathnam, Cryogenic Heat Exchangers, Heat Exchanger Design Handbook, Begell House, 2016

Journals & Conferences

1. H. Gurudath Nayak and  G. Venkatarathnam, Performance of an auto refrigerant cascade refrigerator operating in gas refrigerant supply mode with optimized nitrogen- hydrocarbon refrigerant mixtures, Paper No. PA-C-001,the sixth International Conference on Cryogenics and Refrigeration, April 12–14, 2018 at Shanghai Jiao Tong University, Shanghai, China
2. R. Satya Maher and G. Venkatarathnam, Estimation of performance of a J-T Refrigerators Operating With Nitrogen-Hydrocarbon Mixtures and a Coiled tubes-in-tube heat exchanger, Cryogenics, 92, 27-35 (2018)
3. I.Sujatha and G. Venkatarathnam, Comparison of performance of a vapor absorption refrigeration system operating with some hydrofluorocarbons and hydrofluoroolefins as refrigerants along with ionic liquid [hmim][TF2N] as the absorbent, Int. J. Refrigeration, 88,370-382 (2018)
4. V. Narayanan and G. Venkatarathnam, Prediction of Vapour-Liquid and Vapour-Liquid-Liquid equilibria of nitrogen-hydrocarbon mixtures used in J-T refrigerators, Cryogenics, 90, 70-85 (2018)
5. G. Venkatarathnam, density marching method for drawing phase envelopes: 3. P-xy diagrams of binary mixtures, Ind. Eng. Chem. Res., 56 (46),  13894–13904  (2017)
6. I. Sujatha and G. Venkatarathnam, Performance of a vapor absorption heat transformer operating with ionic liquids and ammonia, Energy, 141, 924-936  (2017)
7. S.S. Harish Kruthiventia and G. Venkatarathnam, Studies on capillary tube expansion device used in J-T refrigerators operating with nitrogen-hydrocarbon mixtures, Cryogenics, 87, October 2017, 76-84 (2017)
8. H. Gurudath Nayak and G. Venkatarathnam, Occurrence of Dry out Phenomenon in an Auto Refrigerant Cascade Refrigerator operating with zeotropic mixtures, ASME J. Thermal Sci. Eng., 9(3):031012-031012-6. doi:10.1115/1.4035940 (2017).
9. B. Sreenivas, H. Gurudath Nayak and G. Venkatarathnam, Relationship between composition of mixture charged and that in circulation in an auto refrigerant cascade and a J-T refrigerator operating in liquid refrigerant supply mode, Cryogenics 81, 42-46, (2017)
10. Padmanabhan, C.S. Gurudath, Thota Srikanth, A Ambirajan, S.A. Basavaraj, Kumar Dinesh, and G. Venkatarathnam,  Studies on Phase Shifting Mechanism in PulseTube Cryocooler, IOP Conf. Ser.: Mater. Sci. Eng. 171 012082 (2017)
11. Vineed Narayanan, G VenkatarathnamExperimental investigation on mixed refrigerant cryocooler operating at 70 K for cooling high temperature superconductors, IOP Conference Series: Materials Science and Engineering 171 (1), 012073 (2017)
12. V. Narayanan and G. Venkatarathnam, Performance of two mixed refrigerant processes providing refrigeration at 70K, Cryogenics, 78, 66-73 (2016)
13. P.C. Jayanti, and G. Venkatarathnam, Identification of the phase of a substance from the derivatives of pressure, volume and temperature, without prior knowledge of saturation properties: Extension to solid phase, Fluid Phase Equilibria, 425, 269-277 (2016)
14. G. Sharma, R.L. Gardas, A. Coronas and G. Venkatarathnam, Effect of anion chain length on physicochemical properties of N, N-dimethylethanolammonium based protic ionic liquids, Fluid Phase Equilibria, 415, 1-7 (2016)
15. Harish Kruthiventi SS, Venkatarathnam GG. Comparison of the Straight Adiabatic Capillary Tube Expansion Devices Used in Refrigeration Systems Operating With Refrigerants R134a and R1234yf. ASME. J. Thermal Sci. Eng. Appl., 8, 021015-1–021015-7 (2016)
16. G. Venkatarathnam, Thermodynamics of refrigerant mixtures used in J-T refrigerators, Presented at the 26th International Cryogenic Engineering Conference, March 7-11, 2016, New Delhi
17. G.S.C. Prasad, C.S. Kumar, S.S. Murthy and G. Venkatarathnam, Performance of an organic Rankine cycle with multicomponent mixtures,Energy, 88, 690-696 (2015)
18. B. Sreenivas, D.R. Patel, S.S. Murthy, and G. Venkatarathnam, Performance of mixed refrigerant cascade refrigerator for cooling a space simulation chamber, Indian Journal of Cryogenics 39 (1), 81-85 (2014)
19. G. Venkatarathnam, Density Marching Method for Calculating Phase Envelopes, Ind. Eng. Chem. Res. 53, 3723−3730 (2014)
20. G. Venkatarathnam, Density marching method for calculating phase envelopes: Part II – Three-phase envelopes, Ind. Eng. Chem. Res. Vol. 53, 12122-12128 (2014)
21. Sumit K. Swarnkar, S. Srinivasa Murthy, Ramesh Gardas and G. Venkatarathnam, Performance of a vapour absorption refrigeration system operating with ionic liquid-ammonia combination with water as cosolvent, Applied Thermal Eng. Vol. 72, 249-256 (2014)
22. G. Venkatarathnam, Thermodynamics of refrigerant mixtures used in Cryogenic Mixed Refrigerant Processes, National Symposium on Cryogenics, Hyderabad, December 8-10, 2014, Hyderabad, India
23. Sunil Jerome and G. Venkatarathnam, Comparatative study of Helmholtz, Peng-Robinson and PC-SAFT equation of state applied to a J-T Cryocooler, National Symposium on Cryogenics, Hyderabad, December 8-10, 2014, Hyderabad, India
24. Vineed Narayanan and G. Venkatarathnam, A mixed refirgerant cycle for providing refrigeration below 70 K for superconducting application, National Symposium on Cryogenics, Hyderabad, December 8-10, 2014, Hyderabad, India