Energy Conservation For Mud Wall Construction In India By The Application Of Insulation

Transcription

1 International Journal of Scientific Research and ngineering Studies (IJSRS) nergy Conservation For Mud Wall Construction In India By The Application Of Insulation Subhash Mishra Ph.D Scholar, Department of Mechanical ngineering, Jamia Millia Islamia, New Delhi, India Dr. J A Usmani Mechanical ngineering Department, J.M.I, Jamia Millia Islamia, New Delhi, India Abstract: The energy in building may be considered from two different perspectives. Firstly the energy that goes into the construction of the building using a variety of materials. Secondly the energy that is required to create a comfortable environment within the building. The building sector consumes more energy as compared to other sector like industrial sector, transportation or agriculture. Because of the limited energy resources, higher cost of fuels and environmental pollution coming from using the fuels, energy saving has become a necessity. The energy saving is achieved by reducing the energy consumption in buildings by the application of thermal insulation. At optimum insulation thickness, the energy saving is maximum. So it is essential to save the energy by using optimum insulation thickness and proper building material. nergy saving due to thermal insulation of Mud walls construction in India for a representative room of size 5 m x 4 m x 3.5 m are consider. An energy saving of 44.55% has been obtained for Mud house in presence of Mud dung slurry insulation.the house is studied with Mud wall material and insulation ( Mud Dung Slurry) on wall and roof(straw). Study suggests that Mud wall with insulation reduce the energy requirement by %. For same thickness of insulation, energy savings are much more with roof insulation than wall insulation.. This investigation indicates the importance of the roof insulation, which results in a reduction up to 13 % of the heating load. In this analysis an approach for selecting the most economic insulation material has been calculated. Mud slurry is the most economic among the Six insulation materials( i.e Rockwool, xpanded Polystyrene PS, xtruded Polystyrene XPS, Foamed Polyurethane, Glass Wool and Mud slurry). so it is used as a insulation material for mud wall construction. xpanded polystyrene is economic insulation material after mud slurry. In this analysis, two different insulation (Mud slurry and xpended Polystyrene) and LPG as a heating source are selected. Optimum insulation thickness of Mud wall construction will calculated by Degree-Day method. The thermal insulation keeps the indoor temperature constant during summer and winter seasons. The mud house aims to save energy by providing a more stable temperature and reduces heat losses. Mud is a thermal mass that absorbs sun light and warms the building over the course of the day. The various parameters which are considered in the paper are orientation of walls, building exposed to sun, surfacevolume ratio, wall materials, ventilation and shading. As a result, the optimum insulation thickness for mud wall construction is.67 m depending on insulation material, external wall material and climatic condition of Ghaziabad, Uttar Pradesh, India. Keywords: nergy Savings, Thermal Insulation, Degree- Day, Cooling Load, Optimum Insulation Thickness. I. INTRODUCTION nergy conservation refers to efforts made to reduce energy consumption. nergy conservation can be achieved through using efficient energy sources, in conjunction with decreased energy consumption or reduced consumption from conventional energy sources. A considerable energy saving can be achieved by using proper thickness of insulation in building walls. Using proper insulation material is the most effective way of energy conservation in residential applications. The energy consumption is distributed among four main sectors: industrial, building (residential or commercial), transportation and agricultural areas. The building sector is the highest energy consumer among the other sectors. nergy consumption rate has gradually increased due to urbanization, industrial growth and population growth. Population growth means constructing Page 6

2 International Journal of Scientific Research and ngineering Studies (IJSRS) more buildings, which increases energy expenditure. The energy conservation has become an important aspect in building construction. nergy conservation supports the ecofriendly lifestyle by providing energy, which saves money. Thermal insulation is a method to reduce the transfer of heat from outside to inside or inside to outside. To make house heat proof, thermal insulation is an appropriate method. An insulated home is more comfortable as the temperature remains consistent over weather changes. It makes the house comfortable and keeps the temperature of house cool in summers and warm in winters. It is very useful to keep the temperature of the house independent from outside temperature. From economic point of view, it may be better to choose an insulating material with a lower thermal conductivity rather than increase the thickness of the insulation in the mud walls. By reducing the thermal conductivity, less insulation will be required for a given amount of heating or cooling load and more usable volume will be available. Insulation reduces fuel consumption, undesirable emissions from the burning of fossil fuels and increases thermal comfort by minimizing heat losses from building. Building insulation will reduce the running cost of space heating at the expense of an increase in the initial investment by the adding insulation material. Insulation as single investment pays for itself many times over, during the life cycle of a building To fulfill the outline of the present paper, a literature review with scope of paper is given as follows. Coffman et al. [1]reported that the mud-house construction have natural air conditioning effect because the rooms are cool during daytime and warm during nighttime. The application of mud as wall material was investigated to control room air temperature for buildings by Duffin and Knowles [2].The most common passive solar building architecture comprises of massive walls to reduce the temperature fluctuations inside a building. This is known as the thermal flywheel effect as mentioned by Duffin and Greg [3]. The popular mud-houses in Yemen city utilize this effect. The use of mud as building material is of great concerns not only for the people in hot developing countries, but also for those in cold industrialized countries in urope and America [4].The engineers from developed countries have realized the special features of mud as reported by ben. The wider use of mud construction has a good reputation in dry and hot places because of its distinct advantages, e.g. the mud habitat suits different weather and geographical conditions as the temperature remains temperate throughout the year inside the mud building as explained by ben. Algifri et al. [5] compared the thermal behavior of adobe house with modern concrete house in Yemen and reported the potential of mud as construction material for energy saving in passive houses. The magic of adobe houses was investigated by Miller [6]. arth as mud bricks, has been used in the construction of shelters for thousands of years, and approximately 3% of the world s present population still live in earthen structures as reported by Cofirman et al. [7].arth is a cheap, environmental friendly and abundantly available building material. It has been used extensively for wall construction around the world, particularly in developing countries reported by Ren and Kagi [8]. Binci et al. [9] investigated that home brick-makers of Turkey and the Middle ast are using fibrous ingredients like straw to improve the tensile strength of mud bricks for millennia. Binici et al. had investigated the thermal isolation and mechanical properties of fibre reinforced mud bricks as wall materials. Stabilized mud blocks are made in India from soil, sand, cement/lime and water. Roofing systems using brick masonry vaults and domes were used extensively in India till the emergence of British rule. It has several advantages as compared to reinforced slab roofing as reported by Reddy [1]. An innovation in vault was developed by Reddy using a moving steel formwork (slip forming) which facilitates construction without excessive cost and time out run. Currently, catenary shaped vaults are being built due to their better performance. Both burnt bricks and stabilized mud blocks were used for building vaults and domes. More than 3 buildings were built since 1986 in and around Bangalore city in India using vaults and domes as reported by Reddy. In this study, I have been analyses insulation of existing our conventional house of mud and agricultural waste. II. STRUCTUR OF BUILDING AND ITS MATRIALS Mud has a number of properties which make it a perfectly suitable material for construction which aim at achieving thermal comfort at a low cost. These houses were constructed without any mechanical means. nergy saving due to mud wall construction in rural region of india for a representative room size is 5m x 4m x 3.5m is consider. Timber, Bamboo, Clay, straw, cow dung and a special variety of grass is used to bulid houses. Mud is mixed with cow dung, chopped straw and gravel to make the raw material for the walls. Fibrous ingredient like straw are used to improve tensile strength of mud brick. The external wall is formed by applying a thin coating of mud plaster on both sides of mud brick. Mud is act as a insulation. The roof rested on eight wooden post erected in three row. The mud wall construction usually has a thatch roof. Bamboo sticks formed the mullions to support the thatch. The thick thatch used as roofing material prevented rain from entering the house and at the same time provided insulation to the roof. This type of housing construction is commonly found in rural areas. The roof loads are directly supported by the walls, whose loads are supported by the wall foundations. Walls are provided with wooden posts at the corners. The door and windows opening of mud wall construction building are very small. The doors are typically of size 1.75m x.75m. Both gravity and lateral loads are resisted by mud walls. The building material for walls is mud and roof material is straw. The structure of external wall of mud Wall is made by 2.5 cm internal mud plaster, 36 cm mud brick thick and 2.5 cm outer plaster with optimum thickness of mud dung slurry insulation. Mud house with pitch roof structure building as shown on fig.1 Page 7

3 International Journal of Scientific Research and ngineering Studies (IJSRS) nergy saving obtained during the life time of insulation material can be calculated as follow (4) S C C t Ins IV. CALCULATION OF OPTIMUM INSULATION THICKNSS FOR MUD HOUS ROOF Figure 1: Mud house with pitch roof structure building III. OPTIMIZATION OF INSULATION THICKNSS AND NRGY SAVING Optimum insulation thickness is the thickness of insulation at which heat loss is minimum from the boundary of building component and energy saving is maximum. Form energy saving point of view, it is essential to determine the optimum insulation thickness of wall and selection of suitable insulation material The total cost of energy is C C C (1) A AH AC Where C AC and C AH are the Cooling and Heating load cost respectively. The total cost is the sum of cost of insulation material and present worth of the cost of energy consumption over the lifetime of the building. acf bc Ta Tr Ct PWF C x H COP i x u. s RW K (2) C t is total cost of heating, PWF is present worth factor, a is number of month for heating, C F is cost of fuel, H u is lower heating value of fuel, η s is efficiency of heating system, b is number of month for cooling, C is cost of energy source, COP is coefficient of performance of cooling system, T a is atmospheric temperature, T r is room temperature, R w is thermal resistance of Mud wall, x is the insulation thickness, K is the thermal conductivity of insulation, C i is insulation cost. The optimum insulation thickness is obtained by minimizing the total heating cost and cooling cost. Hence the derivative of C t with respect to x is taken as zero for finding the optimum thickness. The expression of optimum insulation thickness x opt is given below X opt K PWF acf bc DD C i Hu s COP KR W (3) When straw is used for covering of roof for Mud wall construction, then X opt K PWF a CF b C DD 864 C i H u. s COP.5 KR m The optimum insulation thickness for Roof covered with straw for Mud wall constructions is.1321 m when straw is used as insulation. At different thickness of insulation the total annual cost is represented in Table: 1. S.No Thickness of Annual cost(rs) nergy insulation(m Fuel Insulation Total Saving(Rs) ) cost cost cost 1) ) ) ) ) ) ) Table 1: Total annual cost of roof for mud house construction The optimum insulation thickness for Roof covered with straw for Mud wall constructions is.1321 m when straw is used as an insulation. From the above Table 1., it is observed that nergy saving will gradually increase up to optimal thickness and beyond that energy saving will decrease. It means insulation thickness is more beneficial at Optimum insulation thickness. The energy savings are calculated from the difference between the total costs when the wall is un-insulated and is insulated. The energy saving depends on yearly heating and cooling transmission loads when insulation is not applied. The optimum insulation thicknesses and energy saving per annum for Mud wall construction wall is.67 m and 2857 Rs/year which is calculated by using the values of the parameter are shown in table 2. The optimum insulation thickness for Roof covered with straw for Mud wall constructions is.1321 m when straw is used as an insulation. This investigation indicates that at optimum insulation thickness, 13 % energy saving take place for roof insulation. S.No Parameter Value 1 Convective heat transfer 23 W/m 2 K coefficient (outside room) 2 Convective heat transfer 6 W/m 2 K coefficient (inside room) 3. Thermal conductivity of.519 W/mK W.5 Page 8

4 Total annual cost(rs/m 2 ) International Journal of Scientific Research and ngineering Studies (IJSRS) mud 4 Thermal conductivity of.72 W/mK Mud wall 5 Thickness of inside plaster 2.5 cm 6 Thickness of outside plaster 2.5 cm 7 Thickness of mud wall 36 cm 8 Useful life of mud house 5 years 9 Interest rate 8% 1 Inflation rate 1 % 11 Cost of fuel(lpg) 7 Rs/Kg 12 Heating value of fuel 4.59 x 1 6 J/Kg 13 fficiency of heating source 9% 14 Cost of energy(lectricity) 5.5 Rs per Kwh 15 Coefficient of performance of cooling system 4 16 Cost of insulation(mud 5 Rs/m 3 slurry) 17 Thermal conductivity of.3w/mk insulation(mud slurry) 18 Degree-Day 2 Value(Ghaziabad) 19 Present worth factor Thermal conductivity of.9 Straw w/m k Table 2: Design details and thermal properties for thermal model of mud-house V. RSULTS AND DISCUSSION For energy saving, it is essential to select the proper insulating material and optimum insulation thickness value for Mud wall. As we know that energy saving is maximum at the optimum insulation thickness value. Heat gain from buildings occurs through surface of external wall, window, roof, human occupants, lighting load, infiltration, doors and heat loss occurs from ventilation. In the climatic zones of Ghaziabad, the cooling period is larger than the heating period. Cooling is required for eight months. In rest of the four months, heating is required. During the summer, cross ventilation is good option for cooling of the house. Heat loss occurs from each wall, roof and building envelope because of temperature difference between indoors and atmosphere. Fig. 2 shows variation of cost with insulation thickness for mud dung slurry insulation materials. The fuel or energy cost decreases with increasing insulation thickness. The insulation cost increases linearly with insulation thickness. Total cost is sum of insulation and fuel cost. The insulation thickness at which the total cost is minimum is taken as the optimum insulation thickness. As a result, the optimum insulation thickness is.67 m for Mud wall, when mud dung slurry is selected as the insulation material. As insulation thickness increases the heating load decreases, and hence the cost of fuel and total cost of heating is also decrease. On the other hand, the insulation cost increases as its thickness increases. The insulation thickness at the minimum total cost is taken as the optimum insulation thickness. Fig. 2 shows the variation of fuel cost, insulation cost and total costs in accordance with insulation thickness for Mud wall, when mud dung slurry is selected as an insulation material. Total cost consists of two cost parameter, one is fuel cost and other is insulation cost. Heat loss through building walls will be decrease with increase of insulation thickness. But at the same time the cost of fuel will decrease. The initial investment will increased due to insulation cost and installation cost. So there is a thickness value at which the total cost is minimum. That thickness is known as optimum insulation thickness. From Fig. 2 it can be seen that total cost decreased up to optimum insulation thickness, and after that total cost is increased. At this thickness, increase in insulation cost is compensated by decrease of fuel cost X:.67 Y: 792 Fuel cost Insulation cost Total cost Thickness of insulation(m) Figure 2: Total annual cost for mud wall constructions versus insulation thickness when mud dung slurry as an insulation Fig. 3 shows effect of insulation thickness on energy saving for five different energy sources, when Mud wall is considered. From Fig. 3, it can be seen that as insulation thickness increases, energy saving increases and reaches its maximum value at optimum insulation thickness. And after that energy saving decreases. Lowest value of energy saving is obtained for electricity while highest value of energy saving is obtained for LPG for mud wall. As shown in Fig. 3, the application of insulation thickness up to optimum insulation thickness increases the energy saving. nergy saving is more important for the expensive fuel. We know that energy saving is proportional to cost of fuel and climate condition. The highest energy saving is obtained as 93 Rs/m 2, when LPG is taken as fuel sources for mud wall. Page 9

5 nergy saving(rs/m 2 ) nergy saving(rs/m 2 ) Total annual cost(rs/m 2 ) International Journal of Scientific Research and ngineering Studies (IJSRS) X:.67 Y: 93 LPG Natural gas Fuel oil Coal lectricity X:.67 Y: 93 Fuel Cost Insulation Cost Total Cost nergy Saving Insulation thickness(m) Figure 3: Variation of energy saving versus insulation thickness for different energy sources X:.67 Y: Insulation thickness(m) Figure: 4 Variation of energy saving versus insulation thickness for mud wall Fig. 4 shows effect of insulation thickness on energy saving for Mud wall for mud dung slurry insulation. The energy saving gets increased by increasing the insulation thickness up to optimum insulation thickness and after that, the energy saving decreased with increased insulation thickness. The insulation thickness at the maximum energy saving is taken as the optimum insulation thickness. From Fig.4, it can visualized that energy saving is maximum at optimum insulation thickness. So it is beneficial to use optimum insulation thickness of insulation material over mud wall. As a result, the optimum insulation thickness and energy saving are.67 m and 93 Rs/m 2 respectively for mud wall Insulation thickness(m) Figure 5: Variation of total annual cost and energy saving versus insulation thickness for mud wall Fig. 5 shows the variation of fuel cost, insulation cost, total costs and nergy saving in accordance with insulation thickness for Mud wall, when mud dung slurry is selected as an insulation material. As insulation thickness increases the total annual cost is decreases to some extent and after that total annual cost increases. There is insulation thickness at which the total cost is minimum is taken as the optimum insulation thickness. With increases of insulation thickness the heat transfer rate across the wall decreases so less fuel cost is required to maintain the comfort condition. Total cost consists of two cost parameter, one is fuel cost and other is insulation cost. Heat loss through building walls will be decrease with increase of insulation thickness. But at the same time the cost of fuel will decrease. The initial investment will increased due to insulation cost and installation cost. On the other hand, the insulation cost increases as its thickness increases. The total cost of fuel and insulation material will represented a minimum value when plotted versus the insulation thickness as shown in Fig. 5. There is a thickness value at which the total cost is minimum. That thickness is known as optimum insulation thickness. From Fig. 5 it can be seen that total cost decreased up to optimum insulation thickness, and after that total cost is increased. At this thickness, increase in insulation cost is compensated by decrease of fuel cost. As a result, the optimum insulation thickness is.67 m for Mud wall, when mud dung slurry is selected as the insulation material. Fig. 5 also shows the effect of insulation thickness on energy saving for Mud wall for mud dung slurry insulation. The energy saving gets increased by increasing the insulation thickness up to optimum insulation thickness and after that, the energy saving decreased with increased insulation thickness. The insulation thickness at the maximum energy saving is taken as the optimum insulation thickness. From Fig.5, it can visualized that energy saving is maximum at optimum insulation thickness. So it is beneficial to use optimum insulation thickness of insulation material over mud wall. As a result, the optimum insulation thickness and energy saving are.67 m and 93 Rs/m 2 respectively for mud wall. Page 1

6 Heating/Cooling load(kwh/month) nergy Saving(Rs/m 2 ) International Journal of Scientific Research and ngineering Studies (IJSRS) LPG Natural Gas Fuel Oil Coal lectricity Thermal conductivity of insulation Figure 6: ffect of Thermal conductivity of insulation on nergy Saving for Mud wall for different fuel type Fig. 6 shows effect of thermal conductivity of insulation on energy savings for mud wall for different fuel. As thermal conductivity of insulation increases, energy saving decreases. It is seen that the lowest value of energy saving is obtained for electricity fuel while the highest energy saving are obtained for LPG fuel. It is beneficial to use LPG fuel with less insulation thickness due to more energy saving occurs at less insulation for any kind of fuel sources Jan Feb Mar nergy Requirement without insulation nergy Requirement with insulation Apr May Jun Jul Aug Sep Oct Nov Month of the year Figure 7: Monthly energy requirement with and without insulation for mud house Fig. 7 shows the monthly distribution of energy requirement with and without insulation for mud house. The highest and lowest heating load is required in January and November month respectively. Similarly it is observed that maximum and minimum cooling load required in month May and March. The energy requirement above the base line indicated the heating and below the base line indicates the cooling. The monthly heating/cooling energy consumption for mud house in Ghaziabad is as shown in Fig. 7. Dec VI. CONCLUSIONS In this paper, the optimum insulation thickness and annual energy saving are calculated for Mud wall construction, for Mud dung slurry insulation material and LPG as a fuel in Ghaziabad.. From Fig. 2 it can be seen that total cost decreased up to optimum insulation thickness, and after that total cost is increased. At this thickness, increase in insulation cost is compensated by decrease of fuel cost. At optimum insulation thickness, the total cost is minimum.. So it is beneficial to use optimum insulation thickness for building construction for economic point of view. From Fig. 3 it can be seen that highest value of energy saving is obtained for LPG fuel for mud wall construction. In this paper, the highest energy saving is obtained as 93 Rs/m 2, when LPG is taken as fuel sources for mud wall construction. From Fig.4, it can visualized that energy saving is maximum at optimum insulation thickness. From Fig. 6, it can be observed that energy saving has higher value at less thermal conductivity insulation material for any kind of nergy sources. It is seen from Fig.7 that The highest and lowest heating load is required in January and November month respectively. Similarly it is observed that maximum and minimum cooling load required in month May and March. RFRNCS [1] Coffman, C.V., Duffin, R.J., and Knowles, G.P., 198, Are adobe walls optimal phase Shift filters, Advanced Applied Math, 1(3), pp [2] Duffin, R.J., and Knowles, G., 1981, Temperature control of buildings by adobe wall design, Solar nergy, 27(3), pp [3] Duffin, R.J., and Greg, K., 1984, Use of layered walls to reduce building temperature swings, Solar nergy, 33(6), pp [4] ben, S.M.A., 199, Adobe as a thermal regulating material, Solar Wind Technology, 7, pp [5] Algifri, A.H., Gadhi, B.S.M., and Nijaguna, B.T., 1992, Thermal behavior of adobe and concrete houses in Yemen, Renewable nergy, 2(6), pp [6] Miller, B.T., 1996, The magic of solar adobe, Fuel nergy, 37(3), pp [7] Cofirman, R., Agnew. N., Auiston, G., and Doehne,.,199, Adobe mineralogy characterization of adobes from around the world Proc. 6th international conference on the conservation of earthen architecture, Las Cruces, NM, 14th 19th October, pp [8] Ren, K.B., and Kagi, D.A., 1995, Upgrading the durability of mud bricks by impregnation, Building nvironment, 3, pp [9] Binici, H., Aksogan, O., Bodur, M.N., Akca,., and Kapur, S., 27, Thermal isolation and mechanical properties of fiber reinforced mud bricks as wall materials, Construction Building Material, 21, [1] Reddy, B.V.V., 22, Long-term strength and durability of stabilized mud blocks Proc. 3 rd international Conference on non-conventional materials and Page 11

7 International Journal of Scientific Research and ngineering Studies (IJSRS) technologies, Construction Publishing House, 12th and 13th March, Hanoi, Vietnam; 1, pp [11] Harris, D.J., 1999, A quantitative approach to assessment of the environmental impact of building materials, Building and nvironment, 34, pp [12] Kreiger, P.C., 1998, cological properties of buildings materials, Materials and Structures, 2, pp [13] John Wiler(D), 1997, In environmental resource guide, building materials, a quarterly publication of the American institute of Architect. [14] Gartner,.M and Smith, M.A.,1996, nergy cost of house construction Building Research stablishment, Watford.. [15] Jagdish K.S, nergy efficient building material and technologies Lecture notes, ASTRA, IISC Banglor. Page 12