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Author: search.filters.author.Ashok Babu, T.P.A.

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    Effect of Solar Optical Properties of Building Envelope on Time Lag, Decrement Factor and Energy Saving of Buildings
    (Springer Nature, 2020) Mahapatra, D.; Ashok Babu, T.P.A.
    World has been suffering from energy crisis since 1970. This is because of the increased population and industrialization. Buildings have a significant contribution to total energy consumption across the globe. The increased urbanization leads to boom in construction of buildings. The materials used for the construction of buildings affect the climate of the city up to a great extent and affect the energy consumption as well. So, construction materials should be chosen wisely. The surface temperature of the building envelope is affected by the coatings used. Cool coatings help in reducing the surface temperature of the building envelope. Time lag and decrement factor are the indicators of energy saving in building. In this paper, the effect of cool coating on time lag and decrement factor was studied. Values of time lag and decrement factor were evaluated in different climatic zones of India. It has been found that as the absorptivity of the building envelope increases, the decrement factor increases. By changing the absorptivity from 0.2 to 0.73, a minimum change of 16% (New Delhi) in decrement factor and 11.75% (Jodhpur) in surface temperature was observed. The maximum change in decrement factor was 56.44% (Jodhpur). The maximum change in surface temperature was 39.02% (Bangalore). So, it should always be practised to keep the absorptivity of the building envelope as low as possible. © 2020, Springer Nature Singapore Pte Ltd.
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    Use of vegetable oil ester in CI engine: Some studies under overload condition
    (Combustion Institute, 2007) Bekal, S.; Ashok Babu, T.P.A.
    A CI engine under certain operating condition is subjected to overloading. An experimental investigation has been carried out to compare the NOX and particulate emission of a CI engine when fueled with diesel and vegetable oil ester separately, for overload condition. The resulting increase(or decrease) in parameters like BSEC, exhaust temperature and CO,NOX,CO2 & O2 emission are compared for ester at full load and overload conditions. Proportion of overload considered is 10% more than the full load. The combustion characteristics like peak pressure, crank angle at peak pressure etc., have been obtained from data acquisition system. The vegetable oil chosen for study is sunflower oil ester. To find the appropriate injection timing under overload condition, the engine has been run at three different injection timings Viz., 24.5 bTDC(normal), 23 bTDC and 21.5 bTDC. The results indicated that slight retardation in injection timing is beneficial for vegetable oil ester under overload condition. © 2007 Combustion Institute. All Rights Reserved.
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    Some studies on chemical composition, and properties of ester of edible and inedible vegetable oils, and their use in CI engine
    (Combustion Institute, 2009) Bekal, S.; Ashok Babu, T.P.A.
    In this work, the esters produced from two types of vegetable oils – edible and inedible, with pongamia oil representing the inedible oil, and sunflower oil, the edible, are compared on the basis of various physical and chemical properties, NMR and GC analysis, and performance and emission characteristics of the engine on being fuelled by these esters. The results indicate that there is a difference in chemical composition of certain fatty acids which have bearing on the cetane number and shelf life; additionally, there is substantial difference in chemical properties, though the physical properties have similar values; on the performance and emissions front, the edible oil ester is found to be better than inedible oil ester. © 2009 Combustion Institute. All rights reserved.
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    Effect of denatured spirit-water blends on engine performance and exhaust emissions
    (Combustion Institute, 2009) Ashok Babu, T.P.A.; Hubballi, P.A.
    The obj ective of this study was to investigate the effect of using Denatured spirit (DNS = [Ethanol 93.3% + water 6.7%]) and DNS-Water blends as fuels in a four cylinder four stroke SI engine. In the process of investigation, the performance tests were conducted on the engine to analyze brake thermal efficiency (BThE), brake power (BP), engine torque and brake specific fuel consumption (BSFC). Exhaust emissions were also investigated for carbon monoxide (CO), hydrocarbons (HC), oxides of nitrogen (NOx) and carbon dioxide (CO2). The results of the experiments revealed that, both DNS and DNS95W5 (DNS 95% + water 5%) as fuels increase BThe, BP, engine torque and BSFC. The CO, HC, NOx and CO2 emissions in the exhaust decreased. The DNS and DNS95W5 as fuels produced the encouraging results in engine performance and reduced exhaust emissions for all the tested speeds and measured performance parameters. © 2009 Combustion Institute. All rights reserved.
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    Investigation of Various Low Emissivity Glass Materials for Green Energy Building Construction in Indian Climatic Zones
    (Elsevier Ltd, 2017) Gorantla, G.K.; Saboor, S.; Ashok Babu, T.P.A.
    The buildings are responsible for more than one-third of power consumption in India. Glass is one of the significant building enclosures to control cooling loads in buildings. This paper describes how various low emissivity glasses used for building windows affect thermal performance of green energy buildings. This paper presents the thermal performance of five double glazed low reflective window glass materials such as clear low reflective glass, bronze low reflective glass, green low reflective glass, grey low reflective glass and blue-green low reflective glasses. In this paper, mud brick buildings with five low emissivity glass material windows were designed in three different climatic zones of India such as warm and humid (Mangalore), hot and dry (Jodhpur) and composite (Hyderabad). The results showed that buildings with double glazed low emissivity grey glass window are found to be energy efficient from the least heat gain point of view among all buildings studied in three climatic zones of India. © 2017 Elsevier Ltd. All rights reserved.
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    Thermal Analysis of Wall and Window Glass Materials for Cooling Load Reduction in Green Energy Building Design
    (Elsevier Ltd, 2017) Gorantla, G.K.; Saboor, S.; Ashok Babu, T.P.A.
    Buildings are responsible for huge amount of energy consumption for cooling in hot regions. Energy efficient material wall and window glass materials can reduce power consumption for cooling. This laterite stone, dense concrete, burnt brick and mud brick are used as building materials. The experimentally measured optical properties of four glass materials such as clear glass, bronze glass, green glass and bronze-reflective glasses have been presented in this paper. Spectrophotometer was utilised to measure the spectral optical properties in the infrared region. The heat gain in the building due to placing of window in four orientations (East, West, North and South) was analyzed for Mangalore city (12.870N, 74.880E) in Karnatka state, India. The building models were simulated in Energy plus tool for thermal performance. Total two fifty six building models were investigated. The mud brick buildings were observed to be the most energy efficient as they allow the least heat gain inside the building at all window to wall ratios. Use of reflective glass for the glazing of the window reduces cooling loads in buildings. © 2017 Elsevier Ltd.
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    Study of Various Glass Window and Building Wall Materials in Different Climatic Zones of India for Energy Efficient Building Construction
    (Elsevier Ltd, 2017) Kumar, G.K.; Saboor, S.; Ashok Babu, T.P.A.
    The commercial and residential buildings consume about 33% of energy for cooling and day lighting in India. This paper aims to present thermal performance of buildings constructed with various building and window glass materials in five different climatic zones of India. The climates considered include: hot and dry (Ahmedabad), moderate (Bangalore), cold (Guwahati), warm and humid (Madras), and composite (New Delhi). In this study, four building materials such as laterite stone, dense concrete, burnt brick, and mud brick were selected and four glasses such as clear, bronze, green, and bronze-reflective glasses were used for windows. Spectral characteristics of four glasses were measured experimentally by using Perkin-Elmer lambda 950spectrophotometer in the wavelength range of 300 -2500 nm as per ASTM standards. A mat lab code was developed to compute the solar optical properties such as transmittance and reflectance of glasses as per European standards in entire solar spectrum region. The building models were designed in Design builder 4.3.0.039 and thermal analysis was carried out in Energy plus 8.1.0.009. The solar heat gain in buildings was investigated. The results revealed that the mud brick wall building with south bronze-reflective glass window as energy saving from the least heat gain point of view among eighty building models studied. The results also showed that the mud brick wall building with bronze, green and bronze reflective window glasses reduces heat gain through wall by 2.52%, 3.83%, and 6.46% as compared to the mud brick wall building with clear glass window. The results helps in selecting energy saving combination of wall envelope and window glass materials for reducing air-conditioning loads in residential and commercial buildings of five different climatic zones of India. © 2017 The Authors. Published by Elsevier Ltd.
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    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.
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    Experimental and Theoretical Studies of Window Glazing Materials of Green Energy Building in Indian Climatic Zones
    (Elsevier Ltd, 2017) Gorantla, G.K.; Saboor, S.; Ashok Babu, T.P.A.
    Buildings consume plenty of power for providing thermal and visual comfort inside the buildings. This paper aims at presenting the experimental results of spectral optical properties of the most widely used window glazing materials. The window glazing materials studied include clear glazing, bronze glazing, green glazing and grey coloured glazing materials. A Matlab code employing the British standard method was developed to compute transmittance and reflectance of window glasses at normal incidence angle. This code uses experimentally obtained spectral optical property data from Perkin Elmer lambda 950 spectrophotometer for the computation of transmission and reflection of window glasses. A computer program was developed for computing the total solar radiation passing through glass materials. The heat gain through different glass windows of eight coordinal orientations such as east, west, north, south, northeast, northwest, southeast and southwest in four climatic zones of India was investigated. The solar radiation through south oriented glass was found to be the least among all other orientations studied in four Indian climatic zones. The cooling load through south oriented bronze, glass, green glass and grey glass window were reduced by 23%, 31% and 37%, respectively, as compared to the south oriented clear glass window in four climatic zones of India. The grey glass window is observed to be the most energy efficient as it reduces maximum cooling loads within the building as compared to the other considered glazing materials. The results of this paper are helpful in designing energy efficient commercial buildings for reduced cooling loads. © 2017 The Authors.
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    Theoretical Performance Investigation of Vapour Compression Refrigeration System Using HFC and HC Refrigerant Mixtures as Alternatives to Replace R22
    (Elsevier Ltd, 2017) Vali, S.V.; Ashok Babu, T.P.A.
    The present paper describes the theoretical thermodynamic performance of vapour compression refrigeration system using HFC and HC blends as an alternatives to replace the refrigerant R22. In this study thermodynamic analysis of window air conditioner with R431A, R410A, R419A, R134a, R1270, R290 and fifteen refrigerant mixtures consists of R134a, R1270 and R290 was carried out based on actual vapour compression cycle. All the investigated refrigerant mixtures are ozone friendly in nature and they possess GWP in the range of 0.0244 to 1.685 times the GWP of R22. Thermodynamic performance analysis of all the investigated refrigerant mixtures were evaluated at the condensing and evaporating temperatures of 54.4oC and 7.2oC respectively. The results show that COP for the refrigerant mixture R134a/R1270/R290 (50/5/45 by mass percentage) is 2.10% higher among the R22, R431A, R410A, R419A, R134a, R1270, R290, and fifteen studied refrigerant mixtures. The compressor discharge temperature of all the studied refrigerants were lower than that of R22 by 4.8oC-22.2oC. The power consumption per ton of refrigeration for the refrigerant mixture R134a/R1270/R290 (50/5/45 by mass percentage) is 2.01% lower among R22, R431A, R410A, R419A, R134a, R1270, R290, and fifteen studied refrigerant mixtures. Overall the thermodynamic performance of refrigerant mixture R134a/R1270/R290 (50/5/45 by mass percentage) is better than that of R22 with reasonable savings in the energy and hence it is an appropriate ecologically energy efficient alternative refrigerant to substitute R22 used in air conditioning applications. © 2017 The Authors.