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1 Reearch Paper ENERGY CONSERVATION IN MUD HOUSE AS COMPARED TO BRICK WALL BUILDING IN INDIA Subhah Mihra 1, Dr. J A Umani 2 Addre for Correpondence 1 Ph.d Scholar, 2 Profeor, Department of Mechanical Engineering, Jamia Millia Ilamia, New Delhi, India ABSTRACT: In thi paper, energy aving in Mud houe a compared to brick wall building i dicued by electing a proper inulation material and different wall material. Building made of mud brick act a environmental friendly. The thermal inulation keep the indoor temperature contant during ummer and winter eaon. The mud houe aim to ave energy by providing a more table temperature and reduce heat loe. Mud i a thermal ma that aborb un light and warm the building over the coure of the day. The variou parameter which are conidered in the paper are orientation of wall, building expoed to un, urface-volume ratio, wall material, ventilation and hading. Sutainable contruction i achieved uing natural reource, uch a mud to conerve the energy both during contruction a well a for achieving thermal comfort inide the houe. The effect of heating and cooling load on energy conumption i determined. The annual heating and cooling load requirement can be obtained by Degree- Day (DD) method. Expended Polytyrene (EPS) and Rockwool (RW) are elected a inulation material. In thi paper the optimum inulation thickne for mud houe and brick wall houe wa calculated. The calculation wa carried out for four different energy ource i.e. coal, LPG, Natural Ga and Fuel Oil. Thi paper contribute to the promotion of mud houe (paive) and low energy architecture toward a utainable future. Reult how that optimum inulation thickne varie between cm to 6.18 cm, the energy aving per q. meter varie between R. 28 to 1479 and payback period varie between to 6.99 year depending on type of building wall, inulation material, climatic condition and fuel cot KEYWORDS: Thermal comfort, Mud houe, Degree- Day, Optimum inulation thickne, Energy Saving. I. INTRODUCTION We know that the rate of Energy conumption will gradually increae due to population growth, rie in the tandard of living and technological development. The ource of energy (Fuel) are limited. At the ame time, the energy loe in building will take place through building envelope. In order to reduce heat loe, either ue of inulation material in building or ue of high thermal ma are the option for minimizing energy lo and keep the houe cool in ummer and hot in winter. Variou building material, uch a Extruded hollow brick, Concrete block, Sun dried mud-brick and fired red brick have been in ue for contruction work in India. Thi tudy focued mainly on energy aving of a traditional red brick tructure and un dried mudbrick tructure by the application of thermal inulation. Indigenou material uch a mud brick ha been widely ued in rural area of India. Mud brick i environmentally friendly. It poee high thermal capacity and act a heat ink in extreme weather condition. Straw which i an agricultural wate can alo be ued a a building material. Traditionally, it i mixed with clay or oil to produce mud brick. It alo poee good inulation propertie. The energy requirement in a building can be reduced to minimum by the application of thermal ma of mud wall. Heat-gain modulation can be achieved by properly uing the thermal ma of the building itelf in order to aborb and tore heat during the daytime hour and releae it to the atmophere after few hour. Lack of inulation need lower capital invetment but larger life cycle energy cot. On the other hand, exceive inulation lead to lower life cycle energy but require high capital invetment. Optimum thickne i required for economy a well a energy conervation point of view. The annual heating and cooling requirement of building in certain climatic region can be calculated by Degree-Day (DD) method. Annual energy aving per quare meter of external wall area i calculated a the difference between the cot of heating the inulated and uninulated building. At optimum inulation thickne, the total cot i minimum and energy aving i maximum. It i, therefore, recommended to apply the optimum inulation thickne for building wall. To fulfill the outline of the preent paper, a literature review with cope of paper i given a follow. Coffman et al. [1] reported that the mud houe contruction have natural air conditioning effect becaue the room are cool during day time and warm during night time. The application of mud a wall material wa invetigated to control room air temperature for building by Duffin and Knowle [2]. The mot common paive olar building architecture comprie of maive wall to reduce the temperature fluctuation inide a building. Thi i known a the thermal flywheel effect a mentioned by Duffin and Greg [3]. The popular mud-houe in Yemen city utilize thi effect. The ue of mud a building material i of great concern not only for the people in hot developing countrie, but alo for thoe in cold indutrialized countrie in Europe and America. The engineer from developed countrie have realized the pecial feature of mud. The wider ue of mud contruction ha a good reputation in dry and hot place becaue of it ditinct advantage, e.g. the mud habitat uit different weather and geographical condition a the temperature remain temperate throughout the year inide the mud building a explained by Eben [4]. Algifri et al. [5] compared the thermal behavior of adobe houe with modern concrete houe in Yemen and reported the potential of mud a contruction material for energy aving in paive houe. The magic of adobe houe wa invetigated by Miller [6]. Earth a mud brick, ha been ued in the contruction of helter for thouand of year, and approximately 30% of the world preent population till live in earthen tructure a reported by Cofirman et al. [7]. Earth i a cheap, environmental friendly and abundantly available building material. It ha been ued extenively for wall contruction around the world, particularly in developing countrie reported by Ren and Kagi [8]. Binici et al. [9] had

2 invetigated the thermal iolation and mechanical propertie of fiber reinforced mud brick a wall material. Stabilized mud block are made in India from oil, and, cement/lime and water. Roofing ytem uing brick maonry vault and dome were ued extenively in India till the emergence of Britih rule. It ha everal advantage a compared to reinforced lab roofing a reported by Reddy [10]. An innovation in vault wa developed by Reddy uing a moving teel formwork (lip forming) which facilitate contruction without exceive cot and time out run. Currently, centenary haped vault are being built due to their better performance. Both burnt brick and tabilized mud block were ued for building vault and dome. Energy requirement for production and proceing of different building material and the CO 2 emiion and the implication on environment have been tudied by Buchanan and Honey [11], Suzki et al. [12], Oka et al. [13], and Debnath et al. [14] among other. Thee tudie pertain to New Zealand, Japan and India. Indian contruction indutry i one of the larget in term of employing manpower and volume of material produced (cement, brick, teel and other material). Contruction ector in India i reponible for major input of energy reulting in the larget hare of CO 2 emiion (22%) into the atmophere [15]. Apart from the office, commercial and indutrial building, (>2x10 6 reidential building) are built annually, in India. Demand and upply gap for reidential building i increaing every year (20 million unit in 1980 to 40 million unit in 2000 [16]. Majumdar [17] report ome conceptual idea in reducing the energy ue in building epecially for heating, cooling, ventilation and lighting in different climatic zone of India. Thi tudy preent 41 cae tudie of building deigned by variou architect incorporating energy aving feature in the deign, without quantifying the energy aving/conumption in thee building The energy aving of mud houe tructure wa rarely reported and compared with another type of building (Red brick tructure) in the literature. Hence the objective of thi paper i to compare the energy aving for mud houe and traditional red brick tructure by the application of thermal inulation. II. BUILDING MATERIAL AND STRUCTURE OF BUILDING Mud houe i made of the mixture of clay, mud, and, water and binding material uch a rice huk or traw. The main ingredient for making cob are clay, and and traw. Both burnt brick and tabilized mud block were ued for mud wall contruction. Stabilized mud block are made in India from oil, and, cement/ lime and water. Mould of brick are filled with the right mix of wet mud. The mould i then removed and the brick dried in the un. Thi i the mot popular form of brick-making ince it ue only olar energy, which i free. The building material for wall i mud and roof material i khapra. Brick i the common material ued for the contruction of external wall. To minimize the heat lo the inulation can be placed on the inide urface, outide urface or in between the wall. In thi analyi, the inulation i placed on the outide urface of the wall cold region of India, the external wall inulation application are generally made by the andwiche wall type. The tructure of the external wall of red brick contruction i made by 3 cm internal plater, different wall material (brick or mud brick), inulation and 3 cm external plater. In thi Figure 1: Cro ectional view of ide wall paper, the calculation were carried out for a two different type of wall, which have been contructed with brick (18 cm) and mud wall (35 cm). The urface of the brick wall are inulated on the external ide and platered on both ide are a hown in Fig. 1. The tructure of external wall of mud houe room i made by 02 cm internal mud plater, 35 cm mud brick and 03 cm outer plater with inulation. Mud houe with pitched roof tructure building a hown in Fig. 2. Fig. 2 Mud houe with pitched roof tructure building II.1. Mathematical model for annual fuel conumption: Heat lo from building occur through urface of external wall, window, ceiling and air infiltration. In

3 thi analyi, heating lo i oberved only on the external wall urface. The heat lo per unit area of external wall i Q= U ( T ) a T (1) b Where U i the overall heat tranfer coefficient. T b i the bae temperature and T a i mean air temperature. Annual heating lo per unit area from external wall in the term of Degree-day i Q A = 86400DDU (2) Where DD i the Degree- Day. The annual energy requirement i given by E = DD ( R + x k) n (3) A tw Where η i the efficiency of pace heating ytem. and the annual fuel conumption i M fa= DD ( Rtw+ x k) LHV. n (4) Where LHV i lower heating value of fuel. II.2.Optimization of inulation thickne and energy aving: The life-cycle cot analyi (LCCA) i ued in thi analyi. It determine the cot analyi of a ytem. The total cot of heating over the life time of the inulation material which wa taken a 8 year. Total heating cot i indicated together with life cycle (N) and preent worth factor (PWF). PWF can be calculated by uing inflation rate g and interet rate i. Inflation and the interet rate are taken a 5 % and 4 % repectively. The interet rate adapted for inflation rate r i given by If i> g then, r = ( i g) (1+ g) If i< g then, r = ( g i) (1+ i) And N PWF = ( 1+ 1 r(1+ If i= g then, N PWF = N ( 1+ i) (5) The total heating cot of the inulated building i Ct = C APWF+ Ci x (6) The optimum inulation thickne i obtained by minimizing total heating cot of inulation building (C t ). So the derivative of C t with repect to x i taken and equal to zero from which the optimum inulation thickne X opt obtained. 0.5 X = ( DDCPWFK. H C n ) K. R (7) opt t Pay-Back Period(PP) i calculated by olving the equation (8) PP PP C in A = ( 1+ 1 r(1+ (8) Where C in / A i the imple Pay-Back Period. Energy aving obtained during the lifetime of inulation material can be calculated a follow: E = C C (9) to in III. PARAMETERS OF STUDY There are following parameter which are ued for mud houe contruction. (1) Orientation (2) Surface area to volume ratio (3) Ventilation (4) Building material (5) Shading U i tw Orientation: The mud houe ha it longer ide oriented along Eat-Wet axi. The two door are placed in the outhern ide. The mall void like opening i placed on the northern wall. The bet orientation for leat heat gain for rectangular built form with one ide longer than other i the longer ide facing the Eat-South and North-Wet direction making an angle of about 40 degree or 45 degree with the Eat-Wet axi. Surface area to volume ratio: For minimum heat gain, the ratio of urface area to volume ratio i low. In compoite climate the Surface area to volume ratio(s/v) hould be a low a poible to minimize the heat gain. A vaulted roof would alo increae the attic area, which can act a a thermal buffer and help in thermal inulation both during ummer and winter. Ventilation: The portion through which cool air at night come in at the top portion of the roof and through which warm air can go out by convective proce ha been blocked in thi particular mud houe due to rain water coming inide the mud houe during rain. Thi caue lack of ventilation in ummer and convective air flow at evening and night. Building material: The building material for wall i mud and roof material i khapra. Cob i an earthen building material that i made of clay, and, traw and water. Cob i a thermal ma that aborb unlight and warm the building over the coure of the day. Thi i called paive olar heating and it will keep the inide of the building warm in the winter and cool in the ummer. Unlike conventional home which are contructed with ynthetic, indutrial-foamed material, mud home are built almot entirely out of natural and clean material. The choice of material ued in the contruction of a building ha a direct impact on the environment. A the energy conumption of a building depend mainly on the building contruction and material. The material ued for contruction uch a oil, and, cow dung and other that are not energy intenive. Shading: The hading of curved roof tructure that diipate more heat a compared to flat roof by convection and thermal radiation at night due to enlarge urface area. IV. METHOD FOR SELECTING THE MOST ECONOMIC INSULATION MATERIAL: An approach of electing the mot economic inulation material, uing C A index which i calculated by multiplying the thermal conductivity (λ in ) with the inulation price per cubic meter (C i ) i developed. The lower the value of C A, the higher the economical efficiency of the inulation material ince C A index of expanded polytyrene i le a compared to R W. Expanded polytyrene i the mot economic among the two inulation material. V. RESULTS AND DISCUSSION Inulation application i one of the mot important method to conerve energy in building. So chooing the appropriate inulation material and determining the optimum inulation thickne i very important for energy aving. The optimum thickne of two inulation material (Expanded polytyrene and Rockwool) are calculated with outide inulated wall type building. The optimum inulation thickne for variou wall tructure i given in table 1. Optimum inulation thickne between and m for EPS and optimum inulation thickne

4 between and m for RW, depending on the type of wall contruction. Table 1: OPTIMUM INSULATION THICKNESS FOR VARIOUS WALLS STRUCTURES Payback period (in yea,energy aving for different type of wall contruction and for different type of inulating material are hown in table 2. Payback period (in yea for Brick Wall lie between to 4.67 and for Mud Brick lie between to TABLE 2: PAYBACK PERIOD AND ENERGY SAVING FOR DIFFERENT TYPE OF WALLS CONSTRUCTION IN INDIA Fig. 2(a) Variation of total cot with inulation thickne for EPS inulation for wall contructed of Brick. Some typical wall tructure for building in India and their thermal propertie are hown in table 3. TABLE 3: WALL STRUCTURE AND THERMAL CHARACTERISTIC OF MATERIALS The optimum inulation thicknee for the variou wall type pecified in table 1 were calculated by uing equation (7) and the value of the parameter are hown in table 4. TABLE 4: PARAMETERS USED IN THE CALCULATION OF INSULATION- THICKNESS Fig. 2(b) Variation of total cot with inulation thickne for EPS inulation for wall contructed of Mud brick. Fig. 2(a and b) how the effect of inulation thickne on the total annual cot over the 8 year lifetime of a Brick and Mud wall in Gauhati (91.59 E, N), north eat India. Inulation cot increae linearly with inulation thickne. On the other hand, energy cot a well a heat load decreae with increae of inulation thickne. Total cot of heating i the um of fuel cot and inulation cot. There i a point above which the aving in total cot will not compenate for the extra cot of inulation material. So there mut be an optimum inulation thickne at which the total cot i minimum. The reult how that optimum inulation thickne i m for Brick wall while it i m for Mud, when EPS i elected a the inulation material. Fig. 3(a) Variation of total cot with inulation thickne for Rockwool(RW) inulation for wall contructed of Brick Fig. 3(a and b) how the variation of fuel cot, inulation cot and total cot in accordance with inulation thickne for Brick and Mud wall, when Rockwool(RW) i elected a an inulation material. Total cot conit of two cot parameter, one i fuel cot and other i inulation cot. Heat lo through building wall will be decreae with increae of inulation thickne. But at the ame time the cot of fuel will decreae. The initial invetment will

5 increaed due to inulation cot and intallation cot. So there i a thickne value at which the total cot i minimum. That thickne i known a optimum inulation thickne. of energy aving i obtained for RW inulation, when external wall i contructed by Mud wall. Annual energy aving per quare metre of external wall area i difference between cot of heating the inulated and un-inulated building. Very low value of energy aving i obtained in the cae of mud external wall. It mean there i no need of inulation for mud houe contruction due to low thermal conductivity and high thermal ma. Fig. 3(b) Variation of total cot with inulation thickne for Rockwool (RW) inulation for wall contructed of Mud brick. From Fig. 3(a and b), it can be een that total cot decreaed up to optimum inulation thickne, and after that total cot i increaed. At thi thickne, increae in inulation cot i compenated by decreae of fuel cot. A a reult, the optimum inulation thickne i m for Brick wall while it i m for Mud wall, when RW i elected a the inulation material. Fig. 5 (a) Effect of inulation thickne on energy aving for different fuel type and EPS a an inulation material- wall type I (Brick) Fig. 4(a) Variation of energy aving veru inulation thickne for different type of wall and EPS i elected a an inulation material. Fig. 4(b) Variation of energy aving veru inulation thickne for different type of wall and RW i elected a an inulation material. Fig. 4(a and b) how effect of inulation thickne on energy aving for different wall for different inulation material (EPS and RW). The energy aving get increaed by increaing the inulation thickne up to optimum inulation thickne on building wall. And after that the energy aving decreaed with increaed inulation thickne. From Fig. 4(a and b), it i een that higher energy aving are obtained for wall type I (Brick). According to energy aving point of view, wall type I (Brick) i better a compared to wall type II (Mud brick) wall. From Fig. 4 (b), it can be concluded that lower value Fig. 5 (b) Effect of inulation thickne on energy aving for different fuel type and EPS a an inulation material- wall type II (Mud brick). Fig. 5(a and b) how effect of inulation thickne on energy aving for four different energy ource, when wall type I (Brick) and wall type II (Mud Brick) i conidered repectively. From Fig. 5, it can be een that a inulation thickne increae, energy aving increae and reache it maximum value at optimum inulation thickne. And after that energy aving decreae. Lowet value of energy aving i obtained for natural ga for either type of wall material. But highet value of energy aving i obtained for LPG for Brick material and for Mud Brick material. A hown in fig 5 (a and b), the application of inulation thickne increae the energy aving up to optimum inulation thickne. Energy aving i more important for the expenive fuel. We know that energy aving i proportional to cot of fuel and climatic condition. The highet energy aving i obtained a R/m 2, when LPG i taken a fuel ource for wall II (Mud brick). The variation in fuel conumption veru the inulation thickne for different wall material i hown in Fig. 6(a and b). From Fig. 6(a), it i een that for coal, the ue of optimum inulation thickne with inulation will reduce the amount of fuel by 72.7%. The ue of inulation material at it optimum thickne in external wall will reduce the fuel conumption through thee ection of the building for any type of energy application. From Fig. 6(a and

6 b), it can be concluded that a inulation thickne increae, fuel conumption decreae. Fig. 6(a) Fuel conumption veru inulation thickne for different fuel type and EPS a an inulation material-wall type I (Brick). Fig. 6(b) Fuel conumption veru inulation thickne for different fuel type and EPS a an inulation material-wall type II (Mud Brick) But thi decreae i more rapid at maller value of inulation thickne. When inulation thickne i exceeding the optimal thickne then the decreae of fuel conumption i very le. It mean after optimum inulation thickne, the increae of inulation thickne i not beneficial. The highet value of fuel conumption i obtained for coal fuel, wherea the lowet value of fuel conumption are obtained for LPG fuel. When the foil fuel i conidered, then pollution (due to emiion of co 2 and o 2 ) will produce. So in thi ituation natural ga will be more acceptable and economic. VI. CONCLUSION In thi paper, the optimum inulation thickne, payback period and annual energy aving are calculated for two different type of external wall, for two type of inulation material and four type of fuel in Gauhati(91.59 E,26.11 N) north eat India. A een from Fig. 5(a and b) that energy aving rate i highet for LPG fuel and lowet for Natural ga. Energy aving rate i proportional to climatic condition and fuel cot. It i een from Fig. (2), chooing a thickne value apart from optimum thickne will increae the total cot. From economic point of view, optimum inulation thickne mut be applied to the building. The mot uitable fuel for all climate zone i natural ga. A a reult, Rockwool (RW) ha the lowet value of optimum inulation thickne of cm, while Expanded polytyrene (EPS) ha the highet value of optimum inulation thickne of 6.18 cm. Reult how that optimum inulation thickne varie between cm to 6.18 cm, the energy aving per q. meter varie between R. 28 to 1479 and payback period varie between to 6.99 year depending on type of building wall, inulation material, climatic condition and fuel cot. Nomenclature: Q : Heat lo per unit area U : Overall heat tranfer Coefficient T b : Bae temperature T a : Mean air temperature DD : Degree- Day E A : Annual energy requirement R tw : Thermal Reitance of Wall X : Thickne of Wall K : Thermal Conductivity η : Efficiency of pace heating ytem M fa : Annual fuel conumption LHV : lower heating value of Fuel. g : inflation rate i : interet rate PWF : Preent worth Factor N : Life Cycle C t : Total heating cot of the inulated building C in : Inulation Cot X opt : Optimum Inulation Thickne H U. : Calorific value of fuel C in/ A : imple Pay-Back Period. E : Energy aving REFERENCES 1. 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