Browsing by Author "Saboor, S."

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Analytical computation of thermal response characteristics of homogeneous and composite walls of building and insulating materials used in India
(CEPT University Press, 2014) Saboor, S.; Ashok Babu, T.P.
Climate responsive building design involves the study of the thermal response of building and insulating materials exposed to periodic changes of environmental conditions. For calculation of such unsteady thermal characteristics, one dimensional heat flow diffusion equation under periodic boundary conditions was solved using matrix algebra and thermal characteristics like admittance, transmittance, decrement factor, time lag, surface factor and surface factor time lags were calculated for homogeneous and composite walls. In this study, ten building and ten insulating materials were studied. Optimum wall thicknesses of building and insulating materials were calculated. From the results, it was concluded that mud phuska and coconut pitch are the most recommended homogeneous building and insulation materials respectively, among studied building and insulating materials, from lower decrement factor and higher time lag point of view. It is found that the insulation materials are highly responsive to short wave radiation than that of building materials. From the study, ultimately it is concluded that Burnt brick composite walls with Coconut pitch insulation is the best composite wall among all studied walls for reduced cooling loads and the most energy efficient building construction. Â© 2014 30th International PLEA Conference: Sustainable Habitat for Developing Societies: Choosing the Way Forward - Proceedings. All rights reserved.
Analytical computation of thermodynamic performance of various new eco-friendly alternative refrigerants applicable for air conditioners
(Springer Science and Business Media Deutschland GmbH info@springer-sbm.com, 2021) Vali, S.V.; Ashok Babu, T.P.; Mahapatra, D.; Saboor, S.; Gorantla, K.K.; Sai Siva Subramanyam, V.
The objective of the present investigation is to do the theoretical thermodynamic analysis of various new eco-friendly R22 substitutes used in vapour compression refrigeration (VCR) cycle. In this work, nine mixture refrigerants were considered at different compositions. Thermodynamic properties of all the considered refrigerants were developed and the same properties were used in the performance analysis of alternative refrigerants. Standard VCR cycle was considered for the thermodynamic assessment of alternative refrigerants. The working conditions considered are expressed as TeÂ =Â 7.2Â Â°C, TkÂ =Â 54.4Â Â°C, Î”TsupÂ =Â 11.1Â Â°C and Î”TsubÂ =Â 8.3Â Â°C, respectively. Results revealed that the COP of mixture refrigerant MR20 (R600a/R134a/R1270 5/47.5/47.5 in mass%) was 2.02% higher than the COP of R22 and other nine investigated refrigerants. Discharge temperature of compressor obtained for MR20 was 11.79Â Â°C lower compared to that of R22. Compressor power obtained for MR20 was 1.96% lower than that of R22. Volumetric refrigeration capacity obtained for MR20 was relatively closer to that of R22. GWP100 of MR20 (619) was lower compared to the GWP100 of R22 (1760). Overall, the performance of mixture refrigerant MR20 was better compared to all the considered R22 alternatives, and therefore it might be an appropriate candidate to replace R22 used in air conditioners. Â© Springer Nature Singapore Pte Ltd 2021.
Automotive air-conditioning system technology: A review
(Inderscience Publishers editor@inderscience.com 29, route de Pre-Bois Case Postale 856, CH-1215 Geneva 15 CH-1215, 2020) Vali, S.S.; Saboor, S.; Prithivi Rajan, S.; Ashok Babu, T.P.A.
Air conditioning in the automobile has become an important area of research. The performance of an air conditioning system in an automobile depends upon three basic important factors such as compressor speed, evaporator load, and condensing temperature. How these factors when varied affects the COP of the system have been detailed in this review paper. Several performance studies on various refrigerants (R134a, R152a, CO2 and R1234yf) used in the automotive air conditioning system operating with various conditions revealed the better COP for R152a in comparison with R134a, whereas COP of R1234yf and CO2 was observed to be slightly lower than R134a. However, safety measures must be followed while using R152a due to its slightly flammable nature (ASHRAE A2 group). In this work, various alternative air conditioning systems used for automobiles have been presented in detail. Â© Â© 2020 Inderscience Enterprises Ltd.
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.
Effect of Air Space Thickness within the External Walls on the Dynamic Thermal Behaviour of Building Envelopes for Energy Efficient Building Construction
(2015) Saboor, S.; Ashok, Babu, T.P.
This paper presents the comprehensive investigation of the effect divided air space thickness within the wall on unsteady heat transfer characteristics such as thermal transmittance, thermal admittance, decrement factor and time lag of five building material walls for energy efficient building enclosure design. The five building material composite walls such as laterite stone, mud brick, cellular concrete, dense concrete and cinder concrete with total thirty configurations were studied. A computer simulation program was developed to compute unsteady heat transfer characteristics using the cyclic admittance procedure. From the results, it is observed that the decrement factor decreases with the increase in the divided air space thickness within the composite wall for all building materials. Dense concrete was observed to be the energy efficient from the lowest decrement factor point of view among five studied building materials. Dense concrete decrement factor decreases by 23.65% for 0.02 m air space thickness compared to the conventional composite wall without air space. It is also noticed that the time lag increases with the increase in the divided air space thickness within the composite wall for all building materials. Cellular concrete was observed to be the energy efficient from highest time lag perspective among five studied building materials. Cellular concrete time lag increases by 6.23% for 0.02 m air space thickness compared to the conventional composite wall without air space. The results of the study help in designing energy efficient building enclosures. � 2015 The Authors. Published by Elsevier Ltd.
Effect of Air Space Thickness within the External Walls on the Dynamic Thermal Behaviour of Building Envelopes for Energy Efficient Building Construction
(Elsevier Ltd, 2015) Saboor, S.; Ashok Babu, A.B.T.
This paper presents the comprehensive investigation of the effect divided air space thickness within the wall on unsteady heat transfer characteristics such as thermal transmittance, thermal admittance, decrement factor and time lag of five building material walls for energy efficient building enclosure design. The five building material composite walls such as laterite stone, mud brick, cellular concrete, dense concrete and cinder concrete with total thirty configurations were studied. A computer simulation program was developed to compute unsteady heat transfer characteristics using the cyclic admittance procedure. From the results, it is observed that the decrement factor decreases with the increase in the divided air space thickness within the composite wall for all building materials. Dense concrete was observed to be the energy efficient from the lowest decrement factor point of view among five studied building materials. Dense concrete decrement factor decreases by 23.65% for 0.02 m air space thickness compared to the conventional composite wall without air space. It is also noticed that the time lag increases with the increase in the divided air space thickness within the composite wall for all building materials. Cellular concrete was observed to be the energy efficient from highest time lag perspective among five studied building materials. Cellular concrete time lag increases by 6.23% for 0.02 m air space thickness compared to the conventional composite wall without air space. The results of the study help in designing energy efficient building enclosures. Â© 2015 The Authors. Published by Elsevier Ltd.
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. Â© 2017 Elsevier Ltd.
Effect of Various External Shading Devices on Windows for Minimum Heat Gain and Adequate Day lighting into Buildings of Hot and Dry Climatic Zone in India
(2018) Kirankumar, G.; Saboor, S.; Talanki, Setty, P.R.; Babu, A.
Glass is the major component of the building envelope to provide visual comfort to inside the buildings. In g�n�ral clear and bronze glass was used as a main building envelope for both residential and commercial buildings to provide better day lighting into the buildings. If we use more glass area as a building envelope more radiation allows into the buildings. So that it is necessary to reduce more solar radiation and provide sufficient daylight factor inside the building's through glass windows with the help of external devices called shading devices. In this work four shading devices was tried on bronze glass window to find the heat gain and daylighting into buildings. This paper presents the experimental measurement of spectral characteristics of bronze glass which include transmission and reflection in entire solar spectrum region (300nm-2500nm) based on ASTM standards. A MATLAB code was developed to compute visible and solar optical properties as per the British standards. A building model was designed by design builder software tool. 40% window to wall ratio was considered for building models, thermal and day lighting analysis of buildings through windows was carried out in Energy plus software tool for hot and dry climatic zone of India. � The Authors, published by EDP Sciences, 2018.
Effect of Various External Shading Devices on Windows for Minimum Heat Gain and Adequate Day lighting into Buildings of Hot and Dry Climatic Zone in India
(EDP Sciences edps@edpsciences.com, 2018) Gorantla, G.; Saboor, S.; Talanki Setty, P.R.; Babu, A.
Glass is the major component of the building envelope to provide visual comfort to inside the buildings. In gÃ©nÃ©ral clear and bronze glass was used as a main building envelope for both residential and commercial buildings to provide better day lighting into the buildings. If we use more glass area as a building envelope more radiation allows into the buildings. So that it is necessary to reduce more solar radiation and provide sufficient daylight factor inside the building's through glass windows with the help of external devices called shading devices. In this work four shading devices was tried on bronze glass window to find the heat gain and daylighting into buildings. This paper presents the experimental measurement of spectral characteristics of bronze glass which include transmission and reflection in entire solar spectrum region (300nm-2500nm) based on ASTM standards. A MATLAB code was developed to compute visible and solar optical properties as per the British standards. A building model was designed by design builder software tool. 40% window to wall ratio was considered for building models, thermal and day lighting analysis of buildings through windows was carried out in Energy plus software tool for hot and dry climatic zone of India. Â© The Authors, published by EDP Sciences, 2018.
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.
Experimental and Theoretical Studies of Window Glazing Materials of Green Energy Building in Indian Climatic Zones
(2017) Kumar, G.K.; Saboor, S.; 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.
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. Â© 2017 The Authors.
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.
Investigation of unsteady thermal response characteristics of hollow bricks exposed to sinusoidal solar thermal excitation
(International Building Performance Simulation Association, 2015) Saboor, S.; Ashok Babu, A.B.T.P.
This paper presents the unsteady thermal response characteristics such as, admittance, transmittance, decrement factor, time lag, surface factor, surface factor time lag and areal thermal heat capacity of hollow bricks with different materials and varying air gap in hollow bricks for reducing heat gain into the buildings. A computer simulation program was developed which employs a cyclic admittance method. The results showed that thermal admittance, surface factor time lag, decrement factor time lag and areal thermal heat capacity values increase and thermal transmittance and decrement factor decrease with the increase in the number of air gaps in hollow bricks.
Investigation of Various Low Emissivity Glass Materials for Green Energy Building Construction in Indian Climatic Zones
(2017) Kirankumar, G.; Saboor, S.; Ashok, Babu, T.P.
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.
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. Â© 2017 Elsevier Ltd. All rights reserved.
Investigation of various wall and window glass material buildings in different climatic zones of India for energy efficient building construction
(2018) Kiran, Kumar, G.; Saboor, S.; Ashok, Babu, T.P.
The commercial and residential buildings consume about 33% of energy for cooling and day lighting in India. This paper presents the thermal performance of buildings constructed with various building and window glass materials in five different climatic zones of India such as hot and dry (Ahmedabad), moderate (Bangalore), cold (Guwahati), warm and humid (Madras) and composite (New Delhi) climatic zones. In this study, four building materials such as laterite stone, dense concrete, burnt brick and mud brick were selected and four window glass materials such as clear, bronze, green and bronze-reflective glasses were selected. The spectral optical properties of four glass materials were measured experimentally using Perkin-Elmer lambda 950 spectrophotometer from wavelengths ranging from 300 nm- 2500 nm. Total eighty building models were designed using Design builder 4.3.0.039 and thermal analysis was carried out in Energy plus 8.1 simulation tool. From the results, it is observed that mud brick with bronze-reflective glass window buildings were found to be energy efficient from the least heat gain point of view among eighty building models studied in five climatic zones of India. The results of the study help in selecting the best combination of building and window glass materials for reducing cooling loads in buildings of five different climatic zones of India. � 2018 Elsevier Ltd.
Investigation of various wall and window glass material buildings in different climatic zones of India for energy efficient building construction
(Elsevier Ltd, 2018) Gorantla, G.; Saboor, S.; Ashok Babu, T.P.
The commercial and residential buildings consume about 33% of energy for cooling and day lighting in India. This paper presents the thermal performance of buildings constructed with various building and window glass materials in five different climatic zones of India such as hot and dry (Ahmedabad), moderate (Bangalore), cold (Guwahati), warm and humid (Madras) and composite (New Delhi) climatic zones. In this study, four building materials such as laterite stone, dense concrete, burnt brick and mud brick were selected and four window glass materials such as clear, bronze, green and bronze-reflective glasses were selected. The spectral optical properties of four glass materials were measured experimentally using Perkin-Elmer lambda 950 spectrophotometer from wavelengths ranging from 300 nm- 2500 nm. Total eighty building models were designed using Design builder 4.3.0.039 and thermal analysis was carried out in Energy plus 8.1 simulation tool. From the results, it is observed that mud brick with bronze-reflective glass window buildings were found to be energy efficient from the least heat gain point of view among eighty building models studied in five climatic zones of India. The results of the study help in selecting the best combination of building and window glass materials for reducing cooling loads in buildings of five different climatic zones of India. Â© 2018 Elsevier Ltd.
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.
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.