Faculty Publications
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Item Theoretical Computation of Performance of Sustainable Energy Efficient R22 Alternatives for Residential Air Conditioners(Elsevier Ltd, 2017) Vali, S.V.; Ashok Babu, T.P.A.The present paper focuses on theoretical investigation of various new R22 alternatives. In this study R407C and four new R22 alternative refrigerant mixtures composed of R1270, R290, RE170, R134a and R32 at different compositions are considered. All the four new refrigerants possess zero ODP and low GWP compared to R22.The chief objective of the present work is to compute the thermodynamic performance of a standard vapour compression refrigeration cycle with R22 and its alternative refrigerants. A MATLAB code is developed to compute the thermodynamic performance of all the considered refrigerants. Thermodynamic analysis of all the refrigerants are evaluated at the condensing and evaporating temperatures of 54.4°C and 7.2°C respectively. The results showed that COP for the refrigerant mixture R134a/R1270/RE170 (55/37.5/7.5 by mass percentage) is 5.35% higher among the R22, R407C and four studied refrigerants. The compressor discharge temperature for R134a/R1270/RE170 (55/37.5/7.5 by mass percentage) is 11.9°C lower when compared to R22 and hence this mixture indicates the durability of the compressor life. The energy spent by the compressor per ton of refrigeration for the mixture R134a/R1270/RE170 (55/37.5/7.5 by mass percentage) is 5.12% lower among R22, R407C and four investigated refrigerants. The GWP of R134a/ R1270/ RE170 (55/37.5/7.5 by mass percentage) is 716 which is low compared to GWP of R22 (1760). Therefore R134a/R1270/RE170 (55/37.5/7.5 by mass percentage) is a sustainable energy efficient refrigerant to replace R22 used in residential air conditioners from the stand point of COP, compressor discharge temperature, energy savings, GWP and ODP. And also in this study thermodynamic performance of refrigerants are computed at various evaporating temperatures by keeping condenser temperature as constant. © 2017 The Authors. Published by Elsevier Ltd.Item Theoretical Evaluation of Energy Performance of a Vapour Compression Refrigeration System Using Sustainable Refrigerants(Springer, 2020) Vali, S.V.; Ashok Babu, T.P.The chief goal of this present investigation is to evaluate performance parameters of various sustainable refrigerants as R22 alternatives. In this investigation apart from R290, R134a and R22, twelve mixture refrigerants were developed at various composition. Results showed that energy efficiency ratio (EER) of mixture refrigerant MR40 (R290/R134a 95/5 in mass%) (4.546) stood greatest among twelve investigated alternatives and it was closer to the EER of R22 (4.602). Compressor discharge temperature of MR40 was lower than R22 by 16.020C. Volumetric refrigeration capacity of MR40 (3424 kJ/m3) was relatively lesser than R22 (3801 kJ/m3). Power spent per ton of refrigeration (PPTR) of MR40 (0.773 kW/TR) stood lowest among twelve investigated alternatives and it was fairly greater than R22 (0.764 kW/TR). Global warming potential (GWP100) of MR40 (68) was very low compared to R22 (1760). Overall, performance of MR40 was closer to R22, when compared with all the twelve investigated alternatives, and hence, it might be treated as a suitable replacement to refrigerant R22. © 2020, Springer Nature Singapore Pte Ltd.Item Thermodynamic performance analysis and flammability study of various new ozone friendly non azeotropic refrigerant mixtures as alternatives to replace R22 used in residential air conditioners(International Information and Engineering Technology Association info@iieta.org, 2018) Vali, S.V.; Ashok Babu, T.P.A.The present study investigates the theoretical thermodynamic performance analysis and flammability study of various new ozone friendly refrigerants as replacements to R22. In this work, five non azeotropic refrigerant blends comprising of R152a, R134a, R32, R290 and R1270, at various compositions were developed. Flammability study of all the five refrigerant mixtures considered were carried out by using Refrigerant Flammability (RF) number. The cycle followed during the performance investigation of refrigerants was the actual vapour compression refrigeration cycle. Thermodynamic performance characteristics of all the five investigated refrigerants were compared with the baseline refrigerant R22. Theoretical results showed that COP of refrigerant M40 was 0.51% higher, compared to R22 and the five refrigerants studied. Compressor discharge temperature of M40 was lowered by 11.6°C compared to R22. Power consumed to produce per ton of refrigeration of M40 was 0.52% lower, compared to R22 and the five refrigerants considered. Heat transfer rate through the condenser for M40 was 3.66% higher than R22. Volumetric refrigeration capacity of M40 was the highest among the five studied refrigerants and it was very close to the volumetric capacity of R22. Flammability analysis revealed that all the five investigated refrigerant mixtures were classified into the weakly flammable category. Overall, the thermodynamic performance of new ternary blend M40 (R32/R134a/R1270 5/60/35 by mass percentage) was higher than R22 with reasonable saving in power consumption and hence, M40 is a viable candidate to replace R22. © 2018 International Information and Engineering Technology Association. All Rights Reserved.Item Thermodynamic analysis of window air conditioner using sustainable refrigerant R290/RE170 and R1270/RE170 blends as substitutes to refrigerant R22(International Information and Engineering Technology Association info@iieta.org, 2019) Vali, S.V.; Setty, A.B.T.P.The present work emphasis on theoretical computation of thermodynamic performance of window air conditioner using various sustainable R290/RE170 and R1270/RE170 refrigerant mixtures as substitutes to R22. In this work, apart from R407C, twelve new binary mixtures comprising of R290, R1270 and RE170 at various compositions were developed. And also in this investigation, a MATLAB code was developed to compute the thermodynamic performance characteristics of various considered R22 alternatives at Tk=54.4 0C and Te=7.2 °C. The various performance characteristics computed are mass flow rate, refrigeration effect, compressor work, coefficient of performance (COP), pressure ratio, compressor discharge temperature, power consumed per ton of refrigeration, condenser heat rejection and volumetric cooling capacity. Results showed that the COP of refrigerant mixture RM7 (R1270/RE170 95/5 by mass %) was the highest among twelve refrigerants studied and it was 0.23 % higher than R22. Pressure ratio of RM7 (3.174) was 7.49 % lower than that of R22 (3.431). Compressor discharge temperature of all the twelve investigated refrigerants was lower in the range of 9.35 0C to 17.15 0C when compared with R22. Power consumed per ton of refrigeration of RM7 was 0.27 % lower than that of R22. Volumetric cooling capacity of RM7 (3833 kJ/m3) was very close to that of R22 volumetric capacity (3863 kJ/m3). Heat transfer through condenser of RM7 (6.372 kW) was similar to that of R22 (6.377 kW). Overall, thermodynamic performance of RM7 matches well with the performance of base line refrigerant R22 and hence, refrigerant RM7 can be considered as sustainable alternative to R22 used in air conditioners. © 2019 International Information and Engineering Technology Association. All rights reserved.