Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 3 ….2015 386 Assessment of embedding phase change materials in heavyweight buildings in Iraq using ESP-r Alaa Liaq Hashem PhD, Department of Mechanical Engineering, College of Engineering, Al-Qadisyah University, Al- Diwanyah, Iraq. Email address: alaaliag@yahoo.com Received 16 June 2015 Accepted 21 July 2015 ABSTRACT The traditional approaches employ massive components to moderate temperature fluctuations. The thermo-physical properties of the construction materials will have a strong influence on a building’s energy consumption. Within a passive solar design, the heat capacity of the inner wall layer is dominated. This approach is applicable in locations that have effective daily temperature variations, else that, heavy weight constructions can give rise to problems of excessive thermal mass and cost. The nature of the climate of Iraq can be represented in a two typical seasons; short and cold winter and long, hot and dry summer with short periods of the moderate months. The daily temperature variation is very limited and causes to accumulated heat in the buildings of heavy mass. The use of cooling system, in hot climate, is increased especially with heavy mass constructions. In Iraq, more than 6 million new building unit should be added until 2020, the rapid growth in building sectors become the largest consumer of electric power produced, where the building sector consumes more than 38% from the total energy produced. In this investigation, the phase change materials behaviour was embedded within traditional heavyweight building internal surfaces. The two identical simple single zones modelled and simulated in a professional energy systems program called ESP-r. Global meteorological database software called Meteonorm7 has been used to generate a climate file for Baghdad city (33.3 o N and 44.4 o E) into ESP-r program. The results represent a preliminary investigation into the effect of PCM modelling with heavy structured construction under hot climate. In addition, a comparison of an internal surface with different phase change temperature ranges. It is found that the presence of PCM could have a significant effect on the internal surfaces and thus the zone temperatures. The results encourage a full yearly investigation for the tested model, the simulation under realistic operational loads and with fixed internal boundary conditions underneath control loops using appropriate heating, cooling and ventilation strategies. Keywords: Phase change materials, PCM, Building energy simulation, latent heat storage, Thermal energy storage. Thermal mass. ESP-R. الخالصة وتوفيرفي درجات الحرارة الخارجية لتقلباتلمعادلة ا وكتل كبيرةبأبعاد توظف مكوناتالمستخدمة في البناء النهج التقليدية .يائية لمواد البناء يكون لها تأثير قوي على استهالك الطاقة في المبانيالفيز-الخصائص الحرارية .معتدلةداخلية درجات الحرارة النوع من هذا على الخصائص االخرى. السعة الحرارية لطبقة الجدار الداخلية خاصيةهيمن ت ضمن التصميم الشمسي السلبي، يمكن أن كتلةأن اإلنشاءات الثقيلة الفإال وليومية، قابلة للتطبيق في المواقع التي لديها اختالفات فعالة درجة الحرارة االتصميم يكون أن طبيعة المناخ في العراق يمكنان .العالية التكلفةوأيضا الكتلة الحرارية الزائدة ارتفاع درجات الحرارة بسبب تؤدي إلى مشاكل اف مع فترات قصيرة من جالالطويل، حار و وفصل الصيففصل الشتاء القصير والبارد ،ينتكون ممثلة في موسمين نموذجي mailto:alaaliag@yahoo.com Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 3 ….2015 387 كتلة الفي المباني من المخزنة خصوصاالحرارة تراكم للغاية ويسبب الحرارة محدود درجات ل اليومي تباينان .المعتدلةاألشهر عفي العراق، م .كتلة ثقيلةذات خصوصا مع المنشآت بشكل فعال ، ويزداد هو الشائع في المناخ الحار استخدام نظام التبريد ان.ثقيلة قطاع أصبح السكنية قطاعاتالالنمو السريع في بناء بسبب ، و0202ماليين وحدة بناء جديدة في عام 6أكثر من الحاجة الى تم دراسة البحث،في هذا .٪ من إجمالي الطاقة المنتجة83من يستهلك أكثرمستهلك للطاقة الكهربائية المنتجة، حيث أكبراالسكان المقارنة تمت مع حيز اخر مطابق ال يحتوي في ة. الثقيل الكتلة ذو الداخلية للمباني لمبنىداخل األسطح متغيرة الطورسلوك المواد وقد استخدم .ESP-R تسمى محاكاةجدرانه الداخلية على هذه المادة وضمن نفس الشروط التشغيلية عن طريق استخدام برنامج تم حيث 44.4Eو N 88.8المناخ لمدينة بغداد بياناتلتوليد Meteonorm7الجوية برنامج قواعد البيانات العالمية لألرصاد جيد البناء الثقيلة منظم مواد مع المدمجة PCM النتائج تمثل تحقيقا أوليا في تأثيروكانت .ESP-R إدخال البيانات في برنامج متغيرة الطور ذات وادمبين سطح داخلي مع وباإلضافة إلى ذلك، يتم إجراء مقارنة .تحت المناخ الحارلدرجات الحرارة للحيز النتائج حيز. انخلية وبالتالي درجة حرارة اليمكن أن يكون له تأثير كبير على األسطح الدا PCM أن وجوددرجات طور مختلفة. ط الداخلية ثابتة شروتثبيت واقعية ومع المحاكاة تحت األحمال التشغيلية اجراء الو لنموذجلتحقيق سنوي الكامل اجراء تشجع على .تدفئة والتبريد والتهويةال السيطرة على استخدام استراتيجياتب 1. INTRODUCTION The distribution of thermal mass within a building is the result of structural and architectural decisions and can greatly influence how the building reacts to internal heat gains, solar radiation entering the building or changes in outside conditions. Lightweight components react quickly to changes in internal gains and radiation. The traditional approaches employ massive components to moderate temperature fluctuations. The thermo-physical properties of the construction materials will have a strong influence on a building’s energy consumption. Within a passive solar design, the heat capacity of the inner wall layer is dominated. In this approach is applicable in locations that have effective daily temperature variations, else that, heavy weight constructions can give rise to problems of excessive thermal mass and cost, (Sara and Mina, 2012). The nature of the climate of Iraq can be represented in a two typical seasons, short and cold winter and long, hot and dry summer with short periods of the moderate months. The daily temperature variation is very limited and causes to accumulated heat in the buildings of heavy mass, (Kazem et al, 2012). The use of cooling system, in hot climate, is increased especially with heavy mass constructions. In Iraq, with more than 6 million new building unit in 2020 , the rapid growth in building sectors become the largest consumer of electric power produced, where the building sector consumes more than 38% from the total energy produced, (MOELC). Through the integrated of a phase change materials (PCM) to traditional building materials will improve the thermal properties of these materials, especially thermal capacity. The increasing in thermal capacity could shift most of the load coming from residential air conditioners from peak to off peak time periods (Khudhair and Farid, 2004). Integrating phase change materials within light construction showed efficient reduction in cooling and heating load especially in cold and moderate climate regions, (Neeper, 2000). The present work will assess a building model with heavy structures integrated phase change materials (PCM) within the internal material layers. The model simulated and tested in Baghdad climate conditions using ESP-r (Energy Simulation Program for Research) program, (ESP-R). 2. PCM AND FIELD OF APPLICATIONS The fields of PCM’s applications can be divided into high storage density for storage heat or cold, temperature control and thermal resistance contact enhancements. PCM’s can be integrated in both building materials and buildings components; implemented in gypsum board, plaster board, mixing with concrete or other wall finishing materials. Thermal storage can be part of the building structure even for lightweight buildings; also can be part in heating ventilation and air conditioning (HVAC) systems, (Zalba, 2003). There are several types of organic and inorganic chemical materials that Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 3 ….2015 388 can classified as PCM’s according to melting temperature and latent heat of fusion. In general, inorganic materials have almost double volumetric latent heat storage capacity (250–400kJ/m 3 ) than that of the organic materials (128–200 kJ/m 3 ), (Sharma et al., 2009). The PCM must encapsulated so that it does not affect or change the function of the building construction material. Three ways are used as means of PCM integration with an any component; direct incorporation, immersion and encapsulation. The first and second types affect the function of the construction material due to the direct contact with construction materials. For examples, concrete blocks impregnated with PCM’s and PCM’s mixed with heating/cooling system working fluid. The third one can be defined as the containment of PCM within a capsule of various materials forms and sizes prior to incorporation so that it may be introduced to the mix in a convenient manner. In Macro-encapsulation, the inclusion of PCM in some form of containers such as tubes, pouches and spheres in boards, (Pasupathy et al., 2008). Microencapsulated of paraffin wax, which work as phase change material covered by polymer was prepared locally in Iraq. The diameter of the prepared capsules was about (170-220) micron, the thermal analysis appears as a best value of enthalpy which was (12 J/gm) when the temperature was (60˚C), (Mohammed et al., 2012). 3. BUILDING MODEL AND BACKGROUND INFORMATION 3.1 ESP-r program ESP-r is a modelling tool for building performance simulation. In undertaking its assessments, the system is equipped to model heat, air, moisture light and electrical power flows at user specified spatial and temporal resolution. (ESP-R). The ESP-r allow to modelling and simulation PCM effect within buildings context using special materials components facilities. In ESP-r, Phase change occurred between melting phase (PCM becomes melts) and solidification phase (PCM becomes solidified) temperatures. Below melting temperature, PCM is considered as a solid and the conductivity of the layer is equal to conductivity in solid phase. Over melting temperature, PCM is considered as a liquid and conductivity of the layer is equal to conductivity in liquid phase. Beyond phase change temperature range, latent heat of material is equal to zero, (Heim and Clarke, 2004). 3.2 Weather information A global meteorological database software called Meteonorm7 used to generate a climate file for Baghdad city (33.3 o N and 44.4 o E) as input data for ESP-r program, (Meteonorm). Meteonorm 7 generate a climate database for long period 1991- 2010. The climate data sets interpolated from the satellite data for nearest climate stations from Baghdad city location. The weather file exported from epw format (Energy Plus Weather) to binary format (esp-r climate file format) using Meteonorm converter tools facilities (ESP-R). The climate data sets interpolated from the satellite data for the nearest climate stations from Baghdad city location. Fig. 1 and Fig. 2 shows the dry air temperature in degree-centigrade and the direct radiation in W/m 2 . Weather data for Baghdad city define the boundary condition for the simulations. Corresponds to the hottest summer between 1991 and 2010. The average ambient air temperature from June to August is 32.49 o C and the maximum direct normal solar radiation is 812.8 Watt/m 2 . The period from the beginning of June to the end of August was selected for the analysis. 3.3 Building model To investigate the effect of PCMs effect, a two identical simple single rooms introduced in ESP-r, as shown in Fig 3. The model has dimensions of (5 m * 4 m) and a height of 3m. There is a single Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 3 ….2015 389 window with double glass south facing with 15% the south wall. ESP-r has an adopted database of materials and construction layers that can used directly or modified. In this model a new structure databases created to representing heavy weight structure used in traditional Iraqi’s buildings as shown in Table 1. PCM layers placed inside the interior surface for three walls only (walls-2, 3 and 4) as shown in Fig.3. A typical phase change material is of the liquid-solid type, where energy is stored as latent heat during the phase change of the material. The phase change temperature selected in range 2°C and the latent heat of fusion is 1000J/kg K. The physical properties summarized in Table.2. No cooling system used to control the space temperature, only the solar load considerate in this investigation. 4. NUMERICAL SETUP AND RESULTS ANALYSIS The interior layer made from 10 mm of PCM–gypsum composite layer, this applied to all surfaces except the floors, roof and wall-1in the Room and Test-Room zones. Based on the dry bulb ambient temperature and the Room model resultant temperature profile obtained from the initial simulation (no PCM), the melting-solidification temperatures selected to be 24-26, 25-27, 26-28 and 28-30 o C respectively. The phase change temperature rang was assumed to be 2 o C in each case. In addition, each case has the same value of latent heat of fusion given by 24000 J/kg. The simulation period selected between June and August 2007 as shown in Fig. 2. 4.1 Walls temperatures The Figure 4, 5 and 6 showing the internal surface temperature of the walls 2, 3 and 4 with PCM. The PCM has a significant effect on the internal surfaces temperature, especially for the days when the PCM temperature reach its phase change range. While, there is no difference for the days with the temperature outside the phase change temperature range (below/above). It is therefore behaving as a regular sensible material. Thus, as long as the phase change materials in charging-discharging continuously, there will be a visible effect on room temperature. Because the two models not supported with a cooling and air ventilation-infiltration systems, the rooms space temperature is allowed to increase, Thus, The PCM reach the full charging state and the temperature of the internal surfaces of the Test-Room increased steadily. For comparison, all the Figs. 4-7 taken at the same snapshot in time (June to August). The snapshots chosen to clarify the differences between walls with PCM (Test-Room model) and without PCM (Room model). A PCM layer with phase change rang 24-26 o C shown in Fig. 4, the temperature profiles for surfaces with PCM diverted from first days of simulation and the temperatures decrease below the surfaces without PCM. The same behaviour is founded in all other phase change ranges while the delay depends on the value of melting temperature. 4.2 ROOM TEMPERATUERS The thermal response of the internal surfaces affects the internal zones temperature. Figs. 8–11 show the temperature profiles snapshot for Room and Test-Room model over a selected simulation periods. An analysis of these data does not show significant differences in the zone’s temperatures profile. The phase change material succeeded in avoid the rise of the internal surfaces temperature in Test-Room's walls, where the reduction achieved compared with the surfaces, which does not contain this materials. Through the figures, it can be noted that the length of this effect depends on the melting temperature and the solidification temperature, because the absence of both cooling and ventilation systems the internal zones temperature continue rising. The other reasons, the floor, glazing, wall-3 and ceiling components receiving solar energy and causing warming the zone space. Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 3 ….2015 390 Thus, the PCM temperature out of the phase change range. The other reasons, the floor, glazing, wall-3 and ceiling components receiving solar energy and causing warming the zone space. Thus, the PCM temperature out of the phase change range and kept in continuous charging state. 5. CONCLUSIONS AND REMARKS Different strategies can be used for integration PCM within walls, celling and ground components. The purpose depends on the PCM layer location within the construction, the PCM located an interior layer for controlling zone temperature with cooling or heating processes where the application should be with phase change range. If the PCM located in the external layer, the PCM phase change temperatures should responding with ambient temperature and react as insulation materials with high latent heat capacity. While, if the PCM located in internal layer, the phase change limit equal the comfort temperature range of the users. In this investigation, the effect of phase change material embedded within heavy structured buildings using building energy simulation software called ESP-r. A comparison of an internal surface with different phase change temperature ranges is made. The results represent a preliminary investigation into the effect of PCM modelling with heavy structured construction under hot climate. It is found that the presence of PCM could have a significant effect on the internal surfaces and thus the zone temperatures. The results encourage a full yearly investigation for the tested model, the simulation under realistic operational loads and with fixed internal boundary conditions under control using appropriate heating, cooling and ventilation strategies. 6. REFERENCES [1] A.M. Khudhair, and M.M. Farid, 2004, A review on energy conservation in building applications with thermal storage by latent heat using phase change materials, Energy Conversion and Management, 45, 263–275. [2] A. Sharma et al., 2009, Review on thermal energy storage with phase change materials and applications, Renewable and Sustainable Energy Reviews, 13, pp 318–345. [3] B. Zalba et al., 2003, Review on thermal energy storage with phase change: materials, heat transfer analysis and applications, Applied Thermal Engineering, 23, pp251–283. [4] D. Heim and J.A. Clarke, 2004, Numerical modelling and thermal simulation of PCM– gypsum composites with ESP-r, Energy and Buildings, 36, pp: 795–805. [5] ESP-R, Energy System Program for Research, http://www.esru.strath.ac.uk/Programs/ESP- r.htm. [6] H.A. Kazem, M.T. Chaichan, Status and future prospects of renewable energy in Iraq, Renewable and Sustainable Energy Reviews, no. 16, pp: 6007–6012. [7] H. S. Mohammed et al., 2012, A New Method For Preparation of Microencapsulated Phase Change Materials (PCMs) For Low Coast Energy in Cooling of Building, Ibn Al- Haitham Journal for Pure and Applied Science, vol. 25, No. 3. [8] MOELC, Ministry of Electricity, http://www.moelc.gov.iq, Statistical data. http://www.esru.strath.ac.uk/Programs/ESP-r.htm http://www.esru.strath.ac.uk/Programs/ESP-r.htm http://www.moelc.gov.iq/ Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 3 ….2015 391 [9] Meteonorm, www.meteonorm.com. [10] Neeper, D. A., 2000, Thermal dynamics of wallboard with latent heat storage, Solar energy, 68, no. 5, pp393-403. [11] Sara M. and Mina A.,2012, Energy Analysis of Using Thermal Mass in a Hot Humid climate, Recent Advances in Energy, Environment and Economic Development, ISBN: 978-1- 61804-139-5. [12] Pasupathy, A. et al., 2008, Phase change material-based building architecture for thermal management in residential and commercial establishments, Renewable and Sustainable Energy Reviews 12, no. 1, pp: 39-64. Table.1: Test Roof and walls constructions. Table.2: PCM specification. Property Value Phase change temperature rang ( o C) 2 Conductivity in solid phase J/kg 0.4 Conductivity in liquid phase J/kg 0.8 Specific heat (J/kg K) 1000 Walls External/Cement layer (mm) 25 Brick layer (mm) 240 Cement layer (mm) 20 Internal/ Gypsum layer (mm) 10 Roof Concrete Tile layer(mm) 25 Sand layer(mm) 100 Corks layer(mm) 50 Mastic layer(mm) 5 Heavy mix concrete layer (mm) 150 Cement layer (mm) 20 Gypsum layer (mm) 10 http://www.meteonorm.com/ Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 3 ….2015 392 Figure (2): Dry bulb air temperature boundary conditions. Simulation period Phase temperature rang Figure (1): Direct normal solar radiation boundary conditions. Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 3 ….2015 393 Figure (3): Building model (identical rooms with and without PCM). PCM-layer Inside Outsid e Walls-2,3,4-Room Walls-2,3,4-Test-Room Figure(4) : The internal surface temperature for walls 2, 3 and 4 without PCM and PCM (melting temp. = 24 o C and solidification temperature. =26 o C) simulation period June-August. Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 3 ….2015 394 Figure (5): The internal surface temperature for walls 2, 3 and 4 without PCM and PCM (melting temp. = 25 o C and solidification temperature. =27 o C) for period June-August. Walls-2,3,4-Room Walls-2,3,4-Test-Room Figure (6): The internal surface temperature for walls 2, 3 and 4 without PCM and PCM (melting temp. = 26 o C and solidification temperature. =28 o C) for period June-August. Walls-2,3,4-Room Walls-2,3,4-Test-Room Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 3 ….2015 395 Figure (7): The internal surface temperature for walls 2, 3 and 4 without PCM and PCM (melting temp. = 28 o C and solidification temp. =30 o C) for period June-August. Walls-2,3,4-Room Walls-2,3,4-Test-Room Figure (8): Room temperature with and without PCM (melting temp. 24 o C and solidification temp. 26 o C). Room Test-Room Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 3 ….2015 396 Figure (10): Room temperature with and without PCM (melting temp. 26 o C and solidification temp. 28 o C). Room Test-Room Room Test-Room Figure (9): Room temperature with and without PCM (melting temp. 25 o C and solidification temp. 27 o C). Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 3 ….2015 397 Figure (11): Room temperature with and without PCM (melting temp. 28 o C and solidification temp. 30 o C). Room Test-Room