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    Effect of Different Double Glazing Window Combinations on Heat gain in Buildings for Passive Cooling in Various Climatic Regions of India
    (Elsevier Ltd, 2017) Gorantla, G.K.; Saboor, S.; Setty, A.B.T.P.
    The buildings account for more than 30% of energy consumption for cooling and day lighting in India. This paper presents the thermal performance of buildings with various double glazing window glass material combinations in four different climatic zones of India such as moderate (Bangalore), composite (Hyderabad) hot and dry (Jodhpur) and warm and humid (Vishakhapatnam) climatic zones. In this study, four double glazing window material combinations such as clear-clear, bronze-clear, green-clear and grey-clear were selected. An unventilated air space of 10 mm is maintained between the two glass layers. The spectral optical properties of four glass materials were measured experimentally using UV 3600 Shimadzu spectrophotometer from wavelengths ranging from 300 nm-2500 nm. Total sixty four building models were designed using Design builder 4.3.0.039 and thermal analysis was carried out using Energy plus 8.1 simulation tool. From the results, it is observed that concrete buildings with double grey-clear glass window were found to be energy efficient from the least heat gain point of view among sixty four building models studied in four climatic zones of India. The results of the study help in selecting the best combination of double glazing window glass material for reducing cooling loads in buildings of four different climatic zones of India. © 2017 Elsevier Ltd.
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    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.
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    Investigation on thermodynamic performance analysis and environmental effects of various new refrigerants used in air conditioners
    (Springer Science and Business Media Deutschland GmbH info@springer-sbm.com, 2020) Vali, S.V.; Saboor, S.; Gorantla, K.; Mahapatra, D.; Setty, A.B.T.P.
    The main aim of this present investigation is to evaluate performance and environmental impact analysis of various novel mixture refrigerants as R22 replacements theoretically. Refrigerants with lower global warming potential (GWP) can be adequate for bringing down emissions which are concerned for air conditioners. In this investigation, twenty-seven refrigerants were developed at several compositions. Important studies such as computation of CO2 emissions using total equivalent warming impact (TEWI), toxicity and flammability analysis of various considered refrigerants were also carried out in this investigation. Performance analysis of refrigerants was conducted under different operating conditions. Results showed that the energy efficiency ratios (EERs) of refrigerants such as R1270, RM30 (R152a/R1270/RE170 of 25/71/4 by mass percentage) and RM50 (R152a/R1270/RE170 of 10/85/5 by mass percentage) were closer to that of R22 and they are relatively lower than R22 by 0.95%, 1.34% and 1.80%, respectively. Toxicity investigation exhibited that all the refrigerants studied were classified into nontoxic category (A) whereas flammability investigation revealed that all the novel refrigerant mixtures (RM10 to RM50) were classified into flammable category (A3). CO2 emissions (TEWI) released from air conditioner working with R1270, RM30 and RM50 were 7.41%, 6.85% and 6.51%, respectively, lower than that of R22. In terms of several thermodynamic aspects, the performance of refrigerants such as R1270, RM30 and RM50 were superior to those of R22 and its various considered alternatives working under different operating conditions, although their EERs are fairly lower than R22 and hence, these refrigerants could be considered suitable environment-friendly alternatives to R22 used in air conditioners. The present study gives essential information and a road map towards the development of low GWP R22 alternative refrigerant blends from the viewpoint of toxicity, flammability, performance aspects, environmental and safety aspects, respectively. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.