ANALYSING THE EFFECT OF GLAZING MATERIALS TOWARDS BUILDING ENERGY CONSUMPTION IN DIFFERENT CLIMATE

ZONES

Siti Birkha Mohd Ali1, 2, 3, Johari, N.S. 1, Mehdipoor Amirhosein4, Md Hasanuzzaman2,

Nasrudin A.Rahim2

1Faculty of Engineering and Life Sciences, Universiti Selangor, 45600, Bestari Jaya, Selangor. 2UM Power Energy Dedicated Advanced Centre (UMPEDAC), Level 4, Wisma R&D UM, Jalan

Pantai Baharu, 59990 Kuala Lumpur, Malaysia 2Institute of Graduate Studies, University of Malaya, 50603, Kuala Lumpur, Malaysia.

4Department of Building Surveying, Faculty of Built Environment, University of Malaya, 50603,

Kuala Lumpur, Malaysia.

birkha@unisel.edu.my, hasan@um.edu.my, nasrudin@um.edu.my,amirhossin.me@gmail.com

ABSTRACT

The purpose of this research is to analyse the effect of glazing materials towards the building energy consumption in different climate zones. A virtual building is model using ArchiCAD software; one out of numerous tools that is capable to inculcate the Building Information Modeling (BIM) process that is widely gaining its popularity. Three different types of glazing materials are selected to examine their effect towards the building energy consumption. In addition, this research has further analysed on how these selected glazing materials had contributed differently towards building energy consumption in different climate zones. In short, this research portrays the importance of selecting a proper glazing material during a design or refurbishment process of a building in different countries (with different climate zones) in order to optimize the energy conservation initiative which lead to lesser carbon emission as well as minimizing the global warming effect. The energy evaluation result is obtained from the simulation process of the virtual building in ArchiCAD. Commonly, a higher performance glazing material (based on u-value of the material) will reduce the energy consumption of one building but practically it acts differently depending on different environment profile. Theoretically, a cooler environment will reduce the internal heat gain of a building which leads to the unnecessarily of having high glazing type of material in the design. In addition, a larger gap between indoor and outdoor building temperatures has shown a significance impact towards the energy saving when a higher performance of glazing material is selected. The outcome from this research will assist the respective parties in selecting the most suitable and affordable glazing material for a sustainable building design as well as for a refurbishment need in a specific country/region.

Keywords: building information modeling (BIM), climate zone, glazing material and refurbishment.

INTRODUCTION

The building development and construction sector is showing an increasing trends in many countries (Xu et al., 2019, Yin et al., 2018) including Malaysia. This was due to various reasons such as urbanization, economy growth and modernization (Xu et al., 2019, Wong and Fan, 2013). In addition, the level of awareness on health effects (Hoisington et al., 2019) as well as comfortable living (Evola et al., 2017, Ascione et al., 2014, Fasi and Budaiwi, 2015) had become the principles of the people worldwide in setting higher demand on life quality. As buildings are parts of the entity that contribute to the world energy consumption, which statistically has shown a significant grow (Marin et al., 2016,

S.Sadrzadehrafiei et al., 2012, Thuy and Limmeechokchai, 2015, Calautit et al., 2017), the construction industry is no longer able to continue with the existing conventional approaches. New strategies, approaches and processes which inculcate the recent technologies are critically in need to be adopted within the construction industry. Furthermore, due to the concerns of the rising Greenhouse gas (GHGs) emissions (Thuy and Limmeechokchai, 2015) which is mainly contributed by the building sector (Wang et al., 2016), it is everyone’s aim to push on the need to develop and construct a sustainable or also known as ‘green’ building. According to (Ahmad et al., 2019), what sets ‘green’ buildings apart from conventional buildings is their emphasis on environmental and social aspects, hence it is important to examine the contributing factors that could assist in developing it. Beside various building contributors such as the material selection, orientation and many others, the trend of energy consumption is driven by the effect of its location (Goudarzi and Mostafaeipour, 2017). For instance, a hot and humid climate country had recorded an increasing demand on the space cooling where else cold/equable climate countries are showing an increasing trend on the space heating consumption. For instance, a study indicated that the average consumption per person in Gulf countries was almost four times higher than global average, mainly due to the use of energy-intensive air conditioning (AC). In addition, the steadily increasing global temperature could render the future operation of the unsustainable built environment in hot climate countries, particularly in the Middle east (Calautit et al., 2017). A similar trend is shown in the tropical climate country such as Malaysia. For instance, the commercial sector had recorded an energy consumption between 38 - 47% in space cooling which had beat other appliances/equipment (EC, 2016). In the case of cold climate countries like United Kingdom (UK) and Switzerland, the space heating system had shown a positive relationship towards the increasing of total energy consumption and greenhouse gas (GHG) emissions for building categories (Bruce-Konuah et al., 2019, Streicher et al., 2019). Specifically, space heating covers for over two third of total final energy consumption in both UK residential buildings as well as the Swiss built environment.

The location of one building plays a significant role in energy consumption as different climate condition could differently affected the indoor and outdoor temperature of a building. According to (Mushore et al., 2017, Poirazis et al., 2008), depending on the season, the thermal characteristics has a direct influence towards the consumption of heating and cooling in a building. Nevertheless, the main aim is to optimise the occupant comfort throughout all seasons. Hence, rather than to merely depending on these building systems to remain comfortable, a proper building design and material selection could eventually lead to a comfortable indoor building environment without highly utilizing the energy extensively on both the cooling and heating system. In addition, these techniques could possibly reduce the peak loads and indoor air temperature fluctuations (Goudarzi and Mostafaeipour, 2017). A proper glazing material selection could be a good insulation in preventing heat from both inside and outside to pass through. The possibility of reducing the peak loads is through ensuring lesser gap between the indoor and outdoor temperature. Even though it is known that most heat is lost through wall (40%) (Streicher et al., 2019, Sadrzadehrafiei et al., 2012), this research is intended to analyse the effect of glazing materials of a building in different climate zones as the difference between indoor and outdoor temperature plays a significant role in determining the energy consumption by either the cooling or heating system. Glazing systems are proven to significantly affect the energy consumption of a building (Sadrzadehrafiei et al., 2012, Westphal et al., 2011), where higher affect can be clearly measured in the mild to hot and humid countries. Therefore, it is seen as an economical and a practical solution in reducing the amount of heat entering the building by upgrading the window performance. On top of providing more energy saving to the building owner, glazing devices is known to provide better comfort to the occupant through reducing the thermal and visual discomfort issues especially with buildings with large glazed surfaces (Evola et al., 2017).

In any building energy performance analysis, the starting point was to select a reference building. In this research, a single floor office building (non-residential) is selected. The single floor office model is virtualize based on the layout of level 4, Wisma R&D building which is located in Kuala Lumpur. A bit of modification is made from the initial building layout. This floor is currently the administrative office of Universiti Malaya Power Energy Dedicated Centre (UMPEDAC), a research unit under the administration of Universiti Malaya (UM) which is conducting various research and laboratories work. On top of the above, the work reported in this paper aims to encourage and guide the building professionals in properly selecting a suitable glazing material for buildings at their specific project location. Due to this, this research aims to analyse the impact of different glazing materials in different climate; i.e. location of the building. Four different countries which have different climate environment are selected in the research. The specific locations selected are Kuala Lumpur, Bangkok, Riyadh and Canberra which represent the tropical climate (Kuala Lumpur and Bangkok), hot and humid climate (Riyadh) and cold/equable climate country (Canberra) respectively.

ENERGY CONSUMPTION TRENDS IN BUILDING SECTOR

According to (Goudarzi and Mostafaeipour, 2017), the recent statistics shown that 30-40% of the world energy consumption is consumed by the building sector. It is even worrying when the expected share is foresee to increase by 50% in future years. To support the above trend, (Eskin and Türkmen, 2008) declared in their finding that the great amount of world energy demand is connected to the built environment and 40% of the energy used in most cities is used to heat or cool buildings (Siddharth et al., 2011). Unfortunately, the direct effect of greater energy consumption is the amount of greenhouse gasses (GHGs) release, unless the establishment of the renewable energy (RE) is actively initiated. Many existing buildings are not energy efficient where their Building Energy Index (BEI) measurement is more than 250 kWh/m2/annum. This sick building syndromes (Halawa et al., 2018) have led many government worldwide to identify and establish a sustainable building design strategies. Today, there are numerous initiative, strategies and approaches which had been identified in encouraging all the building professionals to embark on the sustainable development. Sustainable development, which is defined as development that meets the need of the present generation (Bekhet and Othman, 2017), which contribute towards the increased of number of activities, buildings and appliances use, is an important concept in the present day. According to (Wong and Fan, 2013), because of global environmental concerns, sustainable design has become a mainstream building design goal in recent years as it assist towards lowering the risk of global warming, human health and the ecosystem (Bekhet and Othman, 2017). The available technologies have enhance the growing interest in the development of the sustainable building which include the element of energy efficient performances. It is because, an energy efficient building is proved to reduce the energy and resources consumption (Wong and Fan, 2013) and provide occupant comfort throughout the life cycle. Figure I shows the global energy demand which had rose by nearly 2% in 2017 which is driven by the economic growth and changes in consumer behavior. In parallel, the amount of carbon (CO2) emission had risen by 1.4% after three years of being flat (IEA, 2019).

Figure I Change in global primary energy demand 2011-2017

Even with the alarming fact that the global energy demand had shown an increasing trend, building sectors has inadequately contribute to the energy saving potential. Referring to Figure II, IEA had reported that both major economies countries like China, Brazil and Russia as well as the major emerging economies countries had recorded that buildings contributions towards energy saving is less than 40%. In this case, Industrial sector is far ahead and had contributed more than half on the energy efficiency initiative in both of these country groups. Due to this, greater initiatives have to be carried out by the government, public and private sectors, building professionals, academia and whoever related within the mentioned group.

Figure II Sectoral contributions to energy savings from improvements in energy efficiency

Moreover, it is expected that in climates with more hourly occurrences of high temperatures, buildings will significantly contribute towards the countries’ energy consumption. Specifically in developing countries, like Malaysia, where its commercial related businesses is facing intense development, major commercial buildings like shopping complexes, hotels, hospital and universities are showing an increasing trends in energy consumption (Commission, 2015). In related to this, the use of thermal insulation (Westphal et al., 2011) and proper glazing materials (Evola et al., 2017) could minimize the heat gain inside the building. Despite the above, (Melo and Lamberts, 2009) added that energy saving in one buildings depends on the weather, the building size and shape, glazed areas and the material characteristics used in the building as well. Hence, to make a more informed decision, building materials such as wall insulation, opening and glazing materials should be properly selected based on the climatic condition (location) where the building is plan to build. This is due to high temperature gaps between the indoor and outdoor environment which influence the utilization of either the cooling or heating building systems.

Glazing materials performances in different climatic countries

Buildings with large glazed surfaces may show severe thermal and visual discomfort issues, as an effect of the large incoming direct solar radiation (Evola et al., 2017). In addressing this issue, it is necessary to review the suitable solutions that may limit the amount of sunlight entering to the building. There are lots of research findings which emphasizes on the suitable glazing materials which could significantly reduce the energy consumption (Poirazis et al., 2008, Gasparella et al., 2011, Fasi and Budaiwi, 2015). For instance, heat gain through windows in particular represents a significant component of the cooling load and consequently a major contributor to energy consumption (Fasi and Budaiwi, 2015) in buildings especially in a hot climates countries. The aforementioned issues could be resolved through a proper selection of glazing material. Instead of just selecting the highest thermal resistance material, which has a direct impact on the cost and payback period, the building professionals should put into consideration the effect of different glazing materials base on the climate condition in which the building is located. Analysis on the energy consumption of different or potential glazing materials can be carried out on the virtual building model which later could potentially assist in the decision making. This comparison to the author’s knowledge has not been done so far, hence this research is to analyse on how critical a proper selection of glazing material in different climatic zones. Based on the research findings by (Gasparella et al., 2011) which emphasised that triple glazing windows, for instance, are also characterised by low solar transmittance. This is very useful and effective in controlling solar gains during the summer (or in hot climate countries) as it leads to reduce the cooling energy use. However, if the triple layer glazing windows are installed, it will provide different effects to the energy consumption because in winter, the reduction of solar gains can overcome the reduction of thermal losses and increase the energy needs by the occupants in the building. With this regards, instead of replacing to the highest performance of glazing material (lowest u-value), a proper analysis on the virtual building may help the building professionals to select the best performance glazing material that is suitable for the design, location and climate condition of the building. This may as well apply to the refurbishment project in enhancing the energy efficiency of the existing building. The ultimate aim is to provide clear understanding, proper knowledge and skills to the professional parties in order to promote a proper selection of glazing material which can reduce the energy consumption, energy cost as well as carbon emission from its operation. This can be achieved through the ArchiCAD virtual building energy simulation. On top of the above, the occupant’s comfort can be attain in parallel with the other important aspect of a building life cycle for both short and long term sustainability of green operation. As mentioned earlier, four capital cities have been selected which represents three different climate conditions. Three different glazing materials will be analysed on the same virtual building model which is originally inspired from the Level 4, Wisma R&D, UM administration office layout. The impact of these three glazing materials on the window design of this building is compare at four different climatic zone which obviously had different weather conditions. A brief of each climate zone selected is discussed in the following sub section.

Climate Zone 1: Hot and low humidity country

In hot countries like Saudi Arabia (SA), buildings are the largest energy consumers in 2016. This includes residential, commercial and governmental sectors which makes the total building consumption in the country up to 80.6%, which has the largest consumers compared to the industrial and other sector’s consumption (Faris A.Alfaraidy and Azzam, 2019). Table I lists the annual electricity consumption for different sectors in SA. The building sector obviously outweigh the industrial and others sector, which total was only 19.4%. Riyadh city was found to be one of the zones in SA that consumed high electricity for operating the air-conditioning, which is said to be 70% from the remaining appliances/equipment in building. Riyadh is the largest and most populated city with a

population of 6.9 million in 2018. Based on (ASHRAE, 2017), the average temperature in Riyadh is 25.9°C with peak temperature in a month rose up to 35.2°C. In 2017, the record shown five continuous months of high temperature which was between May and September. The remaining months are averagely between 25°C to 30°C and three months recording between 14°C to 16°C. Besides being the capital city of SA, the buildings in this area are mostly poor energy efficient (Faris A.Alfaraidy and Azzam, 2019), hence, this research could assist and support their future building design and refurbishment initiative.

Table I Electricity Consumption in Saudi Arabia (2016)

Climate Zone 2: Tropical climate country

Based on the statistics presented in Malaysia National Energy Balance 2016 (EC, 2016), for residential sector, space cooling is one of the category that had shown a tremendous increased in year 2016 compare to the previous years recorded. The report stated that this category had consumed up to 327 kilo ton per oil equivalent (ktoe) in 2016, an increase of 9.5% from the previous year. It was one of the highest consumption recorded in 2013 to 2016, as the increment recorded in the previous years were only around 3.4%. In one hand, the energy consumption shows an increasing trend, but on the other hand, space cooling energy consumption percentage lied as the third highest contributors in the residential sector compare to appliances and cooking categories. This is different with the commercial sector, where the space cooling is recorded as the highest consumption compare to the others appliances such as water heating, lighting and other use. In majority of the commercial building operating categories, the space cooling consumption is between 40 - 47% (EC, 2016). With this regards, it is important to pay higher attention to the future construction of the commercial building in Malaysia especially in the big cities like Kuala Lumpur where the construction projects are facing an intense development in term of number of activities. In term of its climate condition, the city of Kuala Lumpur had recorded an average temperature of 27.9°C in 2017. Based on (ASHRAE, 2017), the month of May had been recorded as the hottest temperature at 28.6°C and December was recorded as the coolest month with a temperature measurement at 27.5°C. The temperature recorded was in contrast with the one in SA as Malaysia is located within the equatorial region with a tropical climate which is hot and wet all year round. Similar climate condition is to be acknowledged for the Bangkok city of Thailand. Based on the ArchiCAD online climate data, the minimum and maximum outdoor temperatures for a year are recorded as 15°C and 38.5°C with an average of 26.75°C. The difference between Bangkok and Kuala Lumpur’s temperature is not obvious but a research on the impact of building energy consumption in these two locations could possibly assist in appropriate glazing material selection.

Climate Zone 3: Cold/equable climate country

Australia is one of the four seasons’ country in the world. It can be categorised as having more cold days with an average outdoor temperature recorded as 14.7C in the ArchiCAD software. As different

states in Australia are having different environment and temperature conditions, hence Canberra has been selected as one of the specific location in this research due to its outdoor temperature rates. Based on (ASHRAE, 2017), the average temperature recorded in Canberra is 13.5°C with the coolest temperature recorded as 6.3°C and the warmest to be 21.2°C. Ten out of the twelve month in a year is recording an outdoor temperature below than 20°C. Hence, Canberra will be the selected location which later represent the cold/equable climate country building energy performances based on different glazing materials.

METHODOLOGY AND INPUT DATA

In this research, a single floor administration office is model using a software named ArchiCAD. The authors had model the building block using the latest ArchiCAD version, which is name as ArchiCAD 22. One of the benefits of using the ArchiCAD modeling software compare to the others with similar functions is the availability of the Energy Evaluation tool that is embedded in the software. Although its energy evaluation performance function is not so popular compare to Eco-Designer and Energy Plus, the capability of the embedded tool function is found useful. It ease the energy evaluation task which are mainly carried out by the electrical engineer and facility manager from the complete model design by the architect, structural engineer and the Mechanical and Electrical (M&E) Engineer. The tools functions are user friendly which can also be utilize and benefits by the home owners if they are capable to model their own building. In this section, the authors will explain the development of the model, the inclusive parameters and the whole processes up to the results obtained from the energy evaluation performances.

Description of the building

The office building shown in Figure III is modelled in ArchiCAD 22 software based on a little modification of the floor plan layout of Wisma R&D, Universiti Malaya (UM). The reference building consists of few rooms and sections (part of the administration office), kitchen and toilets. In ArchiCAD, the different type or function of the room are remark as zoning and can be differentiate with different colors. In this research, the office zone is remarked in pink, kitchen zone in green and the toilets section in grey color. The total floor area is 1144 m2 and the office zone is equipped with several split unit wall mounted air-conditioning system. As the existing block is fix with the fluorescent light type, the same lighting type is thus applied throughout the energy performance evaluation. In order to study the effects of one parameter, several other building parameters including the appliances/equipment need to be set as constant. Due to this, the entire appliances and equipment remain unchanged throughout the analysis as the objective of this research is to analyse the effect of glazing material in building at different climatic countries location. The 3Dimension (3D) of the building model in different view are shown in Figure IV, Figure V and Figure VI. The performance of the glazing materials is analysed based on the window glazed area only. In this simulation, the glazing ratio is measured at 38% and a specific type of single, double and triple glazed glazing materials are selected and evaluated at four different building locations i.e. Kuala Lumpur, Bangkok, Riyadh and Canberra. The average outside temperature for these locations are 28.34°C, 26.75°C, 25°C and 14.7°C. The average was based on the google climate data provided in the ‘Environment Setting’ built-in-tool in the software.

Figure III The floor layout of the reference building

Figure IV The side view of the reference building modelled in 3D using the ArchiCAD

Figure V The front view of the reference building

Figure VI The bottom view of the reference building

Input data

In running the energy performance evaluation using the built-in tool in ArchiCAD software, numerous input data need to be included. Details cover the operating time, location of the building, type of building, lighting type, cooling/heating system use and many others. In order to ensure high level of accuracy, this research had identified several information related to this reference building. The details of the other main building parameters such as the external wall, roof and slab are described in Table II and Table III. Most of the materials selected are the generic types which are available in the software. The effects of these materials are not discussed in particular through this research eventhough it is well known that each part of the building envelope and appliances selected have different consequences towards the energy consumption of one building. Hence, these parameters are set as constants. As this research aims to analyse only the glazing material, hence the selection of the glazing materials are clearly identified. Three different glazing materials selected are single glazing-clear, double glazing standard: Air-fill type and triple glazing Argon-fill – clear. The u-value of the selective glazing materials are 5.8 W/m2K, 1.7 W/m2K and 0.7 W/m2K respectively. Theoretically, the lower the u-value is better as it indicates the rate of the heat transfer and how well the window is insulated. Through this research, this common understanding is to be evaluate at different building location. As per mentioned earlier, besides the glazing materials, the location of the building is the second variable that is examine in this research. The aim is to analyse how much energy is consumed as well as the carbon emission emitted under the different glazed materials. This allows more informed decision to be made according to the impact on the energy saving that could be gained in selecting a high thermal resistivity (low u-value) at different building location.

Table II Other building parameters of the reference building that remain unchanged throughout the analysis

Details Description Thickness (mm)

Illustration

External wall (A)

Generic wall 300

Roof Flat roof 199

Slab Concrete Floor

with 10mm tiles

240

Table III Details on the input that are included in the virtual building model in ArchiCAD simulation

Details

Description

Building location

Kuala Lumpur Bangkok Riyadh Canberra

Building coordinate

3°7’2”N 101°40”1” E

13°44’0”N 100°30”0”E

24°39’00”N 46°43”00” E

-35°15’0”S 149°8”0” E

Building type Non-residential

Unchanged

Gross area 1144.65 m2

• Landscaped office: 957.34 m2

• Kitchen/pantry: 110.02 m2

• 2 toilet: 77.3 m2

Thermal blocks

Landscaped office Unchanged Kitchen

Toilet

Operating time (hrs)

9 hours/5 days a week

Unchanged

Lighting Fluorescent lighting tubes

Unchanged

Ventilation syst Supply & Exhaust All days

Internal temperature (°C)

Min = 20°C Max = 26°C

Unchanged

Soil type Gravel

Energy source Coal

Type of glazing materials and the building location selected are set in the virtual building model before the energy evaluation is performed. When a building location is allocated, for example, Kuala Lumpur, the coordinate of the building location is indicated in the software, where it will automatically define the maximum, minimum and the average external temperature of the selected location based on the online climate data. The energy evaluation analysis was carried out based on these selections. The screenshots of the location setting and the glazing material selection are shown in Figure VII and Figure VIII. In addition to the material type, details such as its u-value, infiltration, Tuberculin Skin Test (TST %) and Drug Susceptibility Test (DST %) are defined for each glazing material selected. The final performances of each material at four different locations are presented in the next section.

Figure VII The location of the building can be selected in ArchiCAD which automatically reflect the online climate data

Figure VIII Some of the glazing materials that are available in ArchiCAD software.

RESULTS AND DISCUSSION

From the energy performance evaluation conducted on the reference building at four different locations, it is concluded that the biggest impact of the higher performance glazing material towards the energy consumption in building is shown at the tropical zone countries like Malaysia. As Kuala Lumpur was selected as the specific location of the virtual building model, hence the result presented may not exactly accurate for the other location either to the higher north or lower south states in Malaysia. The energy performance evaluation outcome from the triple glazing type i.e. Argon fill clear with a u-value of 0.7 W/m2K selected on the building model situated in Kuala Lumpur had shown to be the most significant in term of cutting down the energy consumption. In other word, triple glazing is the preferred choice only for the office building type located in Kuala Lumpur if compare to the double and single glazing type of materials. The remaining locations i.e. Bangkok, Riyadh and Canberra did not show significant effect of the triple glazing window material. In Bangkok and Riyadh for instance, the additional layer of the glazing material applied to all window within the building model did not assist in tremendous cut of the energy consumption. This foreseeing is due to the average outdoor temperature which ranging in between 25°C to 26.75°C, which is lower to the one recorded in Kuala Lumpur. The outdoor temperature is not so much different compare to the indoor building temperature set during the simulation which is between 20°C to 26°C. Due to a very small gap between the indoor and outdoor temperature, hence the cooling system pattern is quite stable, hence lesser energy is consumed from the cooling equipment. Table IV tabulates the result from the energy performance evaluation of the virtual office building in four different locations; i.e. Kuala Lumpur, Bangkok, Riyadh and Canberra. As per mentioned earlier, as the building indoor temperature is set to be between 20°C to 26°C, hence the highest consumption by the air-conditioning system is seen in the energy performance evaluation result for a building situated in Kuala Lumpur. It is because, the outdoor temperature was measured at 28°C in average which is the highest if compare to other countries. Due to the biggest gap different (+ve), hence the internal heat gain obtained from the high outdoor temperature could be minimized from the installation of an appropriate glazing material, which in parallel reduces the energy consumption by the cooling system.

Table IV Energy performance evaluation results for four countries with different climate data

Location Kuala Lumpur Bangkok Riyadh Canberra

Average outdoor T (°C) 28°C 26.75°C 25°C 14.7°C

1. Single glazing Material type: Single clear (u-value 5.8 W/m2K)

• EC (kWh/m2a) 65.28 64.32 64.04 61.20

• CO2 emission (kg/ m2a) 20.70 20.70 20.59 20.10

• CO2 emission (kg/a) 22797 22802 22682 22135

2. Double glazing Material type: Double standard air fill-clear (u-value 1.7 W/m2K)

• EC (kWh/m2a) 64.91 64.31 64.22 62.03

• CO2 emission (kg/ m2a) 20.66 20.70 20.59 20.10

• CO2 emission (kg/a) 22753 22800 22685 22142

3. Triple glazing Material type: Triple Argon fill-clear (u-value 0.7 W/m2K)

• EC (kWh/m2a) 64.85 64.31 64.22 61.81

• CO2 emission (kg/ m2a) 20.65 20.70 20.60 20.10

• CO2 emission (kg/a) 22747 22800 22685 22142

EC = Energy Consumption

Energy consumption from the air-conditioning system

In the virtual building model, all the building zones i.e. office, kitchen and toilets are equipped with the lighting appliances. On the other hand, only office zone is equipped with air-conditioning system. As of the kitchen and toilet, they are equipped with a ventilation fans. Throughout this research, the entire lighting fixtures and ventilation fans are set as constant parameters, hence the energy consumption from these two appliances are consistent throughout the simulation. The only difference was seen in the air-conditioning energy consumption. As the cooling and heating systems are the highest consumed appliances in most building, mainly the commercial building (Vakiloroaya et al., 2014), hence it is important to analyse the most suitable system or initiate a method of controlling and reducing the energy consumption from this equipment. Kuala Lumpur and Bangkok are chosen due to its nearby location as well as the climatic zone type, hence comparison can be made accordingly. Nevertheless, the average outdoor temperature is not similar. Kuala Lumpur’s maximum outdoor temperature (max) is 35.6°C and minimum outdoor temperature (min) is 18.44°C where else Bangkok’s max and min outdoor temperature are 38.5°C and 15°C respectively. When the outdoor temperature is hotter than the internal temperature, the cooling system will try to maintain the internal comfort by adjusting the cooling basic need. Due to this, it had impacted the amount of energy consumption by the air-conditioning due to the larger gap between the internal and outdoor temperature. For Bangkok, the outdoor temperature is less warm compared to the one recorded in Kuala Lumpur, hence the energy consumption recorded by the air-conditioning system is lesser than the one recorded in the building located in Kuala Lumpur eventhough their climatic conditions are quite similar. Table V shows the detailed findings. In addition, the air-conditioning characteristic is determined by the glazing material too. In a situation of the climate zone which had cooler outdoor compare to the indoor, selecting a higher layer of glazing material (or smaller u-value) will cause the reduction of thermal losses from the inside of the building which later required higher heating load. Eventhough the heating aspect is not part of this research, this has caused lesser cooling demand to the building at the cooler climatic zone. With this regards, replacing to the highest performance of glazing material (lowest u-value) is not the best decision.

Table V The annual energy consumption by air-conditioning system with different glazing material

Location Kuala Lumpur Bangkok Riyadh Canberra

Average outdoor T (°C) 28°C 26.75°C 25°C 14.7°C

1. Single glazing Material type: Single clear (u-value 5.8 W/m2K)

• EC by air-conditioning (kWh/a)

9687 8627 8315 5189

2. Double glazing Material type: Double standard air fill-clear (u-value 1.7 W/m2K)

• EC by air-conditioning (kWh/a)

9274 8613 8511 6102

3. Triple glazing Material type: Triple Argon fill-clear (u-value 0.7 W/m2K)

• EC by air-conditioning (kWh/a)

9212 8613 8516 5858

EC = Energy Consumption

From the results obtained through ArchiCAD simulation, it can be summarized that the triple glazing material selected had influenced the reduction of the energy consumption by the air-conditioning system. This was due to the low u-value shown in the triple glazing material, follow by the double glazing and the single glazing. The impact was highly seen in the building located in Kuala Lumpur and Bangkok, follow by Riyadh but vice versa in the building located in Canberra. The energy consumption by the cooling system in a building located in Kuala Lumpur is tremendously reduced between 0.5 - 4% when a higher u-value material was selected for the window glazing. However, this is not the case for a building located in a cold climatic zone. For instance, as Canberra is experiencing more than half of its year with an outdoor temperature lower than the annual average outdoor temperature (refer Figure IX), hence, the amount of energy consumed by the cooling system is not as much as in the hot and dry climate zone countries. As per described earlier, as for Canberra, having higher layer of glazing material is not recommended as it act as the barrier and reduce the potential of thermal losses from inside of the building. This trends is clearly shown in the result which is presented in Table IV. As this research focuses mainly on the cooling system requirement, hence the heating system energy requirement is not discussed. In specific, building located in Canberra, Australia shown 40% less energy consumption for a building cooling requirement compare to a building located in Kuala Lumpur, Bangkok as well as Riyadh where the hot and humid temperature are almost throughout the year. In addition, the additional glazing material used in the building located at the cold climate countries (or countries located in the climatic zone which has more cold days compared to warm days) do not significantly assist in the reduction of the energy consume by the cooling system. Hence, it is not necessary to design a building with high thermal insulation or low u-value glazing material. As for example, a single glazing material is sufficient for a building located in cold countries’ climate.

Figure IX The climate data shown for Canberra, Australia

Carbon emission versus the glazing material selection

As coal is chosen as the sole resource for energy generation throughout the simulation, hence the impact of the carbon (CO2) release with the relationship of the glazing material selection is analysed and presented. The results of the carbon emission was based on the factor of the electricity resources which is embedded in the ArchiCAD software. For instance, the factor of coal per kilowatt hours (kWh) generated is 0.29 kg as compare to the natural gas which is only 0.22 kg/kWh (refer Figure X). In ArchiCAD, the factor for the renewable type of resources such as solar, geothermal and nuclear are set as zero. This is true as the renewable resources are clean and do not release any harmful gasses

during the generation process. The amount of carbon emission released from the simulation of the virtual building situated in Kuala Lumpur reduced with the increment of the glazing material layers. For example, the triple layer glazing material had reduced the CO2 release by 0.2% compare to a single layer type. In total, a triple layer glazing material has reduced 50 kg/annum CO2 from 22797 kg/a (single layer) down to 22747 kg/a (triple layer). Even situated in a similar climate zone, the building located in the Bangkok city did not show a significant reduction in its CO2 release compare to the building situated in Kuala Lumpur. In specific, the reduction of the CO2 emission in the building which is situated in Bangkok was only 2 kg/a from a single glazing to the double glazing material while there was no reduction obtained from upgrading the window glazing to the triple layer. This was due to its lower average outdoor temperature compare to the one in Kuala Lumpur, which make the temperature gap between the indoor and outdoor became smaller. The similar trend was shown in the analysis of this building when it was located in Riyadh city. Last but not least, the opposite results were seen when the analysis of this building energy performance is located in Canberra. From this analysis, it can be conclude that the impact of higher glazing material on the building window is not significantly effective in all countries around the world. The detail of CO2 emission data from different building locations is presented in Table IV.

Figure X Energy source factor set in ArchiCAD software

CONCLUSION

From the research, it is concluded that ArchiCAD software is capable to provide appropriate

estimation on the energy consumption from a virtual building model. The ‘energy performance

evaluation’ built-in-tool in ArchiCAD is highly useful and practical in developing a sustainable building.

This apply for not only new building development but is foresee as a sophisticated tool in assisting a

refurbishment project. A user can build a virtual building model based on the building layout and

conduct an energy performance evaluation in advance of building construction or a refurbishment

project. There are numerous building parameters that can be analyse in terms of its contribution and

effect towards energy consumption in a building. This research, for instance had focus on analyzing

the effect of the glazing material (on building windows) at different climate zones towards the energy

consumption. From the research findings, it can be summarized that the triple glazing material which

was chosen during the simulation has strongly impacted in the reduction of the energy consumption

by the air-conditioning system in the tropical climate countries like Malaysia and Thailand. This

ultimately due to its low u-value as well as the average outdoor temperature which is higher than the

indoor temperature. The impact of the double and single layer glazing materials comes afterwards.

Generally, the impact of different types and layers of the glazing material towards the energy

consumption was obviously shown in the building located in Kuala Lumpur and Bangkok, followed by

Riyadh city. In addition, the carbon (CO2) emission released from the building operation can be

obtained through this software too. In one hand, the significance impact of the glazing material (from

single to triple glazing) towards the CO2 reduction was seen in the simulation of the building located

in Kuala Lumpur, followed by Bangkok and Riyadh. On the other hand, the reversed impact was seen

in the building located in Canberra city. In specific, the utilization of different energy resources, for

example; coal and natural gas, will provide a different amount of CO2 emission throughout the building

lifecycle as each has its impact factor towards the generation of electricity. Further investigation

should include both the heating and cooling systems elements simultaneously so that the effects of

both on the building energy consumption could be analyse. In addition, the energy cost should be

included in the future research as this will assist in selecting the best and affordable parameters for

the building design or refurbishment project in order to acquire a great return of investment (ROI). As

the construction industry need to move towards sustainable development, hence utilizing this kind of

software or any related software which are available in the market is highly crucial. In addition, as the

need of promoting sustainable development has become a mainstream goal in recent years as well as

the future, hence, building professionals should be equipped with the relevant knowledge and skill in

the light of overcoming the challenge to fight the climate change.

ACKNOWLEDGEMENTS

Authors gratefully acknowledge the support of this research by the grant no. UMPEDAC-2018 and

R007-2018 from UMPEDAC and the Selangor state government grant no. GPNS/18/01-UNISEL050

through Universiti Selangor (UNISEL).

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