DETERMINATION OF OPTIMUM INSULATION THICKNESS FOR DIFFERENT CLIMATIC ZONES OF TURKEY

Transcription

1 Proceedings of the ASME 29 DRAFT International PAPER Mechanical Engineering ongress & Eposition ASME INTERNATIONAL MEHANIAL ENGINEERING ONGRESSAND EXPOSITION IMEE29 November 3-9, Lake Buena Vista, IMEE Florida, USA November 3-9, 29, Lake Buena Vista, FL, USA IMEE IMEE DETERMINATION OF OPTIMUM INSULATION THIKNESS FOR DIFFERENT LIMATI ZONES OF TURKEY Nuri Alpay KÜREKİ Heat and Thermodynamics Division, Department of Mechanical Engineering, Yildiz Technical University (YTU), Yildiz, Besiktas, Istanbul, 34349, Turkey Özden AĞRA Heat and Thermodynamics Division, Department of Mechanical Engineering, Yildiz Technical University (YTU), Yildiz, Besiktas, Istanbul, 34349, Turkey Özlem EMANET Heat and Thermodynamics Division, Department of Mechanical Engineering, Yildiz Technical University (YTU) Yildiz, Besiktas, Istanbul, 34349, Turkey ABSTRAT Turkey has dynamic economic development and rapid population growth. It also has macro-economic and especially, monetary instability. The net effect of these factors is that Turkey s energy demand has grown rapidly almost every and is epected to continue growing. Since 99, energy consumption has increased at an annual average rate of 4.3%. The energy consumption is distributed among four main sectors which are industrial, building (residential), transportation and agriculture. Approimately 33% of total energy consumption in Turkey is used by residential sector. This situation makes it more important to insulate buildings in our country where fuel prices are too high. Turkey is divided into four climatic zones depending on average temperature degree days of heating. In this study, the four different cities of Turkey, Izmir, Istanbul, Ankara and Erzurum are selected to determine the optimum thickness of the eternal wall of buildings. Optimum thickness for si different energy sources (Soma coal, natural gas, coal, LPG, fuel-oil, diesel fuel) and two different insulants (etruded polystyrene, rock wool) is calculated and compared to each other. In addition, by using life cycle cost analysis method. Pay back period is calculated for each zone.. INTRODUTION Fossil fuel reserves such as oil, natural gas and coal that are the mostly used energy resources rapidly deplete today. In parallel to the population growth and industrial development, energy consumption drastically increases too. Both the increase in energy need and the environmental problems caused by these resources has made it necessary to utilize energy in the most efficient way. 33% of energy utilized in Turkey is for heating purposes []. This situation has increased the significance of using energy efficiently at houses in the country that mainly fulfills the majority of its energy need by importing. Heat loss in houses mostly occurs in eternal walls. As majority of houses in Turkey are deprived of heat, there is a great deal of energy consumption. For this reason, heat in houses gains critical significance. While cutting heat loss by heat in buildings is on one side, increases on the costs depending on the employed insulant is on the other side, requiring us to conduct a cost analysis and determine the optimum thickness. In studies within the literature aimed at determining the optimum thickness; Hasan [2] calculated the optimum thicknesses for four fuel types and two insulants across a degree-day and life cycle cost analysis approach. As a result, he reported that the pay-back period ranges are between s for with rock wool and -.7 s for with polystyrene. Çomaklı and Yüksel [3] calculated the optimum thickness for three coldest cities in the 4th degree-day zone of Turkey in accordance with the Rules of Heat Insulation in Buildings according to the relevant TS Standard No 825. opyright 29 by ASME Downloaded From: on 2/8/26 Terms of Use:

2 Gölcü et al [4] calculated the optimum thickness of eternal walls by using two different energy sources for heating at buildings in Denizli on the basis of degree-day value. Bolattürk [5] calculated the optimum thickness and pay-back periods for five different fuel types in 6 cities from four different climatic zones of Turkey. In another study [6], he calculated the optimum thickness of eternal walls of buildings situated in the first climatic zone of Turkey in consideration of the annual heating and cooling loads, and then determined the pay-back period by means of the P-P2 method. Dombaycı et al [7] calculated the optimum thickness for Denizli by using two different insulants and five different fuel types. Dombaycı [8] further calculated the optimum thickness of eternal walls of buildings in Denizli by using the epanded polystyrene insulant and coal. He determined that a decrease of 46.6% in fuel consumption had caused the O 2 and SO 2 emissions to drop by 4.53%. Aytaç and Aksoy [9] calculated the optimum thicknesses of two different wall types, namely the eternallyinsulated and sandwich wall with respect to different fuel types and two different insulants for the Elazığ province situated in the 3 rd climatic zone of Turkey as per the current heat standard. Şişman et al [] calculated the optimum thickness for houses on degree-day basis for four climatic zones in consideration of the heat loss occurring in the eternal wall and ceiling. Kaynaklı [] determined the optimum thickness for Bursa province by calculating the degree-hour values for the heating season in consideration of outdoor ambient air temperature values between the s of 992 and 25. Özel and Pıhtılı [2] calculated the optimum thickness of applied to eternal walls for the Adana, Elazığ, Erzurum, Istanbul and Izmir provinces in consideration of the heating and cooling degree-day values. Uçar and Balo [3] calculated the optimum thickness of sandwich wall for four different insulants and five fuel types for four climatic zones of Turkey, and determined the net energy saving by means of the P-P2 method. In this study, optimum thicknesses of eternal walls were calculated by using si different fuel types and two different insulants for heating in buildings in selected cities of Turkey in four degree-day zones. Specifications of fuel types used in the study are shown in Table. DRAFT PAPER Table Low heat value, efficiency and prices of the fuels used in the study. (IGDAS 29) Fuel Hu η Price ( fuel ) oal (Soma) 22,99 kj/kg.6.6 $/kg Natural gas 34,526 kj/m $/m 3 oal (import) 25,8 kj/kg $/kg LPG 45,98 kj/kg.9.36 $/kg Fuel-oil 4,546 kj/kg.8.8 $/kg Diesel-oil 42,636 kj/kg $/kg Table 2 shows the degree-day values with reference to an equilibrium temperature of 8 o in provinces within the four degree-day zones of Turkey as per the TS Standard no 825 on Rules of Heat Insulation in Buildings [4]. Table 2 Degree-day values with reference to an equilibrium temperature of 8 Region Provinces Degree-day value I Izmir 88 II Istanbul 865 III Ankara 2677 IV Erzurum METHOD 2.. The Structure of the Eternal Walls Heat losses in buildings generally occur through eternal walls, windows, roof, floors and air infiltration. In this study, the optimum thickness has been calculated in consideration of heat losses only occurring in the eternal walls. The eternal wall of a building is an eternally-insulated wall composed of a 2 cm internal plaster. 3 cm bricks, insulant and a 3 cm eternal plaster as shown in Fig. below. Physical characteristics of constituents of the wall are given in Table 3. In calculations, only the heat losses occurring in eternal walls were considered in order to calculate the optimum thickness. Fig. Eternal wall structure 2 opyright 29 by ASME Downloaded From: on 2/8/26 Terms of Use:

3 Table 3 Physical properties of the materials of eternal wall onstituent Thickness (m) k ( W/mK) R ( m 2 K/W) Internal Plaster (Lime-based) Bricks Eternal plaster (cement-based) R i.3 R o.4 R wall total.5 Table 4 Parameters of the wall Insulation k (W/mK) y ($/m 3 ) Etruded polystyrene Rock wool Heating Load for Eternal Walls Heat loss occurring on the unit surface of the eternal wall is calculated with Eq. q = U ΔT () where; U is heat transfer coefficient and ΔT is the difference between the outdoor ambient temperature and the constant indoor ambient temperature. Accordingly, the annual heat loss occurring on the unit surface is calculated by using U and the degree-day value [2]. q = 864 DD U (2) Total heat transfer coefficient for a typical wall is U = (3) R + R + R + R i wall o where; R i and R o are the heat transfer coefficients of the indoor and outdoor environment respectively and R wall is the heat transfer resistance of wall layers without heat. R is the thermal resistance of the insulant and calculated as follows: R = (4) k where; and k are the thickness and heat transfer coefficient of the insulant respectively. Total resistance of the noninsulated wall layer R wall. total is R = R + R + R (5) i wall o then, total heat transfer coefficient U is epressed as U = (6) R wall, + R total Annual energy need for heating E is calculated as follows: E 864 DD = (7) ( R + R ) η 2.3 alculation of the Optimum Insulation Thickness and Annual ost of Energy By applying to the eternal walls of buildings, heat loss through the building surfaces is significantly reduced. However, a cost analysis should be performed to determine the optimum thickness. Annual energy cost for unit surface is calculated with the following equation: 864 DD fuel = (8) ( R + R ) Hu η where; fuel is the unit fuel price. Hu is the heating value of the fuel and η is the efficiency of the heating system. The life cycle cost analysis method was used in calculating the optimum thickness. Annual energy cost was calculated based on the present worth factor and the epected lifetime determined [2]. The present worth factor is calculated based upon the inflation and interest rates as follows: i g r = (9) + g PWF N ( + r) = () r ( + r) N where; PWF is the present worth factor, i is the interest rate, g is the inflation rate and N is the lifetime which is assumed to be s. Net, cost is calculated as follows: = () y Ultimately, the total heating cost of an insulated building as per the life cycle cost analysis is calculated as follows: or, total, total = PWF + (2) = 864 DD ( R + R ) y fuel PWF + Hu η y (3) Optimum thickness minimizing the total heating cost is calculated with the equation below [2]. 3 opyright 29 by ASME Downloaded From: on 2/8/26 Terms of Use:

4 DD PWF k 2 fuel opt = 293,94 k Hu η y R wall,total 2.4 Pay-back period Difference of total annual total heating cost is (4) total cost is minimum will yield the optimum thickness. As shown in the figure, while the optimum thickness for Istanbul with etruded polystyrene used for the of the eternal wall within a natural-gas fuelled heating system is 6 cm, it is 8 cm with rock wool used as the insulant. A = (5), total Pay-back period total 6 5 Fuel ost Insulation ost Total ost A total pp = (6) 3. Results and Discussion ost ($/m 2 ) The greater the thickness of applied to the eternal wall of the building, the lower the heat loss of the building, therefore the heating heat energy and fuel costs as well. Increase in thickness augments the investment cost and the initial investment cost. Increase in investment cost affects the total cost. In this study, the optimum thickness of to be applied to eternal walls has been calculated in consideration of heating degree-day values. In the study, optimum thicknesses with respect to si different fuel types and two different investment materials have been calculated for four different climatic zones of Turkey. Specifications of insulants involved in the calculation of investment thickness are provided in Table 4. By applying etrude polystyrene and rock wool as insulants to the eternal walls, the optimum thickness, energy saving over a period of ten s and payback period has been calculated with increasing thicknesses. Life cycle, interest and inflation values employed in calculating the present worth factor are summarized in Table5. Table 5 Parameters used in the calculations Interest rate (i) %6 Inflation rate (g) % Life cycle (N) s Present Worth Factor (PWF) 7.55 The major effect of thickness on total cost, fuel cost and investment cost for Izmir, Istanbul, Ankara and Erzurum provinces has been calculated. Etruded polystyrene and rock wool applications for Istanbul, situated in the 2 nd climatic zone are shown in Fig. 2 and 3. Total cost resulting from the sum of fuel and investment cost drops down to a particular value, and then begins to increase. The value where Insulation Thickness (m) Fig. 2 Annual cost of heating versus - thickness by thicknesses for etruded polystyrene and natural gas for Istanbul ost ($/m 2 ) Insulation Thickness (m) Fuel ost Insulation ost Total ost Fig. 3 Annual cost of heating versus - thickness by thicknesses for rock wool and natural gas for Istanbul Optimum thickness for different fuel types has been calculated with Eq.4. Optimum investment thickness, pay-back period and the energy saved over a period of s calculated per insulant for different fuel types are shown in Table 6. 4 opyright 29 by ASME Downloaded From: on 2/8/26 Terms of Use:

5 Table 6 Optimum thickness, pay-back period and energy saving for different fuel types Insulant Etruded polystyrene Rock wool ity Fuel type Thickness (m) Pay-back period () Energy Saving ( s) Thickness (m) Pay-back period () Izmir Istanbul Ankara Erzurum Energy Saving ( s) ($/m 2 ) ($/m 2 ) oal (Soma) Natural gas oal (import) LPG Fuel-oil Diesel oil oal (Soma) Natural gas oal (import) LPG Fuel-oil Diesel oil oal (Soma) Natural gas oal (import) LPG Fuel-oil Diesel oil oal (Soma) Natural gas oal (import) LPG Fuel-oil Diesel oil Energy Saving for s ($/m 2 ) oal Soma Natural gas oal LPG Fuel-oil Diesel Energy Saving for s ($/m 2 ) oal Soma Natural gas oal LPG Fuel-oil Diesel Optimum Insulation Thickness (m) Optimum Insulation Thickness (m) Fig. 4 Energy saving over ten s with etruded polystyrene Fig. 5 Energy saving over ten s with rock wool 5 opyright 29 by ASME Downloaded From: on 2/8/26 Terms of Use:

6 In this study, which was carried out for four climatic zones, the effect of si different fuel types on optimum thickness and energy saving over a - period with the use of etruded polystyrene as the insulant for Istanbul situated within the 2 nd climatic zone is shown in Fig. 4. Likewise, the variation that occurs when rock wool is used as the insulant is shown in Fig. 5. The characteristics of the climatic zone directly affect the thickness and energy saving figures. In cold climates where degree-day value is high, the thickness shows an increase (Fig. 6). Accordingly, saving amounts to be yielded by different fuel types for each climatic zone per optimum thickness are shown in Fig. 7. Optimum Insulation Thickness (m) İzmir İstanbul Ankara Erzurum oal Soma Naturalgas oal LPG Fuel-oil Diesel Fig. 6 Optimum thickness versus analized fuels for different climate zones Energy Saving for s ($/m 2 ) 3 2 İzmir İstanbul Ankara Erzurum oal Soma Naturalgas oal LPG Fuel-oil Diesel Fig. 7 Energy savings versus analized fuels for different climate zones over ten s Data obtained for si different fuel types in the present study are assessed in consideration of optimum thickness and pay-back period in Fig. 8 and 9. The figures reveal us that the best fuel type in the respect of the study is coal. However, use of coal is the main cause of high emissions into the atmosphere. Furthermore, among fuel types selected, natural gas stands as both a cheaper and environment-friendly fuel compared to other fuel types. Therefore, a better alternative to coal is natural gas as a fuel Insulation Thickness(m) oal Soma Insulation Thickness Pay Back Periods Natural gas oal LPG Fuel-oil Diesel Fig. 8 Optimum thickness and pay-back period per fuel type for the etruded polystyrene Insulation Thickness(m) oal Soma Insulation Thickness Pay Back Periods Natural gas oal LPG Fuel-oil Diesel Fig. 9 Optimum thickness and pay-back period per fuel type for the rock wool insulant 4. ONLUSION As energy sources of our country are limited and foreigndependent, conservation and efficient use of energy particularly in housing sector where energy is intensively consumed and heat losses are much gains more significance day by day Pay Back Periods (Years) Pay Back Periods (Years) 6 opyright 29 by ASME Downloaded From: on 2/8/26 Terms of Use:

7 In this study, optimum thickness for eternal walls with two different insulants for si different fuels in four climatic zones of Turkey has been calculated. The life cycle cost analysis method has been used in the calculations. Though variable by the fuel used and the insulant selected, pay-back period of s applied to buildings are usually too short. Investments in shortly pay off and contribute to diminishing the dependency of our country in terms of fuel sources. In present time where fuel and energy costs drastically increase, this situation becomes vitally important. onsidering the optimum thickness calculated with respect to different fuel types, and environmental pollution caused by fuel wastes, natural gas has been found to be the optimum fuel among other fuel types selected. Meanwhile, as optimum thickness with natural gas is lower compared to other fuels, the initial investment cost will be lower as well. NOMENLATURE A Difference of annual total heating cost ($/m 2 ) fuel ost of the fuel, ($/m 3, $/kg ) ost of the insulant, ($/m 2 ) total Total heating cost of the insulated building, ($/m 2 ) total Total heating cost of the insulated building, ($/m 2 ) y ost of the insulant ($/m 3 ) Annual heating cost for unit surface, ($/m 2 ) DD Degree-day value, ( o -days) g Inflation rate, (%) Hu Low heat value of the fuel, (J/kg) i Interest rate, (%) k Heat transfer coefficient of the insulant, (W/mK) N Lifetime, () pp Pay-back period () PWF Present worth factor q Annual heat loss, (W/m 2 ) r Actual interest rate R Heat transfer resistance, (m 2 K/W) R d Outdoor heat transfer resistance, (m 2 K/W) R i Indoor heat transfer resistance, (m 2 K/W) R Thermal resistance of the insulant, (m 2 K/W) R wall Thermal resistance of wall layers without, (m 2 K/W) R wall total Thermal resistance of non-insulated wall, (m 2 K/W) U Total heat transfer coefficient, (W/m 2 K) Insulation thickness, (m) opt Optimum thickness, (m) η Efficiency of the combustion system REFERENES []. Özgür. N., Enerji Verimliliği ve Suyun Verimli Kullanılması, 28, Ankara. [2]. Hasan. A., Optimizing Insulation Thickness for Buildings Using Life ycle ost, Applied Energy, 63 (999) [3]. Çomaklı. K., Yüksel. B., Optimum Insulation thickness of Eternal Walls for Energy Saving, Applied Thermal Engineering, 23 (23) [4]. Gölcü. M., Dombaycı. A., Abalı. S., Denizli için Optimum Yalıtım Kalınlığının Enerji Tasarrufuna Etkisi ve Sonuçları, Gazi University s Faculty of Engineering and Architecture Journal, 2 (26) [5]. Bolattürk. A., Determination of Optimum Insulation Thickness for building Walls with Respect to various and limate Zones in Turkey, Applied Thermal Engineering, 26 (26) [6]. Bolattürk. A., Optimum Insulation thickness for Building Walls with Respect to ooling and Heating Degree-Hours in the warmest Zone of Turkey, Building and Environment, 43 (28) [7]. Gölcü. M., Dombaycı. A., Abalı. S., Optimization of Insulation Thickness for Eternal Walls Using Different Energy-Sources, Applied Energy, v 83,92-928, 26 [8]. Dombaycı. Ö.A., The environmental Impact of Optimum Insulation Thickness for Eternal Walls of Buildings,Building and Environment 42 (27) [9]. Aytaç. A., Aksoy. U.T., Enerji Tasarrufu İçin Dış Duvarlarda Optimum Yalıtım Kalınlığı ve Isıtma Maliyeti İlişkisi, Gazi University s Faculty of Engineering and Architecture Journal, 2 (26) []. Sisman. N., Kahya. E., Aras. N., Aras. H., Determination of Optimum Insulation thicknesses of The Eternal Walls and Roof (eiling) for Turkey s Different Degree-Day Zones, Energy Policy, 35 (27) []. Kaynaklı. O., A Study on Residential Heating Energy Requirement and Optimum Insulation Thickness, Renewable Energy, 33 (28) [2]. Özel. M., Pıhtılı. K., Determination of Optimum Insulation Thickness by Using Heating and ooling Degree- Day Values, Sigma Engineering and Sciences Journal, 26 (28) [3]. Uçar. A., Balo. F., Effect of Fuel Type on the Optimum Thickness on Selected Insulants for the Four Different limatic Zones of Turkey, Applied Energy, doi:.6/j.apenergy [4]. Bulut. H., Büyükalaca. O., Yılmaz. T., Türkiye için Isıtma ve Soğutma Derece-Gün Bölgeleri, 6 th Heat Science and Technique ongress, May 3 June 2, 27 - Kayseri 7 opyright 29 by ASME Downloaded From: on 2/8/26 Terms of Use: