Journal Articles
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884
Browse
10 results
Search Results
Item Influence of ambient air relative humidity and temperature on thermal properties and unsteady thermal response characteristics of laterite wall houses(Elsevier Ltd, 2016) Saboor, S.; Ashok Babu, A.B.P.S.This paper presents the experimental investigation of the effect of ambient air humidity and temperature on thermal properties of the laterite rocks used in South-West coastal India. The experimental technique employed was transient plane source method in the saturated salt solution humidity controlled chamber. Experimental results showed an increase of thermal conductivity by 14.7% and specific heat by 9.15% with an increase in the relative humidity of ambient air in the hygroscopic range. A porous and ferruginous matrix of laterite was studied using a scanning electron microscope. The effects of relative humidity of the ambient air and temperature on the unsteady state thermal heat transfer characteristics such as transmittance, admittance, decrement factor, time lag, surface factor, surface factor time lag and heat capacity for different thicknesses of the laterite rock walls were investigated analytically. One dimensional heat flow equation under periodic convective boundary conditions was solved using matrix algebra and a computer simulation program which employs a cyclic admittance method was developed using MATLAB to compute unsteady state thermal characteristics. Results indicate that the decrement factor reduces by 8.35% and time lag increases by 2.88% with an increase in the relative humidity of ambient air compared to the dry state for the Indian standard laterite rock thickness. © 2016 Elsevier Ltd.Item Optimizing the position of insulating materials in flat roofs exposed to sunshine to gain minimum heat into buildings under periodic heat transfer conditions(Springer Verlag service@springer.de, 2016) Saboor, S.; Ashok Babu, A.B.P.S.Building roofs are responsible for the huge heat gain in buildings. In the present work, an analysis of the influence of insulation location inside a flat roof exposed directly to the sun’s radiation was performed to reduce heat gain in buildings. The unsteady thermal response parameters of the building roof such as admittance, transmittance, decrement factor, and time lags have been investigated by solving a one-dimensional diffusion equation under convective periodic boundary conditions. Theoretical results of four types of walls were compared with the experimental results available in literature. The results reveal that the roof with insulation placed at the outer side and at the center plane of the roof is the most energy efficient from the lower decrement factor point of view and the roof with insulation placed at the center plane and the inner side of the roof is the best from the highest time lag point of view among the seven studied configurations. The composite roof with expanded polystyrene insulation located at the outer side and at the center plane of the roof is found to be the best roof from the lowest decrement factor (0.130) point of view, and the composite roof with resin-bonded mineral wool insulation located at the center plane and at the inner side of the roof is found to be energy efficient from the highest time lag point (9.33 h) of view among the seven configurations with five different insulation materials studied. The optimum fabric energy storage thicknesses of reinforced cement concrete, expanded polystyrene, foam glass, rock wool, rice husk, resin-bonded mineral wool, and cement plaster were computed. From the results, it is concluded that rock wool has the least optimum fabric energy storage thickness (0.114 m) among the seven studied building roof materials. © 2015, Springer-Verlag Berlin Heidelberg.Item Thermal and cost analysis of float and various tinted double window glass configurations on heat gain into buildings of hot & dry climatic zone in India(International Information and Engineering Technology Association info@iieta.org, 2018) Gorantla, G.; Saboor, S.; Setty, A.B.T.P.R.Glass window enclosures for buildings consume a lot of energy for affording thermal and visual comfort. Reducing solar radiation in summer and increase in winter through different double window glasses for making energy efficient building design is the theme of this paper. Therefore this work measures the spectral characteristics of four glasses namely grey, green, bronze and clear glasses in entire solar spectrum region from 300nm to 2500nm at normal angle of incidence by using Shimadzu UV 3600 spectrophotometer based on ASTM standards. To find the solar optical properties a MATLAB code was used which is based on British standards. To find the solar radiation transmission from different double window glass configurations and cost analysis from eight coordinal directions at peak summer and winter day were selected as per Indian standards with a MATLAB code to hot and dry climatic zone of Jodhpur (26.300N, 73.020E). From these results it is shows that in south direction all double glass windows are gaining less heat in summer and more heat in winter season when compared to other orientations. It is found that south orientation C1(Greyglasswindow-Airgap10mm-Greenglasswindow) and C12(Clearglasswindow-Airgap10mm-Bronzeglasswindow) configuration windows are gaining minimum and maximum heat in summer and winter respectively when compared to other configuration windows. Among all windows C1 configuration window is saving more cost annually. © 2018 International Information and Engineering Technology Association. All rights reserved.Item Thermal and energy saving analysis by using tinted double window glass combinations for heat gain in buildings(Regional Energy Resources Information Center (RERIC) rericjournal@ait.ac.th, 2018) Gorantla, K.; Saboor, S.; Babu, A.; Ranga, P.; Setty, T.Buildings consume large amount of energy to accommodate thermal and visual comforts, in which glass windows play an important role as we used as building envelope. Universally clear glass is used as chief building envelope for buildings. As clear glass is having more transmission property it permits more radiation and day light into the buildings which creates uneasy feeling to the occupants. This paper presents the experimental measurement of spectral characteristics of three tinted glasses which include transmission and reflection in entire solar spectrum wavelength region from 300nm to 2500nm as per ASTM standards by using UV 3600 Shimadzu spectrophotometer. These measured spectral characteristics were used to compute solar optical properties as per British standard by using MATLAB code. To find the total solar radiation through double tinted window glass combinations GC1 to GC6 place as building envelopes of New Delhi climatic zone by using MATLAB code and to find the monthly solar radiation passing into the building which is helpful to calculate the cost energy saving annually for cooling and heating loads. From the results GC6 combination windows are saving cost i.e. 61.16 (US Dollars/year) in south, 60.54 (US Dollars/year) in south east and 59.23 (US Dollars/year) in south west orientations annually than other combination windows.Item Experimental and theoretical studies of various solar control window glasses for the reduction of cooling and heating loads in buildings across different climatic regions(Elsevier Ltd, 2018) G, K.K.; Saboor, S.; Kumar, V.; Kim, K.-H.; Babu, A.The glass material and position/orientation of windows are very important to control the heat gain in buildings. In this article, we studied the effect of different window glazing materials (such as bronze, green, grey, bronze-reflective, green-reflective, grey-reflective, gold-reflective, opal blue-reflective, and sapphire blue-reflective glass) in controlling the heat gain by the buildings. The spectral data of diverse window glasses have thus been measured in solar spectrum range of 300–2500 nm. Moreover, the MATLAB codes have been developed to compute solar optical properties (including transmittance, reflectance, and absorbance), solar heat gain coefficient (SHGC), and heat transfer through the glazing material. Thermal analysis was carried out using a total of nine window glasses in eight coordinal directions (E, W, N, S, SE, SW, NE, and NW) against three climatic conditions (hot and dry, warm and humid and composite) in India. In terms of net annual cooling and heating cost savings per window, the grey reflective glass was found to be the most energy saving glass among all glasses tested in this study. The grey reflective glass exhibited the highest cost saving in net annual cooling and heating in all eight orientations across three climatic regions. The grey reflective glass saved the net cost of heating and cooling by $ 61.24 per annum in the south orientation of Jodhpur climatic conditions. © 2018 Elsevier B.V.Item Day lighting and thermal analysis using various double reflective window glasses for green energy buildings(International Information and Engineering Technology Association info@iieta.org, 2018) Gorantla, K.K.; Saboor, S.; Setty, A.B.T.P.R.The objective of this research work is to identify the best double reflective window glass which provides adequate daylighting by controlling solar heat gain as per the requirement of summer and winter seasons of composite climatic zone in India. To attain this objective an investigation of spectral characteristics of different reflective glasses such like gold, sapphire blue, opal blue, grey, green and bronze reflective glasses is carried out experimentally using Shimadzu UV 3600 spectrophotometer in the entire solar spectrum wavelength range from 300 nm to 2500 nm based on ASTM E 424 standards.The measured spectral characteristics were used to compute the visible optical properties in the visible zone and solar optical properties in solar spectrum zone by using International standard method with a MATLAB code. The computed optical properties transmittance, reflectance and absorbance are used in the simulation tool for heat gain and daylight calculations for a school room building. As far as both hottest and coolest days are concerned double gold reflective window glass (DGLDRGW) is found to be the best in the South orientation. During hottest day, DGLDRGW gains minimum heat of 2.13 kWh with adequate daylight factor (2.049% at 9 A.M. and 2.025% at 4 P.M.) and also it gains maximum heat of 8.55 kWh with adequate daylight factor (2.729% at 9 A.M. and 2.732% at 4 P.M.) for school room building among six studied double reflective window glasses. © 2018 International Information and Engineering Technology Association. All Rights Reserved.Item Thermal and cost analysis of various air filled double glazed reflective windows for energy efficient buildings(Elsevier Ltd, 2020) Gorantla, G.; Saboor, S.; Vali, S.S.; Mahapatra, D.; Talanki Puttaranga Setty, A.B.; Kim, K.-H.The enormous amount of energy is being consumed by buildings in an attempt to deliver thermal comfort in buildings. This paper aims at reducing/increasing the total solar heat gain through various combinations of double glazed reflective windows of buildings. The spectral characteristics of six reflective glasses namely bronze, green, grey, opal blue, sapphire blue and gold-reflective glasses at a normal angle of incidence by using UV-3600 Shimadzu spectrophotometer according to ASTM E 424 standards were experimentally measured. The solar optical properties of the glasses were deduced by developing a MATLAB code using spectral data which was obtained from experiments in the solar spectrum wavelength range of 300 nm–2500 nm. Thirty air-filled double-glazed reflective windows have been studied for both thermal and cost analysis in the Indian composite climatic zone (New Delhi 28.580 N, 77.200 E). The configuration C13 (Grey reflective glass-Air gap 10 mm-Gold reflective glass) is observed to be the best air-filled double glazed window from the highest annual cost savings ($ 79.29 per annum in SE direction) and lower payback period (1.42 years) point of views among thirty double-glazed reflective glasses studied. The results of this paper are useful in the design of sustainable passive solar buildings. © 2019 Elsevier LtdItem 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.Item Sustainable reflective triple glazing design strategies: Spectral characteristics, air-conditioning cost savings, daylight factors, and payback periods(Elsevier Ltd, 2021) Gorantla, K.; Saboor, S.; Kontoleon, K.J.; Mazzeo, D.; Maduru, V.R.; Vali, S.V.Buildings with conventional glazing systems are responsible for excessive cooling and heating costs. Sustainable use of energy in building environments requires the use of high-performing opaque and windowed walls. Triple glazing units attenuate solar heat gain/loss compared to single- and double-glazing assemblies, thus reducing air-conditioning costs and greenhouse gas emissions. The optical, energy, economic and environmental performances of a glazing unit are strictly correlated with each other. An improvement of optical properties leads to higher glazing energy performance, cost savings, and greenhouse gas emission mitigations. This work aims to suggest and define an energy-efficient triple glazing unit for lowering cooling and heating costs in buildings while experimentally testing the spectral performance of reflective glasses and assessing heat gains/losses. In this regard, bronze, green, grey, sapphire blue, and gold reflective glasses were considered and settled in sixty different triple glazing combinations. Spectral characteristics of reflective glasses were measured experimentally using a spectrophotometer over the entire solar spectral range (300–2500 nm). For the aims of this investigation, a numerical model was developed to assess the net annual cost saving ($/m2) and the payback period of the examined glazing units for the eight cardinal directions (N, N-E, E, S-E, S, S–W, W and N–W). The results confirmed that the TWG35 window glass unit in the S-E orientation was the most energy-efficient glazing in terms of alleviating this critical challenge (air-conditioning cost-saving 16.72 $/m2 among all other studied window glass units), while a payback period of 2.2 years was revealed. On the other hand, the TWG33 window glass unit has led to the optimal-lowest payback period (2.1 years), with a net annual cost saving of 16.55 $/m2. The findings of this paper demonstrate the significance of triple-glazing design approaches from an economic and environmental point of view. © 2021 Elsevier LtdItem Quantitative Analysis of Solar Photovoltaic Panel Performance with Size-Varied Dust Pollutants Deposition Using Different Machine Learning Approaches(MDPI, 2022) Tripathi, A.K.; Mangalpady, M.; Elumalai, E.P.; Abbas, M.; Afzal, A.; Saboor, S.; Linul, E.In this paper, the impact of dust deposition on solar photovoltaic (PV) panels was examined, using experimental and machine learning (ML) approaches for different sizes of dust pollutants. The experimental investigation was performed using five different sizes of dust pollutants with a deposition density of 33.48 g/m2 on the panel surface. It has been noted that the zero-resistance current of the PV panel is reduced by up to 49.01% due to the presence of small-size particles and 15.68% for large-size (ranging from 600 µ to 850 µ). In addition, a significant reduction of nearly 40% in sunlight penetration into the PV panel surface was observed due to the deposition of a smaller size of dust pollutants compared to the larger size. Subsequently, different ML regression models, namely support vector machine (SVMR), multiple linear (MLR) and Gaussian (GR), were considered and compared to predict the output power of solar PV panels under the varied size of dust deposition. The outcomes of the ML approach showed that the SVMR algorithms provide optimal performance with MAE, MSE and R2 values of 0.1589, 0.0328 and 0.9919, respectively; while GR had the worst performance. The predicted output power values are in good agreement with the experimental values, showing that the proposed ML approaches are suitable for predicting the output power in any harsh and dusty environment. © 2022 by the authors.